[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. Kvm side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

v3:
  - Simplify old patch 1(log format fix) and move it to the end of patchset.
  - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
  - Patch 5: Add some accessor functions to pass aligned base and size to
  dma_contiguous_early_fixup() function
  - Patch 5: Move MAX_CMA_AREAS definition to cma.h
  - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
  - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
  - Remaining minor fixes are noted in commit description of each one

v2:
  - Although this patchset looks very different with v1, the end result,
  that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.

This patchset is based on linux-next 20140610.

Patch 1-4 prepare some features to cover PPC KVM's requirements.
Patch 5-6 generalize CMA reserved area management code and change users
to use it.
Patch 7-9 clean-up minor things.

Joonsoo Kim (9):
  DMA, CMA: fix possible memory leak
  DMA, CMA: separate core CMA management codes from DMA APIs
  DMA, CMA: support alignment constraint on CMA region
  DMA, CMA: support arbitrary bitmap granularity
  CMA: generalize CMA reserved area management functionality
  PPC, KVM, CMA: use general CMA reserved area management framework
  mm, CMA: clean-up CMA allocation error path
  mm, CMA: change cma_declare_contiguous() to obey coding convention
  mm, CMA: clean-up log message

 arch/arm/mm/dma-mapping.c            |    1 +
 arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
 arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
 arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
 arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
 drivers/base/Kconfig                 |   10 -
 drivers/base/dma-contiguous.c        |  210 ++-------------------
 include/linux/cma.h                  |   21 +++
 include/linux/dma-contiguous.h       |   11 +-
 mm/Kconfig                           |   11 ++
 mm/Makefile                          |    1 +
 mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
 12 files changed, 397 insertions(+), 493 deletions(-)
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
 create mode 100644 include/linux/cma.h
 create mode 100644 mm/cma.c

-- 
1.7.9.5

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. Kvm side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

v3:
  - Simplify old patch 1(log format fix) and move it to the end of patchset.
  - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
  - Patch 5: Add some accessor functions to pass aligned base and size to
  dma_contiguous_early_fixup() function
  - Patch 5: Move MAX_CMA_AREAS definition to cma.h
  - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
  - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
  - Remaining minor fixes are noted in commit description of each one

v2:
  - Although this patchset looks very different with v1, the end result,
  that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.

This patchset is based on linux-next 20140610.

Patch 1-4 prepare some features to cover PPC KVM's requirements.
Patch 5-6 generalize CMA reserved area management code and change users
to use it.
Patch 7-9 clean-up minor things.

Joonsoo Kim (9):
  DMA, CMA: fix possible memory leak
  DMA, CMA: separate core CMA management codes from DMA APIs
  DMA, CMA: support alignment constraint on CMA region
  DMA, CMA: support arbitrary bitmap granularity
  CMA: generalize CMA reserved area management functionality
  PPC, KVM, CMA: use general CMA reserved area management framework
  mm, CMA: clean-up CMA allocation error path
  mm, CMA: change cma_declare_contiguous() to obey coding convention
  mm, CMA: clean-up log message

 arch/arm/mm/dma-mapping.c            |    1 +
 arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
 arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
 arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
 arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
 drivers/base/Kconfig                 |   10 -
 drivers/base/dma-contiguous.c        |  210 ++-------------------
 include/linux/cma.h                  |   21 +++
 include/linux/dma-contiguous.h       |   11 +-
 mm/Kconfig                           |   11 ++
 mm/Makefile                          |    1 +
 mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
 12 files changed, 397 insertions(+), 493 deletions(-)
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
 create mode 100644 include/linux/cma.h
 create mode 100644 mm/cma.c

-- 
1.7.9.5

--
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[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. Kvm side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

v3:
  - Simplify old patch 1(log format fix) and move it to the end of patchset.
  - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
  - Patch 5: Add some accessor functions to pass aligned base and size to
  dma_contiguous_early_fixup() function
  - Patch 5: Move MAX_CMA_AREAS definition to cma.h
  - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
  - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
  - Remaining minor fixes are noted in commit description of each one

v2:
  - Although this patchset looks very different with v1, the end result,
  that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.

This patchset is based on linux-next 20140610.

Patch 1-4 prepare some features to cover PPC KVM's requirements.
Patch 5-6 generalize CMA reserved area management code and change users
to use it.
Patch 7-9 clean-up minor things.

Joonsoo Kim (9):
  DMA, CMA: fix possible memory leak
  DMA, CMA: separate core CMA management codes from DMA APIs
  DMA, CMA: support alignment constraint on CMA region
  DMA, CMA: support arbitrary bitmap granularity
  CMA: generalize CMA reserved area management functionality
  PPC, KVM, CMA: use general CMA reserved area management framework
  mm, CMA: clean-up CMA allocation error path
  mm, CMA: change cma_declare_contiguous() to obey coding convention
  mm, CMA: clean-up log message

 arch/arm/mm/dma-mapping.c            |    1 +
 arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
 arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
 arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
 arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
 drivers/base/Kconfig                 |   10 -
 drivers/base/dma-contiguous.c        |  210 ++-------------------
 include/linux/cma.h                  |   21 +++
 include/linux/dma-contiguous.h       |   11 +-
 mm/Kconfig                           |   11 ++
 mm/Makefile                          |    1 +
 mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
 12 files changed, 397 insertions(+), 493 deletions(-)
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
 create mode 100644 include/linux/cma.h
 create mode 100644 mm/cma.c

-- 
1.7.9.5

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. Kvm side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

v3:
  - Simplify old patch 1(log format fix) and move it to the end of patchset.
  - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
  - Patch 5: Add some accessor functions to pass aligned base and size to
  dma_contiguous_early_fixup() function
  - Patch 5: Move MAX_CMA_AREAS definition to cma.h
  - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
  - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
  - Remaining minor fixes are noted in commit description of each one

v2:
  - Although this patchset looks very different with v1, the end result,
  that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.

This patchset is based on linux-next 20140610.

Patch 1-4 prepare some features to cover PPC KVM's requirements.
Patch 5-6 generalize CMA reserved area management code and change users
to use it.
Patch 7-9 clean-up minor things.

Joonsoo Kim (9):
  DMA, CMA: fix possible memory leak
  DMA, CMA: separate core CMA management codes from DMA APIs
  DMA, CMA: support alignment constraint on CMA region
  DMA, CMA: support arbitrary bitmap granularity
  CMA: generalize CMA reserved area management functionality
  PPC, KVM, CMA: use general CMA reserved area management framework
  mm, CMA: clean-up CMA allocation error path
  mm, CMA: change cma_declare_contiguous() to obey coding convention
  mm, CMA: clean-up log message

 arch/arm/mm/dma-mapping.c            |    1 +
 arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
 arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
 arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
 arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
 drivers/base/Kconfig                 |   10 -
 drivers/base/dma-contiguous.c        |  210 ++-------------------
 include/linux/cma.h                  |   21 +++
 include/linux/dma-contiguous.h       |   11 +-
 mm/Kconfig                           |   11 ++
 mm/Makefile                          |    1 +
 mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
 12 files changed, 397 insertions(+), 493 deletions(-)
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
 create mode 100644 include/linux/cma.h
 create mode 100644 mm/cma.c

-- 
1.7.9.5

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
From my guess, it is caused by some needs on bitmap management. Kvm side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

v3:
  - Simplify old patch 1(log format fix) and move it to the end of patchset.
  - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
  - Patch 5: Add some accessor functions to pass aligned base and size to
  dma_contiguous_early_fixup() function
  - Patch 5: Move MAX_CMA_AREAS definition to cma.h
  - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
  - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
  - Remaining minor fixes are noted in commit description of each one

v2:
  - Although this patchset looks very different with v1, the end result,
  that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.

This patchset is based on linux-next 20140610.

Patch 1-4 prepare some features to cover PPC KVM's requirements.
Patch 5-6 generalize CMA reserved area management code and change users
to use it.
Patch 7-9 clean-up minor things.

Joonsoo Kim (9):
  DMA, CMA: fix possible memory leak
  DMA, CMA: separate core CMA management codes from DMA APIs
  DMA, CMA: support alignment constraint on CMA region
  DMA, CMA: support arbitrary bitmap granularity
  CMA: generalize CMA reserved area management functionality
  PPC, KVM, CMA: use general CMA reserved area management framework
  mm, CMA: clean-up CMA allocation error path
  mm, CMA: change cma_declare_contiguous() to obey coding convention
  mm, CMA: clean-up log message

 arch/arm/mm/dma-mapping.c            |    1 +
 arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
 arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
 arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
 arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
 drivers/base/Kconfig                 |   10 -
 drivers/base/dma-contiguous.c        |  210 ++-------------------
 include/linux/cma.h                  |   21 +++
 include/linux/dma-contiguous.h       |   11 +-
 mm/Kconfig                           |   11 ++
 mm/Makefile                          |    1 +
 mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
 12 files changed, 397 insertions(+), 493 deletions(-)
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
 delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
 create mode 100644 include/linux/cma.h
 create mode 100644 mm/cma.c

-- 
1.7.9.5

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

We should free memory for bitmap when we find zone mis-match,
otherwise this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform
why we need to check zone mis-match.

* Note
Minchan suggested to add a tag for the stable, but, I don't do it,
because I found this possibility during code-review and, IMO,
this patch isn't suitable for stable tree.

Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8..6467c91 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
 		base_pfn = pfn;
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
 			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
+				goto err;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
 
 	mutex_init(&cma->lock);
 	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];
-- 
1.7.9.5

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

We should free memory for bitmap when we find zone mis-match,
otherwise this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform
why we need to check zone mis-match.

* Note
Minchan suggested to add a tag for the stable, but, I don't do it,
because I found this possibility during code-review and, IMO,
this patch isn't suitable for stable tree.

Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8..6467c91 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
 		base_pfn = pfn;
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
 			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
+				goto err;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
 
 	mutex_init(&cma->lock);
 	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];
-- 
1.7.9.5

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

We should free memory for bitmap when we find zone mis-match,
otherwise this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform
why we need to check zone mis-match.

* Note
Minchan suggested to add a tag for the stable, but, I don't do it,
because I found this possibility during code-review and, IMO,
this patch isn't suitable for stable tree.

Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8..6467c91 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
 		base_pfn = pfn;
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
 			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
+				goto err;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
 
 	mutex_init(&cma->lock);
 	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];
-- 
1.7.9.5

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

We should free memory for bitmap when we find zone mis-match,
otherwise this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform
why we need to check zone mis-match.

* Note
Minchan suggested to add a tag for the stable, but, I don't do it,
because I found this possibility during code-review and, IMO,
this patch isn't suitable for stable tree.

Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8..6467c91 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
 		base_pfn = pfn;
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
 			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
+				goto err;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
 
 	mutex_init(&cma->lock);
 	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];
-- 
1.7.9.5

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

We should free memory for bitmap when we find zone mis-match,
otherwise this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform
why we need to check zone mis-match.

* Note
Minchan suggested to add a tag for the stable, but, I don't do it,
because I found this possibility during code-review and, IMO,
this patch isn't suitable for stable tree.

Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8..6467c91 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
 		base_pfn = pfn;
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
 			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
+				goto err;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
 
 	mutex_init(&cma->lock);
 	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];
-- 
1.7.9.5

[PATCH v3 -next 2/9] DMA, CMA: separate core CMA management codes from DMA APIs

[Joonsoo Kim]

To prepare future generalization work on CMA area management code,
we need to separate core CMA management codes from DMA APIs.
We will extend these core functions to cover requirements of
PPC KVM's CMA area management functionality in following patches.
This separation helps us not to touch DMA APIs while extending
core functions.

v3: move decriptions to exporeted APIs (Minchan)
    pass aligned base and size to dma_contiguous_early_fixup() (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6467c91..9021762 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -213,26 +213,9 @@ static int __init cma_init_reserved_areas(void)
 }
 core_initcall(cma_init_reserved_areas);
 
-/**
- * dma_contiguous_reserve_area() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
- * @base: Base address of the reserved area optional, use 0 for any
- * @limit: End address of the reserved memory (optional, 0 for any).
- * @res_cma: Pointer to store the created cma region.
- * @fixed: hint about where to place the reserved area
- *
- * This function reserves memory from early allocator. It should be
- * called by arch specific code once the early allocator (memblock or bootmem)
- * has been activated and all other subsystems have already allocated/reserved
- * memory. This function allows to create custom reserved areas for specific
- * devices.
- *
- * If @fixed is true, reserve contiguous area at exactly @base.  If false,
- * reserve in range from @base to @limit.
- */
-int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
-				       phys_addr_t limit, struct cma **res_cma,
-				       bool fixed)
+static int __init __dma_contiguous_reserve_area(phys_addr_t size,
+				phys_addr_t base, phys_addr_t limit,
+				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	phys_addr_t alignment;
@@ -286,15 +269,47 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 
 	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
-
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(base, size);
 	return 0;
+
 err:
 	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
+				(*res_cma)->count << PAGE_SHIFT);
+
+	return 0;
+}
+
 static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 {
 	mutex_lock(&cma->lock);
@@ -302,31 +317,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 	mutex_unlock(&cma->lock);
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
 	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
 	struct page *page = NULL;
 	int ret;
 
 	if (!cma || !cma->count)
 		return NULL;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
 	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
@@ -375,19 +375,30 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 }
 
 /**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
  *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
  */
-bool dma_release_from_contiguous(struct device *dev, struct page *pages,
-				 int count)
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
 {
 	struct cma *cma = dev_get_cma_area(dev);
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return __dma_alloc_from_contiguous(cma, count, align);
+}
+
+static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
+				 int count)
+{
 	unsigned long pfn;
 
 	if (!cma || !pages)
@@ -407,3 +418,21 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 	return true;
 }
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+
+	return __dma_release_from_contiguous(cma, pages, count);
+}
-- 
1.7.9.5

[PATCH v3 -next 2/9] DMA, CMA: separate core CMA management codes from DMA APIs

[Joonsoo Kim]

To prepare future generalization work on CMA area management code,
we need to separate core CMA management codes from DMA APIs.
We will extend these core functions to cover requirements of
PPC KVM's CMA area management functionality in following patches.
This separation helps us not to touch DMA APIs while extending
core functions.

v3: move decriptions to exporeted APIs (Minchan)
    pass aligned base and size to dma_contiguous_early_fixup() (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6467c91..9021762 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -213,26 +213,9 @@ static int __init cma_init_reserved_areas(void)
 }
 core_initcall(cma_init_reserved_areas);
 
-/**
- * dma_contiguous_reserve_area() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
- * @base: Base address of the reserved area optional, use 0 for any
- * @limit: End address of the reserved memory (optional, 0 for any).
- * @res_cma: Pointer to store the created cma region.
- * @fixed: hint about where to place the reserved area
- *
- * This function reserves memory from early allocator. It should be
- * called by arch specific code once the early allocator (memblock or bootmem)
- * has been activated and all other subsystems have already allocated/reserved
- * memory. This function allows to create custom reserved areas for specific
- * devices.
- *
- * If @fixed is true, reserve contiguous area at exactly @base.  If false,
- * reserve in range from @base to @limit.
- */
-int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
-				       phys_addr_t limit, struct cma **res_cma,
-				       bool fixed)
+static int __init __dma_contiguous_reserve_area(phys_addr_t size,
+				phys_addr_t base, phys_addr_t limit,
+				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	phys_addr_t alignment;
@@ -286,15 +269,47 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 
 	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
-
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(base, size);
 	return 0;
+
 err:
 	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
+				(*res_cma)->count << PAGE_SHIFT);
+
+	return 0;
+}
+
 static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 {
 	mutex_lock(&cma->lock);
@@ -302,31 +317,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 	mutex_unlock(&cma->lock);
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
 	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
 	struct page *page = NULL;
 	int ret;
 
 	if (!cma || !cma->count)
 		return NULL;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
 	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
@@ -375,19 +375,30 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 }
 
 /**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
  *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
  */
-bool dma_release_from_contiguous(struct device *dev, struct page *pages,
-				 int count)
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
 {
 	struct cma *cma = dev_get_cma_area(dev);
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return __dma_alloc_from_contiguous(cma, count, align);
+}
+
+static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
+				 int count)
+{
 	unsigned long pfn;
 
 	if (!cma || !pages)
@@ -407,3 +418,21 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 	return true;
 }
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+
+	return __dma_release_from_contiguous(cma, pages, count);
+}
-- 
1.7.9.5

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[PATCH v3 -next 2/9] DMA, CMA: separate core CMA management codes from DMA APIs

[Joonsoo Kim]

To prepare future generalization work on CMA area management code,
we need to separate core CMA management codes from DMA APIs.
We will extend these core functions to cover requirements of
PPC KVM's CMA area management functionality in following patches.
This separation helps us not to touch DMA APIs while extending
core functions.

v3: move decriptions to exporeted APIs (Minchan)
    pass aligned base and size to dma_contiguous_early_fixup() (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6467c91..9021762 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -213,26 +213,9 @@ static int __init cma_init_reserved_areas(void)
 }
 core_initcall(cma_init_reserved_areas);
 
-/**
- * dma_contiguous_reserve_area() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
- * @base: Base address of the reserved area optional, use 0 for any
- * @limit: End address of the reserved memory (optional, 0 for any).
- * @res_cma: Pointer to store the created cma region.
- * @fixed: hint about where to place the reserved area
- *
- * This function reserves memory from early allocator. It should be
- * called by arch specific code once the early allocator (memblock or bootmem)
- * has been activated and all other subsystems have already allocated/reserved
- * memory. This function allows to create custom reserved areas for specific
- * devices.
- *
- * If @fixed is true, reserve contiguous area at exactly @base.  If false,
- * reserve in range from @base to @limit.
- */
-int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
-				       phys_addr_t limit, struct cma **res_cma,
-				       bool fixed)
+static int __init __dma_contiguous_reserve_area(phys_addr_t size,
+				phys_addr_t base, phys_addr_t limit,
+				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	phys_addr_t alignment;
@@ -286,15 +269,47 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 
 	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
-
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(base, size);
 	return 0;
+
 err:
 	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
+				(*res_cma)->count << PAGE_SHIFT);
+
+	return 0;
+}
+
 static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 {
 	mutex_lock(&cma->lock);
@@ -302,31 +317,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 	mutex_unlock(&cma->lock);
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
 	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
 	struct page *page = NULL;
 	int ret;
 
 	if (!cma || !cma->count)
 		return NULL;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
 	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
@@ -375,19 +375,30 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 }
 
 /**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
  *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
  */
-bool dma_release_from_contiguous(struct device *dev, struct page *pages,
-				 int count)
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
 {
 	struct cma *cma = dev_get_cma_area(dev);
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return __dma_alloc_from_contiguous(cma, count, align);
+}
+
+static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
+				 int count)
+{
 	unsigned long pfn;
 
 	if (!cma || !pages)
@@ -407,3 +418,21 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 	return true;
 }
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+
+	return __dma_release_from_contiguous(cma, pages, count);
+}
-- 
1.7.9.5

[PATCH v3 -next 2/9] DMA, CMA: separate core CMA management codes from DMA APIs

[Joonsoo Kim]

To prepare future generalization work on CMA area management code,
we need to separate core CMA management codes from DMA APIs.
We will extend these core functions to cover requirements of
PPC KVM's CMA area management functionality in following patches.
This separation helps us not to touch DMA APIs while extending
core functions.

v3: move decriptions to exporeted APIs (Minchan)
    pass aligned base and size to dma_contiguous_early_fixup() (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6467c91..9021762 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -213,26 +213,9 @@ static int __init cma_init_reserved_areas(void)
 }
 core_initcall(cma_init_reserved_areas);
 
-/**
- * dma_contiguous_reserve_area() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
- * @base: Base address of the reserved area optional, use 0 for any
- * @limit: End address of the reserved memory (optional, 0 for any).
- * @res_cma: Pointer to store the created cma region.
- * @fixed: hint about where to place the reserved area
- *
- * This function reserves memory from early allocator. It should be
- * called by arch specific code once the early allocator (memblock or bootmem)
- * has been activated and all other subsystems have already allocated/reserved
- * memory. This function allows to create custom reserved areas for specific
- * devices.
- *
- * If @fixed is true, reserve contiguous area at exactly @base.  If false,
- * reserve in range from @base to @limit.
- */
-int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
-				       phys_addr_t limit, struct cma **res_cma,
-				       bool fixed)
+static int __init __dma_contiguous_reserve_area(phys_addr_t size,
+				phys_addr_t base, phys_addr_t limit,
+				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	phys_addr_t alignment;
@@ -286,15 +269,47 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 
 	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
-
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(base, size);
 	return 0;
+
 err:
 	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
+				(*res_cma)->count << PAGE_SHIFT);
+
+	return 0;
+}
+
 static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 {
 	mutex_lock(&cma->lock);
@@ -302,31 +317,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 	mutex_unlock(&cma->lock);
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
 	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
 	struct page *page = NULL;
 	int ret;
 
 	if (!cma || !cma->count)
 		return NULL;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
 	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
@@ -375,19 +375,30 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 }
 
 /**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
  *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
  */
-bool dma_release_from_contiguous(struct device *dev, struct page *pages,
-				 int count)
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
 {
 	struct cma *cma = dev_get_cma_area(dev);
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return __dma_alloc_from_contiguous(cma, count, align);
+}
+
+static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
+				 int count)
+{
 	unsigned long pfn;
 
 	if (!cma || !pages)
@@ -407,3 +418,21 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 	return true;
 }
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+
+	return __dma_release_from_contiguous(cma, pages, count);
+}
-- 
1.7.9.5

[PATCH v3 -next 2/9] DMA, CMA: separate core CMA management codes from DMA APIs

[Joonsoo Kim]

To prepare future generalization work on CMA area management code,
we need to separate core CMA management codes from DMA APIs.
We will extend these core functions to cover requirements of
PPC KVM's CMA area management functionality in following patches.
This separation helps us not to touch DMA APIs while extending
core functions.

v3: move decriptions to exporeted APIs (Minchan)
    pass aligned base and size to dma_contiguous_early_fixup() (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6467c91..9021762 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -213,26 +213,9 @@ static int __init cma_init_reserved_areas(void)
 }
 core_initcall(cma_init_reserved_areas);
 
-/**
- * dma_contiguous_reserve_area() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
- * @base: Base address of the reserved area optional, use 0 for any
- * @limit: End address of the reserved memory (optional, 0 for any).
- * @res_cma: Pointer to store the created cma region.
- * @fixed: hint about where to place the reserved area
- *
- * This function reserves memory from early allocator. It should be
- * called by arch specific code once the early allocator (memblock or bootmem)
- * has been activated and all other subsystems have already allocated/reserved
- * memory. This function allows to create custom reserved areas for specific
- * devices.
- *
- * If @fixed is true, reserve contiguous area at exactly @base.  If false,
- * reserve in range from @base to @limit.
- */
-int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
-				       phys_addr_t limit, struct cma **res_cma,
-				       bool fixed)
+static int __init __dma_contiguous_reserve_area(phys_addr_t size,
+				phys_addr_t base, phys_addr_t limit,
+				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	phys_addr_t alignment;
@@ -286,15 +269,47 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 
 	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
-
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(base, size);
 	return 0;
+
 err:
 	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
+				(*res_cma)->count << PAGE_SHIFT);
+
+	return 0;
+}
+
 static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 {
 	mutex_lock(&cma->lock);
@@ -302,31 +317,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
 	mutex_unlock(&cma->lock);
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
 	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
 	struct page *page = NULL;
 	int ret;
 
 	if (!cma || !cma->count)
 		return NULL;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
 	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
@@ -375,19 +375,30 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 }
 
 /**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
  *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
  */
-bool dma_release_from_contiguous(struct device *dev, struct page *pages,
-				 int count)
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
 {
 	struct cma *cma = dev_get_cma_area(dev);
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return __dma_alloc_from_contiguous(cma, count, align);
+}
+
+static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
+				 int count)
+{
 	unsigned long pfn;
 
 	if (!cma || !pages)
@@ -407,3 +418,21 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 	return true;
 }
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+
+	return __dma_release_from_contiguous(cma, pages, count);
+}
-- 
1.7.9.5

[PATCH v3 -next 3/9] DMA, CMA: support alignment constraint on CMA region

[Joonsoo Kim]

PPC KVM's CMA area management needs alignment constraint on
CMA region. So support it to prepare generalization of CMA area
management functionality.

Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.

v3: fix wrongly spelled word, align_order->alignment (Minchan)
    clear code documentation by Minchan's comment (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 9021762..5f62c28 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
+#include <linux/log2.h>
 
 struct cma {
 	unsigned long	base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 				phys_addr_t base, phys_addr_t limit,
+				phys_addr_t alignment,
 				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
 	int ret = 0;
 
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
 
-	/* Sanity checks */
 	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
 		pr_err("Not enough slots for CMA reserved regions!\n");
 		return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	if (!size)
 		return -EINVAL;
 
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+						res_cma, fixed);
 	if (ret)
 		return ret;
 
-- 
1.7.9.5

[PATCH v3 -next 3/9] DMA, CMA: support alignment constraint on CMA region

[Joonsoo Kim]

PPC KVM's CMA area management needs alignment constraint on
CMA region. So support it to prepare generalization of CMA area
management functionality.

Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.

v3: fix wrongly spelled word, align_order->alignment (Minchan)
    clear code documentation by Minchan's comment (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 9021762..5f62c28 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
+#include <linux/log2.h>
 
 struct cma {
 	unsigned long	base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 				phys_addr_t base, phys_addr_t limit,
+				phys_addr_t alignment,
 				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
 	int ret = 0;
 
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
 
-	/* Sanity checks */
 	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
 		pr_err("Not enough slots for CMA reserved regions!\n");
 		return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	if (!size)
 		return -EINVAL;
 
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+						res_cma, fixed);
 	if (ret)
 		return ret;
 
-- 
1.7.9.5

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[PATCH v3 -next 3/9] DMA, CMA: support alignment constraint on CMA region

[Joonsoo Kim]

PPC KVM's CMA area management needs alignment constraint on
CMA region. So support it to prepare generalization of CMA area
management functionality.

Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.

v3: fix wrongly spelled word, align_order->alignment (Minchan)
    clear code documentation by Minchan's comment (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 9021762..5f62c28 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
+#include <linux/log2.h>
 
 struct cma {
 	unsigned long	base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 				phys_addr_t base, phys_addr_t limit,
+				phys_addr_t alignment,
 				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
 	int ret = 0;
 
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
 
-	/* Sanity checks */
 	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
 		pr_err("Not enough slots for CMA reserved regions!\n");
 		return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	if (!size)
 		return -EINVAL;
 
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+						res_cma, fixed);
 	if (ret)
 		return ret;
 
-- 
1.7.9.5

[PATCH v3 -next 3/9] DMA, CMA: support alignment constraint on CMA region

[Joonsoo Kim]

PPC KVM's CMA area management needs alignment constraint on
CMA region. So support it to prepare generalization of CMA area
management functionality.

Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.

v3: fix wrongly spelled word, align_order->alignment (Minchan)
    clear code documentation by Minchan's comment (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 9021762..5f62c28 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
+#include <linux/log2.h>
 
 struct cma {
 	unsigned long	base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 				phys_addr_t base, phys_addr_t limit,
+				phys_addr_t alignment,
 				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
 	int ret = 0;
 
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
 
-	/* Sanity checks */
 	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
 		pr_err("Not enough slots for CMA reserved regions!\n");
 		return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	if (!size)
 		return -EINVAL;
 
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+						res_cma, fixed);
 	if (ret)
 		return ret;
 
-- 
1.7.9.5

[PATCH v3 -next 3/9] DMA, CMA: support alignment constraint on CMA region

[Joonsoo Kim]

PPC KVM's CMA area management needs alignment constraint on
CMA region. So support it to prepare generalization of CMA area
management functionality.

Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.

v3: fix wrongly spelled word, align_order->alignment (Minchan)
    clear code documentation by Minchan's comment (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 9021762..5f62c28 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
+#include <linux/log2.h>
 
 struct cma {
 	unsigned long	base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 				phys_addr_t base, phys_addr_t limit,
+				phys_addr_t alignment,
 				struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
 	int ret = 0;
 
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
 
-	/* Sanity checks */
 	if (cma_area_count = ARRAY_SIZE(cma_areas)) {
 		pr_err("Not enough slots for CMA reserved regions!\n");
 		return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	if (!size)
 		return -EINVAL;
 
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+						res_cma, fixed);
 	if (ret)
 		return ret;
 
-- 
1.7.9.5

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region
with bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

v3: use consistent local variable name (Minchan)
    use unsigned int for order_per_bit (Michal)
    change clear_cma_bitmap to cma_clear_bitmap for consistency (Michal)
    remove un-needed local variable, bitmap_maxno (Michal)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 5f62c28..c6eeb2c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -38,6 +38,7 @@ struct cma {
 	unsigned long	base_pfn;
 	unsigned long	count;
 	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
 	struct mutex	lock;
 };
 
@@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 
 static DEFINE_MUTEX(cma_mutex);
 
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
 static int __init cma_activate_area(struct cma *cma)
 {
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
 	unsigned i = cma->count >> pageblock_order;
 	struct zone *zone;
@@ -215,9 +244,9 @@ static int __init cma_init_reserved_areas(void)
 core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-				phys_addr_t base, phys_addr_t limit,
-				phys_addr_t alignment,
-				struct cma **res_cma, bool fixed)
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	int ret = 0;
@@ -249,6 +278,10 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
 
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
 	/* Reserve memory */
 	if (base && fixed) {
 		if (memblock_is_region_reserved(base, size) ||
@@ -273,6 +306,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	 */
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
 
@@ -308,7 +342,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
 						res_cma, fixed);
 	if (ret)
 		return ret;
@@ -320,17 +354,11 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 	return 0;
 }
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
-}
-
 static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 	struct page *page = NULL;
 	int ret;
 
@@ -343,18 +371,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 	if (!count)
 		return NULL;
 
-	mask = (1 << align) - 1;
-
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	for (;;) {
 		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
 			mutex_unlock(&cma->lock);
 			break;
 		}
-		bitmap_set(cma->bitmap, pageno, count);
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 		/*
 		 * It's safe to drop the lock here. We've marked this region for
 		 * our exclusive use. If the migration fails we will take the
@@ -362,7 +391,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 		 */
 		mutex_unlock(&cma->lock);
 
-		pfn = cma->base_pfn + pageno;
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 		mutex_unlock(&cma_mutex);
@@ -370,14 +399,14 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 			page = pfn_to_page(pfn);
 			break;
 		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
+			cma_clear_bitmap(cma, pfn, count);
 			break;
 		}
-		clear_cma_bitmap(cma, pfn, count);
+		cma_clear_bitmap(cma, pfn, count);
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
+		start = bitmap_no + mask + 1;
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
@@ -424,7 +453,7 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
 
 	return true;
 }
-- 
1.7.9.5

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region
with bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

v3: use consistent local variable name (Minchan)
    use unsigned int for order_per_bit (Michal)
    change clear_cma_bitmap to cma_clear_bitmap for consistency (Michal)
    remove un-needed local variable, bitmap_maxno (Michal)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 5f62c28..c6eeb2c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -38,6 +38,7 @@ struct cma {
 	unsigned long	base_pfn;
 	unsigned long	count;
 	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
 	struct mutex	lock;
 };
 
@@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 
 static DEFINE_MUTEX(cma_mutex);
 
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
 static int __init cma_activate_area(struct cma *cma)
 {
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
 	unsigned i = cma->count >> pageblock_order;
 	struct zone *zone;
@@ -215,9 +244,9 @@ static int __init cma_init_reserved_areas(void)
 core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-				phys_addr_t base, phys_addr_t limit,
-				phys_addr_t alignment,
-				struct cma **res_cma, bool fixed)
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	int ret = 0;
@@ -249,6 +278,10 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
 
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
 	/* Reserve memory */
 	if (base && fixed) {
 		if (memblock_is_region_reserved(base, size) ||
@@ -273,6 +306,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	 */
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
 
@@ -308,7 +342,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
 						res_cma, fixed);
 	if (ret)
 		return ret;
@@ -320,17 +354,11 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 	return 0;
 }
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
-}
-
 static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 	struct page *page = NULL;
 	int ret;
 
@@ -343,18 +371,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 	if (!count)
 		return NULL;
 
-	mask = (1 << align) - 1;
-
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	for (;;) {
 		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
 			mutex_unlock(&cma->lock);
 			break;
 		}
-		bitmap_set(cma->bitmap, pageno, count);
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 		/*
 		 * It's safe to drop the lock here. We've marked this region for
 		 * our exclusive use. If the migration fails we will take the
@@ -362,7 +391,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 		 */
 		mutex_unlock(&cma->lock);
 
-		pfn = cma->base_pfn + pageno;
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 		mutex_unlock(&cma_mutex);
@@ -370,14 +399,14 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 			page = pfn_to_page(pfn);
 			break;
 		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
+			cma_clear_bitmap(cma, pfn, count);
 			break;
 		}
-		clear_cma_bitmap(cma, pfn, count);
+		cma_clear_bitmap(cma, pfn, count);
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
+		start = bitmap_no + mask + 1;
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
@@ -424,7 +453,7 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
 
 	return true;
 }
-- 
1.7.9.5

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[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region
with bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

v3: use consistent local variable name (Minchan)
    use unsigned int for order_per_bit (Michal)
    change clear_cma_bitmap to cma_clear_bitmap for consistency (Michal)
    remove un-needed local variable, bitmap_maxno (Michal)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 5f62c28..c6eeb2c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -38,6 +38,7 @@ struct cma {
 	unsigned long	base_pfn;
 	unsigned long	count;
 	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
 	struct mutex	lock;
 };
 
@@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 
 static DEFINE_MUTEX(cma_mutex);
 
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
 static int __init cma_activate_area(struct cma *cma)
 {
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
 	unsigned i = cma->count >> pageblock_order;
 	struct zone *zone;
@@ -215,9 +244,9 @@ static int __init cma_init_reserved_areas(void)
 core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-				phys_addr_t base, phys_addr_t limit,
-				phys_addr_t alignment,
-				struct cma **res_cma, bool fixed)
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	int ret = 0;
@@ -249,6 +278,10 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
 
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
 	/* Reserve memory */
 	if (base && fixed) {
 		if (memblock_is_region_reserved(base, size) ||
@@ -273,6 +306,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	 */
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
 
@@ -308,7 +342,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
 						res_cma, fixed);
 	if (ret)
 		return ret;
@@ -320,17 +354,11 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 	return 0;
 }
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
-}
-
 static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 	struct page *page = NULL;
 	int ret;
 
@@ -343,18 +371,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 	if (!count)
 		return NULL;
 
-	mask = (1 << align) - 1;
-
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	for (;;) {
 		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
 			mutex_unlock(&cma->lock);
 			break;
 		}
-		bitmap_set(cma->bitmap, pageno, count);
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 		/*
 		 * It's safe to drop the lock here. We've marked this region for
 		 * our exclusive use. If the migration fails we will take the
@@ -362,7 +391,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 		 */
 		mutex_unlock(&cma->lock);
 
-		pfn = cma->base_pfn + pageno;
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 		mutex_unlock(&cma_mutex);
@@ -370,14 +399,14 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 			page = pfn_to_page(pfn);
 			break;
 		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
+			cma_clear_bitmap(cma, pfn, count);
 			break;
 		}
-		clear_cma_bitmap(cma, pfn, count);
+		cma_clear_bitmap(cma, pfn, count);
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
+		start = bitmap_no + mask + 1;
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
@@ -424,7 +453,7 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
 
 	return true;
 }
-- 
1.7.9.5

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region
with bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

v3: use consistent local variable name (Minchan)
    use unsigned int for order_per_bit (Michal)
    change clear_cma_bitmap to cma_clear_bitmap for consistency (Michal)
    remove un-needed local variable, bitmap_maxno (Michal)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 5f62c28..c6eeb2c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -38,6 +38,7 @@ struct cma {
 	unsigned long	base_pfn;
 	unsigned long	count;
 	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
 	struct mutex	lock;
 };
 
@@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 
 static DEFINE_MUTEX(cma_mutex);
 
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
 static int __init cma_activate_area(struct cma *cma)
 {
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
 	unsigned i = cma->count >> pageblock_order;
 	struct zone *zone;
@@ -215,9 +244,9 @@ static int __init cma_init_reserved_areas(void)
 core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-				phys_addr_t base, phys_addr_t limit,
-				phys_addr_t alignment,
-				struct cma **res_cma, bool fixed)
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	int ret = 0;
@@ -249,6 +278,10 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
 
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
 	/* Reserve memory */
 	if (base && fixed) {
 		if (memblock_is_region_reserved(base, size) ||
@@ -273,6 +306,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	 */
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
 
@@ -308,7 +342,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
 						res_cma, fixed);
 	if (ret)
 		return ret;
@@ -320,17 +354,11 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 	return 0;
 }
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
-}
-
 static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 	struct page *page = NULL;
 	int ret;
 
@@ -343,18 +371,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 	if (!count)
 		return NULL;
 
-	mask = (1 << align) - 1;
-
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	for (;;) {
 		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
 			mutex_unlock(&cma->lock);
 			break;
 		}
-		bitmap_set(cma->bitmap, pageno, count);
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 		/*
 		 * It's safe to drop the lock here. We've marked this region for
 		 * our exclusive use. If the migration fails we will take the
@@ -362,7 +391,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 		 */
 		mutex_unlock(&cma->lock);
 
-		pfn = cma->base_pfn + pageno;
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 		mutex_unlock(&cma_mutex);
@@ -370,14 +399,14 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 			page = pfn_to_page(pfn);
 			break;
 		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
+			cma_clear_bitmap(cma, pfn, count);
 			break;
 		}
-		clear_cma_bitmap(cma, pfn, count);
+		cma_clear_bitmap(cma, pfn, count);
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
+		start = bitmap_no + mask + 1;
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
@@ -424,7 +453,7 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
 
 	return true;
 }
-- 
1.7.9.5

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region
with bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

v3: use consistent local variable name (Minchan)
    use unsigned int for order_per_bit (Michal)
    change clear_cma_bitmap to cma_clear_bitmap for consistency (Michal)
    remove un-needed local variable, bitmap_maxno (Michal)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 5f62c28..c6eeb2c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -38,6 +38,7 @@ struct cma {
 	unsigned long	base_pfn;
 	unsigned long	count;
 	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
 	struct mutex	lock;
 };
 
@@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 
 static DEFINE_MUTEX(cma_mutex);
 
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
 static int __init cma_activate_area(struct cma *cma)
 {
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
 	unsigned i = cma->count >> pageblock_order;
 	struct zone *zone;
@@ -215,9 +244,9 @@ static int __init cma_init_reserved_areas(void)
 core_initcall(cma_init_reserved_areas);
 
 static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-				phys_addr_t base, phys_addr_t limit,
-				phys_addr_t alignment,
-				struct cma **res_cma, bool fixed)
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
 {
 	struct cma *cma = &cma_areas[cma_area_count];
 	int ret = 0;
@@ -249,6 +278,10 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
 
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
 	/* Reserve memory */
 	if (base && fixed) {
 		if (memblock_is_region_reserved(base, size) ||
@@ -273,6 +306,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
 	 */
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
 	*res_cma = cma;
 	cma_area_count++;
 
@@ -308,7 +342,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
 						res_cma, fixed);
 	if (ret)
 		return ret;
@@ -320,17 +354,11 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 	return 0;
 }
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
-}
-
 static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 	struct page *page = NULL;
 	int ret;
 
@@ -343,18 +371,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 	if (!count)
 		return NULL;
 
-	mask = (1 << align) - 1;
-
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	for (;;) {
 		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
 			mutex_unlock(&cma->lock);
 			break;
 		}
-		bitmap_set(cma->bitmap, pageno, count);
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 		/*
 		 * It's safe to drop the lock here. We've marked this region for
 		 * our exclusive use. If the migration fails we will take the
@@ -362,7 +391,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 		 */
 		mutex_unlock(&cma->lock);
 
-		pfn = cma->base_pfn + pageno;
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
 		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 		mutex_unlock(&cma_mutex);
@@ -370,14 +399,14 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 			page = pfn_to_page(pfn);
 			break;
 		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
+			cma_clear_bitmap(cma, pfn, count);
 			break;
 		}
-		clear_cma_bitmap(cma, pfn, count);
+		cma_clear_bitmap(cma, pfn, count);
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
+		start = bitmap_no + mask + 1;
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
@@ -424,7 +453,7 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
 
 	return true;
 }
-- 
1.7.9.5

[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. KVM side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

In previous patches, we have prepared some features to generalize
CMA reserved area management and now it's time to do it. This patch
moves core functions to mm/cma.c and change DMA APIs to use
these functions.

There is no functional change in DMA APIs.

v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
v3: remove log2.h in dma-contiguous.c (Minchan)
    add some accessor functions to pass aligned base and size to
    dma_contiguous_early_fixup() function
    move MAX_CMA_AREAS to cma.h

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-#include <linux/log2.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	unsigned int order_per_bit; /* Order of pages represented by one bit */
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
-	return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
-						unsigned long pages)
-{
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	unsigned long bitmap_no, bitmap_count;
-
-	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
-	mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-
-err:
-	kfree(cma->bitmap);
-	return -EINVAL;
-}
-
-static struct cma cma_areas[MAX_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
-			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
-{
-	struct cma *cma = &cma_areas[cma_area_count];
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-		__func__, (unsigned long)size, (unsigned long)base,
-		(unsigned long)limit, (unsigned long)alignment);
-
-	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	if (alignment && !is_power_of_2(alignment))
-		return -EINVAL;
-
-	/*
-	 * Sanitise input arguments.
-	 * Pages both ends in CMA area could be merged into adjacent unmovable
-	 * migratetype page by page allocator's buddy algorithm. In the case,
-	 * you couldn't get a contiguous memory, which is not what we want.
-	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* size should be aligned with order_per_bit */
-	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
-		return -EINVAL;
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	cma->order_per_bit = order_per_bit;
-	*res_cma = cma;
-	cma_area_count++;
-
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
-	return 0;
-
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
-						res_cma, fixed);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
 	if (ret)
 		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
-				(*res_cma)->count << PAGE_SHIFT);
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
 
 	return 0;
 }
 
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
-				       unsigned int align)
-{
-	unsigned long mask, pfn, start = 0;
-	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = cma_bitmap_aligned_mask(cma, align);
-	bitmap_maxno = cma_bitmap_maxno(cma);
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
-				bitmap_maxno, start, bitmap_count, mask);
-		if (bitmap_no >= bitmap_maxno) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret == 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
-		}
-		cma_clear_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = bitmap_no + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
 /**
  * dma_alloc_from_contiguous() - allocate pages from contiguous area
  * @dev:   Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
-				 int count)
-{
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	cma_clear_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
 /**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
-	return __dma_release_from_contiguous(cma, pages, count);
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
-
 extern struct cma *dma_contiguous_default_area;
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
-
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
 	return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
+	struct mutex	lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+	return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+	return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
+
+	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret == 0) {
+			page = pfn_to_page(pfn);
+			break;
+		} else if (ret != -EBUSY) {
+			cma_clear_bitmap(cma, pfn, count);
+			break;
+		}
+		cma_clear_bitmap(cma, pfn, count);
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmap_no + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
+
+	return true;
+}
-- 
1.7.9.5

[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. KVM side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

In previous patches, we have prepared some features to generalize
CMA reserved area management and now it's time to do it. This patch
moves core functions to mm/cma.c and change DMA APIs to use
these functions.

There is no functional change in DMA APIs.

v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
v3: remove log2.h in dma-contiguous.c (Minchan)
    add some accessor functions to pass aligned base and size to
    dma_contiguous_early_fixup() function
    move MAX_CMA_AREAS to cma.h

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-#include <linux/log2.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	unsigned int order_per_bit; /* Order of pages represented by one bit */
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
-	return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
-						unsigned long pages)
-{
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	unsigned long bitmap_no, bitmap_count;
-
-	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
-	mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-
-err:
-	kfree(cma->bitmap);
-	return -EINVAL;
-}
-
-static struct cma cma_areas[MAX_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
-			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
-{
-	struct cma *cma = &cma_areas[cma_area_count];
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-		__func__, (unsigned long)size, (unsigned long)base,
-		(unsigned long)limit, (unsigned long)alignment);
-
-	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	if (alignment && !is_power_of_2(alignment))
-		return -EINVAL;
-
-	/*
-	 * Sanitise input arguments.
-	 * Pages both ends in CMA area could be merged into adjacent unmovable
-	 * migratetype page by page allocator's buddy algorithm. In the case,
-	 * you couldn't get a contiguous memory, which is not what we want.
-	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* size should be aligned with order_per_bit */
-	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
-		return -EINVAL;
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	cma->order_per_bit = order_per_bit;
-	*res_cma = cma;
-	cma_area_count++;
-
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
-	return 0;
-
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
-						res_cma, fixed);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
 	if (ret)
 		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
-				(*res_cma)->count << PAGE_SHIFT);
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
 
 	return 0;
 }
 
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
-				       unsigned int align)
-{
-	unsigned long mask, pfn, start = 0;
-	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = cma_bitmap_aligned_mask(cma, align);
-	bitmap_maxno = cma_bitmap_maxno(cma);
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
-				bitmap_maxno, start, bitmap_count, mask);
-		if (bitmap_no >= bitmap_maxno) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret == 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
-		}
-		cma_clear_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = bitmap_no + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
 /**
  * dma_alloc_from_contiguous() - allocate pages from contiguous area
  * @dev:   Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
-				 int count)
-{
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	cma_clear_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
 /**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
-	return __dma_release_from_contiguous(cma, pages, count);
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
-
 extern struct cma *dma_contiguous_default_area;
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
-
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
 	return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
+	struct mutex	lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+	return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+	return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
+
+	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret == 0) {
+			page = pfn_to_page(pfn);
+			break;
+		} else if (ret != -EBUSY) {
+			cma_clear_bitmap(cma, pfn, count);
+			break;
+		}
+		cma_clear_bitmap(cma, pfn, count);
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmap_no + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
+
+	return true;
+}
-- 
1.7.9.5

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[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. KVM side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

In previous patches, we have prepared some features to generalize
CMA reserved area management and now it's time to do it. This patch
moves core functions to mm/cma.c and change DMA APIs to use
these functions.

There is no functional change in DMA APIs.

v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
v3: remove log2.h in dma-contiguous.c (Minchan)
    add some accessor functions to pass aligned base and size to
    dma_contiguous_early_fixup() function
    move MAX_CMA_AREAS to cma.h

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-#include <linux/log2.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	unsigned int order_per_bit; /* Order of pages represented by one bit */
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
-	return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
-						unsigned long pages)
-{
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	unsigned long bitmap_no, bitmap_count;
-
-	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
-	mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-
-err:
-	kfree(cma->bitmap);
-	return -EINVAL;
-}
-
-static struct cma cma_areas[MAX_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
-			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
-{
-	struct cma *cma = &cma_areas[cma_area_count];
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-		__func__, (unsigned long)size, (unsigned long)base,
-		(unsigned long)limit, (unsigned long)alignment);
-
-	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	if (alignment && !is_power_of_2(alignment))
-		return -EINVAL;
-
-	/*
-	 * Sanitise input arguments.
-	 * Pages both ends in CMA area could be merged into adjacent unmovable
-	 * migratetype page by page allocator's buddy algorithm. In the case,
-	 * you couldn't get a contiguous memory, which is not what we want.
-	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* size should be aligned with order_per_bit */
-	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
-		return -EINVAL;
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	cma->order_per_bit = order_per_bit;
-	*res_cma = cma;
-	cma_area_count++;
-
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
-	return 0;
-
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
-						res_cma, fixed);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
 	if (ret)
 		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
-				(*res_cma)->count << PAGE_SHIFT);
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
 
 	return 0;
 }
 
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
-				       unsigned int align)
-{
-	unsigned long mask, pfn, start = 0;
-	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = cma_bitmap_aligned_mask(cma, align);
-	bitmap_maxno = cma_bitmap_maxno(cma);
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
-				bitmap_maxno, start, bitmap_count, mask);
-		if (bitmap_no >= bitmap_maxno) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret == 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
-		}
-		cma_clear_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = bitmap_no + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
 /**
  * dma_alloc_from_contiguous() - allocate pages from contiguous area
  * @dev:   Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
-				 int count)
-{
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	cma_clear_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
 /**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
-	return __dma_release_from_contiguous(cma, pages, count);
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
-
 extern struct cma *dma_contiguous_default_area;
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
-
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
 	return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
+	struct mutex	lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+	return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+	return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
+
+	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret == 0) {
+			page = pfn_to_page(pfn);
+			break;
+		} else if (ret != -EBUSY) {
+			cma_clear_bitmap(cma, pfn, count);
+			break;
+		}
+		cma_clear_bitmap(cma, pfn, count);
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmap_no + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
+
+	return true;
+}
-- 
1.7.9.5

[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
>From my guess, it is caused by some needs on bitmap management. KVM side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

In previous patches, we have prepared some features to generalize
CMA reserved area management and now it's time to do it. This patch
moves core functions to mm/cma.c and change DMA APIs to use
these functions.

There is no functional change in DMA APIs.

v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
v3: remove log2.h in dma-contiguous.c (Minchan)
    add some accessor functions to pass aligned base and size to
    dma_contiguous_early_fixup() function
    move MAX_CMA_AREAS to cma.h

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-#include <linux/log2.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	unsigned int order_per_bit; /* Order of pages represented by one bit */
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
-	return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
-						unsigned long pages)
-{
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	unsigned long bitmap_no, bitmap_count;
-
-	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
-	mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-
-err:
-	kfree(cma->bitmap);
-	return -EINVAL;
-}
-
-static struct cma cma_areas[MAX_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
-			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
-{
-	struct cma *cma = &cma_areas[cma_area_count];
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-		__func__, (unsigned long)size, (unsigned long)base,
-		(unsigned long)limit, (unsigned long)alignment);
-
-	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	if (alignment && !is_power_of_2(alignment))
-		return -EINVAL;
-
-	/*
-	 * Sanitise input arguments.
-	 * Pages both ends in CMA area could be merged into adjacent unmovable
-	 * migratetype page by page allocator's buddy algorithm. In the case,
-	 * you couldn't get a contiguous memory, which is not what we want.
-	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* size should be aligned with order_per_bit */
-	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
-		return -EINVAL;
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	cma->order_per_bit = order_per_bit;
-	*res_cma = cma;
-	cma_area_count++;
-
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
-	return 0;
-
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
-						res_cma, fixed);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
 	if (ret)
 		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
-				(*res_cma)->count << PAGE_SHIFT);
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
 
 	return 0;
 }
 
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
-				       unsigned int align)
-{
-	unsigned long mask, pfn, start = 0;
-	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = cma_bitmap_aligned_mask(cma, align);
-	bitmap_maxno = cma_bitmap_maxno(cma);
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
-				bitmap_maxno, start, bitmap_count, mask);
-		if (bitmap_no >= bitmap_maxno) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret == 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
-		}
-		cma_clear_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = bitmap_no + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
 /**
  * dma_alloc_from_contiguous() - allocate pages from contiguous area
  * @dev:   Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
-				 int count)
-{
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	cma_clear_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
 /**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
-	return __dma_release_from_contiguous(cma, pages, count);
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
-
 extern struct cma *dma_contiguous_default_area;
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
-
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
 	return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
+	struct mutex	lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+	return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+	return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area@exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
+
+	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret == 0) {
+			page = pfn_to_page(pfn);
+			break;
+		} else if (ret != -EBUSY) {
+			cma_clear_bitmap(cma, pfn, count);
+			break;
+		}
+		cma_clear_bitmap(cma, pfn, count);
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmap_no + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
+
+	return true;
+}
-- 
1.7.9.5

[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Joonsoo Kim]

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc. They have their own code
to manage CMA reserved area even if they looks really similar.
From my guess, it is caused by some needs on bitmap management. KVM side
wants to maintain bitmap not for 1 page, but for more size. Eventually it
use bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me. I want to change
this situation and reduce future code management overhead through
this patch.

This change could also help developer who want to use CMA in their
new feature development, since they can use CMA easily without
copying & pasting this reserved area management code.

In previous patches, we have prepared some features to generalize
CMA reserved area management and now it's time to do it. This patch
moves core functions to mm/cma.c and change DMA APIs to use
these functions.

There is no functional change in DMA APIs.

v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
v3: remove log2.h in dma-contiguous.c (Minchan)
    add some accessor functions to pass aligned base and size to
    dma_contiguous_early_fixup() function
    move MAX_CMA_AREAS to cma.h

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-#include <linux/log2.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	unsigned int order_per_bit; /* Order of pages represented by one bit */
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
-	return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
-						unsigned long pages)
-{
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	unsigned long bitmap_no, bitmap_count;
-
-	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
-	mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-
-err:
-	kfree(cma->bitmap);
-	return -EINVAL;
-}
-
-static struct cma cma_areas[MAX_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
-			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
-{
-	struct cma *cma = &cma_areas[cma_area_count];
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-		__func__, (unsigned long)size, (unsigned long)base,
-		(unsigned long)limit, (unsigned long)alignment);
-
-	if (cma_area_count = ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	if (alignment && !is_power_of_2(alignment))
-		return -EINVAL;
-
-	/*
-	 * Sanitise input arguments.
-	 * Pages both ends in CMA area could be merged into adjacent unmovable
-	 * migratetype page by page allocator's buddy algorithm. In the case,
-	 * you couldn't get a contiguous memory, which is not what we want.
-	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* size should be aligned with order_per_bit */
-	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
-		return -EINVAL;
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	cma->order_per_bit = order_per_bit;
-	*res_cma = cma;
-	cma_area_count++;
-
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
-	return 0;
-
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
-						res_cma, fixed);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
 	if (ret)
 		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
-				(*res_cma)->count << PAGE_SHIFT);
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
 
 	return 0;
 }
 
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
-				       unsigned int align)
-{
-	unsigned long mask, pfn, start = 0;
-	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = cma_bitmap_aligned_mask(cma, align);
-	bitmap_maxno = cma_bitmap_maxno(cma);
-	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
-				bitmap_maxno, start, bitmap_count, mask);
-		if (bitmap_no >= bitmap_maxno) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret = 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
-		}
-		cma_clear_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = bitmap_no + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
 /**
  * dma_alloc_from_contiguous() - allocate pages from contiguous area
  * @dev:   Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
-				 int count)
-{
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	cma_clear_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
 /**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-
-	return __dma_release_from_contiguous(cma, pages, count);
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
-
 extern struct cma *dma_contiguous_default_area;
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
-
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
 	return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned int order_per_bit; /* Order of pages represented by one bit */
+	struct mutex	lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+	return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+	return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+	return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+	return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmap_no, bitmap_count;
+
+	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+			phys_addr_t base, phys_addr_t limit,
+			phys_addr_t alignment, unsigned int order_per_bit,
+			struct cma **res_cma, bool fixed)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+		__func__, (unsigned long)size, (unsigned long)base,
+		(unsigned long)limit, (unsigned long)alignment);
+
+	if (cma_area_count = ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	if (alignment && !is_power_of_2(alignment))
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * Pages both ends in CMA area could be merged into adjacent unmovable
+	 * migratetype page by page allocator's buddy algorithm. In the case,
+	 * you couldn't get a contiguous memory, which is not what we want.
+	 */
+	alignment = max(alignment,
+		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* size should be aligned with order_per_bit */
+	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+		return -EINVAL;
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->order_per_bit = order_per_bit;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_aligned_mask(cma, align);
+	bitmap_maxno = cma_bitmap_maxno(cma);
+	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+				bitmap_maxno, start, bitmap_count, mask);
+		if (bitmap_no >= bitmap_maxno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret = 0) {
+			page = pfn_to_page(pfn);
+			break;
+		} else if (ret != -EBUSY) {
+			cma_clear_bitmap(cma, pfn, count);
+			break;
+		}
+		cma_clear_bitmap(cma, pfn, count);
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmap_no + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	cma_clear_bitmap(cma, pfn, count);
+
+	return true;
+}
-- 
1.7.9.5

[PATCH v3 -next 6/9] PPC, KVM, CMA: use general CMA reserved area management framework

[Joonsoo Kim]

Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

v3: add zeroing to CMA region (Aneesh)
    fix compile error (Aneesh)
    move VM_BUG_ON() to kvm_alloc_hpt() in book3s_hv_builtin.c (Aneesh)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..a41e625 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -37,8 +37,6 @@
 #include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 
-#include "book3s_hv_cma.h"
-
 /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
 #define MAX_LPID_970	63
 
@@ -64,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 	}
 
 	kvm->arch.hpt_cma_alloc = 0;
-	VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
 	page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
 	if (page) {
 		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1 << order));
 		kvm->arch.hpt_cma_alloc = 1;
 	}
 
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7cde8a6..3960e0b 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -16,12 +16,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)
@@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);
@@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }
@@ -131,16 +135,18 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 {
 	unsigned long align_pages = HPT_ALIGN_PAGES;
 
+	VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
+
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
@@ -179,7 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
 	}
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
deleted file mode 100644
index d9d3d85..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret == 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);
diff --git a/arch/powerpc/kvm/book3s_hv_cma.h b/arch/powerpc/kvm/book3s_hv_cma.h
deleted file mode 100644
index 655144f..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif
-- 
1.7.9.5

[PATCH v3 -next 6/9] PPC, KVM, CMA: use general CMA reserved area management framework

[Joonsoo Kim]

Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

v3: add zeroing to CMA region (Aneesh)
    fix compile error (Aneesh)
    move VM_BUG_ON() to kvm_alloc_hpt() in book3s_hv_builtin.c (Aneesh)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..a41e625 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -37,8 +37,6 @@
 #include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 
-#include "book3s_hv_cma.h"
-
 /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
 #define MAX_LPID_970	63
 
@@ -64,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 	}
 
 	kvm->arch.hpt_cma_alloc = 0;
-	VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
 	page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
 	if (page) {
 		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1 << order));
 		kvm->arch.hpt_cma_alloc = 1;
 	}
 
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7cde8a6..3960e0b 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -16,12 +16,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)
@@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);
@@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }
@@ -131,16 +135,18 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 {
 	unsigned long align_pages = HPT_ALIGN_PAGES;
 
+	VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
+
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
@@ -179,7 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
 	}
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
deleted file mode 100644
index d9d3d85..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret == 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);
diff --git a/arch/powerpc/kvm/book3s_hv_cma.h b/arch/powerpc/kvm/book3s_hv_cma.h
deleted file mode 100644
index 655144f..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif
-- 
1.7.9.5

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[PATCH v3 -next 6/9] PPC, KVM, CMA: use general CMA reserved area management framework

[Joonsoo Kim]

Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

v3: add zeroing to CMA region (Aneesh)
    fix compile error (Aneesh)
    move VM_BUG_ON() to kvm_alloc_hpt() in book3s_hv_builtin.c (Aneesh)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..a41e625 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -37,8 +37,6 @@
 #include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 
-#include "book3s_hv_cma.h"
-
 /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
 #define MAX_LPID_970	63
 
@@ -64,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 	}
 
 	kvm->arch.hpt_cma_alloc = 0;
-	VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
 	page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
 	if (page) {
 		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1 << order));
 		kvm->arch.hpt_cma_alloc = 1;
 	}
 
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7cde8a6..3960e0b 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -16,12 +16,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)
@@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);
@@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }
@@ -131,16 +135,18 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 {
 	unsigned long align_pages = HPT_ALIGN_PAGES;
 
+	VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
+
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
@@ -179,7 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
 	}
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
deleted file mode 100644
index d9d3d85..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret == 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);
diff --git a/arch/powerpc/kvm/book3s_hv_cma.h b/arch/powerpc/kvm/book3s_hv_cma.h
deleted file mode 100644
index 655144f..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif
-- 
1.7.9.5

[PATCH v3 -next 6/9] PPC, KVM, CMA: use general CMA reserved area management framework

[Joonsoo Kim]

Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

v3: add zeroing to CMA region (Aneesh)
    fix compile error (Aneesh)
    move VM_BUG_ON() to kvm_alloc_hpt() in book3s_hv_builtin.c (Aneesh)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..a41e625 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -37,8 +37,6 @@
 #include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 
-#include "book3s_hv_cma.h"
-
 /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
 #define MAX_LPID_970	63
 
@@ -64,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 	}
 
 	kvm->arch.hpt_cma_alloc = 0;
-	VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
 	page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
 	if (page) {
 		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1 << order));
 		kvm->arch.hpt_cma_alloc = 1;
 	}
 
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7cde8a6..3960e0b 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -16,12 +16,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)
@@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);
@@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }
@@ -131,16 +135,18 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 {
 	unsigned long align_pages = HPT_ALIGN_PAGES;
 
+	VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
+
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
@@ -179,7 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
 	}
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
deleted file mode 100644
index d9d3d85..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret == 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range@%p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);
diff --git a/arch/powerpc/kvm/book3s_hv_cma.h b/arch/powerpc/kvm/book3s_hv_cma.h
deleted file mode 100644
index 655144f..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif
-- 
1.7.9.5

[PATCH v3 -next 6/9] PPC, KVM, CMA: use general CMA reserved area management framework

[Joonsoo Kim]

Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

v3: add zeroing to CMA region (Aneesh)
    fix compile error (Aneesh)
    move VM_BUG_ON() to kvm_alloc_hpt() in book3s_hv_builtin.c (Aneesh)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..a41e625 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -37,8 +37,6 @@
 #include <asm/ppc-opcode.h>
 #include <asm/cputable.h>
 
-#include "book3s_hv_cma.h"
-
 /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
 #define MAX_LPID_970	63
 
@@ -64,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 	}
 
 	kvm->arch.hpt_cma_alloc = 0;
-	VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
 	page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
 	if (page) {
 		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1 << order));
 		kvm->arch.hpt_cma_alloc = 1;
 	}
 
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7cde8a6..3960e0b 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -16,12 +16,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)
@@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);
@@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }
@@ -131,16 +135,18 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 {
 	unsigned long align_pages = HPT_ALIGN_PAGES;
 
+	VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
+
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
@@ -179,7 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
 	}
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
deleted file mode 100644
index d9d3d85..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret = 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);
diff --git a/arch/powerpc/kvm/book3s_hv_cma.h b/arch/powerpc/kvm/book3s_hv_cma.h
deleted file mode 100644
index 655144f..0000000
--- a/arch/powerpc/kvm/book3s_hv_cma.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif
-- 
1.7.9.5

[PATCH v3 -next 7/9] mm, CMA: clean-up CMA allocation error path

[Joonsoo Kim]

We can remove one call sites for clear_cma_bitmap() if we first
call it before checking error number.

Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 0cf50da..b442a13 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -285,11 +285,12 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
 			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
 		}
+
 		cma_clear_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-- 
1.7.9.5

[PATCH v3 -next 7/9] mm, CMA: clean-up CMA allocation error path

[Joonsoo Kim]

We can remove one call sites for clear_cma_bitmap() if we first
call it before checking error number.

Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 0cf50da..b442a13 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -285,11 +285,12 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
 			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
 		}
+
 		cma_clear_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-- 
1.7.9.5

--
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[PATCH v3 -next 7/9] mm, CMA: clean-up CMA allocation error path

[Joonsoo Kim]

We can remove one call sites for clear_cma_bitmap() if we first
call it before checking error number.

Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 0cf50da..b442a13 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -285,11 +285,12 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
 			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
 		}
+
 		cma_clear_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-- 
1.7.9.5

[PATCH v3 -next 7/9] mm, CMA: clean-up CMA allocation error path

[Joonsoo Kim]

We can remove one call sites for clear_cma_bitmap() if we first
call it before checking error number.

Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 0cf50da..b442a13 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -285,11 +285,12 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
 			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
 		}
+
 		cma_clear_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-- 
1.7.9.5

[PATCH v3 -next 7/9] mm, CMA: clean-up CMA allocation error path

[Joonsoo Kim]

We can remove one call sites for clear_cma_bitmap() if we first
call it before checking error number.

Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 0cf50da..b442a13 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -285,11 +285,12 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		if (ret = 0) {
 			page = pfn_to_page(pfn);
 			break;
-		} else if (ret != -EBUSY) {
-			cma_clear_bitmap(cma, pfn, count);
-			break;
 		}
+
 		cma_clear_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
 		/* try again with a bit different memory target */
-- 
1.7.9.5

[PATCH v3 -next 8/9] mm, CMA: change cma_declare_contiguous() to obey coding convention

[Joonsoo Kim]

Conventionally, we put output param to the end of param list
and put the 'base' ahead of 'size', but cma_declare_contiguous()
doesn't look like that, so change it.

Additionally, move down cma_areas reference code to the position
where it is really needed.

v3: put 'base' ahead of 'size' (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 3960e0b..6cf498a 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -185,8 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		cma_declare_contiguous(selected_size, 0, 0, align_size,
-			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
+		cma_declare_contiguous(0, selected_size, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }
 
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0411c1c..6606abd 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -165,7 +165,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 69d3726..32cab7a 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -15,7 +15,7 @@ extern unsigned long cma_get_size(struct cma *cma);
 extern int __init cma_declare_contiguous(phys_addr_t size,
 			phys_addr_t base, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed);
+			bool fixed, struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
 extern bool cma_release(struct cma *cma, struct page *pages, int count);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index b442a13..9961120 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -141,13 +141,13 @@ core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_declare_contiguous() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
  * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
  * @limit: End address of the reserved memory (optional, 0 for any).
  * @alignment: Alignment for the CMA area, should be power of 2 or zero
  * @order_per_bit: Order of pages represented by one bit on bitmap.
- * @res_cma: Pointer to store the created cma region.
  * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
  *
  * This function reserves memory from early allocator. It should be
  * called by arch specific code once the early allocator (memblock or bootmem)
@@ -157,12 +157,12 @@ core_initcall(cma_init_reserved_areas);
  * If @fixed is true, reserve contiguous area at exactly @base.  If false,
  * reserve in range from @base to @limit.
  */
-int __init cma_declare_contiguous(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
+int __init cma_declare_contiguous(phys_addr_t base,
+			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
+			bool fixed, struct cma **res_cma)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
+	struct cma *cma;
 	int ret = 0;
 
 	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -218,6 +218,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
 	 * Each reserved area must be initialised later, when more kernel
 	 * subsystems (like slab allocator) are available.
 	 */
+	cma = &cma_areas[cma_area_count];
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
 	cma->order_per_bit = order_per_bit;
-- 
1.7.9.5

[PATCH v3 -next 8/9] mm, CMA: change cma_declare_contiguous() to obey coding convention

[Joonsoo Kim]

Conventionally, we put output param to the end of param list
and put the 'base' ahead of 'size', but cma_declare_contiguous()
doesn't look like that, so change it.

Additionally, move down cma_areas reference code to the position
where it is really needed.

v3: put 'base' ahead of 'size' (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 3960e0b..6cf498a 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -185,8 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		cma_declare_contiguous(selected_size, 0, 0, align_size,
-			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
+		cma_declare_contiguous(0, selected_size, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }
 
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0411c1c..6606abd 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -165,7 +165,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 69d3726..32cab7a 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -15,7 +15,7 @@ extern unsigned long cma_get_size(struct cma *cma);
 extern int __init cma_declare_contiguous(phys_addr_t size,
 			phys_addr_t base, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed);
+			bool fixed, struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
 extern bool cma_release(struct cma *cma, struct page *pages, int count);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index b442a13..9961120 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -141,13 +141,13 @@ core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_declare_contiguous() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
  * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
  * @limit: End address of the reserved memory (optional, 0 for any).
  * @alignment: Alignment for the CMA area, should be power of 2 or zero
  * @order_per_bit: Order of pages represented by one bit on bitmap.
- * @res_cma: Pointer to store the created cma region.
  * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
  *
  * This function reserves memory from early allocator. It should be
  * called by arch specific code once the early allocator (memblock or bootmem)
@@ -157,12 +157,12 @@ core_initcall(cma_init_reserved_areas);
  * If @fixed is true, reserve contiguous area at exactly @base.  If false,
  * reserve in range from @base to @limit.
  */
-int __init cma_declare_contiguous(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
+int __init cma_declare_contiguous(phys_addr_t base,
+			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
+			bool fixed, struct cma **res_cma)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
+	struct cma *cma;
 	int ret = 0;
 
 	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -218,6 +218,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
 	 * Each reserved area must be initialised later, when more kernel
 	 * subsystems (like slab allocator) are available.
 	 */
+	cma = &cma_areas[cma_area_count];
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
 	cma->order_per_bit = order_per_bit;
-- 
1.7.9.5

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[PATCH v3 -next 8/9] mm, CMA: change cma_declare_contiguous() to obey coding convention

[Joonsoo Kim]

Conventionally, we put output param to the end of param list
and put the 'base' ahead of 'size', but cma_declare_contiguous()
doesn't look like that, so change it.

Additionally, move down cma_areas reference code to the position
where it is really needed.

v3: put 'base' ahead of 'size' (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 3960e0b..6cf498a 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -185,8 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		cma_declare_contiguous(selected_size, 0, 0, align_size,
-			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
+		cma_declare_contiguous(0, selected_size, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }
 
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0411c1c..6606abd 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -165,7 +165,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 69d3726..32cab7a 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -15,7 +15,7 @@ extern unsigned long cma_get_size(struct cma *cma);
 extern int __init cma_declare_contiguous(phys_addr_t size,
 			phys_addr_t base, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed);
+			bool fixed, struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
 extern bool cma_release(struct cma *cma, struct page *pages, int count);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index b442a13..9961120 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -141,13 +141,13 @@ core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_declare_contiguous() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
  * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
  * @limit: End address of the reserved memory (optional, 0 for any).
  * @alignment: Alignment for the CMA area, should be power of 2 or zero
  * @order_per_bit: Order of pages represented by one bit on bitmap.
- * @res_cma: Pointer to store the created cma region.
  * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
  *
  * This function reserves memory from early allocator. It should be
  * called by arch specific code once the early allocator (memblock or bootmem)
@@ -157,12 +157,12 @@ core_initcall(cma_init_reserved_areas);
  * If @fixed is true, reserve contiguous area at exactly @base.  If false,
  * reserve in range from @base to @limit.
  */
-int __init cma_declare_contiguous(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
+int __init cma_declare_contiguous(phys_addr_t base,
+			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
+			bool fixed, struct cma **res_cma)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
+	struct cma *cma;
 	int ret = 0;
 
 	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -218,6 +218,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
 	 * Each reserved area must be initialised later, when more kernel
 	 * subsystems (like slab allocator) are available.
 	 */
+	cma = &cma_areas[cma_area_count];
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
 	cma->order_per_bit = order_per_bit;
-- 
1.7.9.5

[PATCH v3 -next 8/9] mm, CMA: change cma_declare_contiguous() to obey coding convention

[Joonsoo Kim]

Conventionally, we put output param to the end of param list
and put the 'base' ahead of 'size', but cma_declare_contiguous()
doesn't look like that, so change it.

Additionally, move down cma_areas reference code to the position
where it is really needed.

v3: put 'base' ahead of 'size' (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 3960e0b..6cf498a 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -185,8 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		cma_declare_contiguous(selected_size, 0, 0, align_size,
-			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
+		cma_declare_contiguous(0, selected_size, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }
 
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0411c1c..6606abd 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -165,7 +165,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 69d3726..32cab7a 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -15,7 +15,7 @@ extern unsigned long cma_get_size(struct cma *cma);
 extern int __init cma_declare_contiguous(phys_addr_t size,
 			phys_addr_t base, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed);
+			bool fixed, struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
 extern bool cma_release(struct cma *cma, struct page *pages, int count);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index b442a13..9961120 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -141,13 +141,13 @@ core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_declare_contiguous() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
  * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
  * @limit: End address of the reserved memory (optional, 0 for any).
  * @alignment: Alignment for the CMA area, should be power of 2 or zero
  * @order_per_bit: Order of pages represented by one bit on bitmap.
- * @res_cma: Pointer to store the created cma region.
  * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
  *
  * This function reserves memory from early allocator. It should be
  * called by arch specific code once the early allocator (memblock or bootmem)
@@ -157,12 +157,12 @@ core_initcall(cma_init_reserved_areas);
  * If @fixed is true, reserve contiguous area@exactly @base.  If false,
  * reserve in range from @base to @limit.
  */
-int __init cma_declare_contiguous(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
+int __init cma_declare_contiguous(phys_addr_t base,
+			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
+			bool fixed, struct cma **res_cma)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
+	struct cma *cma;
 	int ret = 0;
 
 	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -218,6 +218,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
 	 * Each reserved area must be initialised later, when more kernel
 	 * subsystems (like slab allocator) are available.
 	 */
+	cma = &cma_areas[cma_area_count];
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
 	cma->order_per_bit = order_per_bit;
-- 
1.7.9.5

[PATCH v3 -next 8/9] mm, CMA: change cma_declare_contiguous() to obey coding convention

[Joonsoo Kim]

Conventionally, we put output param to the end of param list
and put the 'base' ahead of 'size', but cma_declare_contiguous()
doesn't look like that, so change it.

Additionally, move down cma_areas reference code to the position
where it is really needed.

v3: put 'base' ahead of 'size' (Minchan)

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 3960e0b..6cf498a 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -185,8 +185,8 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		cma_declare_contiguous(selected_size, 0, 0, align_size,
-			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
+		cma_declare_contiguous(0, selected_size, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }
 
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0411c1c..6606abd 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -165,7 +165,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 {
 	int ret;
 
-	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 69d3726..32cab7a 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -15,7 +15,7 @@ extern unsigned long cma_get_size(struct cma *cma);
 extern int __init cma_declare_contiguous(phys_addr_t size,
 			phys_addr_t base, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed);
+			bool fixed, struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
 extern bool cma_release(struct cma *cma, struct page *pages, int count);
 #endif
diff --git a/mm/cma.c b/mm/cma.c
index b442a13..9961120 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -141,13 +141,13 @@ core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_declare_contiguous() - reserve custom contiguous area
- * @size: Size of the reserved area (in bytes),
  * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
  * @limit: End address of the reserved memory (optional, 0 for any).
  * @alignment: Alignment for the CMA area, should be power of 2 or zero
  * @order_per_bit: Order of pages represented by one bit on bitmap.
- * @res_cma: Pointer to store the created cma region.
  * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
  *
  * This function reserves memory from early allocator. It should be
  * called by arch specific code once the early allocator (memblock or bootmem)
@@ -157,12 +157,12 @@ core_initcall(cma_init_reserved_areas);
  * If @fixed is true, reserve contiguous area at exactly @base.  If false,
  * reserve in range from @base to @limit.
  */
-int __init cma_declare_contiguous(phys_addr_t size,
-			phys_addr_t base, phys_addr_t limit,
+int __init cma_declare_contiguous(phys_addr_t base,
+			phys_addr_t size, phys_addr_t limit,
 			phys_addr_t alignment, unsigned int order_per_bit,
-			struct cma **res_cma, bool fixed)
+			bool fixed, struct cma **res_cma)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
+	struct cma *cma;
 	int ret = 0;
 
 	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
@@ -218,6 +218,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
 	 * Each reserved area must be initialised later, when more kernel
 	 * subsystems (like slab allocator) are available.
 	 */
+	cma = &cma_areas[cma_area_count];
 	cma->base_pfn = PFN_DOWN(base);
 	cma->count = size >> PAGE_SHIFT;
 	cma->order_per_bit = order_per_bit;
-- 
1.7.9.5

[PATCH v3 -next 9/9] mm, CMA: clean-up log message

[Joonsoo Kim]

We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt. So remove it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 9961120..4b251b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -225,12 +225,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	*res_cma = cma;
 	cma_area_count++;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+	pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
 	return 0;
 
 err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
-- 
1.7.9.5

[PATCH v3 -next 9/9] mm, CMA: clean-up log message

[Joonsoo Kim]

We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt. So remove it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 9961120..4b251b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -225,12 +225,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	*res_cma = cma;
 	cma_area_count++;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+	pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
 	return 0;
 
 err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
-- 
1.7.9.5

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v3 -next 9/9] mm, CMA: clean-up log message

[Joonsoo Kim]

We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt. So remove it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 9961120..4b251b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -225,12 +225,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	*res_cma = cma;
 	cma_area_count++;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+	pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
 	return 0;
 
 err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
-- 
1.7.9.5

[PATCH v3 -next 9/9] mm, CMA: clean-up log message

[Joonsoo Kim]

We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt. So remove it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 9961120..4b251b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -225,12 +225,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	*res_cma = cma;
 	cma_area_count++;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+	pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
 	return 0;
 
 err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
-- 
1.7.9.5

[PATCH v3 -next 9/9] mm, CMA: clean-up log message

[Joonsoo Kim]

We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt. So remove it.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/cma.c b/mm/cma.c
index 9961120..4b251b0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -225,12 +225,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	*res_cma = cma;
 	cma_area_count++;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+	pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 		(unsigned long)base);
 	return 0;
 
 err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 	return ret;
 }
 
-- 
1.7.9.5

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Minchan Kim]

Hi, Joonsoo

On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> We should free memory for bitmap when we find zone mis-match,
> otherwise this memory will leak.
> 
> Additionally, I copy code comment from PPC KVM's CMA code to inform
> why we need to check zone mis-match.
> 
> * Note
> Minchan suggested to add a tag for the stable, but, I don't do it,
> because I found this possibility during code-review and, IMO,
> this patch isn't suitable for stable tree.

Nice idea to put the comment in here. Thanks Joonsoo.

It seems you obey "It must fix a real bug that bothers people"
on Documentation/stable_kernel_rules.txt but it's a really obvious
bug and hard to get a report from people because limited user and
hard to detect small such small memory leak.

In my experince, Andrew perfered stable marking for such a obvious
problem but simple fix like this but not sure so let's pass the decision
to him and will learn a lesson from him and will follow the decision
from now on.

Thanks.

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..6467c91 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
>  		base_pfn = pfn;
>  		for (j = pageblock_nr_pages; j; --j, pfn++) {
>  			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
>  			if (page_zone(pfn_to_page(pfn)) != zone)
> -				return -EINVAL;
> +				goto err;
>  		}
>  		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
>  	} while (--i);
>  
>  	mutex_init(&cma->lock);
>  	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
>  }
>  
>  static struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 1.7.9.5
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

-- 
Kind regards,
Minchan Kim

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Minchan Kim]

Hi, Joonsoo

On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> We should free memory for bitmap when we find zone mis-match,
> otherwise this memory will leak.
> 
> Additionally, I copy code comment from PPC KVM's CMA code to inform
> why we need to check zone mis-match.
> 
> * Note
> Minchan suggested to add a tag for the stable, but, I don't do it,
> because I found this possibility during code-review and, IMO,
> this patch isn't suitable for stable tree.

Nice idea to put the comment in here. Thanks Joonsoo.

It seems you obey "It must fix a real bug that bothers people"
on Documentation/stable_kernel_rules.txt but it's a really obvious
bug and hard to get a report from people because limited user and
hard to detect small such small memory leak.

In my experince, Andrew perfered stable marking for such a obvious
problem but simple fix like this but not sure so let's pass the decision
to him and will learn a lesson from him and will follow the decision
from now on.

Thanks.

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..6467c91 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
>  		base_pfn = pfn;
>  		for (j = pageblock_nr_pages; j; --j, pfn++) {
>  			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
>  			if (page_zone(pfn_to_page(pfn)) != zone)
> -				return -EINVAL;
> +				goto err;
>  		}
>  		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
>  	} while (--i);
>  
>  	mutex_init(&cma->lock);
>  	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
>  }
>  
>  static struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 1.7.9.5
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

-- 
Kind regards,
Minchan Kim

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Minchan Kim]

Hi, Joonsoo

On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> We should free memory for bitmap when we find zone mis-match,
> otherwise this memory will leak.
> 
> Additionally, I copy code comment from PPC KVM's CMA code to inform
> why we need to check zone mis-match.
> 
> * Note
> Minchan suggested to add a tag for the stable, but, I don't do it,
> because I found this possibility during code-review and, IMO,
> this patch isn't suitable for stable tree.

Nice idea to put the comment in here. Thanks Joonsoo.

It seems you obey "It must fix a real bug that bothers people"
on Documentation/stable_kernel_rules.txt but it's a really obvious
bug and hard to get a report from people because limited user and
hard to detect small such small memory leak.

In my experince, Andrew perfered stable marking for such a obvious
problem but simple fix like this but not sure so let's pass the decision
to him and will learn a lesson from him and will follow the decision
from now on.

Thanks.

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..6467c91 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
>  		base_pfn = pfn;
>  		for (j = pageblock_nr_pages; j; --j, pfn++) {
>  			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
>  			if (page_zone(pfn_to_page(pfn)) != zone)
> -				return -EINVAL;
> +				goto err;
>  		}
>  		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
>  	} while (--i);
>  
>  	mutex_init(&cma->lock);
>  	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
>  }
>  
>  static struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 1.7.9.5
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

-- 
Kind regards,
Minchan Kim

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Minchan Kim]

Hi, Joonsoo

On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> We should free memory for bitmap when we find zone mis-match,
> otherwise this memory will leak.
> 
> Additionally, I copy code comment from PPC KVM's CMA code to inform
> why we need to check zone mis-match.
> 
> * Note
> Minchan suggested to add a tag for the stable, but, I don't do it,
> because I found this possibility during code-review and, IMO,
> this patch isn't suitable for stable tree.

Nice idea to put the comment in here. Thanks Joonsoo.

It seems you obey "It must fix a real bug that bothers people"
on Documentation/stable_kernel_rules.txt but it's a really obvious
bug and hard to get a report from people because limited user and
hard to detect small such small memory leak.

In my experince, Andrew perfered stable marking for such a obvious
problem but simple fix like this but not sure so let's pass the decision
to him and will learn a lesson from him and will follow the decision
from now on.

Thanks.

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..6467c91 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
>  		base_pfn = pfn;
>  		for (j = pageblock_nr_pages; j; --j, pfn++) {
>  			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
>  			if (page_zone(pfn_to_page(pfn)) != zone)
> -				return -EINVAL;
> +				goto err;
>  		}
>  		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
>  	} while (--i);
>  
>  	mutex_init(&cma->lock);
>  	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
>  }
>  
>  static struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 1.7.9.5
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo at kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email at kvack.org </a>

-- 
Kind regards,
Minchan Kim

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Minchan Kim]

Hi, Joonsoo

On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> We should free memory for bitmap when we find zone mis-match,
> otherwise this memory will leak.
> 
> Additionally, I copy code comment from PPC KVM's CMA code to inform
> why we need to check zone mis-match.
> 
> * Note
> Minchan suggested to add a tag for the stable, but, I don't do it,
> because I found this possibility during code-review and, IMO,
> this patch isn't suitable for stable tree.

Nice idea to put the comment in here. Thanks Joonsoo.

It seems you obey "It must fix a real bug that bothers people"
on Documentation/stable_kernel_rules.txt but it's a really obvious
bug and hard to get a report from people because limited user and
hard to detect small such small memory leak.

In my experince, Andrew perfered stable marking for such a obvious
problem but simple fix like this but not sure so let's pass the decision
to him and will learn a lesson from him and will follow the decision
from now on.

Thanks.

Acked-by: Minchan Kim <minchan@kernel.org>

> 
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..6467c91 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
>  		base_pfn = pfn;
>  		for (j = pageblock_nr_pages; j; --j, pfn++) {
>  			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
>  			if (page_zone(pfn_to_page(pfn)) != zone)
> -				return -EINVAL;
> +				goto err;
>  		}
>  		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
>  	} while (--i);
>  
>  	mutex_init(&cma->lock);
>  	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
>  }
>  
>  static struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 1.7.9.5
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

-- 
Kind regards,
Minchan Kim

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> v3:
>    - Simplify old patch 1(log format fix) and move it to the end of patchset.
>    - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
>    - Patch 5: Add some accessor functions to pass aligned base and size to
>    dma_contiguous_early_fixup() function
>    - Patch 5: Move MAX_CMA_AREAS definition to cma.h
>    - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
>    - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
>    - Remaining minor fixes are noted in commit description of each one
>
> v2:
>    - Although this patchset looks very different with v1, the end result,
>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>
> This patchset is based on linux-next 20140610.

Thanks for taking care of this. I will test it with my setup and if
everything goes well, I will take it to my -next tree. If any branch
is required for anyone to continue his works on top of those patches,
let me know, I will also prepare it.

> Patch 1-4 prepare some features to cover PPC KVM's requirements.
> Patch 5-6 generalize CMA reserved area management code and change users
> to use it.
> Patch 7-9 clean-up minor things.
>
> Joonsoo Kim (9):
>    DMA, CMA: fix possible memory leak
>    DMA, CMA: separate core CMA management codes from DMA APIs
>    DMA, CMA: support alignment constraint on CMA region
>    DMA, CMA: support arbitrary bitmap granularity
>    CMA: generalize CMA reserved area management functionality
>    PPC, KVM, CMA: use general CMA reserved area management framework
>    mm, CMA: clean-up CMA allocation error path
>    mm, CMA: change cma_declare_contiguous() to obey coding convention
>    mm, CMA: clean-up log message
>
>   arch/arm/mm/dma-mapping.c            |    1 +
>   arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
>   arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
>   arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
>   arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
>   drivers/base/Kconfig                 |   10 -
>   drivers/base/dma-contiguous.c        |  210 ++-------------------
>   include/linux/cma.h                  |   21 +++
>   include/linux/dma-contiguous.h       |   11 +-
>   mm/Kconfig                           |   11 ++
>   mm/Makefile                          |    1 +
>   mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
>   12 files changed, 397 insertions(+), 493 deletions(-)
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
>   create mode 100644 include/linux/cma.h
>   create mode 100644 mm/cma.c
>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> v3:
>    - Simplify old patch 1(log format fix) and move it to the end of patchset.
>    - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
>    - Patch 5: Add some accessor functions to pass aligned base and size to
>    dma_contiguous_early_fixup() function
>    - Patch 5: Move MAX_CMA_AREAS definition to cma.h
>    - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
>    - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
>    - Remaining minor fixes are noted in commit description of each one
>
> v2:
>    - Although this patchset looks very different with v1, the end result,
>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>
> This patchset is based on linux-next 20140610.

Thanks for taking care of this. I will test it with my setup and if
everything goes well, I will take it to my -next tree. If any branch
is required for anyone to continue his works on top of those patches,
let me know, I will also prepare it.

> Patch 1-4 prepare some features to cover PPC KVM's requirements.
> Patch 5-6 generalize CMA reserved area management code and change users
> to use it.
> Patch 7-9 clean-up minor things.
>
> Joonsoo Kim (9):
>    DMA, CMA: fix possible memory leak
>    DMA, CMA: separate core CMA management codes from DMA APIs
>    DMA, CMA: support alignment constraint on CMA region
>    DMA, CMA: support arbitrary bitmap granularity
>    CMA: generalize CMA reserved area management functionality
>    PPC, KVM, CMA: use general CMA reserved area management framework
>    mm, CMA: clean-up CMA allocation error path
>    mm, CMA: change cma_declare_contiguous() to obey coding convention
>    mm, CMA: clean-up log message
>
>   arch/arm/mm/dma-mapping.c            |    1 +
>   arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
>   arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
>   arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
>   arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
>   drivers/base/Kconfig                 |   10 -
>   drivers/base/dma-contiguous.c        |  210 ++-------------------
>   include/linux/cma.h                  |   21 +++
>   include/linux/dma-contiguous.h       |   11 +-
>   mm/Kconfig                           |   11 ++
>   mm/Makefile                          |    1 +
>   mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
>   12 files changed, 397 insertions(+), 493 deletions(-)
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
>   create mode 100644 include/linux/cma.h
>   create mode 100644 mm/cma.c
>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> v3:
>    - Simplify old patch 1(log format fix) and move it to the end of patchset.
>    - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
>    - Patch 5: Add some accessor functions to pass aligned base and size to
>    dma_contiguous_early_fixup() function
>    - Patch 5: Move MAX_CMA_AREAS definition to cma.h
>    - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
>    - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
>    - Remaining minor fixes are noted in commit description of each one
>
> v2:
>    - Although this patchset looks very different with v1, the end result,
>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>
> This patchset is based on linux-next 20140610.

Thanks for taking care of this. I will test it with my setup and if
everything goes well, I will take it to my -next tree. If any branch
is required for anyone to continue his works on top of those patches,
let me know, I will also prepare it.

> Patch 1-4 prepare some features to cover PPC KVM's requirements.
> Patch 5-6 generalize CMA reserved area management code and change users
> to use it.
> Patch 7-9 clean-up minor things.
>
> Joonsoo Kim (9):
>    DMA, CMA: fix possible memory leak
>    DMA, CMA: separate core CMA management codes from DMA APIs
>    DMA, CMA: support alignment constraint on CMA region
>    DMA, CMA: support arbitrary bitmap granularity
>    CMA: generalize CMA reserved area management functionality
>    PPC, KVM, CMA: use general CMA reserved area management framework
>    mm, CMA: clean-up CMA allocation error path
>    mm, CMA: change cma_declare_contiguous() to obey coding convention
>    mm, CMA: clean-up log message
>
>   arch/arm/mm/dma-mapping.c            |    1 +
>   arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
>   arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
>   arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
>   arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
>   drivers/base/Kconfig                 |   10 -
>   drivers/base/dma-contiguous.c        |  210 ++-------------------
>   include/linux/cma.h                  |   21 +++
>   include/linux/dma-contiguous.h       |   11 +-
>   mm/Kconfig                           |   11 ++
>   mm/Makefile                          |    1 +
>   mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
>   12 files changed, 397 insertions(+), 493 deletions(-)
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
>   create mode 100644 include/linux/cma.h
>   create mode 100644 mm/cma.c
>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> v3:
>    - Simplify old patch 1(log format fix) and move it to the end of patchset.
>    - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
>    - Patch 5: Add some accessor functions to pass aligned base and size to
>    dma_contiguous_early_fixup() function
>    - Patch 5: Move MAX_CMA_AREAS definition to cma.h
>    - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
>    - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
>    - Remaining minor fixes are noted in commit description of each one
>
> v2:
>    - Although this patchset looks very different with v1, the end result,
>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>
> This patchset is based on linux-next 20140610.

Thanks for taking care of this. I will test it with my setup and if
everything goes well, I will take it to my -next tree. If any branch
is required for anyone to continue his works on top of those patches,
let me know, I will also prepare it.

> Patch 1-4 prepare some features to cover PPC KVM's requirements.
> Patch 5-6 generalize CMA reserved area management code and change users
> to use it.
> Patch 7-9 clean-up minor things.
>
> Joonsoo Kim (9):
>    DMA, CMA: fix possible memory leak
>    DMA, CMA: separate core CMA management codes from DMA APIs
>    DMA, CMA: support alignment constraint on CMA region
>    DMA, CMA: support arbitrary bitmap granularity
>    CMA: generalize CMA reserved area management functionality
>    PPC, KVM, CMA: use general CMA reserved area management framework
>    mm, CMA: clean-up CMA allocation error path
>    mm, CMA: change cma_declare_contiguous() to obey coding convention
>    mm, CMA: clean-up log message
>
>   arch/arm/mm/dma-mapping.c            |    1 +
>   arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
>   arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
>   arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
>   arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
>   drivers/base/Kconfig                 |   10 -
>   drivers/base/dma-contiguous.c        |  210 ++-------------------
>   include/linux/cma.h                  |   21 +++
>   include/linux/dma-contiguous.h       |   11 +-
>   mm/Kconfig                           |   11 ++
>   mm/Makefile                          |    1 +
>   mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
>   12 files changed, 397 insertions(+), 493 deletions(-)
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
>   create mode 100644 include/linux/cma.h
>   create mode 100644 mm/cma.c
>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> v3:
>    - Simplify old patch 1(log format fix) and move it to the end of patchset.
>    - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
>    - Patch 5: Add some accessor functions to pass aligned base and size to
>    dma_contiguous_early_fixup() function
>    - Patch 5: Move MAX_CMA_AREAS definition to cma.h
>    - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
>    - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
>    - Remaining minor fixes are noted in commit description of each one
>
> v2:
>    - Although this patchset looks very different with v1, the end result,
>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>
> This patchset is based on linux-next 20140610.

Thanks for taking care of this. I will test it with my setup and if
everything goes well, I will take it to my -next tree. If any branch
is required for anyone to continue his works on top of those patches,
let me know, I will also prepare it.

> Patch 1-4 prepare some features to cover PPC KVM's requirements.
> Patch 5-6 generalize CMA reserved area management code and change users
> to use it.
> Patch 7-9 clean-up minor things.
>
> Joonsoo Kim (9):
>    DMA, CMA: fix possible memory leak
>    DMA, CMA: separate core CMA management codes from DMA APIs
>    DMA, CMA: support alignment constraint on CMA region
>    DMA, CMA: support arbitrary bitmap granularity
>    CMA: generalize CMA reserved area management functionality
>    PPC, KVM, CMA: use general CMA reserved area management framework
>    mm, CMA: clean-up CMA allocation error path
>    mm, CMA: change cma_declare_contiguous() to obey coding convention
>    mm, CMA: clean-up log message
>
>   arch/arm/mm/dma-mapping.c            |    1 +
>   arch/powerpc/kvm/book3s_64_mmu_hv.c  |    4 +-
>   arch/powerpc/kvm/book3s_hv_builtin.c |   19 +-
>   arch/powerpc/kvm/book3s_hv_cma.c     |  240 ------------------------
>   arch/powerpc/kvm/book3s_hv_cma.h     |   27 ---
>   drivers/base/Kconfig                 |   10 -
>   drivers/base/dma-contiguous.c        |  210 ++-------------------
>   include/linux/cma.h                  |   21 +++
>   include/linux/dma-contiguous.h       |   11 +-
>   mm/Kconfig                           |   11 ++
>   mm/Makefile                          |    1 +
>   mm/cma.c                             |  335 ++++++++++++++++++++++++++++++++++
>   12 files changed, 397 insertions(+), 493 deletions(-)
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.c
>   delete mode 100644 arch/powerpc/kvm/book3s_hv_cma.h
>   create mode 100644 include/linux/cma.h
>   create mode 100644 mm/cma.c
>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 11:11:35AM +0200, Marek Szyprowski wrote:
> Hello,
> 
> On 2014-06-16 07:40, Joonsoo Kim wrote:
> >Currently, there are two users on CMA functionality, one is the DMA
> >subsystem and the other is the KVM on powerpc. They have their own code
> >to manage CMA reserved area even if they looks really similar.
> >>From my guess, it is caused by some needs on bitmap management. Kvm side
> >wants to maintain bitmap not for 1 page, but for more size. Eventually it
> >use bitmap where one bit represents 64 pages.
> >
> >When I implement CMA related patches, I should change those two places
> >to apply my change and it seem to be painful to me. I want to change
> >this situation and reduce future code management overhead through
> >this patch.
> >
> >This change could also help developer who want to use CMA in their
> >new feature development, since they can use CMA easily without
> >copying & pasting this reserved area management code.
> >
> >v3:
> >   - Simplify old patch 1(log format fix) and move it to the end of patchset.
> >   - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
> >   - Patch 5: Add some accessor functions to pass aligned base and size to
> >   dma_contiguous_early_fixup() function
> >   - Patch 5: Move MAX_CMA_AREAS definition to cma.h
> >   - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
> >   - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
> >   - Remaining minor fixes are noted in commit description of each one
> >
> >v2:
> >   - Although this patchset looks very different with v1, the end result,
> >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> >
> >This patchset is based on linux-next 20140610.
> 
> Thanks for taking care of this. I will test it with my setup and if
> everything goes well, I will take it to my -next tree. If any branch
> is required for anyone to continue his works on top of those patches,
> let me know, I will also prepare it.

Hello,

I'm glad to hear that. :)
But, there is one concern. As you already know, I am preparing further
patches (Aggressively allocate the pages on CMA reserved memory). It
may be highly related to MM branch and also slightly depends on this CMA
changes. In this case, what is the best strategy to merge this
patchset? IMHO, Anrew's tree is more appropriate branch. If there is
no issue in this case, I am willing to develope further patches based
on your tree.

Thanks.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 11:11:35AM +0200, Marek Szyprowski wrote:
> Hello,
> 
> On 2014-06-16 07:40, Joonsoo Kim wrote:
> >Currently, there are two users on CMA functionality, one is the DMA
> >subsystem and the other is the KVM on powerpc. They have their own code
> >to manage CMA reserved area even if they looks really similar.
> >>From my guess, it is caused by some needs on bitmap management. Kvm side
> >wants to maintain bitmap not for 1 page, but for more size. Eventually it
> >use bitmap where one bit represents 64 pages.
> >
> >When I implement CMA related patches, I should change those two places
> >to apply my change and it seem to be painful to me. I want to change
> >this situation and reduce future code management overhead through
> >this patch.
> >
> >This change could also help developer who want to use CMA in their
> >new feature development, since they can use CMA easily without
> >copying & pasting this reserved area management code.
> >
> >v3:
> >   - Simplify old patch 1(log format fix) and move it to the end of patchset.
> >   - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
> >   - Patch 5: Add some accessor functions to pass aligned base and size to
> >   dma_contiguous_early_fixup() function
> >   - Patch 5: Move MAX_CMA_AREAS definition to cma.h
> >   - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
> >   - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
> >   - Remaining minor fixes are noted in commit description of each one
> >
> >v2:
> >   - Although this patchset looks very different with v1, the end result,
> >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> >
> >This patchset is based on linux-next 20140610.
> 
> Thanks for taking care of this. I will test it with my setup and if
> everything goes well, I will take it to my -next tree. If any branch
> is required for anyone to continue his works on top of those patches,
> let me know, I will also prepare it.

Hello,

I'm glad to hear that. :)
But, there is one concern. As you already know, I am preparing further
patches (Aggressively allocate the pages on CMA reserved memory). It
may be highly related to MM branch and also slightly depends on this CMA
changes. In this case, what is the best strategy to merge this
patchset? IMHO, Anrew's tree is more appropriate branch. If there is
no issue in this case, I am willing to develope further patches based
on your tree.

Thanks.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 11:11:35AM +0200, Marek Szyprowski wrote:
> Hello,
> 
> On 2014-06-16 07:40, Joonsoo Kim wrote:
> >Currently, there are two users on CMA functionality, one is the DMA
> >subsystem and the other is the KVM on powerpc. They have their own code
> >to manage CMA reserved area even if they looks really similar.
> >>From my guess, it is caused by some needs on bitmap management. Kvm side
> >wants to maintain bitmap not for 1 page, but for more size. Eventually it
> >use bitmap where one bit represents 64 pages.
> >
> >When I implement CMA related patches, I should change those two places
> >to apply my change and it seem to be painful to me. I want to change
> >this situation and reduce future code management overhead through
> >this patch.
> >
> >This change could also help developer who want to use CMA in their
> >new feature development, since they can use CMA easily without
> >copying & pasting this reserved area management code.
> >
> >v3:
> >   - Simplify old patch 1(log format fix) and move it to the end of patchset.
> >   - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
> >   - Patch 5: Add some accessor functions to pass aligned base and size to
> >   dma_contiguous_early_fixup() function
> >   - Patch 5: Move MAX_CMA_AREAS definition to cma.h
> >   - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
> >   - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
> >   - Remaining minor fixes are noted in commit description of each one
> >
> >v2:
> >   - Although this patchset looks very different with v1, the end result,
> >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> >
> >This patchset is based on linux-next 20140610.
> 
> Thanks for taking care of this. I will test it with my setup and if
> everything goes well, I will take it to my -next tree. If any branch
> is required for anyone to continue his works on top of those patches,
> let me know, I will also prepare it.

Hello,

I'm glad to hear that. :)
But, there is one concern. As you already know, I am preparing further
patches (Aggressively allocate the pages on CMA reserved memory). It
may be highly related to MM branch and also slightly depends on this CMA
changes. In this case, what is the best strategy to merge this
patchset? IMHO, Anrew's tree is more appropriate branch. If there is
no issue in this case, I am willing to develope further patches based
on your tree.

Thanks.

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 11:11:35AM +0200, Marek Szyprowski wrote:
> Hello,
> 
> On 2014-06-16 07:40, Joonsoo Kim wrote:
> >Currently, there are two users on CMA functionality, one is the DMA
> >subsystem and the other is the KVM on powerpc. They have their own code
> >to manage CMA reserved area even if they looks really similar.
> >>From my guess, it is caused by some needs on bitmap management. Kvm side
> >wants to maintain bitmap not for 1 page, but for more size. Eventually it
> >use bitmap where one bit represents 64 pages.
> >
> >When I implement CMA related patches, I should change those two places
> >to apply my change and it seem to be painful to me. I want to change
> >this situation and reduce future code management overhead through
> >this patch.
> >
> >This change could also help developer who want to use CMA in their
> >new feature development, since they can use CMA easily without
> >copying & pasting this reserved area management code.
> >
> >v3:
> >   - Simplify old patch 1(log format fix) and move it to the end of patchset.
> >   - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
> >   - Patch 5: Add some accessor functions to pass aligned base and size to
> >   dma_contiguous_early_fixup() function
> >   - Patch 5: Move MAX_CMA_AREAS definition to cma.h
> >   - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
> >   - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
> >   - Remaining minor fixes are noted in commit description of each one
> >
> >v2:
> >   - Although this patchset looks very different with v1, the end result,
> >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> >
> >This patchset is based on linux-next 20140610.
> 
> Thanks for taking care of this. I will test it with my setup and if
> everything goes well, I will take it to my -next tree. If any branch
> is required for anyone to continue his works on top of those patches,
> let me know, I will also prepare it.

Hello,

I'm glad to hear that. :)
But, there is one concern. As you already know, I am preparing further
patches (Aggressively allocate the pages on CMA reserved memory). It
may be highly related to MM branch and also slightly depends on this CMA
changes. In this case, what is the best strategy to merge this
patchset? IMHO, Anrew's tree is more appropriate branch. If there is
no issue in this case, I am willing to develope further patches based
on your tree.

Thanks.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 11:11:35AM +0200, Marek Szyprowski wrote:
> Hello,
> 
> On 2014-06-16 07:40, Joonsoo Kim wrote:
> >Currently, there are two users on CMA functionality, one is the DMA
> >subsystem and the other is the KVM on powerpc. They have their own code
> >to manage CMA reserved area even if they looks really similar.
> >>From my guess, it is caused by some needs on bitmap management. Kvm side
> >wants to maintain bitmap not for 1 page, but for more size. Eventually it
> >use bitmap where one bit represents 64 pages.
> >
> >When I implement CMA related patches, I should change those two places
> >to apply my change and it seem to be painful to me. I want to change
> >this situation and reduce future code management overhead through
> >this patch.
> >
> >This change could also help developer who want to use CMA in their
> >new feature development, since they can use CMA easily without
> >copying & pasting this reserved area management code.
> >
> >v3:
> >   - Simplify old patch 1(log format fix) and move it to the end of patchset.
> >   - Patch 2: Pass aligned base and size to dma_contiguous_early_fixup()
> >   - Patch 5: Add some accessor functions to pass aligned base and size to
> >   dma_contiguous_early_fixup() function
> >   - Patch 5: Move MAX_CMA_AREAS definition to cma.h
> >   - Patch 6: Add CMA region zeroing to PPC KVM's CMA alloc function
> >   - Patch 8: put 'base' ahead of 'size' in cma_declare_contiguous()
> >   - Remaining minor fixes are noted in commit description of each one
> >
> >v2:
> >   - Although this patchset looks very different with v1, the end result,
> >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> >
> >This patchset is based on linux-next 20140610.
> 
> Thanks for taking care of this. I will test it with my setup and if
> everything goes well, I will take it to my -next tree. If any branch
> is required for anyone to continue his works on top of those patches,
> let me know, I will also prepare it.

Hello,

I'm glad to hear that. :)
But, there is one concern. As you already know, I am preparing further
patches (Aggressively allocate the pages on CMA reserved memory). It
may be highly related to MM branch and also slightly depends on this CMA
changes. In this case, what is the best strategy to merge this
patchset? IMHO, Anrew's tree is more appropriate branch. If there is
no issue in this case, I am willing to develope further patches based
on your tree.

Thanks.

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 03:27:19PM +0900, Minchan Kim wrote:
> Hi, Joonsoo
> 
> On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> > We should free memory for bitmap when we find zone mis-match,
> > otherwise this memory will leak.
> > 
> > Additionally, I copy code comment from PPC KVM's CMA code to inform
> > why we need to check zone mis-match.
> > 
> > * Note
> > Minchan suggested to add a tag for the stable, but, I don't do it,
> > because I found this possibility during code-review and, IMO,
> > this patch isn't suitable for stable tree.
> 
> Nice idea to put the comment in here. Thanks Joonsoo.
> 
> It seems you obey "It must fix a real bug that bothers people"
> on Documentation/stable_kernel_rules.txt but it's a really obvious
> bug and hard to get a report from people because limited user and
> hard to detect small such small memory leak.
> 
> In my experince, Andrew perfered stable marking for such a obvious
> problem but simple fix like this but not sure so let's pass the decision
> to him and will learn a lesson from him and will follow the decision
> from now on.

Yes, I intended to pass the decision to others. :)

> 
> Thanks.
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

Thanks.

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 03:27:19PM +0900, Minchan Kim wrote:
> Hi, Joonsoo
> 
> On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> > We should free memory for bitmap when we find zone mis-match,
> > otherwise this memory will leak.
> > 
> > Additionally, I copy code comment from PPC KVM's CMA code to inform
> > why we need to check zone mis-match.
> > 
> > * Note
> > Minchan suggested to add a tag for the stable, but, I don't do it,
> > because I found this possibility during code-review and, IMO,
> > this patch isn't suitable for stable tree.
> 
> Nice idea to put the comment in here. Thanks Joonsoo.
> 
> It seems you obey "It must fix a real bug that bothers people"
> on Documentation/stable_kernel_rules.txt but it's a really obvious
> bug and hard to get a report from people because limited user and
> hard to detect small such small memory leak.
> 
> In my experince, Andrew perfered stable marking for such a obvious
> problem but simple fix like this but not sure so let's pass the decision
> to him and will learn a lesson from him and will follow the decision
> from now on.

Yes, I intended to pass the decision to others. :)

> 
> Thanks.
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

Thanks.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 03:27:19PM +0900, Minchan Kim wrote:
> Hi, Joonsoo
> 
> On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> > We should free memory for bitmap when we find zone mis-match,
> > otherwise this memory will leak.
> > 
> > Additionally, I copy code comment from PPC KVM's CMA code to inform
> > why we need to check zone mis-match.
> > 
> > * Note
> > Minchan suggested to add a tag for the stable, but, I don't do it,
> > because I found this possibility during code-review and, IMO,
> > this patch isn't suitable for stable tree.
> 
> Nice idea to put the comment in here. Thanks Joonsoo.
> 
> It seems you obey "It must fix a real bug that bothers people"
> on Documentation/stable_kernel_rules.txt but it's a really obvious
> bug and hard to get a report from people because limited user and
> hard to detect small such small memory leak.
> 
> In my experince, Andrew perfered stable marking for such a obvious
> problem but simple fix like this but not sure so let's pass the decision
> to him and will learn a lesson from him and will follow the decision
> from now on.

Yes, I intended to pass the decision to others. :)

> 
> Thanks.
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

Thanks.

[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 03:27:19PM +0900, Minchan Kim wrote:
> Hi, Joonsoo
> 
> On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> > We should free memory for bitmap when we find zone mis-match,
> > otherwise this memory will leak.
> > 
> > Additionally, I copy code comment from PPC KVM's CMA code to inform
> > why we need to check zone mis-match.
> > 
> > * Note
> > Minchan suggested to add a tag for the stable, but, I don't do it,
> > because I found this possibility during code-review and, IMO,
> > this patch isn't suitable for stable tree.
> 
> Nice idea to put the comment in here. Thanks Joonsoo.
> 
> It seems you obey "It must fix a real bug that bothers people"
> on Documentation/stable_kernel_rules.txt but it's a really obvious
> bug and hard to get a report from people because limited user and
> hard to detect small such small memory leak.
> 
> In my experince, Andrew perfered stable marking for such a obvious
> problem but simple fix like this but not sure so let's pass the decision
> to him and will learn a lesson from him and will follow the decision
> from now on.

Yes, I intended to pass the decision to others. :)

> 
> Thanks.
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

Thanks.

Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

[Joonsoo Kim]

On Mon, Jun 16, 2014 at 03:27:19PM +0900, Minchan Kim wrote:
> Hi, Joonsoo
> 
> On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
> > We should free memory for bitmap when we find zone mis-match,
> > otherwise this memory will leak.
> > 
> > Additionally, I copy code comment from PPC KVM's CMA code to inform
> > why we need to check zone mis-match.
> > 
> > * Note
> > Minchan suggested to add a tag for the stable, but, I don't do it,
> > because I found this possibility during code-review and, IMO,
> > this patch isn't suitable for stable tree.
> 
> Nice idea to put the comment in here. Thanks Joonsoo.
> 
> It seems you obey "It must fix a real bug that bothers people"
> on Documentation/stable_kernel_rules.txt but it's a really obvious
> bug and hard to get a report from people because limited user and
> hard to detect small such small memory leak.
> 
> In my experince, Andrew perfered stable marking for such a obvious
> problem but simple fix like this but not sure so let's pass the decision
> to him and will learn a lesson from him and will follow the decision
> from now on.

Yes, I intended to pass the decision to others. :)

> 
> Thanks.
> 
> Acked-by: Minchan Kim <minchan@kernel.org>

Thanks.

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Andrew Morton]

On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> PPC KVM's CMA area management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
> 
> ...
>
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
>  	unsigned long	base_pfn;
>  	unsigned long	count;
>  	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
>  	struct mutex	lock;
>  };
>  
> @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>  
>  static DEFINE_MUTEX(cma_mutex);
>  
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}

Might want a "1UL << ..." here.

> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}

Ditto.  I'm not really sure what the compiler will do in these cases,
but would prefer not to rely on it anyway!


--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix
+++ a/drivers/base/dma-contiguous.c
@@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex);
 
 static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
 {
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
+	return (1UL << (align_order >> cma->order_per_bit)) - 1;
 }
 
 static unsigned long cma_bitmap_maxno(struct cma *cma)
@@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st
 static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
 						unsigned long pages)
 {
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
 }
 
 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
_

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Andrew Morton]

On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> PPC KVM's CMA area management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
> 
> ...
>
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
>  	unsigned long	base_pfn;
>  	unsigned long	count;
>  	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
>  	struct mutex	lock;
>  };
>  
> @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>  
>  static DEFINE_MUTEX(cma_mutex);
>  
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}

Might want a "1UL << ..." here.

> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}

Ditto.  I'm not really sure what the compiler will do in these cases,
but would prefer not to rely on it anyway!


--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix
+++ a/drivers/base/dma-contiguous.c
@@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex);
 
 static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
 {
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
+	return (1UL << (align_order >> cma->order_per_bit)) - 1;
 }
 
 static unsigned long cma_bitmap_maxno(struct cma *cma)
@@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st
 static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
 						unsigned long pages)
 {
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
 }
 
 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
_

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Andrew Morton]

On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> PPC KVM's CMA area management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
> 
> ...
>
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
>  	unsigned long	base_pfn;
>  	unsigned long	count;
>  	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
>  	struct mutex	lock;
>  };
>  
> @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>  
>  static DEFINE_MUTEX(cma_mutex);
>  
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}

Might want a "1UL << ..." here.

> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}

Ditto.  I'm not really sure what the compiler will do in these cases,
but would prefer not to rely on it anyway!


--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix
+++ a/drivers/base/dma-contiguous.c
@@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex);
 
 static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
 {
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
+	return (1UL << (align_order >> cma->order_per_bit)) - 1;
 }
 
 static unsigned long cma_bitmap_maxno(struct cma *cma)
@@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st
 static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
 						unsigned long pages)
 {
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
 }
 
 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
_

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Andrew Morton]

On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> PPC KVM's CMA area management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
> 
> ...
>
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
>  	unsigned long	base_pfn;
>  	unsigned long	count;
>  	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
>  	struct mutex	lock;
>  };
>  
> @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>  
>  static DEFINE_MUTEX(cma_mutex);
>  
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}

Might want a "1UL << ..." here.

> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}

Ditto.  I'm not really sure what the compiler will do in these cases,
but would prefer not to rely on it anyway!


--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix
+++ a/drivers/base/dma-contiguous.c
@@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex);
 
 static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
 {
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
+	return (1UL << (align_order >> cma->order_per_bit)) - 1;
 }
 
 static unsigned long cma_bitmap_maxno(struct cma *cma)
@@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st
 static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
 						unsigned long pages)
 {
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
 }
 
 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
_

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Andrew Morton]

On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> PPC KVM's CMA area management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
> 
> ...
>
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
>  	unsigned long	base_pfn;
>  	unsigned long	count;
>  	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
>  	struct mutex	lock;
>  };
>  
> @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>  
>  static DEFINE_MUTEX(cma_mutex);
>  
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}

Might want a "1UL << ..." here.

> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}

Ditto.  I'm not really sure what the compiler will do in these cases,
but would prefer not to rely on it anyway!


--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix
+++ a/drivers/base/dma-contiguous.c
@@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex);
 
 static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
 {
-	return (1 << (align_order >> cma->order_per_bit)) - 1;
+	return (1UL << (align_order >> cma->order_per_bit)) - 1;
 }
 
 static unsigned long cma_bitmap_maxno(struct cma *cma)
@@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st
 static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
 						unsigned long pages)
 {
-	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
 }
 
 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
_

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> > >v2:
> > >   - Although this patchset looks very different with v1, the end result,
> > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > >
> > >This patchset is based on linux-next 20140610.
> > 
> > Thanks for taking care of this. I will test it with my setup and if
> > everything goes well, I will take it to my -next tree. If any branch
> > is required for anyone to continue his works on top of those patches,
> > let me know, I will also prepare it.
> 
> Hello,
> 
> I'm glad to hear that. :)
> But, there is one concern. As you already know, I am preparing further
> patches (Aggressively allocate the pages on CMA reserved memory). It
> may be highly related to MM branch and also slightly depends on this CMA
> changes. In this case, what is the best strategy to merge this
> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> no issue in this case, I am willing to develope further patches based
> on your tree.

That's probably easier.  Marek, I'll merge these into -mm (and hence
-next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
and shall hold them pending you review/ack/test/etc, OK?

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> > >v2:
> > >   - Although this patchset looks very different with v1, the end result,
> > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > >
> > >This patchset is based on linux-next 20140610.
> > 
> > Thanks for taking care of this. I will test it with my setup and if
> > everything goes well, I will take it to my -next tree. If any branch
> > is required for anyone to continue his works on top of those patches,
> > let me know, I will also prepare it.
> 
> Hello,
> 
> I'm glad to hear that. :)
> But, there is one concern. As you already know, I am preparing further
> patches (Aggressively allocate the pages on CMA reserved memory). It
> may be highly related to MM branch and also slightly depends on this CMA
> changes. In this case, what is the best strategy to merge this
> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> no issue in this case, I am willing to develope further patches based
> on your tree.

That's probably easier.  Marek, I'll merge these into -mm (and hence
-next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
and shall hold them pending you review/ack/test/etc, OK?

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> > >v2:
> > >   - Although this patchset looks very different with v1, the end result,
> > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > >
> > >This patchset is based on linux-next 20140610.
> > 
> > Thanks for taking care of this. I will test it with my setup and if
> > everything goes well, I will take it to my -next tree. If any branch
> > is required for anyone to continue his works on top of those patches,
> > let me know, I will also prepare it.
> 
> Hello,
> 
> I'm glad to hear that. :)
> But, there is one concern. As you already know, I am preparing further
> patches (Aggressively allocate the pages on CMA reserved memory). It
> may be highly related to MM branch and also slightly depends on this CMA
> changes. In this case, what is the best strategy to merge this
> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> no issue in this case, I am willing to develope further patches based
> on your tree.

That's probably easier.  Marek, I'll merge these into -mm (and hence
-next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
and shall hold them pending you review/ack/test/etc, OK?

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> > >v2:
> > >   - Although this patchset looks very different with v1, the end result,
> > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > >
> > >This patchset is based on linux-next 20140610.
> > 
> > Thanks for taking care of this. I will test it with my setup and if
> > everything goes well, I will take it to my -next tree. If any branch
> > is required for anyone to continue his works on top of those patches,
> > let me know, I will also prepare it.
> 
> Hello,
> 
> I'm glad to hear that. :)
> But, there is one concern. As you already know, I am preparing further
> patches (Aggressively allocate the pages on CMA reserved memory). It
> may be highly related to MM branch and also slightly depends on this CMA
> changes. In this case, what is the best strategy to merge this
> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> no issue in this case, I am willing to develope further patches based
> on your tree.

That's probably easier.  Marek, I'll merge these into -mm (and hence
-next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
and shall hold them pending you review/ack/test/etc, OK?

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> > >v2:
> > >   - Although this patchset looks very different with v1, the end result,
> > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > >
> > >This patchset is based on linux-next 20140610.
> > 
> > Thanks for taking care of this. I will test it with my setup and if
> > everything goes well, I will take it to my -next tree. If any branch
> > is required for anyone to continue his works on top of those patches,
> > let me know, I will also prepare it.
> 
> Hello,
> 
> I'm glad to hear that. :)
> But, there is one concern. As you already know, I am preparing further
> patches (Aggressively allocate the pages on CMA reserved memory). It
> may be highly related to MM branch and also slightly depends on this CMA
> changes. In this case, what is the best strategy to merge this
> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> no issue in this case, I am willing to develope further patches based
> on your tree.

That's probably easier.  Marek, I'll merge these into -mm (and hence
-next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
and shall hold them pending you review/ack/test/etc, OK?

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote:
> On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > PPC KVM's CMA area management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> > 
> > ...
> >
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> >  	unsigned long	base_pfn;
> >  	unsigned long	count;
> >  	unsigned long	*bitmap;
> > +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> >  	struct mutex	lock;
> >  };
> >  
> > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >  
> >  static DEFINE_MUTEX(cma_mutex);
> >  
> > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> > +{
> > +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> > +}
> 
> Might want a "1UL << ..." here.

Okay!

> 
> > +static unsigned long cma_bitmap_maxno(struct cma *cma)
> > +{
> > +	return cma->count >> cma->order_per_bit;
> > +}
> > +
> > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> > +						unsigned long pages)
> > +{
> > +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> > +}
> 
> Ditto.  I'm not really sure what the compiler will do in these cases,
> but would prefer not to rely on it anyway!

Okay!

Thanks for fix!

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote:
> On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > PPC KVM's CMA area management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> > 
> > ...
> >
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> >  	unsigned long	base_pfn;
> >  	unsigned long	count;
> >  	unsigned long	*bitmap;
> > +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> >  	struct mutex	lock;
> >  };
> >  
> > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >  
> >  static DEFINE_MUTEX(cma_mutex);
> >  
> > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> > +{
> > +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> > +}
> 
> Might want a "1UL << ..." here.

Okay!

> 
> > +static unsigned long cma_bitmap_maxno(struct cma *cma)
> > +{
> > +	return cma->count >> cma->order_per_bit;
> > +}
> > +
> > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> > +						unsigned long pages)
> > +{
> > +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> > +}
> 
> Ditto.  I'm not really sure what the compiler will do in these cases,
> but would prefer not to rely on it anyway!

Okay!

Thanks for fix!

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote:
> On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > PPC KVM's CMA area management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> > 
> > ...
> >
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> >  	unsigned long	base_pfn;
> >  	unsigned long	count;
> >  	unsigned long	*bitmap;
> > +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> >  	struct mutex	lock;
> >  };
> >  
> > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >  
> >  static DEFINE_MUTEX(cma_mutex);
> >  
> > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> > +{
> > +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> > +}
> 
> Might want a "1UL << ..." here.

Okay!

> 
> > +static unsigned long cma_bitmap_maxno(struct cma *cma)
> > +{
> > +	return cma->count >> cma->order_per_bit;
> > +}
> > +
> > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> > +						unsigned long pages)
> > +{
> > +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> > +}
> 
> Ditto.  I'm not really sure what the compiler will do in these cases,
> but would prefer not to rely on it anyway!

Okay!

Thanks for fix!

[PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote:
> On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > PPC KVM's CMA area management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> > 
> > ...
> >
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> >  	unsigned long	base_pfn;
> >  	unsigned long	count;
> >  	unsigned long	*bitmap;
> > +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> >  	struct mutex	lock;
> >  };
> >  
> > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >  
> >  static DEFINE_MUTEX(cma_mutex);
> >  
> > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> > +{
> > +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> > +}
> 
> Might want a "1UL << ..." here.

Okay!

> 
> > +static unsigned long cma_bitmap_maxno(struct cma *cma)
> > +{
> > +	return cma->count >> cma->order_per_bit;
> > +}
> > +
> > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> > +						unsigned long pages)
> > +{
> > +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> > +}
> 
> Ditto.  I'm not really sure what the compiler will do in these cases,
> but would prefer not to rely on it anyway!

Okay!

Thanks for fix!

Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote:
> On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > PPC KVM's CMA area management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> > 
> > ...
> >
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> >  	unsigned long	base_pfn;
> >  	unsigned long	count;
> >  	unsigned long	*bitmap;
> > +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> >  	struct mutex	lock;
> >  };
> >  
> > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >  
> >  static DEFINE_MUTEX(cma_mutex);
> >  
> > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> > +{
> > +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> > +}
> 
> Might want a "1UL << ..." here.

Okay!

> 
> > +static unsigned long cma_bitmap_maxno(struct cma *cma)
> > +{
> > +	return cma->count >> cma->order_per_bit;
> > +}
> > +
> > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> > +						unsigned long pages)
> > +{
> > +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> > +}
> 
> Ditto.  I'm not really sure what the compiler will do in these cases,
> but would prefer not to rely on it anyway!

Okay!

Thanks for fix!

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:51:44PM -0700, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > > >v2:
> > > >   - Although this patchset looks very different with v1, the end result,
> > > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > > >
> > > >This patchset is based on linux-next 20140610.
> > > 
> > > Thanks for taking care of this. I will test it with my setup and if
> > > everything goes well, I will take it to my -next tree. If any branch
> > > is required for anyone to continue his works on top of those patches,
> > > let me know, I will also prepare it.
> > 
> > Hello,
> > 
> > I'm glad to hear that. :)
> > But, there is one concern. As you already know, I am preparing further
> > patches (Aggressively allocate the pages on CMA reserved memory). It
> > may be highly related to MM branch and also slightly depends on this CMA
> > changes. In this case, what is the best strategy to merge this
> > patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> > no issue in this case, I am willing to develope further patches based
> > on your tree.
> 
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Hello, Marek.

Could you share your decision about this patchset?

Thanks.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:51:44PM -0700, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > > >v2:
> > > >   - Although this patchset looks very different with v1, the end result,
> > > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > > >
> > > >This patchset is based on linux-next 20140610.
> > > 
> > > Thanks for taking care of this. I will test it with my setup and if
> > > everything goes well, I will take it to my -next tree. If any branch
> > > is required for anyone to continue his works on top of those patches,
> > > let me know, I will also prepare it.
> > 
> > Hello,
> > 
> > I'm glad to hear that. :)
> > But, there is one concern. As you already know, I am preparing further
> > patches (Aggressively allocate the pages on CMA reserved memory). It
> > may be highly related to MM branch and also slightly depends on this CMA
> > changes. In this case, what is the best strategy to merge this
> > patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> > no issue in this case, I am willing to develope further patches based
> > on your tree.
> 
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Hello, Marek.

Could you share your decision about this patchset?

Thanks.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:51:44PM -0700, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > > >v2:
> > > >   - Although this patchset looks very different with v1, the end result,
> > > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > > >
> > > >This patchset is based on linux-next 20140610.
> > > 
> > > Thanks for taking care of this. I will test it with my setup and if
> > > everything goes well, I will take it to my -next tree. If any branch
> > > is required for anyone to continue his works on top of those patches,
> > > let me know, I will also prepare it.
> > 
> > Hello,
> > 
> > I'm glad to hear that. :)
> > But, there is one concern. As you already know, I am preparing further
> > patches (Aggressively allocate the pages on CMA reserved memory). It
> > may be highly related to MM branch and also slightly depends on this CMA
> > changes. In this case, what is the best strategy to merge this
> > patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> > no issue in this case, I am willing to develope further patches based
> > on your tree.
> 
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Hello, Marek.

Could you share your decision about this patchset?

Thanks.

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:51:44PM -0700, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > > >v2:
> > > >   - Although this patchset looks very different with v1, the end result,
> > > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > > >
> > > >This patchset is based on linux-next 20140610.
> > > 
> > > Thanks for taking care of this. I will test it with my setup and if
> > > everything goes well, I will take it to my -next tree. If any branch
> > > is required for anyone to continue his works on top of those patches,
> > > let me know, I will also prepare it.
> > 
> > Hello,
> > 
> > I'm glad to hear that. :)
> > But, there is one concern. As you already know, I am preparing further
> > patches (Aggressively allocate the pages on CMA reserved memory). It
> > may be highly related to MM branch and also slightly depends on this CMA
> > changes. In this case, what is the best strategy to merge this
> > patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> > no issue in this case, I am willing to develope further patches based
> > on your tree.
> 
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Hello, Marek.

Could you share your decision about this patchset?

Thanks.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Joonsoo Kim]

On Wed, Jun 18, 2014 at 01:51:44PM -0700, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> 
> > > >v2:
> > > >   - Although this patchset looks very different with v1, the end result,
> > > >   that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
> > > >
> > > >This patchset is based on linux-next 20140610.
> > > 
> > > Thanks for taking care of this. I will test it with my setup and if
> > > everything goes well, I will take it to my -next tree. If any branch
> > > is required for anyone to continue his works on top of those patches,
> > > let me know, I will also prepare it.
> > 
> > Hello,
> > 
> > I'm glad to hear that. :)
> > But, there is one concern. As you already know, I am preparing further
> > patches (Aggressively allocate the pages on CMA reserved memory). It
> > may be highly related to MM branch and also slightly depends on this CMA
> > changes. In this case, what is the best strategy to merge this
> > patchset? IMHO, Anrew's tree is more appropriate branch. If there is
> > no issue in this case, I am willing to develope further patches based
> > on your tree.
> 
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Hello, Marek.

Could you share your decision about this patchset?

Thanks.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-18 22:51, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
>>>> v2:
>>>>    - Although this patchset looks very different with v1, the end result,
>>>>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>>>>
>>>> This patchset is based on linux-next 20140610.
>>> Thanks for taking care of this. I will test it with my setup and if
>>> everything goes well, I will take it to my -next tree. If any branch
>>> is required for anyone to continue his works on top of those patches,
>>> let me know, I will also prepare it.
>> Hello,
>>
>> I'm glad to hear that. :)
>> But, there is one concern. As you already know, I am preparing further
>> patches (Aggressively allocate the pages on CMA reserved memory). It
>> may be highly related to MM branch and also slightly depends on this CMA
>> changes. In this case, what is the best strategy to merge this
>> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
>> no issue in this case, I am willing to develope further patches based
>> on your tree.
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Ok. I've tested them and they work fine. I'm sorry that you had to wait for
me for a few days. You can now add:

Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've also rebased my pending patches onto this set (I will send them soon).

The question is now if you want to keep the discussed patches in your 
-mm tree,
or should I take them to my -next branch. If you like to keep them, I assume
you will also take the patches which depends on the discussed changes.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-18 22:51, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
>>>> v2:
>>>>    - Although this patchset looks very different with v1, the end result,
>>>>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>>>>
>>>> This patchset is based on linux-next 20140610.
>>> Thanks for taking care of this. I will test it with my setup and if
>>> everything goes well, I will take it to my -next tree. If any branch
>>> is required for anyone to continue his works on top of those patches,
>>> let me know, I will also prepare it.
>> Hello,
>>
>> I'm glad to hear that. :)
>> But, there is one concern. As you already know, I am preparing further
>> patches (Aggressively allocate the pages on CMA reserved memory). It
>> may be highly related to MM branch and also slightly depends on this CMA
>> changes. In this case, what is the best strategy to merge this
>> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
>> no issue in this case, I am willing to develope further patches based
>> on your tree.
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Ok. I've tested them and they work fine. I'm sorry that you had to wait for
me for a few days. You can now add:

Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've also rebased my pending patches onto this set (I will send them soon).

The question is now if you want to keep the discussed patches in your 
-mm tree,
or should I take them to my -next branch. If you like to keep them, I assume
you will also take the patches which depends on the discussed changes.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-18 22:51, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
>>>> v2:
>>>>    - Although this patchset looks very different with v1, the end result,
>>>>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>>>>
>>>> This patchset is based on linux-next 20140610.
>>> Thanks for taking care of this. I will test it with my setup and if
>>> everything goes well, I will take it to my -next tree. If any branch
>>> is required for anyone to continue his works on top of those patches,
>>> let me know, I will also prepare it.
>> Hello,
>>
>> I'm glad to hear that. :)
>> But, there is one concern. As you already know, I am preparing further
>> patches (Aggressively allocate the pages on CMA reserved memory). It
>> may be highly related to MM branch and also slightly depends on this CMA
>> changes. In this case, what is the best strategy to merge this
>> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
>> no issue in this case, I am willing to develope further patches based
>> on your tree.
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Ok. I've tested them and they work fine. I'm sorry that you had to wait for
me for a few days. You can now add:

Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've also rebased my pending patches onto this set (I will send them soon).

The question is now if you want to keep the discussed patches in your 
-mm tree,
or should I take them to my -next branch. If you like to keep them, I assume
you will also take the patches which depends on the discussed changes.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-18 22:51, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
>>>> v2:
>>>>    - Although this patchset looks very different with v1, the end result,
>>>>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>>>>
>>>> This patchset is based on linux-next 20140610.
>>> Thanks for taking care of this. I will test it with my setup and if
>>> everything goes well, I will take it to my -next tree. If any branch
>>> is required for anyone to continue his works on top of those patches,
>>> let me know, I will also prepare it.
>> Hello,
>>
>> I'm glad to hear that. :)
>> But, there is one concern. As you already know, I am preparing further
>> patches (Aggressively allocate the pages on CMA reserved memory). It
>> may be highly related to MM branch and also slightly depends on this CMA
>> changes. In this case, what is the best strategy to merge this
>> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
>> no issue in this case, I am willing to develope further patches based
>> on your tree.
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Ok. I've tested them and they work fine. I'm sorry that you had to wait for
me for a few days. You can now add:

Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've also rebased my pending patches onto this set (I will send them soon).

The question is now if you want to keep the discussed patches in your 
-mm tree,
or should I take them to my -next branch. If you like to keep them, I assume
you will also take the patches which depends on the discussed changes.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Marek Szyprowski]

Hello,

On 2014-06-18 22:51, Andrew Morton wrote:
> On Tue, 17 Jun 2014 10:25:07 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
>>>> v2:
>>>>    - Although this patchset looks very different with v1, the end result,
>>>>    that is, mm/cma.c is same with v1's one. So I carry Ack to patch 6-7.
>>>>
>>>> This patchset is based on linux-next 20140610.
>>> Thanks for taking care of this. I will test it with my setup and if
>>> everything goes well, I will take it to my -next tree. If any branch
>>> is required for anyone to continue his works on top of those patches,
>>> let me know, I will also prepare it.
>> Hello,
>>
>> I'm glad to hear that. :)
>> But, there is one concern. As you already know, I am preparing further
>> patches (Aggressively allocate the pages on CMA reserved memory). It
>> may be highly related to MM branch and also slightly depends on this CMA
>> changes. In this case, what is the best strategy to merge this
>> patchset? IMHO, Anrew's tree is more appropriate branch. If there is
>> no issue in this case, I am willing to develope further patches based
>> on your tree.
> That's probably easier.  Marek, I'll merge these into -mm (and hence
> -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> and shall hold them pending you review/ack/test/etc, OK?

Ok. I've tested them and they work fine. I'm sorry that you had to wait for
me for a few days. You can now add:

Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

I've also rebased my pending patches onto this set (I will send them soon).

The question is now if you want to keep the discussed patches in your 
-mm tree,
or should I take them to my -next branch. If you like to keep them, I assume
you will also take the patches which depends on the discussed changes.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Wed, 25 Jun 2014 14:33:56 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> > That's probably easier.  Marek, I'll merge these into -mm (and hence
> > -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> > and shall hold them pending you review/ack/test/etc, OK?
> 
> Ok. I've tested them and they work fine. I'm sorry that you had to wait for
> me for a few days. You can now add:
> 
> Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thanks.

> I've also rebased my pending patches onto this set (I will send them soon).
> 
> The question is now if you want to keep the discussed patches in your 
> -mm tree,
> or should I take them to my -next branch. If you like to keep them, I assume
> you will also take the patches which depends on the discussed changes.

Yup, that works.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Wed, 25 Jun 2014 14:33:56 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> > That's probably easier.  Marek, I'll merge these into -mm (and hence
> > -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> > and shall hold them pending you review/ack/test/etc, OK?
> 
> Ok. I've tested them and they work fine. I'm sorry that you had to wait for
> me for a few days. You can now add:
> 
> Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thanks.

> I've also rebased my pending patches onto this set (I will send them soon).
> 
> The question is now if you want to keep the discussed patches in your 
> -mm tree,
> or should I take them to my -next branch. If you like to keep them, I assume
> you will also take the patches which depends on the discussed changes.

Yup, that works.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Wed, 25 Jun 2014 14:33:56 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> > That's probably easier.  Marek, I'll merge these into -mm (and hence
> > -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> > and shall hold them pending you review/ack/test/etc, OK?
> 
> Ok. I've tested them and they work fine. I'm sorry that you had to wait for
> me for a few days. You can now add:
> 
> Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thanks.

> I've also rebased my pending patches onto this set (I will send them soon).
> 
> The question is now if you want to keep the discussed patches in your 
> -mm tree,
> or should I take them to my -next branch. If you like to keep them, I assume
> you will also take the patches which depends on the discussed changes.

Yup, that works.

[PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Wed, 25 Jun 2014 14:33:56 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> > That's probably easier.  Marek, I'll merge these into -mm (and hence
> > -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> > and shall hold them pending you review/ack/test/etc, OK?
> 
> Ok. I've tested them and they work fine. I'm sorry that you had to wait for
> me for a few days. You can now add:
> 
> Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thanks.

> I've also rebased my pending patches onto this set (I will send them soon).
> 
> The question is now if you want to keep the discussed patches in your 
> -mm tree,
> or should I take them to my -next branch. If you like to keep them, I assume
> you will also take the patches which depends on the discussed changes.

Yup, that works.

Re: [PATCH v3 -next 0/9] CMA: generalize CMA reserved area management code

[Andrew Morton]

On Wed, 25 Jun 2014 14:33:56 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> > That's probably easier.  Marek, I'll merge these into -mm (and hence
> > -next and git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
> > and shall hold them pending you review/ack/test/etc, OK?
> 
> Ok. I've tested them and they work fine. I'm sorry that you had to wait for
> me for a few days. You can now add:
> 
> Acked-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thanks.

> I've also rebased my pending patches onto this set (I will send them soon).
> 
> The question is now if you want to keep the discussed patches in your 
> -mm tree,
> or should I take them to my -next branch. If you like to keep them, I assume
> you will also take the patches which depends on the discussed changes.

Yup, that works.

Re: [PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. KVM side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> v3: remove log2.h in dma-contiguous.c (Minchan)
>      add some accessor functions to pass aligned base and size to
>      dma_contiguous_early_fixup() function
>      move MAX_CMA_AREAS to cma.h

I've just noticed that MAX_CMA_AREAS is used also by 
arch/arm/mm/dma-mapping.c,
so we need to provide correct definition if CMA is disabled in kconfig. 
I will
send a fixup patch in a few minutes.

> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4c88935..3116880 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -26,6 +26,7 @@
>   #include <linux/io.h>
>   #include <linux/vmalloc.h>
>   #include <linux/sizes.h>
> +#include <linux/cma.h>
>   
>   #include <asm/memory.h>
>   #include <asm/highmem.h>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>   
>   	  If unsure, leave the default value "8".
>   
> -config CMA_AREAS
> -	int "Maximum count of the CMA device-private areas"
> -	default 7
> -	help
> -	  CMA allows to create CMA areas for particular devices. This parameter
> -	  sets the maximum number of such device private CMA areas in the
> -	  system.
> -
> -	  If unsure, leave the default value "7".
> -
>   endif
>   
>   endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index c6eeb2c..0411c1c 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,9 @@
>   
>   #include <linux/memblock.h>
>   #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
>   #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
>   #include <linux/dma-contiguous.h>
> -#include <linux/log2.h>
> -
> -struct cma {
> -	unsigned long	base_pfn;
> -	unsigned long	count;
> -	unsigned long	*bitmap;
> -	unsigned int order_per_bit; /* Order of pages represented by one bit */
> -	struct mutex	lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>   
>   #ifdef CONFIG_CMA_SIZE_MBYTES
>   #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
>   #define CMA_SIZE_MBYTES 0
>   #endif
>   
> +struct cma *dma_contiguous_default_area;
> +
>   /*
>    * Default global CMA area size can be defined in kernel's .config.
>    * This is useful mainly for distro maintainers to create a kernel
> @@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>   	}
>   }
>   
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> -	return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> -	return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> -						unsigned long pages)
> -{
> -	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> -	unsigned long bitmap_no, bitmap_count;
> -
> -	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	mutex_lock(&cma->lock);
> -	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> -	mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> -	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> -	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> -	unsigned i = cma->count >> pageblock_order;
> -	struct zone *zone;
> -
> -	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> -	if (!cma->bitmap)
> -		return -ENOMEM;
> -
> -	WARN_ON_ONCE(!pfn_valid(pfn));
> -	zone = page_zone(pfn_to_page(pfn));
> -
> -	do {
> -		unsigned j;
> -		base_pfn = pfn;
> -		for (j = pageblock_nr_pages; j; --j, pfn++) {
> -			WARN_ON_ONCE(!pfn_valid(pfn));
> -			/*
> -			 * alloc_contig_range requires the pfn range
> -			 * specified to be in the same zone. Make this
> -			 * simple by forcing the entire CMA resv range
> -			 * to be in the same zone.
> -			 */
> -			if (page_zone(pfn_to_page(pfn)) != zone)
> -				goto err;
> -		}
> -		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> -	} while (--i);
> -
> -	mutex_init(&cma->lock);
> -	return 0;
> -
> -err:
> -	kfree(cma->bitmap);
> -	return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> -	int i;
> -
> -	for (i = 0; i < cma_area_count; i++) {
> -		int ret = cma_activate_area(&cma_areas[i]);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> -			phys_addr_t base, phys_addr_t limit,
> -			phys_addr_t alignment, unsigned int order_per_bit,
> -			struct cma **res_cma, bool fixed)
> -{
> -	struct cma *cma = &cma_areas[cma_area_count];
> -	int ret = 0;
> -
> -	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> -		__func__, (unsigned long)size, (unsigned long)base,
> -		(unsigned long)limit, (unsigned long)alignment);
> -
> -	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> -		pr_err("Not enough slots for CMA reserved regions!\n");
> -		return -ENOSPC;
> -	}
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	if (alignment && !is_power_of_2(alignment))
> -		return -EINVAL;
> -
> -	/*
> -	 * Sanitise input arguments.
> -	 * Pages both ends in CMA area could be merged into adjacent unmovable
> -	 * migratetype page by page allocator's buddy algorithm. In the case,
> -	 * you couldn't get a contiguous memory, which is not what we want.
> -	 */
> -	alignment = max(alignment,
> -		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> -	base = ALIGN(base, alignment);
> -	size = ALIGN(size, alignment);
> -	limit &= ~(alignment - 1);
> -
> -	/* size should be aligned with order_per_bit */
> -	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> -		return -EINVAL;
> -
> -	/* Reserve memory */
> -	if (base && fixed) {
> -		if (memblock_is_region_reserved(base, size) ||
> -		    memblock_reserve(base, size) < 0) {
> -			ret = -EBUSY;
> -			goto err;
> -		}
> -	} else {
> -		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> -							limit);
> -		if (!addr) {
> -			ret = -ENOMEM;
> -			goto err;
> -		} else {
> -			base = addr;
> -		}
> -	}
> -
> -	/*
> -	 * Each reserved area must be initialised later, when more kernel
> -	 * subsystems (like slab allocator) are available.
> -	 */
> -	cma->base_pfn = PFN_DOWN(base);
> -	cma->count = size >> PAGE_SHIFT;
> -	cma->order_per_bit = order_per_bit;
> -	*res_cma = cma;
> -	cma_area_count++;
> -
> -	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> -		(unsigned long)base);
> -	return 0;
> -
> -err:
> -	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> -	return ret;
> -}
> -
>   /**
>    * dma_contiguous_reserve_area() - reserve custom contiguous area
>    * @size: Size of the reserved area (in bytes),
> @@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>   {
>   	int ret;
>   
> -	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> -						res_cma, fixed);
> +	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
>   	if (ret)
>   		return ret;
>   
>   	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
> -				(*res_cma)->count << PAGE_SHIFT);
> +	dma_contiguous_early_fixup(cma_get_base(*res_cma),
> +				cma_get_size(*res_cma));
>   
>   	return 0;
>   }
>   
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> -				       unsigned int align)
> -{
> -	unsigned long mask, pfn, start = 0;
> -	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> -	struct page *page = NULL;
> -	int ret;
> -
> -	if (!cma || !cma->count)
> -		return NULL;
> -
> -	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> -		 count, align);
> -
> -	if (!count)
> -		return NULL;
> -
> -	mask = cma_bitmap_aligned_mask(cma, align);
> -	bitmap_maxno = cma_bitmap_maxno(cma);
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	for (;;) {
> -		mutex_lock(&cma->lock);
> -		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> -				bitmap_maxno, start, bitmap_count, mask);
> -		if (bitmap_no >= bitmap_maxno) {
> -			mutex_unlock(&cma->lock);
> -			break;
> -		}
> -		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> -		/*
> -		 * It's safe to drop the lock here. We've marked this region for
> -		 * our exclusive use. If the migration fails we will take the
> -		 * lock again and unmark it.
> -		 */
> -		mutex_unlock(&cma->lock);
> -
> -		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> -		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> -		mutex_unlock(&cma_mutex);
> -		if (ret == 0) {
> -			page = pfn_to_page(pfn);
> -			break;
> -		} else if (ret != -EBUSY) {
> -			cma_clear_bitmap(cma, pfn, count);
> -			break;
> -		}
> -		cma_clear_bitmap(cma, pfn, count);
> -		pr_debug("%s(): memory range at %p is busy, retrying\n",
> -			 __func__, pfn_to_page(pfn));
> -		/* try again with a bit different memory target */
> -		start = bitmap_no + mask + 1;
> -	}
> -
> -	pr_debug("%s(): returned %p\n", __func__, page);
> -	return page;
> -}
> -
>   /**
>    * dma_alloc_from_contiguous() - allocate pages from contiguous area
>    * @dev:   Pointer to device for which the allocation is performed.
> @@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>   struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   				       unsigned int align)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
>   	if (align > CONFIG_CMA_ALIGNMENT)
>   		align = CONFIG_CMA_ALIGNMENT;
>   
> -	return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> -				 int count)
> -{
> -	unsigned long pfn;
> -
> -	if (!cma || !pages)
> -		return false;
> -
> -	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> -	pfn = page_to_pfn(pages);
> -
> -	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> -		return false;
> -
> -	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> -	free_contig_range(pfn, count);
> -	cma_clear_bitmap(cma, pfn, count);
> -
> -	return true;
> +	return cma_alloc(dev_get_cma_area(dev), count, align);
>   }
>   
>   /**
> @@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>   bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   				 int count)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
> -	return __dma_release_from_contiguous(cma, pages, count);
> +	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..69d3726
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,21 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +
> +struct cma;
> +
> +extern phys_addr_t cma_get_base(struct cma *cma);
> +extern unsigned long cma_get_size(struct cma *cma);
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..569bbd0 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,18 +53,13 @@
>   
>   #ifdef __KERNEL__
>   
> +#include <linux/device.h>
> +
>   struct cma;
>   struct page;
> -struct device;
>   
>   #ifdef CONFIG_DMA_CMA
>   
> -/*
> - * There is always at least global CMA area and a few optional device
> - * private areas configured in kernel .config.
> - */
> -#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> -
>   extern struct cma *dma_contiguous_default_area;
>   
>   static inline struct cma *dev_get_cma_area(struct device *dev)
> @@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   
>   #else
>   
> -#define MAX_CMA_AREAS	(0)
> -
>   static inline struct cma *dev_get_cma_area(struct device *dev)
>   {
>   	return NULL;
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
>   	  processing calls such as dma_alloc_from_contiguous().
>   	  This option does not affect warning and error messages.
>   
> +config CMA_AREAS
> +	int "Maximum count of the CMA areas"
> +	depends on CMA
> +	default 7
> +	help
> +	  CMA allows to create CMA areas for particular purpose, mainly,
> +	  used as device private area. This parameter sets the maximum
> +	  number of CMA area in the system.
> +
> +	  If unsure, leave the default value "7".
> +
>   config ZBUD
>   	tristate
>   	default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
>   obj-$(CONFIG_ZBUD)	+= zbud.o
>   obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
>   obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA)	+= cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..0cf50da
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,333 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + *	Marek Szyprowski <m.szyprowski@samsung.com>
> + *	Michal Nazarewicz <mina86@mina86.com>
> + *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +#  define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +#include <linux/cma.h>
> +
> +struct cma {
> +	unsigned long	base_pfn;
> +	unsigned long	count;
> +	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> +	struct mutex	lock;
> +};
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +phys_addr_t cma_get_base(struct cma *cma)
> +{
> +	return PFN_PHYS(cma->base_pfn);
> +}
> +
> +unsigned long cma_get_size(struct cma *cma)
> +{
> +	return cma->count << PAGE_SHIFT;
> +}
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> +	unsigned long bitmap_no, bitmap_count;
> +
> +	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	mutex_lock(&cma->lock);
> +	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> +	mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> +	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> +	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> +	unsigned i = cma->count >> pageblock_order;
> +	struct zone *zone;
> +
> +	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +
> +	if (!cma->bitmap)
> +		return -ENOMEM;
> +
> +	WARN_ON_ONCE(!pfn_valid(pfn));
> +	zone = page_zone(pfn_to_page(pfn));
> +
> +	do {
> +		unsigned j;
> +
> +		base_pfn = pfn;
> +		for (j = pageblock_nr_pages; j; --j, pfn++) {
> +			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
> +			if (page_zone(pfn_to_page(pfn)) != zone)
> +				goto err;
> +		}
> +		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> +	} while (--i);
> +
> +	mutex_init(&cma->lock);
> +	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < cma_area_count; i++) {
> +		int ret = cma_activate_area(&cma_areas[i]);
> +
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the CMA area, should be power of 2 or zero
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base.  If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed)
> +{
> +	struct cma *cma = &cma_areas[cma_area_count];
> +	int ret = 0;
> +
> +	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> +		__func__, (unsigned long)size, (unsigned long)base,
> +		(unsigned long)limit, (unsigned long)alignment);
> +
> +	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> +		pr_err("Not enough slots for CMA reserved regions!\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	if (alignment && !is_power_of_2(alignment))
> +		return -EINVAL;
> +
> +	/*
> +	 * Sanitise input arguments.
> +	 * Pages both ends in CMA area could be merged into adjacent unmovable
> +	 * migratetype page by page allocator's buddy algorithm. In the case,
> +	 * you couldn't get a contiguous memory, which is not what we want.
> +	 */
> +	alignment = max(alignment,
> +		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> +	base = ALIGN(base, alignment);
> +	size = ALIGN(size, alignment);
> +	limit &= ~(alignment - 1);
> +
> +	/* size should be aligned with order_per_bit */
> +	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> +		return -EINVAL;
> +
> +	/* Reserve memory */
> +	if (base && fixed) {
> +		if (memblock_is_region_reserved(base, size) ||
> +		    memblock_reserve(base, size) < 0) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +	} else {
> +		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> +							limit);
> +		if (!addr) {
> +			ret = -ENOMEM;
> +			goto err;
> +		} else {
> +			base = addr;
> +		}
> +	}
> +
> +	/*
> +	 * Each reserved area must be initialised later, when more kernel
> +	 * subsystems (like slab allocator) are available.
> +	 */
> +	cma->base_pfn = PFN_DOWN(base);
> +	cma->count = size >> PAGE_SHIFT;
> +	cma->order_per_bit = order_per_bit;
> +	*res_cma = cma;
> +	cma_area_count++;
> +
> +	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> +		(unsigned long)base);
> +	return 0;
> +
> +err:
> +	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> +	return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> +	unsigned long mask, pfn, start = 0;
> +	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> +	struct page *page = NULL;
> +	int ret;
> +
> +	if (!cma || !cma->count)
> +		return NULL;
> +
> +	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> +		 count, align);
> +
> +	if (!count)
> +		return NULL;
> +
> +	mask = cma_bitmap_aligned_mask(cma, align);
> +	bitmap_maxno = cma_bitmap_maxno(cma);
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	for (;;) {
> +		mutex_lock(&cma->lock);
> +		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> +				bitmap_maxno, start, bitmap_count, mask);
> +		if (bitmap_no >= bitmap_maxno) {
> +			mutex_unlock(&cma->lock);
> +			break;
> +		}
> +		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> +		/*
> +		 * It's safe to drop the lock here. We've marked this region for
> +		 * our exclusive use. If the migration fails we will take the
> +		 * lock again and unmark it.
> +		 */
> +		mutex_unlock(&cma->lock);
> +
> +		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> +		mutex_lock(&cma_mutex);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		mutex_unlock(&cma_mutex);
> +		if (ret == 0) {
> +			page = pfn_to_page(pfn);
> +			break;
> +		} else if (ret != -EBUSY) {
> +			cma_clear_bitmap(cma, pfn, count);
> +			break;
> +		}
> +		cma_clear_bitmap(cma, pfn, count);
> +		pr_debug("%s(): memory range at %p is busy, retrying\n",
> +			 __func__, pfn_to_page(pfn));
> +		/* try again with a bit different memory target */
> +		start = bitmap_no + mask + 1;
> +	}
> +
> +	pr_debug("%s(): returned %p\n", __func__, page);
> +	return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> +	unsigned long pfn;
> +
> +	if (!cma || !pages)
> +		return false;
> +
> +	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> +	pfn = page_to_pfn(pages);
> +
> +	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> +		return false;
> +
> +	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> +	free_contig_range(pfn, count);
> +	cma_clear_bitmap(cma, pfn, count);
> +
> +	return true;
> +}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. KVM side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> v3: remove log2.h in dma-contiguous.c (Minchan)
>      add some accessor functions to pass aligned base and size to
>      dma_contiguous_early_fixup() function
>      move MAX_CMA_AREAS to cma.h

I've just noticed that MAX_CMA_AREAS is used also by 
arch/arm/mm/dma-mapping.c,
so we need to provide correct definition if CMA is disabled in kconfig. 
I will
send a fixup patch in a few minutes.

> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4c88935..3116880 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -26,6 +26,7 @@
>   #include <linux/io.h>
>   #include <linux/vmalloc.h>
>   #include <linux/sizes.h>
> +#include <linux/cma.h>
>   
>   #include <asm/memory.h>
>   #include <asm/highmem.h>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>   
>   	  If unsure, leave the default value "8".
>   
> -config CMA_AREAS
> -	int "Maximum count of the CMA device-private areas"
> -	default 7
> -	help
> -	  CMA allows to create CMA areas for particular devices. This parameter
> -	  sets the maximum number of such device private CMA areas in the
> -	  system.
> -
> -	  If unsure, leave the default value "7".
> -
>   endif
>   
>   endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index c6eeb2c..0411c1c 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,9 @@
>   
>   #include <linux/memblock.h>
>   #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
>   #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
>   #include <linux/dma-contiguous.h>
> -#include <linux/log2.h>
> -
> -struct cma {
> -	unsigned long	base_pfn;
> -	unsigned long	count;
> -	unsigned long	*bitmap;
> -	unsigned int order_per_bit; /* Order of pages represented by one bit */
> -	struct mutex	lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>   
>   #ifdef CONFIG_CMA_SIZE_MBYTES
>   #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
>   #define CMA_SIZE_MBYTES 0
>   #endif
>   
> +struct cma *dma_contiguous_default_area;
> +
>   /*
>    * Default global CMA area size can be defined in kernel's .config.
>    * This is useful mainly for distro maintainers to create a kernel
> @@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>   	}
>   }
>   
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> -	return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> -	return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> -						unsigned long pages)
> -{
> -	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> -	unsigned long bitmap_no, bitmap_count;
> -
> -	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	mutex_lock(&cma->lock);
> -	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> -	mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> -	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> -	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> -	unsigned i = cma->count >> pageblock_order;
> -	struct zone *zone;
> -
> -	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> -	if (!cma->bitmap)
> -		return -ENOMEM;
> -
> -	WARN_ON_ONCE(!pfn_valid(pfn));
> -	zone = page_zone(pfn_to_page(pfn));
> -
> -	do {
> -		unsigned j;
> -		base_pfn = pfn;
> -		for (j = pageblock_nr_pages; j; --j, pfn++) {
> -			WARN_ON_ONCE(!pfn_valid(pfn));
> -			/*
> -			 * alloc_contig_range requires the pfn range
> -			 * specified to be in the same zone. Make this
> -			 * simple by forcing the entire CMA resv range
> -			 * to be in the same zone.
> -			 */
> -			if (page_zone(pfn_to_page(pfn)) != zone)
> -				goto err;
> -		}
> -		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> -	} while (--i);
> -
> -	mutex_init(&cma->lock);
> -	return 0;
> -
> -err:
> -	kfree(cma->bitmap);
> -	return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> -	int i;
> -
> -	for (i = 0; i < cma_area_count; i++) {
> -		int ret = cma_activate_area(&cma_areas[i]);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> -			phys_addr_t base, phys_addr_t limit,
> -			phys_addr_t alignment, unsigned int order_per_bit,
> -			struct cma **res_cma, bool fixed)
> -{
> -	struct cma *cma = &cma_areas[cma_area_count];
> -	int ret = 0;
> -
> -	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> -		__func__, (unsigned long)size, (unsigned long)base,
> -		(unsigned long)limit, (unsigned long)alignment);
> -
> -	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> -		pr_err("Not enough slots for CMA reserved regions!\n");
> -		return -ENOSPC;
> -	}
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	if (alignment && !is_power_of_2(alignment))
> -		return -EINVAL;
> -
> -	/*
> -	 * Sanitise input arguments.
> -	 * Pages both ends in CMA area could be merged into adjacent unmovable
> -	 * migratetype page by page allocator's buddy algorithm. In the case,
> -	 * you couldn't get a contiguous memory, which is not what we want.
> -	 */
> -	alignment = max(alignment,
> -		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> -	base = ALIGN(base, alignment);
> -	size = ALIGN(size, alignment);
> -	limit &= ~(alignment - 1);
> -
> -	/* size should be aligned with order_per_bit */
> -	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> -		return -EINVAL;
> -
> -	/* Reserve memory */
> -	if (base && fixed) {
> -		if (memblock_is_region_reserved(base, size) ||
> -		    memblock_reserve(base, size) < 0) {
> -			ret = -EBUSY;
> -			goto err;
> -		}
> -	} else {
> -		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> -							limit);
> -		if (!addr) {
> -			ret = -ENOMEM;
> -			goto err;
> -		} else {
> -			base = addr;
> -		}
> -	}
> -
> -	/*
> -	 * Each reserved area must be initialised later, when more kernel
> -	 * subsystems (like slab allocator) are available.
> -	 */
> -	cma->base_pfn = PFN_DOWN(base);
> -	cma->count = size >> PAGE_SHIFT;
> -	cma->order_per_bit = order_per_bit;
> -	*res_cma = cma;
> -	cma_area_count++;
> -
> -	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> -		(unsigned long)base);
> -	return 0;
> -
> -err:
> -	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> -	return ret;
> -}
> -
>   /**
>    * dma_contiguous_reserve_area() - reserve custom contiguous area
>    * @size: Size of the reserved area (in bytes),
> @@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>   {
>   	int ret;
>   
> -	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> -						res_cma, fixed);
> +	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
>   	if (ret)
>   		return ret;
>   
>   	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
> -				(*res_cma)->count << PAGE_SHIFT);
> +	dma_contiguous_early_fixup(cma_get_base(*res_cma),
> +				cma_get_size(*res_cma));
>   
>   	return 0;
>   }
>   
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> -				       unsigned int align)
> -{
> -	unsigned long mask, pfn, start = 0;
> -	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> -	struct page *page = NULL;
> -	int ret;
> -
> -	if (!cma || !cma->count)
> -		return NULL;
> -
> -	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> -		 count, align);
> -
> -	if (!count)
> -		return NULL;
> -
> -	mask = cma_bitmap_aligned_mask(cma, align);
> -	bitmap_maxno = cma_bitmap_maxno(cma);
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	for (;;) {
> -		mutex_lock(&cma->lock);
> -		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> -				bitmap_maxno, start, bitmap_count, mask);
> -		if (bitmap_no >= bitmap_maxno) {
> -			mutex_unlock(&cma->lock);
> -			break;
> -		}
> -		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> -		/*
> -		 * It's safe to drop the lock here. We've marked this region for
> -		 * our exclusive use. If the migration fails we will take the
> -		 * lock again and unmark it.
> -		 */
> -		mutex_unlock(&cma->lock);
> -
> -		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> -		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> -		mutex_unlock(&cma_mutex);
> -		if (ret == 0) {
> -			page = pfn_to_page(pfn);
> -			break;
> -		} else if (ret != -EBUSY) {
> -			cma_clear_bitmap(cma, pfn, count);
> -			break;
> -		}
> -		cma_clear_bitmap(cma, pfn, count);
> -		pr_debug("%s(): memory range at %p is busy, retrying\n",
> -			 __func__, pfn_to_page(pfn));
> -		/* try again with a bit different memory target */
> -		start = bitmap_no + mask + 1;
> -	}
> -
> -	pr_debug("%s(): returned %p\n", __func__, page);
> -	return page;
> -}
> -
>   /**
>    * dma_alloc_from_contiguous() - allocate pages from contiguous area
>    * @dev:   Pointer to device for which the allocation is performed.
> @@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>   struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   				       unsigned int align)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
>   	if (align > CONFIG_CMA_ALIGNMENT)
>   		align = CONFIG_CMA_ALIGNMENT;
>   
> -	return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> -				 int count)
> -{
> -	unsigned long pfn;
> -
> -	if (!cma || !pages)
> -		return false;
> -
> -	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> -	pfn = page_to_pfn(pages);
> -
> -	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> -		return false;
> -
> -	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> -	free_contig_range(pfn, count);
> -	cma_clear_bitmap(cma, pfn, count);
> -
> -	return true;
> +	return cma_alloc(dev_get_cma_area(dev), count, align);
>   }
>   
>   /**
> @@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>   bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   				 int count)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
> -	return __dma_release_from_contiguous(cma, pages, count);
> +	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..69d3726
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,21 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +
> +struct cma;
> +
> +extern phys_addr_t cma_get_base(struct cma *cma);
> +extern unsigned long cma_get_size(struct cma *cma);
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..569bbd0 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,18 +53,13 @@
>   
>   #ifdef __KERNEL__
>   
> +#include <linux/device.h>
> +
>   struct cma;
>   struct page;
> -struct device;
>   
>   #ifdef CONFIG_DMA_CMA
>   
> -/*
> - * There is always at least global CMA area and a few optional device
> - * private areas configured in kernel .config.
> - */
> -#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> -
>   extern struct cma *dma_contiguous_default_area;
>   
>   static inline struct cma *dev_get_cma_area(struct device *dev)
> @@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   
>   #else
>   
> -#define MAX_CMA_AREAS	(0)
> -
>   static inline struct cma *dev_get_cma_area(struct device *dev)
>   {
>   	return NULL;
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
>   	  processing calls such as dma_alloc_from_contiguous().
>   	  This option does not affect warning and error messages.
>   
> +config CMA_AREAS
> +	int "Maximum count of the CMA areas"
> +	depends on CMA
> +	default 7
> +	help
> +	  CMA allows to create CMA areas for particular purpose, mainly,
> +	  used as device private area. This parameter sets the maximum
> +	  number of CMA area in the system.
> +
> +	  If unsure, leave the default value "7".
> +
>   config ZBUD
>   	tristate
>   	default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
>   obj-$(CONFIG_ZBUD)	+= zbud.o
>   obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
>   obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA)	+= cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..0cf50da
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,333 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + *	Marek Szyprowski <m.szyprowski@samsung.com>
> + *	Michal Nazarewicz <mina86@mina86.com>
> + *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +#  define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +#include <linux/cma.h>
> +
> +struct cma {
> +	unsigned long	base_pfn;
> +	unsigned long	count;
> +	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> +	struct mutex	lock;
> +};
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +phys_addr_t cma_get_base(struct cma *cma)
> +{
> +	return PFN_PHYS(cma->base_pfn);
> +}
> +
> +unsigned long cma_get_size(struct cma *cma)
> +{
> +	return cma->count << PAGE_SHIFT;
> +}
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> +	unsigned long bitmap_no, bitmap_count;
> +
> +	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	mutex_lock(&cma->lock);
> +	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> +	mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> +	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> +	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> +	unsigned i = cma->count >> pageblock_order;
> +	struct zone *zone;
> +
> +	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +
> +	if (!cma->bitmap)
> +		return -ENOMEM;
> +
> +	WARN_ON_ONCE(!pfn_valid(pfn));
> +	zone = page_zone(pfn_to_page(pfn));
> +
> +	do {
> +		unsigned j;
> +
> +		base_pfn = pfn;
> +		for (j = pageblock_nr_pages; j; --j, pfn++) {
> +			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
> +			if (page_zone(pfn_to_page(pfn)) != zone)
> +				goto err;
> +		}
> +		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> +	} while (--i);
> +
> +	mutex_init(&cma->lock);
> +	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < cma_area_count; i++) {
> +		int ret = cma_activate_area(&cma_areas[i]);
> +
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the CMA area, should be power of 2 or zero
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base.  If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed)
> +{
> +	struct cma *cma = &cma_areas[cma_area_count];
> +	int ret = 0;
> +
> +	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> +		__func__, (unsigned long)size, (unsigned long)base,
> +		(unsigned long)limit, (unsigned long)alignment);
> +
> +	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> +		pr_err("Not enough slots for CMA reserved regions!\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	if (alignment && !is_power_of_2(alignment))
> +		return -EINVAL;
> +
> +	/*
> +	 * Sanitise input arguments.
> +	 * Pages both ends in CMA area could be merged into adjacent unmovable
> +	 * migratetype page by page allocator's buddy algorithm. In the case,
> +	 * you couldn't get a contiguous memory, which is not what we want.
> +	 */
> +	alignment = max(alignment,
> +		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> +	base = ALIGN(base, alignment);
> +	size = ALIGN(size, alignment);
> +	limit &= ~(alignment - 1);
> +
> +	/* size should be aligned with order_per_bit */
> +	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> +		return -EINVAL;
> +
> +	/* Reserve memory */
> +	if (base && fixed) {
> +		if (memblock_is_region_reserved(base, size) ||
> +		    memblock_reserve(base, size) < 0) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +	} else {
> +		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> +							limit);
> +		if (!addr) {
> +			ret = -ENOMEM;
> +			goto err;
> +		} else {
> +			base = addr;
> +		}
> +	}
> +
> +	/*
> +	 * Each reserved area must be initialised later, when more kernel
> +	 * subsystems (like slab allocator) are available.
> +	 */
> +	cma->base_pfn = PFN_DOWN(base);
> +	cma->count = size >> PAGE_SHIFT;
> +	cma->order_per_bit = order_per_bit;
> +	*res_cma = cma;
> +	cma_area_count++;
> +
> +	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> +		(unsigned long)base);
> +	return 0;
> +
> +err:
> +	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> +	return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> +	unsigned long mask, pfn, start = 0;
> +	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> +	struct page *page = NULL;
> +	int ret;
> +
> +	if (!cma || !cma->count)
> +		return NULL;
> +
> +	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> +		 count, align);
> +
> +	if (!count)
> +		return NULL;
> +
> +	mask = cma_bitmap_aligned_mask(cma, align);
> +	bitmap_maxno = cma_bitmap_maxno(cma);
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	for (;;) {
> +		mutex_lock(&cma->lock);
> +		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> +				bitmap_maxno, start, bitmap_count, mask);
> +		if (bitmap_no >= bitmap_maxno) {
> +			mutex_unlock(&cma->lock);
> +			break;
> +		}
> +		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> +		/*
> +		 * It's safe to drop the lock here. We've marked this region for
> +		 * our exclusive use. If the migration fails we will take the
> +		 * lock again and unmark it.
> +		 */
> +		mutex_unlock(&cma->lock);
> +
> +		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> +		mutex_lock(&cma_mutex);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		mutex_unlock(&cma_mutex);
> +		if (ret == 0) {
> +			page = pfn_to_page(pfn);
> +			break;
> +		} else if (ret != -EBUSY) {
> +			cma_clear_bitmap(cma, pfn, count);
> +			break;
> +		}
> +		cma_clear_bitmap(cma, pfn, count);
> +		pr_debug("%s(): memory range at %p is busy, retrying\n",
> +			 __func__, pfn_to_page(pfn));
> +		/* try again with a bit different memory target */
> +		start = bitmap_no + mask + 1;
> +	}
> +
> +	pr_debug("%s(): returned %p\n", __func__, page);
> +	return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> +	unsigned long pfn;
> +
> +	if (!cma || !pages)
> +		return false;
> +
> +	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> +	pfn = page_to_pfn(pages);
> +
> +	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> +		return false;
> +
> +	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> +	free_contig_range(pfn, count);
> +	cma_clear_bitmap(cma, pfn, count);
> +
> +	return true;
> +}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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Re: [PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. KVM side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> v3: remove log2.h in dma-contiguous.c (Minchan)
>      add some accessor functions to pass aligned base and size to
>      dma_contiguous_early_fixup() function
>      move MAX_CMA_AREAS to cma.h

I've just noticed that MAX_CMA_AREAS is used also by 
arch/arm/mm/dma-mapping.c,
so we need to provide correct definition if CMA is disabled in kconfig. 
I will
send a fixup patch in a few minutes.

> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4c88935..3116880 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -26,6 +26,7 @@
>   #include <linux/io.h>
>   #include <linux/vmalloc.h>
>   #include <linux/sizes.h>
> +#include <linux/cma.h>
>   
>   #include <asm/memory.h>
>   #include <asm/highmem.h>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>   
>   	  If unsure, leave the default value "8".
>   
> -config CMA_AREAS
> -	int "Maximum count of the CMA device-private areas"
> -	default 7
> -	help
> -	  CMA allows to create CMA areas for particular devices. This parameter
> -	  sets the maximum number of such device private CMA areas in the
> -	  system.
> -
> -	  If unsure, leave the default value "7".
> -
>   endif
>   
>   endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index c6eeb2c..0411c1c 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,9 @@
>   
>   #include <linux/memblock.h>
>   #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
>   #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
>   #include <linux/dma-contiguous.h>
> -#include <linux/log2.h>
> -
> -struct cma {
> -	unsigned long	base_pfn;
> -	unsigned long	count;
> -	unsigned long	*bitmap;
> -	unsigned int order_per_bit; /* Order of pages represented by one bit */
> -	struct mutex	lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>   
>   #ifdef CONFIG_CMA_SIZE_MBYTES
>   #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
>   #define CMA_SIZE_MBYTES 0
>   #endif
>   
> +struct cma *dma_contiguous_default_area;
> +
>   /*
>    * Default global CMA area size can be defined in kernel's .config.
>    * This is useful mainly for distro maintainers to create a kernel
> @@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>   	}
>   }
>   
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> -	return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> -	return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> -						unsigned long pages)
> -{
> -	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> -	unsigned long bitmap_no, bitmap_count;
> -
> -	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	mutex_lock(&cma->lock);
> -	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> -	mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> -	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> -	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> -	unsigned i = cma->count >> pageblock_order;
> -	struct zone *zone;
> -
> -	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> -	if (!cma->bitmap)
> -		return -ENOMEM;
> -
> -	WARN_ON_ONCE(!pfn_valid(pfn));
> -	zone = page_zone(pfn_to_page(pfn));
> -
> -	do {
> -		unsigned j;
> -		base_pfn = pfn;
> -		for (j = pageblock_nr_pages; j; --j, pfn++) {
> -			WARN_ON_ONCE(!pfn_valid(pfn));
> -			/*
> -			 * alloc_contig_range requires the pfn range
> -			 * specified to be in the same zone. Make this
> -			 * simple by forcing the entire CMA resv range
> -			 * to be in the same zone.
> -			 */
> -			if (page_zone(pfn_to_page(pfn)) != zone)
> -				goto err;
> -		}
> -		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> -	} while (--i);
> -
> -	mutex_init(&cma->lock);
> -	return 0;
> -
> -err:
> -	kfree(cma->bitmap);
> -	return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> -	int i;
> -
> -	for (i = 0; i < cma_area_count; i++) {
> -		int ret = cma_activate_area(&cma_areas[i]);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> -			phys_addr_t base, phys_addr_t limit,
> -			phys_addr_t alignment, unsigned int order_per_bit,
> -			struct cma **res_cma, bool fixed)
> -{
> -	struct cma *cma = &cma_areas[cma_area_count];
> -	int ret = 0;
> -
> -	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> -		__func__, (unsigned long)size, (unsigned long)base,
> -		(unsigned long)limit, (unsigned long)alignment);
> -
> -	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> -		pr_err("Not enough slots for CMA reserved regions!\n");
> -		return -ENOSPC;
> -	}
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	if (alignment && !is_power_of_2(alignment))
> -		return -EINVAL;
> -
> -	/*
> -	 * Sanitise input arguments.
> -	 * Pages both ends in CMA area could be merged into adjacent unmovable
> -	 * migratetype page by page allocator's buddy algorithm. In the case,
> -	 * you couldn't get a contiguous memory, which is not what we want.
> -	 */
> -	alignment = max(alignment,
> -		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> -	base = ALIGN(base, alignment);
> -	size = ALIGN(size, alignment);
> -	limit &= ~(alignment - 1);
> -
> -	/* size should be aligned with order_per_bit */
> -	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> -		return -EINVAL;
> -
> -	/* Reserve memory */
> -	if (base && fixed) {
> -		if (memblock_is_region_reserved(base, size) ||
> -		    memblock_reserve(base, size) < 0) {
> -			ret = -EBUSY;
> -			goto err;
> -		}
> -	} else {
> -		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> -							limit);
> -		if (!addr) {
> -			ret = -ENOMEM;
> -			goto err;
> -		} else {
> -			base = addr;
> -		}
> -	}
> -
> -	/*
> -	 * Each reserved area must be initialised later, when more kernel
> -	 * subsystems (like slab allocator) are available.
> -	 */
> -	cma->base_pfn = PFN_DOWN(base);
> -	cma->count = size >> PAGE_SHIFT;
> -	cma->order_per_bit = order_per_bit;
> -	*res_cma = cma;
> -	cma_area_count++;
> -
> -	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> -		(unsigned long)base);
> -	return 0;
> -
> -err:
> -	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> -	return ret;
> -}
> -
>   /**
>    * dma_contiguous_reserve_area() - reserve custom contiguous area
>    * @size: Size of the reserved area (in bytes),
> @@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>   {
>   	int ret;
>   
> -	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> -						res_cma, fixed);
> +	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
>   	if (ret)
>   		return ret;
>   
>   	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
> -				(*res_cma)->count << PAGE_SHIFT);
> +	dma_contiguous_early_fixup(cma_get_base(*res_cma),
> +				cma_get_size(*res_cma));
>   
>   	return 0;
>   }
>   
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> -				       unsigned int align)
> -{
> -	unsigned long mask, pfn, start = 0;
> -	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> -	struct page *page = NULL;
> -	int ret;
> -
> -	if (!cma || !cma->count)
> -		return NULL;
> -
> -	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> -		 count, align);
> -
> -	if (!count)
> -		return NULL;
> -
> -	mask = cma_bitmap_aligned_mask(cma, align);
> -	bitmap_maxno = cma_bitmap_maxno(cma);
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	for (;;) {
> -		mutex_lock(&cma->lock);
> -		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> -				bitmap_maxno, start, bitmap_count, mask);
> -		if (bitmap_no >= bitmap_maxno) {
> -			mutex_unlock(&cma->lock);
> -			break;
> -		}
> -		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> -		/*
> -		 * It's safe to drop the lock here. We've marked this region for
> -		 * our exclusive use. If the migration fails we will take the
> -		 * lock again and unmark it.
> -		 */
> -		mutex_unlock(&cma->lock);
> -
> -		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> -		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> -		mutex_unlock(&cma_mutex);
> -		if (ret == 0) {
> -			page = pfn_to_page(pfn);
> -			break;
> -		} else if (ret != -EBUSY) {
> -			cma_clear_bitmap(cma, pfn, count);
> -			break;
> -		}
> -		cma_clear_bitmap(cma, pfn, count);
> -		pr_debug("%s(): memory range at %p is busy, retrying\n",
> -			 __func__, pfn_to_page(pfn));
> -		/* try again with a bit different memory target */
> -		start = bitmap_no + mask + 1;
> -	}
> -
> -	pr_debug("%s(): returned %p\n", __func__, page);
> -	return page;
> -}
> -
>   /**
>    * dma_alloc_from_contiguous() - allocate pages from contiguous area
>    * @dev:   Pointer to device for which the allocation is performed.
> @@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>   struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   				       unsigned int align)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
>   	if (align > CONFIG_CMA_ALIGNMENT)
>   		align = CONFIG_CMA_ALIGNMENT;
>   
> -	return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> -				 int count)
> -{
> -	unsigned long pfn;
> -
> -	if (!cma || !pages)
> -		return false;
> -
> -	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> -	pfn = page_to_pfn(pages);
> -
> -	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> -		return false;
> -
> -	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> -	free_contig_range(pfn, count);
> -	cma_clear_bitmap(cma, pfn, count);
> -
> -	return true;
> +	return cma_alloc(dev_get_cma_area(dev), count, align);
>   }
>   
>   /**
> @@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>   bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   				 int count)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
> -	return __dma_release_from_contiguous(cma, pages, count);
> +	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..69d3726
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,21 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +
> +struct cma;
> +
> +extern phys_addr_t cma_get_base(struct cma *cma);
> +extern unsigned long cma_get_size(struct cma *cma);
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..569bbd0 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,18 +53,13 @@
>   
>   #ifdef __KERNEL__
>   
> +#include <linux/device.h>
> +
>   struct cma;
>   struct page;
> -struct device;
>   
>   #ifdef CONFIG_DMA_CMA
>   
> -/*
> - * There is always at least global CMA area and a few optional device
> - * private areas configured in kernel .config.
> - */
> -#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> -
>   extern struct cma *dma_contiguous_default_area;
>   
>   static inline struct cma *dev_get_cma_area(struct device *dev)
> @@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   
>   #else
>   
> -#define MAX_CMA_AREAS	(0)
> -
>   static inline struct cma *dev_get_cma_area(struct device *dev)
>   {
>   	return NULL;
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
>   	  processing calls such as dma_alloc_from_contiguous().
>   	  This option does not affect warning and error messages.
>   
> +config CMA_AREAS
> +	int "Maximum count of the CMA areas"
> +	depends on CMA
> +	default 7
> +	help
> +	  CMA allows to create CMA areas for particular purpose, mainly,
> +	  used as device private area. This parameter sets the maximum
> +	  number of CMA area in the system.
> +
> +	  If unsure, leave the default value "7".
> +
>   config ZBUD
>   	tristate
>   	default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
>   obj-$(CONFIG_ZBUD)	+= zbud.o
>   obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
>   obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA)	+= cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..0cf50da
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,333 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + *	Marek Szyprowski <m.szyprowski@samsung.com>
> + *	Michal Nazarewicz <mina86@mina86.com>
> + *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +#  define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +#include <linux/cma.h>
> +
> +struct cma {
> +	unsigned long	base_pfn;
> +	unsigned long	count;
> +	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> +	struct mutex	lock;
> +};
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +phys_addr_t cma_get_base(struct cma *cma)
> +{
> +	return PFN_PHYS(cma->base_pfn);
> +}
> +
> +unsigned long cma_get_size(struct cma *cma)
> +{
> +	return cma->count << PAGE_SHIFT;
> +}
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> +	unsigned long bitmap_no, bitmap_count;
> +
> +	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	mutex_lock(&cma->lock);
> +	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> +	mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> +	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> +	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> +	unsigned i = cma->count >> pageblock_order;
> +	struct zone *zone;
> +
> +	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +
> +	if (!cma->bitmap)
> +		return -ENOMEM;
> +
> +	WARN_ON_ONCE(!pfn_valid(pfn));
> +	zone = page_zone(pfn_to_page(pfn));
> +
> +	do {
> +		unsigned j;
> +
> +		base_pfn = pfn;
> +		for (j = pageblock_nr_pages; j; --j, pfn++) {
> +			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
> +			if (page_zone(pfn_to_page(pfn)) != zone)
> +				goto err;
> +		}
> +		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> +	} while (--i);
> +
> +	mutex_init(&cma->lock);
> +	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < cma_area_count; i++) {
> +		int ret = cma_activate_area(&cma_areas[i]);
> +
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the CMA area, should be power of 2 or zero
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base.  If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed)
> +{
> +	struct cma *cma = &cma_areas[cma_area_count];
> +	int ret = 0;
> +
> +	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> +		__func__, (unsigned long)size, (unsigned long)base,
> +		(unsigned long)limit, (unsigned long)alignment);
> +
> +	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> +		pr_err("Not enough slots for CMA reserved regions!\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	if (alignment && !is_power_of_2(alignment))
> +		return -EINVAL;
> +
> +	/*
> +	 * Sanitise input arguments.
> +	 * Pages both ends in CMA area could be merged into adjacent unmovable
> +	 * migratetype page by page allocator's buddy algorithm. In the case,
> +	 * you couldn't get a contiguous memory, which is not what we want.
> +	 */
> +	alignment = max(alignment,
> +		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> +	base = ALIGN(base, alignment);
> +	size = ALIGN(size, alignment);
> +	limit &= ~(alignment - 1);
> +
> +	/* size should be aligned with order_per_bit */
> +	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> +		return -EINVAL;
> +
> +	/* Reserve memory */
> +	if (base && fixed) {
> +		if (memblock_is_region_reserved(base, size) ||
> +		    memblock_reserve(base, size) < 0) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +	} else {
> +		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> +							limit);
> +		if (!addr) {
> +			ret = -ENOMEM;
> +			goto err;
> +		} else {
> +			base = addr;
> +		}
> +	}
> +
> +	/*
> +	 * Each reserved area must be initialised later, when more kernel
> +	 * subsystems (like slab allocator) are available.
> +	 */
> +	cma->base_pfn = PFN_DOWN(base);
> +	cma->count = size >> PAGE_SHIFT;
> +	cma->order_per_bit = order_per_bit;
> +	*res_cma = cma;
> +	cma_area_count++;
> +
> +	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> +		(unsigned long)base);
> +	return 0;
> +
> +err:
> +	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> +	return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> +	unsigned long mask, pfn, start = 0;
> +	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> +	struct page *page = NULL;
> +	int ret;
> +
> +	if (!cma || !cma->count)
> +		return NULL;
> +
> +	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> +		 count, align);
> +
> +	if (!count)
> +		return NULL;
> +
> +	mask = cma_bitmap_aligned_mask(cma, align);
> +	bitmap_maxno = cma_bitmap_maxno(cma);
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	for (;;) {
> +		mutex_lock(&cma->lock);
> +		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> +				bitmap_maxno, start, bitmap_count, mask);
> +		if (bitmap_no >= bitmap_maxno) {
> +			mutex_unlock(&cma->lock);
> +			break;
> +		}
> +		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> +		/*
> +		 * It's safe to drop the lock here. We've marked this region for
> +		 * our exclusive use. If the migration fails we will take the
> +		 * lock again and unmark it.
> +		 */
> +		mutex_unlock(&cma->lock);
> +
> +		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> +		mutex_lock(&cma_mutex);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		mutex_unlock(&cma_mutex);
> +		if (ret == 0) {
> +			page = pfn_to_page(pfn);
> +			break;
> +		} else if (ret != -EBUSY) {
> +			cma_clear_bitmap(cma, pfn, count);
> +			break;
> +		}
> +		cma_clear_bitmap(cma, pfn, count);
> +		pr_debug("%s(): memory range at %p is busy, retrying\n",
> +			 __func__, pfn_to_page(pfn));
> +		/* try again with a bit different memory target */
> +		start = bitmap_no + mask + 1;
> +	}
> +
> +	pr_debug("%s(): returned %p\n", __func__, page);
> +	return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> +	unsigned long pfn;
> +
> +	if (!cma || !pages)
> +		return false;
> +
> +	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> +	pfn = page_to_pfn(pages);
> +
> +	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> +		return false;
> +
> +	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> +	free_contig_range(pfn, count);
> +	cma_clear_bitmap(cma, pfn, count);
> +
> +	return true;
> +}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

[PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. KVM side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> v3: remove log2.h in dma-contiguous.c (Minchan)
>      add some accessor functions to pass aligned base and size to
>      dma_contiguous_early_fixup() function
>      move MAX_CMA_AREAS to cma.h

I've just noticed that MAX_CMA_AREAS is used also by 
arch/arm/mm/dma-mapping.c,
so we need to provide correct definition if CMA is disabled in kconfig. 
I will
send a fixup patch in a few minutes.

> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4c88935..3116880 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -26,6 +26,7 @@
>   #include <linux/io.h>
>   #include <linux/vmalloc.h>
>   #include <linux/sizes.h>
> +#include <linux/cma.h>
>   
>   #include <asm/memory.h>
>   #include <asm/highmem.h>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>   
>   	  If unsure, leave the default value "8".
>   
> -config CMA_AREAS
> -	int "Maximum count of the CMA device-private areas"
> -	default 7
> -	help
> -	  CMA allows to create CMA areas for particular devices. This parameter
> -	  sets the maximum number of such device private CMA areas in the
> -	  system.
> -
> -	  If unsure, leave the default value "7".
> -
>   endif
>   
>   endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index c6eeb2c..0411c1c 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,9 @@
>   
>   #include <linux/memblock.h>
>   #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
>   #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
>   #include <linux/dma-contiguous.h>
> -#include <linux/log2.h>
> -
> -struct cma {
> -	unsigned long	base_pfn;
> -	unsigned long	count;
> -	unsigned long	*bitmap;
> -	unsigned int order_per_bit; /* Order of pages represented by one bit */
> -	struct mutex	lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>   
>   #ifdef CONFIG_CMA_SIZE_MBYTES
>   #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
>   #define CMA_SIZE_MBYTES 0
>   #endif
>   
> +struct cma *dma_contiguous_default_area;
> +
>   /*
>    * Default global CMA area size can be defined in kernel's .config.
>    * This is useful mainly for distro maintainers to create a kernel
> @@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>   	}
>   }
>   
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> -	return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> -	return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> -						unsigned long pages)
> -{
> -	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> -	unsigned long bitmap_no, bitmap_count;
> -
> -	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	mutex_lock(&cma->lock);
> -	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> -	mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> -	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> -	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> -	unsigned i = cma->count >> pageblock_order;
> -	struct zone *zone;
> -
> -	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> -	if (!cma->bitmap)
> -		return -ENOMEM;
> -
> -	WARN_ON_ONCE(!pfn_valid(pfn));
> -	zone = page_zone(pfn_to_page(pfn));
> -
> -	do {
> -		unsigned j;
> -		base_pfn = pfn;
> -		for (j = pageblock_nr_pages; j; --j, pfn++) {
> -			WARN_ON_ONCE(!pfn_valid(pfn));
> -			/*
> -			 * alloc_contig_range requires the pfn range
> -			 * specified to be in the same zone. Make this
> -			 * simple by forcing the entire CMA resv range
> -			 * to be in the same zone.
> -			 */
> -			if (page_zone(pfn_to_page(pfn)) != zone)
> -				goto err;
> -		}
> -		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> -	} while (--i);
> -
> -	mutex_init(&cma->lock);
> -	return 0;
> -
> -err:
> -	kfree(cma->bitmap);
> -	return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> -	int i;
> -
> -	for (i = 0; i < cma_area_count; i++) {
> -		int ret = cma_activate_area(&cma_areas[i]);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> -			phys_addr_t base, phys_addr_t limit,
> -			phys_addr_t alignment, unsigned int order_per_bit,
> -			struct cma **res_cma, bool fixed)
> -{
> -	struct cma *cma = &cma_areas[cma_area_count];
> -	int ret = 0;
> -
> -	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> -		__func__, (unsigned long)size, (unsigned long)base,
> -		(unsigned long)limit, (unsigned long)alignment);
> -
> -	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> -		pr_err("Not enough slots for CMA reserved regions!\n");
> -		return -ENOSPC;
> -	}
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	if (alignment && !is_power_of_2(alignment))
> -		return -EINVAL;
> -
> -	/*
> -	 * Sanitise input arguments.
> -	 * Pages both ends in CMA area could be merged into adjacent unmovable
> -	 * migratetype page by page allocator's buddy algorithm. In the case,
> -	 * you couldn't get a contiguous memory, which is not what we want.
> -	 */
> -	alignment = max(alignment,
> -		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> -	base = ALIGN(base, alignment);
> -	size = ALIGN(size, alignment);
> -	limit &= ~(alignment - 1);
> -
> -	/* size should be aligned with order_per_bit */
> -	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> -		return -EINVAL;
> -
> -	/* Reserve memory */
> -	if (base && fixed) {
> -		if (memblock_is_region_reserved(base, size) ||
> -		    memblock_reserve(base, size) < 0) {
> -			ret = -EBUSY;
> -			goto err;
> -		}
> -	} else {
> -		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> -							limit);
> -		if (!addr) {
> -			ret = -ENOMEM;
> -			goto err;
> -		} else {
> -			base = addr;
> -		}
> -	}
> -
> -	/*
> -	 * Each reserved area must be initialised later, when more kernel
> -	 * subsystems (like slab allocator) are available.
> -	 */
> -	cma->base_pfn = PFN_DOWN(base);
> -	cma->count = size >> PAGE_SHIFT;
> -	cma->order_per_bit = order_per_bit;
> -	*res_cma = cma;
> -	cma_area_count++;
> -
> -	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> -		(unsigned long)base);
> -	return 0;
> -
> -err:
> -	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> -	return ret;
> -}
> -
>   /**
>    * dma_contiguous_reserve_area() - reserve custom contiguous area
>    * @size: Size of the reserved area (in bytes),
> @@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>   {
>   	int ret;
>   
> -	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> -						res_cma, fixed);
> +	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
>   	if (ret)
>   		return ret;
>   
>   	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
> -				(*res_cma)->count << PAGE_SHIFT);
> +	dma_contiguous_early_fixup(cma_get_base(*res_cma),
> +				cma_get_size(*res_cma));
>   
>   	return 0;
>   }
>   
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> -				       unsigned int align)
> -{
> -	unsigned long mask, pfn, start = 0;
> -	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> -	struct page *page = NULL;
> -	int ret;
> -
> -	if (!cma || !cma->count)
> -		return NULL;
> -
> -	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> -		 count, align);
> -
> -	if (!count)
> -		return NULL;
> -
> -	mask = cma_bitmap_aligned_mask(cma, align);
> -	bitmap_maxno = cma_bitmap_maxno(cma);
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	for (;;) {
> -		mutex_lock(&cma->lock);
> -		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> -				bitmap_maxno, start, bitmap_count, mask);
> -		if (bitmap_no >= bitmap_maxno) {
> -			mutex_unlock(&cma->lock);
> -			break;
> -		}
> -		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> -		/*
> -		 * It's safe to drop the lock here. We've marked this region for
> -		 * our exclusive use. If the migration fails we will take the
> -		 * lock again and unmark it.
> -		 */
> -		mutex_unlock(&cma->lock);
> -
> -		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> -		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> -		mutex_unlock(&cma_mutex);
> -		if (ret == 0) {
> -			page = pfn_to_page(pfn);
> -			break;
> -		} else if (ret != -EBUSY) {
> -			cma_clear_bitmap(cma, pfn, count);
> -			break;
> -		}
> -		cma_clear_bitmap(cma, pfn, count);
> -		pr_debug("%s(): memory range at %p is busy, retrying\n",
> -			 __func__, pfn_to_page(pfn));
> -		/* try again with a bit different memory target */
> -		start = bitmap_no + mask + 1;
> -	}
> -
> -	pr_debug("%s(): returned %p\n", __func__, page);
> -	return page;
> -}
> -
>   /**
>    * dma_alloc_from_contiguous() - allocate pages from contiguous area
>    * @dev:   Pointer to device for which the allocation is performed.
> @@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>   struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   				       unsigned int align)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
>   	if (align > CONFIG_CMA_ALIGNMENT)
>   		align = CONFIG_CMA_ALIGNMENT;
>   
> -	return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> -				 int count)
> -{
> -	unsigned long pfn;
> -
> -	if (!cma || !pages)
> -		return false;
> -
> -	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> -	pfn = page_to_pfn(pages);
> -
> -	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> -		return false;
> -
> -	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> -	free_contig_range(pfn, count);
> -	cma_clear_bitmap(cma, pfn, count);
> -
> -	return true;
> +	return cma_alloc(dev_get_cma_area(dev), count, align);
>   }
>   
>   /**
> @@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>   bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   				 int count)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
> -	return __dma_release_from_contiguous(cma, pages, count);
> +	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..69d3726
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,21 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +
> +struct cma;
> +
> +extern phys_addr_t cma_get_base(struct cma *cma);
> +extern unsigned long cma_get_size(struct cma *cma);
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..569bbd0 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,18 +53,13 @@
>   
>   #ifdef __KERNEL__
>   
> +#include <linux/device.h>
> +
>   struct cma;
>   struct page;
> -struct device;
>   
>   #ifdef CONFIG_DMA_CMA
>   
> -/*
> - * There is always at least global CMA area and a few optional device
> - * private areas configured in kernel .config.
> - */
> -#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> -
>   extern struct cma *dma_contiguous_default_area;
>   
>   static inline struct cma *dev_get_cma_area(struct device *dev)
> @@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   
>   #else
>   
> -#define MAX_CMA_AREAS	(0)
> -
>   static inline struct cma *dev_get_cma_area(struct device *dev)
>   {
>   	return NULL;
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
>   	  processing calls such as dma_alloc_from_contiguous().
>   	  This option does not affect warning and error messages.
>   
> +config CMA_AREAS
> +	int "Maximum count of the CMA areas"
> +	depends on CMA
> +	default 7
> +	help
> +	  CMA allows to create CMA areas for particular purpose, mainly,
> +	  used as device private area. This parameter sets the maximum
> +	  number of CMA area in the system.
> +
> +	  If unsure, leave the default value "7".
> +
>   config ZBUD
>   	tristate
>   	default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
>   obj-$(CONFIG_ZBUD)	+= zbud.o
>   obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
>   obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA)	+= cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..0cf50da
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,333 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + *	Marek Szyprowski <m.szyprowski@samsung.com>
> + *	Michal Nazarewicz <mina86@mina86.com>
> + *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +#  define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +#include <linux/cma.h>
> +
> +struct cma {
> +	unsigned long	base_pfn;
> +	unsigned long	count;
> +	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> +	struct mutex	lock;
> +};
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +phys_addr_t cma_get_base(struct cma *cma)
> +{
> +	return PFN_PHYS(cma->base_pfn);
> +}
> +
> +unsigned long cma_get_size(struct cma *cma)
> +{
> +	return cma->count << PAGE_SHIFT;
> +}
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> +	unsigned long bitmap_no, bitmap_count;
> +
> +	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	mutex_lock(&cma->lock);
> +	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> +	mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> +	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> +	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> +	unsigned i = cma->count >> pageblock_order;
> +	struct zone *zone;
> +
> +	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +
> +	if (!cma->bitmap)
> +		return -ENOMEM;
> +
> +	WARN_ON_ONCE(!pfn_valid(pfn));
> +	zone = page_zone(pfn_to_page(pfn));
> +
> +	do {
> +		unsigned j;
> +
> +		base_pfn = pfn;
> +		for (j = pageblock_nr_pages; j; --j, pfn++) {
> +			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
> +			if (page_zone(pfn_to_page(pfn)) != zone)
> +				goto err;
> +		}
> +		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> +	} while (--i);
> +
> +	mutex_init(&cma->lock);
> +	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < cma_area_count; i++) {
> +		int ret = cma_activate_area(&cma_areas[i]);
> +
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the CMA area, should be power of 2 or zero
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base.  If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed)
> +{
> +	struct cma *cma = &cma_areas[cma_area_count];
> +	int ret = 0;
> +
> +	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> +		__func__, (unsigned long)size, (unsigned long)base,
> +		(unsigned long)limit, (unsigned long)alignment);
> +
> +	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> +		pr_err("Not enough slots for CMA reserved regions!\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	if (alignment && !is_power_of_2(alignment))
> +		return -EINVAL;
> +
> +	/*
> +	 * Sanitise input arguments.
> +	 * Pages both ends in CMA area could be merged into adjacent unmovable
> +	 * migratetype page by page allocator's buddy algorithm. In the case,
> +	 * you couldn't get a contiguous memory, which is not what we want.
> +	 */
> +	alignment = max(alignment,
> +		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> +	base = ALIGN(base, alignment);
> +	size = ALIGN(size, alignment);
> +	limit &= ~(alignment - 1);
> +
> +	/* size should be aligned with order_per_bit */
> +	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> +		return -EINVAL;
> +
> +	/* Reserve memory */
> +	if (base && fixed) {
> +		if (memblock_is_region_reserved(base, size) ||
> +		    memblock_reserve(base, size) < 0) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +	} else {
> +		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> +							limit);
> +		if (!addr) {
> +			ret = -ENOMEM;
> +			goto err;
> +		} else {
> +			base = addr;
> +		}
> +	}
> +
> +	/*
> +	 * Each reserved area must be initialised later, when more kernel
> +	 * subsystems (like slab allocator) are available.
> +	 */
> +	cma->base_pfn = PFN_DOWN(base);
> +	cma->count = size >> PAGE_SHIFT;
> +	cma->order_per_bit = order_per_bit;
> +	*res_cma = cma;
> +	cma_area_count++;
> +
> +	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> +		(unsigned long)base);
> +	return 0;
> +
> +err:
> +	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> +	return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> +	unsigned long mask, pfn, start = 0;
> +	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> +	struct page *page = NULL;
> +	int ret;
> +
> +	if (!cma || !cma->count)
> +		return NULL;
> +
> +	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> +		 count, align);
> +
> +	if (!count)
> +		return NULL;
> +
> +	mask = cma_bitmap_aligned_mask(cma, align);
> +	bitmap_maxno = cma_bitmap_maxno(cma);
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	for (;;) {
> +		mutex_lock(&cma->lock);
> +		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> +				bitmap_maxno, start, bitmap_count, mask);
> +		if (bitmap_no >= bitmap_maxno) {
> +			mutex_unlock(&cma->lock);
> +			break;
> +		}
> +		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> +		/*
> +		 * It's safe to drop the lock here. We've marked this region for
> +		 * our exclusive use. If the migration fails we will take the
> +		 * lock again and unmark it.
> +		 */
> +		mutex_unlock(&cma->lock);
> +
> +		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> +		mutex_lock(&cma_mutex);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		mutex_unlock(&cma_mutex);
> +		if (ret == 0) {
> +			page = pfn_to_page(pfn);
> +			break;
> +		} else if (ret != -EBUSY) {
> +			cma_clear_bitmap(cma, pfn, count);
> +			break;
> +		}
> +		cma_clear_bitmap(cma, pfn, count);
> +		pr_debug("%s(): memory range at %p is busy, retrying\n",
> +			 __func__, pfn_to_page(pfn));
> +		/* try again with a bit different memory target */
> +		start = bitmap_no + mask + 1;
> +	}
> +
> +	pr_debug("%s(): returned %p\n", __func__, page);
> +	return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> +	unsigned long pfn;
> +
> +	if (!cma || !pages)
> +		return false;
> +
> +	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> +	pfn = page_to_pfn(pages);
> +
> +	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> +		return false;
> +
> +	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> +	free_contig_range(pfn, count);
> +	cma_clear_bitmap(cma, pfn, count);
> +
> +	return true;
> +}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v3 -next 5/9] CMA: generalize CMA reserved area management functionality

[Marek Szyprowski]

Hello,

On 2014-06-16 07:40, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the KVM on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. KVM side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> v3: remove log2.h in dma-contiguous.c (Minchan)
>      add some accessor functions to pass aligned base and size to
>      dma_contiguous_early_fixup() function
>      move MAX_CMA_AREAS to cma.h

I've just noticed that MAX_CMA_AREAS is used also by 
arch/arm/mm/dma-mapping.c,
so we need to provide correct definition if CMA is disabled in kconfig. 
I will
send a fixup patch in a few minutes.

> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4c88935..3116880 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -26,6 +26,7 @@
>   #include <linux/io.h>
>   #include <linux/vmalloc.h>
>   #include <linux/sizes.h>
> +#include <linux/cma.h>
>   
>   #include <asm/memory.h>
>   #include <asm/highmem.h>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>   
>   	  If unsure, leave the default value "8".
>   
> -config CMA_AREAS
> -	int "Maximum count of the CMA device-private areas"
> -	default 7
> -	help
> -	  CMA allows to create CMA areas for particular devices. This parameter
> -	  sets the maximum number of such device private CMA areas in the
> -	  system.
> -
> -	  If unsure, leave the default value "7".
> -
>   endif
>   
>   endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index c6eeb2c..0411c1c 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,9 @@
>   
>   #include <linux/memblock.h>
>   #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
>   #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
>   #include <linux/dma-contiguous.h>
> -#include <linux/log2.h>
> -
> -struct cma {
> -	unsigned long	base_pfn;
> -	unsigned long	count;
> -	unsigned long	*bitmap;
> -	unsigned int order_per_bit; /* Order of pages represented by one bit */
> -	struct mutex	lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>   
>   #ifdef CONFIG_CMA_SIZE_MBYTES
>   #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
>   #define CMA_SIZE_MBYTES 0
>   #endif
>   
> +struct cma *dma_contiguous_default_area;
> +
>   /*
>    * Default global CMA area size can be defined in kernel's .config.
>    * This is useful mainly for distro maintainers to create a kernel
> @@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>   	}
>   }
>   
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> -	return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> -	return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> -						unsigned long pages)
> -{
> -	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> -	unsigned long bitmap_no, bitmap_count;
> -
> -	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	mutex_lock(&cma->lock);
> -	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> -	mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> -	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> -	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> -	unsigned i = cma->count >> pageblock_order;
> -	struct zone *zone;
> -
> -	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> -	if (!cma->bitmap)
> -		return -ENOMEM;
> -
> -	WARN_ON_ONCE(!pfn_valid(pfn));
> -	zone = page_zone(pfn_to_page(pfn));
> -
> -	do {
> -		unsigned j;
> -		base_pfn = pfn;
> -		for (j = pageblock_nr_pages; j; --j, pfn++) {
> -			WARN_ON_ONCE(!pfn_valid(pfn));
> -			/*
> -			 * alloc_contig_range requires the pfn range
> -			 * specified to be in the same zone. Make this
> -			 * simple by forcing the entire CMA resv range
> -			 * to be in the same zone.
> -			 */
> -			if (page_zone(pfn_to_page(pfn)) != zone)
> -				goto err;
> -		}
> -		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> -	} while (--i);
> -
> -	mutex_init(&cma->lock);
> -	return 0;
> -
> -err:
> -	kfree(cma->bitmap);
> -	return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> -	int i;
> -
> -	for (i = 0; i < cma_area_count; i++) {
> -		int ret = cma_activate_area(&cma_areas[i]);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> -			phys_addr_t base, phys_addr_t limit,
> -			phys_addr_t alignment, unsigned int order_per_bit,
> -			struct cma **res_cma, bool fixed)
> -{
> -	struct cma *cma = &cma_areas[cma_area_count];
> -	int ret = 0;
> -
> -	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> -		__func__, (unsigned long)size, (unsigned long)base,
> -		(unsigned long)limit, (unsigned long)alignment);
> -
> -	if (cma_area_count = ARRAY_SIZE(cma_areas)) {
> -		pr_err("Not enough slots for CMA reserved regions!\n");
> -		return -ENOSPC;
> -	}
> -
> -	if (!size)
> -		return -EINVAL;
> -
> -	if (alignment && !is_power_of_2(alignment))
> -		return -EINVAL;
> -
> -	/*
> -	 * Sanitise input arguments.
> -	 * Pages both ends in CMA area could be merged into adjacent unmovable
> -	 * migratetype page by page allocator's buddy algorithm. In the case,
> -	 * you couldn't get a contiguous memory, which is not what we want.
> -	 */
> -	alignment = max(alignment,
> -		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> -	base = ALIGN(base, alignment);
> -	size = ALIGN(size, alignment);
> -	limit &= ~(alignment - 1);
> -
> -	/* size should be aligned with order_per_bit */
> -	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> -		return -EINVAL;
> -
> -	/* Reserve memory */
> -	if (base && fixed) {
> -		if (memblock_is_region_reserved(base, size) ||
> -		    memblock_reserve(base, size) < 0) {
> -			ret = -EBUSY;
> -			goto err;
> -		}
> -	} else {
> -		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> -							limit);
> -		if (!addr) {
> -			ret = -ENOMEM;
> -			goto err;
> -		} else {
> -			base = addr;
> -		}
> -	}
> -
> -	/*
> -	 * Each reserved area must be initialised later, when more kernel
> -	 * subsystems (like slab allocator) are available.
> -	 */
> -	cma->base_pfn = PFN_DOWN(base);
> -	cma->count = size >> PAGE_SHIFT;
> -	cma->order_per_bit = order_per_bit;
> -	*res_cma = cma;
> -	cma_area_count++;
> -
> -	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> -		(unsigned long)base);
> -	return 0;
> -
> -err:
> -	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> -	return ret;
> -}
> -
>   /**
>    * dma_contiguous_reserve_area() - reserve custom contiguous area
>    * @size: Size of the reserved area (in bytes),
> @@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>   {
>   	int ret;
>   
> -	ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> -						res_cma, fixed);
> +	ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
>   	if (ret)
>   		return ret;
>   
>   	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
> -				(*res_cma)->count << PAGE_SHIFT);
> +	dma_contiguous_early_fixup(cma_get_base(*res_cma),
> +				cma_get_size(*res_cma));
>   
>   	return 0;
>   }
>   
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> -				       unsigned int align)
> -{
> -	unsigned long mask, pfn, start = 0;
> -	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> -	struct page *page = NULL;
> -	int ret;
> -
> -	if (!cma || !cma->count)
> -		return NULL;
> -
> -	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> -		 count, align);
> -
> -	if (!count)
> -		return NULL;
> -
> -	mask = cma_bitmap_aligned_mask(cma, align);
> -	bitmap_maxno = cma_bitmap_maxno(cma);
> -	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> -
> -	for (;;) {
> -		mutex_lock(&cma->lock);
> -		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> -				bitmap_maxno, start, bitmap_count, mask);
> -		if (bitmap_no >= bitmap_maxno) {
> -			mutex_unlock(&cma->lock);
> -			break;
> -		}
> -		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> -		/*
> -		 * It's safe to drop the lock here. We've marked this region for
> -		 * our exclusive use. If the migration fails we will take the
> -		 * lock again and unmark it.
> -		 */
> -		mutex_unlock(&cma->lock);
> -
> -		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> -		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> -		mutex_unlock(&cma_mutex);
> -		if (ret = 0) {
> -			page = pfn_to_page(pfn);
> -			break;
> -		} else if (ret != -EBUSY) {
> -			cma_clear_bitmap(cma, pfn, count);
> -			break;
> -		}
> -		cma_clear_bitmap(cma, pfn, count);
> -		pr_debug("%s(): memory range at %p is busy, retrying\n",
> -			 __func__, pfn_to_page(pfn));
> -		/* try again with a bit different memory target */
> -		start = bitmap_no + mask + 1;
> -	}
> -
> -	pr_debug("%s(): returned %p\n", __func__, page);
> -	return page;
> -}
> -
>   /**
>    * dma_alloc_from_contiguous() - allocate pages from contiguous area
>    * @dev:   Pointer to device for which the allocation is performed.
> @@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>   struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   				       unsigned int align)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
>   	if (align > CONFIG_CMA_ALIGNMENT)
>   		align = CONFIG_CMA_ALIGNMENT;
>   
> -	return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> -				 int count)
> -{
> -	unsigned long pfn;
> -
> -	if (!cma || !pages)
> -		return false;
> -
> -	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> -	pfn = page_to_pfn(pages);
> -
> -	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> -		return false;
> -
> -	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> -	free_contig_range(pfn, count);
> -	cma_clear_bitmap(cma, pfn, count);
> -
> -	return true;
> +	return cma_alloc(dev_get_cma_area(dev), count, align);
>   }
>   
>   /**
> @@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>   bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   				 int count)
>   {
> -	struct cma *cma = dev_get_cma_area(dev);
> -
> -	return __dma_release_from_contiguous(cma, pages, count);
> +	return cma_release(dev_get_cma_area(dev), pages, count);
>   }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..69d3726
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,21 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +
> +struct cma;
> +
> +extern phys_addr_t cma_get_base(struct cma *cma);
> +extern unsigned long cma_get_size(struct cma *cma);
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..569bbd0 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,18 +53,13 @@
>   
>   #ifdef __KERNEL__
>   
> +#include <linux/device.h>
> +
>   struct cma;
>   struct page;
> -struct device;
>   
>   #ifdef CONFIG_DMA_CMA
>   
> -/*
> - * There is always at least global CMA area and a few optional device
> - * private areas configured in kernel .config.
> - */
> -#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> -
>   extern struct cma *dma_contiguous_default_area;
>   
>   static inline struct cma *dev_get_cma_area(struct device *dev)
> @@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>   
>   #else
>   
> -#define MAX_CMA_AREAS	(0)
> -
>   static inline struct cma *dev_get_cma_area(struct device *dev)
>   {
>   	return NULL;
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
>   	  processing calls such as dma_alloc_from_contiguous().
>   	  This option does not affect warning and error messages.
>   
> +config CMA_AREAS
> +	int "Maximum count of the CMA areas"
> +	depends on CMA
> +	default 7
> +	help
> +	  CMA allows to create CMA areas for particular purpose, mainly,
> +	  used as device private area. This parameter sets the maximum
> +	  number of CMA area in the system.
> +
> +	  If unsure, leave the default value "7".
> +
>   config ZBUD
>   	tristate
>   	default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
>   obj-$(CONFIG_ZBUD)	+= zbud.o
>   obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
>   obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA)	+= cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..0cf50da
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,333 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + *	Marek Szyprowski <m.szyprowski@samsung.com>
> + *	Michal Nazarewicz <mina86@mina86.com>
> + *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +#  define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +#include <linux/cma.h>
> +
> +struct cma {
> +	unsigned long	base_pfn;
> +	unsigned long	count;
> +	unsigned long	*bitmap;
> +	unsigned int order_per_bit; /* Order of pages represented by one bit */
> +	struct mutex	lock;
> +};
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +phys_addr_t cma_get_base(struct cma *cma)
> +{
> +	return PFN_PHYS(cma->base_pfn);
> +}
> +
> +unsigned long cma_get_size(struct cma *cma)
> +{
> +	return cma->count << PAGE_SHIFT;
> +}
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> +	return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> +	return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> +						unsigned long pages)
> +{
> +	return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> +	unsigned long bitmap_no, bitmap_count;
> +
> +	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	mutex_lock(&cma->lock);
> +	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
> +	mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> +	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
> +	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> +	unsigned i = cma->count >> pageblock_order;
> +	struct zone *zone;
> +
> +	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +
> +	if (!cma->bitmap)
> +		return -ENOMEM;
> +
> +	WARN_ON_ONCE(!pfn_valid(pfn));
> +	zone = page_zone(pfn_to_page(pfn));
> +
> +	do {
> +		unsigned j;
> +
> +		base_pfn = pfn;
> +		for (j = pageblock_nr_pages; j; --j, pfn++) {
> +			WARN_ON_ONCE(!pfn_valid(pfn));
> +			/*
> +			 * alloc_contig_range requires the pfn range
> +			 * specified to be in the same zone. Make this
> +			 * simple by forcing the entire CMA resv range
> +			 * to be in the same zone.
> +			 */
> +			if (page_zone(pfn_to_page(pfn)) != zone)
> +				goto err;
> +		}
> +		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> +	} while (--i);
> +
> +	mutex_init(&cma->lock);
> +	return 0;
> +
> +err:
> +	kfree(cma->bitmap);
> +	return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < cma_area_count; i++) {
> +		int ret = cma_activate_area(&cma_areas[i]);
> +
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the CMA area, should be power of 2 or zero
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base.  If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> +			phys_addr_t base, phys_addr_t limit,
> +			phys_addr_t alignment, unsigned int order_per_bit,
> +			struct cma **res_cma, bool fixed)
> +{
> +	struct cma *cma = &cma_areas[cma_area_count];
> +	int ret = 0;
> +
> +	pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> +		__func__, (unsigned long)size, (unsigned long)base,
> +		(unsigned long)limit, (unsigned long)alignment);
> +
> +	if (cma_area_count = ARRAY_SIZE(cma_areas)) {
> +		pr_err("Not enough slots for CMA reserved regions!\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (!size)
> +		return -EINVAL;
> +
> +	if (alignment && !is_power_of_2(alignment))
> +		return -EINVAL;
> +
> +	/*
> +	 * Sanitise input arguments.
> +	 * Pages both ends in CMA area could be merged into adjacent unmovable
> +	 * migratetype page by page allocator's buddy algorithm. In the case,
> +	 * you couldn't get a contiguous memory, which is not what we want.
> +	 */
> +	alignment = max(alignment,
> +		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> +	base = ALIGN(base, alignment);
> +	size = ALIGN(size, alignment);
> +	limit &= ~(alignment - 1);
> +
> +	/* size should be aligned with order_per_bit */
> +	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
> +		return -EINVAL;
> +
> +	/* Reserve memory */
> +	if (base && fixed) {
> +		if (memblock_is_region_reserved(base, size) ||
> +		    memblock_reserve(base, size) < 0) {
> +			ret = -EBUSY;
> +			goto err;
> +		}
> +	} else {
> +		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> +							limit);
> +		if (!addr) {
> +			ret = -ENOMEM;
> +			goto err;
> +		} else {
> +			base = addr;
> +		}
> +	}
> +
> +	/*
> +	 * Each reserved area must be initialised later, when more kernel
> +	 * subsystems (like slab allocator) are available.
> +	 */
> +	cma->base_pfn = PFN_DOWN(base);
> +	cma->count = size >> PAGE_SHIFT;
> +	cma->order_per_bit = order_per_bit;
> +	*res_cma = cma;
> +	cma_area_count++;
> +
> +	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> +		(unsigned long)base);
> +	return 0;
> +
> +err:
> +	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> +	return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> +	unsigned long mask, pfn, start = 0;
> +	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
> +	struct page *page = NULL;
> +	int ret;
> +
> +	if (!cma || !cma->count)
> +		return NULL;
> +
> +	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> +		 count, align);
> +
> +	if (!count)
> +		return NULL;
> +
> +	mask = cma_bitmap_aligned_mask(cma, align);
> +	bitmap_maxno = cma_bitmap_maxno(cma);
> +	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
> +
> +	for (;;) {
> +		mutex_lock(&cma->lock);
> +		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
> +				bitmap_maxno, start, bitmap_count, mask);
> +		if (bitmap_no >= bitmap_maxno) {
> +			mutex_unlock(&cma->lock);
> +			break;
> +		}
> +		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
> +		/*
> +		 * It's safe to drop the lock here. We've marked this region for
> +		 * our exclusive use. If the migration fails we will take the
> +		 * lock again and unmark it.
> +		 */
> +		mutex_unlock(&cma->lock);
> +
> +		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> +		mutex_lock(&cma_mutex);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		mutex_unlock(&cma_mutex);
> +		if (ret = 0) {
> +			page = pfn_to_page(pfn);
> +			break;
> +		} else if (ret != -EBUSY) {
> +			cma_clear_bitmap(cma, pfn, count);
> +			break;
> +		}
> +		cma_clear_bitmap(cma, pfn, count);
> +		pr_debug("%s(): memory range at %p is busy, retrying\n",
> +			 __func__, pfn_to_page(pfn));
> +		/* try again with a bit different memory target */
> +		start = bitmap_no + mask + 1;
> +	}
> +
> +	pr_debug("%s(): returned %p\n", __func__, page);
> +	return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma:   Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> +	unsigned long pfn;
> +
> +	if (!cma || !pages)
> +		return false;
> +
> +	pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> +	pfn = page_to_pfn(pages);
> +
> +	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> +		return false;
> +
> +	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> +	free_contig_range(pfn, count);
> +	cma_clear_bitmap(cma, pfn, count);
> +
> +	return true;
> +}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
so we need to provide correct definition even if CMA is disabled.
This patch fixes this issue.

Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/cma.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9a18a2b1934c..c077635cad76 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -5,7 +5,11 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#else
+#define MAX_CMA_AREAS	(0)
+#endif
 
 struct cma;
 
-- 
1.9.2

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
so we need to provide correct definition even if CMA is disabled.
This patch fixes this issue.

Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/cma.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9a18a2b1934c..c077635cad76 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -5,7 +5,11 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#else
+#define MAX_CMA_AREAS	(0)
+#endif
 
 struct cma;
 
-- 
1.9.2

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[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
so we need to provide correct definition even if CMA is disabled.
This patch fixes this issue.

Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/cma.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9a18a2b1934c..c077635cad76 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -5,7 +5,11 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#else
+#define MAX_CMA_AREAS	(0)
+#endif
 
 struct cma;
 
-- 
1.9.2

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
so we need to provide correct definition even if CMA is disabled.
This patch fixes this issue.

Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/cma.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9a18a2b1934c..c077635cad76 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -5,7 +5,11 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#else
+#define MAX_CMA_AREAS	(0)
+#endif
 
 struct cma;
 
-- 
1.9.2

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
so we need to provide correct definition even if CMA is disabled.
This patch fixes this issue.

Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/cma.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9a18a2b1934c..c077635cad76 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -5,7 +5,11 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#else
+#define MAX_CMA_AREAS	(0)
+#endif
 
 struct cma;
 
-- 
1.9.2

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Andrew Morton]

On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
> so we need to provide correct definition even if CMA is disabled.
> This patch fixes this issue.
> 
> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  include/linux/cma.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9a18a2b1934c..c077635cad76 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -5,7 +5,11 @@
>   * There is always at least global CMA area and a few optional
>   * areas configured in kernel .config.
>   */
> +#ifdef CONFIG_CMA
>  #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +#else
> +#define MAX_CMA_AREAS	(0)
> +#endif
>  
>  struct cma;

Joonsoo already fixed this up, a bit differently:
http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch

Which approach makes more sense?



From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition

If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
isn't defined.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cma.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
--- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
+++ a/include/linux/cma.h
@@ -5,8 +5,14 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA_AREAS
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
 
+#else
+#define MAX_CMA_AREAS	(0)
+
+#endif
+
 struct cma;
 
 extern phys_addr_t cma_get_base(struct cma *cma);
_

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Andrew Morton]

On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
> so we need to provide correct definition even if CMA is disabled.
> This patch fixes this issue.
> 
> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  include/linux/cma.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9a18a2b1934c..c077635cad76 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -5,7 +5,11 @@
>   * There is always at least global CMA area and a few optional
>   * areas configured in kernel .config.
>   */
> +#ifdef CONFIG_CMA
>  #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +#else
> +#define MAX_CMA_AREAS	(0)
> +#endif
>  
>  struct cma;

Joonsoo already fixed this up, a bit differently:
http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch

Which approach makes more sense?



From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition

If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
isn't defined.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cma.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
--- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
+++ a/include/linux/cma.h
@@ -5,8 +5,14 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA_AREAS
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
 
+#else
+#define MAX_CMA_AREAS	(0)
+
+#endif
+
 struct cma;
 
 extern phys_addr_t cma_get_base(struct cma *cma);
_


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Andrew Morton]

On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
> so we need to provide correct definition even if CMA is disabled.
> This patch fixes this issue.
> 
> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  include/linux/cma.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9a18a2b1934c..c077635cad76 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -5,7 +5,11 @@
>   * There is always at least global CMA area and a few optional
>   * areas configured in kernel .config.
>   */
> +#ifdef CONFIG_CMA
>  #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +#else
> +#define MAX_CMA_AREAS	(0)
> +#endif
>  
>  struct cma;

Joonsoo already fixed this up, a bit differently:
http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch

Which approach makes more sense?



From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition

If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
isn't defined.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cma.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
--- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
+++ a/include/linux/cma.h
@@ -5,8 +5,14 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA_AREAS
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
 
+#else
+#define MAX_CMA_AREAS	(0)
+
+#endif
+
 struct cma;
 
 extern phys_addr_t cma_get_base(struct cma *cma);
_

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Andrew Morton]

On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
> so we need to provide correct definition even if CMA is disabled.
> This patch fixes this issue.
> 
> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  include/linux/cma.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9a18a2b1934c..c077635cad76 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -5,7 +5,11 @@
>   * There is always at least global CMA area and a few optional
>   * areas configured in kernel .config.
>   */
> +#ifdef CONFIG_CMA
>  #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +#else
> +#define MAX_CMA_AREAS	(0)
> +#endif
>  
>  struct cma;

Joonsoo already fixed this up, a bit differently:
http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch

Which approach makes more sense?



From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition

If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
isn't defined.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cma.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
--- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
+++ a/include/linux/cma.h
@@ -5,8 +5,14 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA_AREAS
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
 
+#else
+#define MAX_CMA_AREAS	(0)
+
+#endif
+
 struct cma;
 
 extern phys_addr_t cma_get_base(struct cma *cma);
_

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Andrew Morton]

On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:

> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
> so we need to provide correct definition even if CMA is disabled.
> This patch fixes this issue.
> 
> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  include/linux/cma.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9a18a2b1934c..c077635cad76 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -5,7 +5,11 @@
>   * There is always at least global CMA area and a few optional
>   * areas configured in kernel .config.
>   */
> +#ifdef CONFIG_CMA
>  #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
> +#else
> +#define MAX_CMA_AREAS	(0)
> +#endif
>  
>  struct cma;

Joonsoo already fixed this up, a bit differently:
http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch

Which approach makes more sense?



From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition

If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
isn't defined.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cma.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
--- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
+++ a/include/linux/cma.h
@@ -5,8 +5,14 @@
  * There is always at least global CMA area and a few optional
  * areas configured in kernel .config.
  */
+#ifdef CONFIG_CMA_AREAS
 #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
 
+#else
+#define MAX_CMA_AREAS	(0)
+
+#endif
+
 struct cma;
 
 extern phys_addr_t cma_get_base(struct cma *cma);
_

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

Hello,

On 2014-07-18 00:06, Andrew Morton wrote:
> On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
>> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
>> so we need to provide correct definition even if CMA is disabled.
>> This patch fixes this issue.
>>
>> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   include/linux/cma.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/cma.h b/include/linux/cma.h
>> index 9a18a2b1934c..c077635cad76 100644
>> --- a/include/linux/cma.h
>> +++ b/include/linux/cma.h
>> @@ -5,7 +5,11 @@
>>    * There is always at least global CMA area and a few optional
>>    * areas configured in kernel .config.
>>    */
>> +#ifdef CONFIG_CMA
>>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>> +#else
>> +#define MAX_CMA_AREAS	(0)
>> +#endif
>>   
>>   struct cma;
> Joonsoo already fixed this up, a bit differently:
> http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch
>
> Which approach makes more sense?

CMA_AREAS depends on CMA being enabled, so both approaches works exactly
the same way. Please keep Joonsoo's patch and just ignore mine to avoid
confusing others by disappearing patches. I'm sorry that I've missed it
before sending mine.

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition
>
> If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
> happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
> isn't defined.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   include/linux/cma.h |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
> --- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
> +++ a/include/linux/cma.h
> @@ -5,8 +5,14 @@
>    * There is always at least global CMA area and a few optional
>    * areas configured in kernel .config.
>    */
> +#ifdef CONFIG_CMA_AREAS
>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>   
> +#else
> +#define MAX_CMA_AREAS	(0)
> +
> +#endif
> +
>   struct cma;
>   
>   extern phys_addr_t cma_get_base(struct cma *cma);
> _

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

Hello,

On 2014-07-18 00:06, Andrew Morton wrote:
> On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
>> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
>> so we need to provide correct definition even if CMA is disabled.
>> This patch fixes this issue.
>>
>> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   include/linux/cma.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/cma.h b/include/linux/cma.h
>> index 9a18a2b1934c..c077635cad76 100644
>> --- a/include/linux/cma.h
>> +++ b/include/linux/cma.h
>> @@ -5,7 +5,11 @@
>>    * There is always at least global CMA area and a few optional
>>    * areas configured in kernel .config.
>>    */
>> +#ifdef CONFIG_CMA
>>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>> +#else
>> +#define MAX_CMA_AREAS	(0)
>> +#endif
>>   
>>   struct cma;
> Joonsoo already fixed this up, a bit differently:
> http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch
>
> Which approach makes more sense?

CMA_AREAS depends on CMA being enabled, so both approaches works exactly
the same way. Please keep Joonsoo's patch and just ignore mine to avoid
confusing others by disappearing patches. I'm sorry that I've missed it
before sending mine.

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition
>
> If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
> happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
> isn't defined.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   include/linux/cma.h |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
> --- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
> +++ a/include/linux/cma.h
> @@ -5,8 +5,14 @@
>    * There is always at least global CMA area and a few optional
>    * areas configured in kernel .config.
>    */
> +#ifdef CONFIG_CMA_AREAS
>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>   
> +#else
> +#define MAX_CMA_AREAS	(0)
> +
> +#endif
> +
>   struct cma;
>   
>   extern phys_addr_t cma_get_base(struct cma *cma);
> _

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

Hello,

On 2014-07-18 00:06, Andrew Morton wrote:
> On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
>> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
>> so we need to provide correct definition even if CMA is disabled.
>> This patch fixes this issue.
>>
>> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   include/linux/cma.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/cma.h b/include/linux/cma.h
>> index 9a18a2b1934c..c077635cad76 100644
>> --- a/include/linux/cma.h
>> +++ b/include/linux/cma.h
>> @@ -5,7 +5,11 @@
>>    * There is always at least global CMA area and a few optional
>>    * areas configured in kernel .config.
>>    */
>> +#ifdef CONFIG_CMA
>>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>> +#else
>> +#define MAX_CMA_AREAS	(0)
>> +#endif
>>   
>>   struct cma;
> Joonsoo already fixed this up, a bit differently:
> http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch
>
> Which approach makes more sense?

CMA_AREAS depends on CMA being enabled, so both approaches works exactly
the same way. Please keep Joonsoo's patch and just ignore mine to avoid
confusing others by disappearing patches. I'm sorry that I've missed it
before sending mine.

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition
>
> If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
> happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
> isn't defined.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   include/linux/cma.h |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
> --- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
> +++ a/include/linux/cma.h
> @@ -5,8 +5,14 @@
>    * There is always at least global CMA area and a few optional
>    * areas configured in kernel .config.
>    */
> +#ifdef CONFIG_CMA_AREAS
>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>   
> +#else
> +#define MAX_CMA_AREAS	(0)
> +
> +#endif
> +
>   struct cma;
>   
>   extern phys_addr_t cma_get_base(struct cma *cma);
> _

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

[PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

Hello,

On 2014-07-18 00:06, Andrew Morton wrote:
> On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
>> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
>> so we need to provide correct definition even if CMA is disabled.
>> This patch fixes this issue.
>>
>> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   include/linux/cma.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/cma.h b/include/linux/cma.h
>> index 9a18a2b1934c..c077635cad76 100644
>> --- a/include/linux/cma.h
>> +++ b/include/linux/cma.h
>> @@ -5,7 +5,11 @@
>>    * There is always at least global CMA area and a few optional
>>    * areas configured in kernel .config.
>>    */
>> +#ifdef CONFIG_CMA
>>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>> +#else
>> +#define MAX_CMA_AREAS	(0)
>> +#endif
>>   
>>   struct cma;
> Joonsoo already fixed this up, a bit differently:
> http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch
>
> Which approach makes more sense?

CMA_AREAS depends on CMA being enabled, so both approaches works exactly
the same way. Please keep Joonsoo's patch and just ignore mine to avoid
confusing others by disappearing patches. I'm sorry that I've missed it
before sending mine.

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition
>
> If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
> happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
> isn't defined.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   include/linux/cma.h |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
> --- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
> +++ a/include/linux/cma.h
> @@ -5,8 +5,14 @@
>    * There is always at least global CMA area and a few optional
>    * areas configured in kernel .config.
>    */
> +#ifdef CONFIG_CMA_AREAS
>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>   
> +#else
> +#define MAX_CMA_AREAS	(0)
> +
> +#endif
> +
>   struct cma;
>   
>   extern phys_addr_t cma_get_base(struct cma *cma);
> _

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] CMA: generalize CMA reserved area management functionality (fixup)

[Marek Szyprowski]

Hello,

On 2014-07-18 00:06, Andrew Morton wrote:
> On Thu, 17 Jul 2014 11:36:07 +0200 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
>> MAX_CMA_AREAS is used by other subsystems (i.e. arch/arm/mm/dma-mapping.c),
>> so we need to provide correct definition even if CMA is disabled.
>> This patch fixes this issue.
>>
>> Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   include/linux/cma.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/include/linux/cma.h b/include/linux/cma.h
>> index 9a18a2b1934c..c077635cad76 100644
>> --- a/include/linux/cma.h
>> +++ b/include/linux/cma.h
>> @@ -5,7 +5,11 @@
>>    * There is always at least global CMA area and a few optional
>>    * areas configured in kernel .config.
>>    */
>> +#ifdef CONFIG_CMA
>>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>> +#else
>> +#define MAX_CMA_AREAS	(0)
>> +#endif
>>   
>>   struct cma;
> Joonsoo already fixed this up, a bit differently:
> http://ozlabs.org/~akpm/mmots/broken-out/cma-generalize-cma-reserved-area-management-functionality-fix.patch
>
> Which approach makes more sense?

CMA_AREAS depends on CMA being enabled, so both approaches works exactly
the same way. Please keep Joonsoo's patch and just ignore mine to avoid
confusing others by disappearing patches. I'm sorry that I've missed it
before sending mine.

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: CMA: fix ARM build failure related to MAX_CMA_AREAS definition
>
> If CMA is disabled, CONFIG_CMA_AREAS isn't defined so compile error
> happens. To fix it, define MAX_CMA_AREAS if CONFIG_CMA_AREAS
> isn't defined.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   include/linux/cma.h |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff -puN include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix include/linux/cma.h
> --- a/include/linux/cma.h~cma-generalize-cma-reserved-area-management-functionality-fix
> +++ a/include/linux/cma.h
> @@ -5,8 +5,14 @@
>    * There is always at least global CMA area and a few optional
>    * areas configured in kernel .config.
>    */
> +#ifdef CONFIG_CMA_AREAS
>   #define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
>   
> +#else
> +#define MAX_CMA_AREAS	(0)
> +
> +#endif
> +
>   struct cma;
>   
>   extern phys_addr_t cma_get_base(struct cma *cma);
> _

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland