[PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Joerg Roedel]

Hi,

here is the next version of this patch-set. Previous
versions can be found here:

	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/

	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/

	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/

	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/

The problem solved here is a limitation of the SWIOTLB implementation,
which does not support allocations larger than 256kb.  When the
virtio-blk driver tries to read/write a block larger than that, the
allocation of the dma-handle fails and an IO error is reported.

Changes to v4 are:

	- Added Reviewed-by tags from Christoph

	- Added missing EXPORT_SYMBOL(_GPL) lines

Please review.

Thanks,

	Joerg
Joerg Roedel (5):
  swiotlb: Introduce swiotlb_max_mapping_size()
  swiotlb: Add is_swiotlb_active() function
  dma: Introduce dma_max_mapping_size()
  virtio: Introduce virtio_max_dma_size()
  virtio-blk: Consider virtio_max_dma_size() for maximum segment size

 Documentation/DMA-API.txt    |  8 ++++++++
 drivers/block/virtio_blk.c   | 10 ++++++----
 drivers/virtio/virtio_ring.c | 11 +++++++++++
 include/linux/dma-mapping.h  | 16 ++++++++++++++++
 include/linux/swiotlb.h      | 11 +++++++++++
 include/linux/virtio.h       |  2 ++
 kernel/dma/direct.c          | 12 ++++++++++++
 kernel/dma/swiotlb.c         | 14 ++++++++++++++
 8 files changed, 80 insertions(+), 4 deletions(-)

-- 
2.17.1

[PATCH 1/5] swiotlb: Introduce swiotlb_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be remapped
by the SWIOTLB implementation. This function will be later
exposed to users through the DMA-API.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/swiotlb.h | 5 +++++
 kernel/dma/swiotlb.c    | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 7c007ed7505f..1c22d96e1742 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -62,6 +62,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
 
 extern int
 swiotlb_dma_supported(struct device *hwdev, u64 mask);
+size_t swiotlb_max_mapping_size(struct device *dev);
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
@@ -95,6 +96,10 @@ static inline unsigned int swiotlb_max_segment(void)
 {
 	return 0;
 }
+static inline size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return SIZE_MAX;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1fb6fd68b9c7..9cb21259cb0b 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -662,3 +662,8 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
 	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
 }
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+}
-- 
2.17.1

[PATCH 1/5] swiotlb: Introduce swiotlb_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be remapped
by the SWIOTLB implementation. This function will be later
exposed to users through the DMA-API.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/swiotlb.h | 5 +++++
 kernel/dma/swiotlb.c    | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 7c007ed7505f..1c22d96e1742 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -62,6 +62,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
 
 extern int
 swiotlb_dma_supported(struct device *hwdev, u64 mask);
+size_t swiotlb_max_mapping_size(struct device *dev);
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
@@ -95,6 +96,10 @@ static inline unsigned int swiotlb_max_segment(void)
 {
 	return 0;
 }
+static inline size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return SIZE_MAX;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1fb6fd68b9c7..9cb21259cb0b 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -662,3 +662,8 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
 	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
 }
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+}
-- 
2.17.1

[PATCH 2/5] swiotlb: Add is_swiotlb_active() function

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

This function will be used from dma_direct code to determine
the maximum segment size of a dma mapping.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/swiotlb.h | 6 ++++++
 kernel/dma/swiotlb.c    | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 1c22d96e1742..e9e786b4b598 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -63,6 +63,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
 extern int
 swiotlb_dma_supported(struct device *hwdev, u64 mask);
 size_t swiotlb_max_mapping_size(struct device *dev);
+bool is_swiotlb_active(void);
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
@@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev)
 {
 	return SIZE_MAX;
 }
+
+static inline bool is_swiotlb_active(void)
+{
+	return false;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9cb21259cb0b..c873f9cc2146 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 {
 	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
 }
+
+bool is_swiotlb_active(void)
+{
+	/*
+	 * When SWIOTLB is initialized, even if io_tlb_start points to physical
+	 * address zero, io_tlb_end surely doesn't.
+	 */
+	return io_tlb_end != 0;
+}
-- 
2.17.1

[PATCH 2/5] swiotlb: Add is_swiotlb_active() function

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

This function will be used from dma_direct code to determine
the maximum segment size of a dma mapping.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/swiotlb.h | 6 ++++++
 kernel/dma/swiotlb.c    | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 1c22d96e1742..e9e786b4b598 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -63,6 +63,7 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
 extern int
 swiotlb_dma_supported(struct device *hwdev, u64 mask);
 size_t swiotlb_max_mapping_size(struct device *dev);
+bool is_swiotlb_active(void);
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
@@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev)
 {
 	return SIZE_MAX;
 }
+
+static inline bool is_swiotlb_active(void)
+{
+	return false;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9cb21259cb0b..c873f9cc2146 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 {
 	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
 }
+
+bool is_swiotlb_active(void)
+{
+	/*
+	 * When SWIOTLB is initialized, even if io_tlb_start points to physical
+	 * address zero, io_tlb_end surely doesn't.
+	 */
+	return io_tlb_end != 0;
+}
-- 
2.17.1

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 12 ++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..81ca8170b928 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,15 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL(dma_direct_max_mapping_size);
-- 
2.17.1

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 12 ++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..81ca8170b928 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,15 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL(dma_direct_max_mapping_size);
-- 
2.17.1

[PATCH 4/5] virtio: Introduce virtio_max_dma_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

This function returns the maximum segment size for a single
dma transaction of a virtio device. The possible limit comes
from the SWIOTLB implementation in the Linux kernel, that
has an upper limit of (currently) 256kb of contiguous
memory it can map. Other DMA-API implementations might also
have limits.

Use the new dma_max_mapping_size() function to determine the
maximum mapping size when DMA-API is in use for virtio.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/virtio/virtio_ring.c | 11 +++++++++++
 include/linux/virtio.h       |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cd7e755484e3..8a31c6862b2b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -266,6 +266,17 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
 	return false;
 }
 
+size_t virtio_max_dma_size(struct virtio_device *vdev)
+{
+	size_t max_segment_size = SIZE_MAX;
+
+	if (vring_use_dma_api(vdev))
+		max_segment_size = dma_max_mapping_size(&vdev->dev);
+
+	return max_segment_size;
+}
+EXPORT_SYMBOL_GPL(virtio_max_dma_size);
+
 static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
 			      dma_addr_t *dma_handle, gfp_t flag)
 {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index fa1b5da2804e..673fe3ef3607 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -157,6 +157,8 @@ int virtio_device_freeze(struct virtio_device *dev);
 int virtio_device_restore(struct virtio_device *dev);
 #endif
 
+size_t virtio_max_dma_size(struct virtio_device *vdev);
+
 #define virtio_device_for_each_vq(vdev, vq) \
 	list_for_each_entry(vq, &vdev->vqs, list)
 
-- 
2.17.1

[PATCH 4/5] virtio: Introduce virtio_max_dma_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

This function returns the maximum segment size for a single
dma transaction of a virtio device. The possible limit comes
from the SWIOTLB implementation in the Linux kernel, that
has an upper limit of (currently) 256kb of contiguous
memory it can map. Other DMA-API implementations might also
have limits.

Use the new dma_max_mapping_size() function to determine the
maximum mapping size when DMA-API is in use for virtio.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/virtio/virtio_ring.c | 11 +++++++++++
 include/linux/virtio.h       |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cd7e755484e3..8a31c6862b2b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -266,6 +266,17 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
 	return false;
 }
 
+size_t virtio_max_dma_size(struct virtio_device *vdev)
+{
+	size_t max_segment_size = SIZE_MAX;
+
+	if (vring_use_dma_api(vdev))
+		max_segment_size = dma_max_mapping_size(&vdev->dev);
+
+	return max_segment_size;
+}
+EXPORT_SYMBOL_GPL(virtio_max_dma_size);
+
 static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
 			      dma_addr_t *dma_handle, gfp_t flag)
 {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index fa1b5da2804e..673fe3ef3607 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -157,6 +157,8 @@ int virtio_device_freeze(struct virtio_device *dev);
 int virtio_device_restore(struct virtio_device *dev);
 #endif
 
+size_t virtio_max_dma_size(struct virtio_device *vdev);
+
 #define virtio_device_for_each_vq(vdev, vq) \
 	list_for_each_entry(vq, &vdev->vqs, list)
 
-- 
2.17.1

[PATCH 5/5] virtio-blk: Consider virtio_max_dma_size() for maximum segment size

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

Segments can't be larger than the maximum DMA mapping size
supported on the platform. Take that into account when
setting the maximum segment size for a block device.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/block/virtio_blk.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b16a887bbd02..4bc083b7c9b5 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -723,7 +723,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	struct request_queue *q;
 	int err, index;
 
-	u32 v, blk_size, sg_elems, opt_io_size;
+	u32 v, blk_size, max_size, sg_elems, opt_io_size;
 	u16 min_io_size;
 	u8 physical_block_exp, alignment_offset;
 
@@ -826,14 +826,16 @@ static int virtblk_probe(struct virtio_device *vdev)
 	/* No real sector limit. */
 	blk_queue_max_hw_sectors(q, -1U);
 
+	max_size = virtio_max_dma_size(vdev);
+
 	/* Host can optionally specify maximum segment size and number of
 	 * segments. */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
 				   struct virtio_blk_config, size_max, &v);
 	if (!err)
-		blk_queue_max_segment_size(q, v);
-	else
-		blk_queue_max_segment_size(q, -1U);
+		max_size = min(max_size, v);
+
+	blk_queue_max_segment_size(q, max_size);
 
 	/* Host can optionally specify the block size of the device */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
-- 
2.17.1

[PATCH 5/5] virtio-blk: Consider virtio_max_dma_size() for maximum segment size

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

Segments can't be larger than the maximum DMA mapping size
supported on the platform. Take that into account when
setting the maximum segment size for a block device.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/block/virtio_blk.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b16a887bbd02..4bc083b7c9b5 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -723,7 +723,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	struct request_queue *q;
 	int err, index;
 
-	u32 v, blk_size, sg_elems, opt_io_size;
+	u32 v, blk_size, max_size, sg_elems, opt_io_size;
 	u16 min_io_size;
 	u8 physical_block_exp, alignment_offset;
 
@@ -826,14 +826,16 @@ static int virtblk_probe(struct virtio_device *vdev)
 	/* No real sector limit. */
 	blk_queue_max_hw_sectors(q, -1U);
 
+	max_size = virtio_max_dma_size(vdev);
+
 	/* Host can optionally specify maximum segment size and number of
 	 * segments. */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
 				   struct virtio_blk_config, size_max, &v);
 	if (!err)
-		blk_queue_max_segment_size(q, v);
-	else
-		blk_queue_max_segment_size(q, -1U);
+		max_size = min(max_size, v);
+
+	blk_queue_max_segment_size(q, max_size);
 
 	/* Host can optionally specify the block size of the device */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
-- 
2.17.1

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Lendacky, Thomas]

On 1/30/19 10:40 AM, Joerg Roedel wrote:
> Hi,
> 
> here is the next version of this patch-set. Previous
> versions can be found here:
> 
> 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> 
> 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> 
> 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> 
> 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> 
> The problem solved here is a limitation of the SWIOTLB implementation,
> which does not support allocations larger than 256kb.  When the
> virtio-blk driver tries to read/write a block larger than that, the
> allocation of the dma-handle fails and an IO error is reported.
> 
> Changes to v4 are:
> 
> 	- Added Reviewed-by tags from Christoph
> 
> 	- Added missing EXPORT_SYMBOL(_GPL) lines
> 
> Please review.

Looks good. Booted and tested using an SEV guest without any issues.

Tested-by: Tom Lendacky <thomas.lendacky@amd.com>

Thanks,
Tom

> 
> Thanks,
> 
> 	Joerg
> Joerg Roedel (5):
>   swiotlb: Introduce swiotlb_max_mapping_size()
>   swiotlb: Add is_swiotlb_active() function
>   dma: Introduce dma_max_mapping_size()
>   virtio: Introduce virtio_max_dma_size()
>   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> 
>  Documentation/DMA-API.txt    |  8 ++++++++
>  drivers/block/virtio_blk.c   | 10 ++++++----
>  drivers/virtio/virtio_ring.c | 11 +++++++++++
>  include/linux/dma-mapping.h  | 16 ++++++++++++++++
>  include/linux/swiotlb.h      | 11 +++++++++++
>  include/linux/virtio.h       |  2 ++
>  kernel/dma/direct.c          | 12 ++++++++++++
>  kernel/dma/swiotlb.c         | 14 ++++++++++++++
>  8 files changed, 80 insertions(+), 4 deletions(-)
> 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Lendacky, Thomas]

On 1/30/19 10:40 AM, Joerg Roedel wrote:
> Hi,
> 
> here is the next version of this patch-set. Previous
> versions can be found here:
> 
> 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> 
> 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> 
> 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> 
> 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> 
> The problem solved here is a limitation of the SWIOTLB implementation,
> which does not support allocations larger than 256kb.  When the
> virtio-blk driver tries to read/write a block larger than that, the
> allocation of the dma-handle fails and an IO error is reported.
> 
> Changes to v4 are:
> 
> 	- Added Reviewed-by tags from Christoph
> 
> 	- Added missing EXPORT_SYMBOL(_GPL) lines
> 
> Please review.

Looks good. Booted and tested using an SEV guest without any issues.

Tested-by: Tom Lendacky <thomas.lendacky@amd.com>

Thanks,
Tom

> 
> Thanks,
> 
> 	Joerg
> Joerg Roedel (5):
>   swiotlb: Introduce swiotlb_max_mapping_size()
>   swiotlb: Add is_swiotlb_active() function
>   dma: Introduce dma_max_mapping_size()
>   virtio: Introduce virtio_max_dma_size()
>   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> 
>  Documentation/DMA-API.txt    |  8 ++++++++
>  drivers/block/virtio_blk.c   | 10 ++++++----
>  drivers/virtio/virtio_ring.c | 11 +++++++++++
>  include/linux/dma-mapping.h  | 16 ++++++++++++++++
>  include/linux/swiotlb.h      | 11 +++++++++++
>  include/linux/virtio.h       |  2 ++
>  kernel/dma/direct.c          | 12 ++++++++++++
>  kernel/dma/swiotlb.c         | 14 ++++++++++++++
>  8 files changed, 80 insertions(+), 4 deletions(-)
> 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Lendacky, Thomas]

On 1/30/19 10:40 AM, Joerg Roedel wrote:
> Hi,
> 
> here is the next version of this patch-set. Previous
> versions can be found here:
> 
> 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> 
> 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> 
> 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> 
> 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> 
> The problem solved here is a limitation of the SWIOTLB implementation,
> which does not support allocations larger than 256kb.  When the
> virtio-blk driver tries to read/write a block larger than that, the
> allocation of the dma-handle fails and an IO error is reported.
> 
> Changes to v4 are:
> 
> 	- Added Reviewed-by tags from Christoph
> 
> 	- Added missing EXPORT_SYMBOL(_GPL) lines
> 
> Please review.

Looks good. Booted and tested using an SEV guest without any issues.

Tested-by: Tom Lendacky <thomas.lendacky@amd.com>

Thanks,
Tom

> 
> Thanks,
> 
> 	Joerg
> Joerg Roedel (5):
>   swiotlb: Introduce swiotlb_max_mapping_size()
>   swiotlb: Add is_swiotlb_active() function
>   dma: Introduce dma_max_mapping_size()
>   virtio: Introduce virtio_max_dma_size()
>   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> 
>  Documentation/DMA-API.txt    |  8 ++++++++
>  drivers/block/virtio_blk.c   | 10 ++++++----
>  drivers/virtio/virtio_ring.c | 11 +++++++++++
>  include/linux/dma-mapping.h  | 16 ++++++++++++++++
>  include/linux/swiotlb.h      | 11 +++++++++++
>  include/linux/virtio.h       |  2 ++
>  kernel/dma/direct.c          | 12 ++++++++++++
>  kernel/dma/swiotlb.c         | 14 ++++++++++++++
>  8 files changed, 80 insertions(+), 4 deletions(-)
> 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Konrad Rzeszutek Wilk]

On Wed, Jan 30, 2019 at 05:40:02PM +0100, Joerg Roedel wrote:
> Hi,
> 
> here is the next version of this patch-set. Previous
> versions can be found here:
> 
> 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> 
> 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> 
> 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> 
> 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> 
> The problem solved here is a limitation of the SWIOTLB implementation,
> which does not support allocations larger than 256kb.  When the
> virtio-blk driver tries to read/write a block larger than that, the
> allocation of the dma-handle fails and an IO error is reported.
> 
> Changes to v4 are:
> 
> 	- Added Reviewed-by tags from Christoph
> 
> 	- Added missing EXPORT_SYMBOL(_GPL) lines
> 
> Please review.

I can put it in my tree and send it to Linus .. unless folks want
to do it through a different tree?


> 
> Thanks,
> 
> 	Joerg
> Joerg Roedel (5):
>   swiotlb: Introduce swiotlb_max_mapping_size()
>   swiotlb: Add is_swiotlb_active() function
>   dma: Introduce dma_max_mapping_size()
>   virtio: Introduce virtio_max_dma_size()
>   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> 
>  Documentation/DMA-API.txt    |  8 ++++++++
>  drivers/block/virtio_blk.c   | 10 ++++++----
>  drivers/virtio/virtio_ring.c | 11 +++++++++++
>  include/linux/dma-mapping.h  | 16 ++++++++++++++++
>  include/linux/swiotlb.h      | 11 +++++++++++
>  include/linux/virtio.h       |  2 ++
>  kernel/dma/direct.c          | 12 ++++++++++++
>  kernel/dma/swiotlb.c         | 14 ++++++++++++++
>  8 files changed, 80 insertions(+), 4 deletions(-)
> 
> -- 
> 2.17.1
> 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Konrad Rzeszutek Wilk]

On Wed, Jan 30, 2019 at 05:40:02PM +0100, Joerg Roedel wrote:
> Hi,
> 
> here is the next version of this patch-set. Previous
> versions can be found here:
> 
> 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> 
> 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> 
> 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> 
> 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> 
> The problem solved here is a limitation of the SWIOTLB implementation,
> which does not support allocations larger than 256kb.  When the
> virtio-blk driver tries to read/write a block larger than that, the
> allocation of the dma-handle fails and an IO error is reported.
> 
> Changes to v4 are:
> 
> 	- Added Reviewed-by tags from Christoph
> 
> 	- Added missing EXPORT_SYMBOL(_GPL) lines
> 
> Please review.

I can put it in my tree and send it to Linus .. unless folks want
to do it through a different tree?


> 
> Thanks,
> 
> 	Joerg
> Joerg Roedel (5):
>   swiotlb: Introduce swiotlb_max_mapping_size()
>   swiotlb: Add is_swiotlb_active() function
>   dma: Introduce dma_max_mapping_size()
>   virtio: Introduce virtio_max_dma_size()
>   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> 
>  Documentation/DMA-API.txt    |  8 ++++++++
>  drivers/block/virtio_blk.c   | 10 ++++++----
>  drivers/virtio/virtio_ring.c | 11 +++++++++++
>  include/linux/dma-mapping.h  | 16 ++++++++++++++++
>  include/linux/swiotlb.h      | 11 +++++++++++
>  include/linux/virtio.h       |  2 ++
>  kernel/dma/direct.c          | 12 ++++++++++++
>  kernel/dma/swiotlb.c         | 14 ++++++++++++++
>  8 files changed, 80 insertions(+), 4 deletions(-)
> 
> -- 
> 2.17.1
> 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Michael S. Tsirkin]

On Wed, Jan 30, 2019 at 01:35:13PM -0500, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 30, 2019 at 05:40:02PM +0100, Joerg Roedel wrote:
> > Hi,
> > 
> > here is the next version of this patch-set. Previous
> > versions can be found here:
> > 
> > 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> > 
> > 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> > 
> > 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> > 
> > 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> > 
> > The problem solved here is a limitation of the SWIOTLB implementation,
> > which does not support allocations larger than 256kb.  When the
> > virtio-blk driver tries to read/write a block larger than that, the
> > allocation of the dma-handle fails and an IO error is reported.
> > 
> > Changes to v4 are:
> > 
> > 	- Added Reviewed-by tags from Christoph
> > 
> > 	- Added missing EXPORT_SYMBOL(_GPL) lines
> > 
> > Please review.
> 
> I can put it in my tree and send it to Linus .. unless folks want
> to do it through a different tree?

I queued it in my tree as it seems virtio specific.

> 
> > 
> > Thanks,
> > 
> > 	Joerg
> > Joerg Roedel (5):
> >   swiotlb: Introduce swiotlb_max_mapping_size()
> >   swiotlb: Add is_swiotlb_active() function
> >   dma: Introduce dma_max_mapping_size()
> >   virtio: Introduce virtio_max_dma_size()
> >   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> > 
> >  Documentation/DMA-API.txt    |  8 ++++++++
> >  drivers/block/virtio_blk.c   | 10 ++++++----
> >  drivers/virtio/virtio_ring.c | 11 +++++++++++
> >  include/linux/dma-mapping.h  | 16 ++++++++++++++++
> >  include/linux/swiotlb.h      | 11 +++++++++++
> >  include/linux/virtio.h       |  2 ++
> >  kernel/dma/direct.c          | 12 ++++++++++++
> >  kernel/dma/swiotlb.c         | 14 ++++++++++++++
> >  8 files changed, 80 insertions(+), 4 deletions(-)
> > 
> > -- 
> > 2.17.1
> > 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Michael S. Tsirkin]

On Wed, Jan 30, 2019 at 01:35:13PM -0500, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 30, 2019 at 05:40:02PM +0100, Joerg Roedel wrote:
> > Hi,
> > 
> > here is the next version of this patch-set. Previous
> > versions can be found here:
> > 
> > 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org/
> > 
> > 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org/
> > 
> > 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org/
> > 
> > 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org/
> > 
> > The problem solved here is a limitation of the SWIOTLB implementation,
> > which does not support allocations larger than 256kb.  When the
> > virtio-blk driver tries to read/write a block larger than that, the
> > allocation of the dma-handle fails and an IO error is reported.
> > 
> > Changes to v4 are:
> > 
> > 	- Added Reviewed-by tags from Christoph
> > 
> > 	- Added missing EXPORT_SYMBOL(_GPL) lines
> > 
> > Please review.
> 
> I can put it in my tree and send it to Linus .. unless folks want
> to do it through a different tree?

I queued it in my tree as it seems virtio specific.

> 
> > 
> > Thanks,
> > 
> > 	Joerg
> > Joerg Roedel (5):
> >   swiotlb: Introduce swiotlb_max_mapping_size()
> >   swiotlb: Add is_swiotlb_active() function
> >   dma: Introduce dma_max_mapping_size()
> >   virtio: Introduce virtio_max_dma_size()
> >   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> > 
> >  Documentation/DMA-API.txt    |  8 ++++++++
> >  drivers/block/virtio_blk.c   | 10 ++++++----
> >  drivers/virtio/virtio_ring.c | 11 +++++++++++
> >  include/linux/dma-mapping.h  | 16 ++++++++++++++++
> >  include/linux/swiotlb.h      | 11 +++++++++++
> >  include/linux/virtio.h       |  2 ++
> >  kernel/dma/direct.c          | 12 ++++++++++++
> >  kernel/dma/swiotlb.c         | 14 ++++++++++++++
> >  8 files changed, 80 insertions(+), 4 deletions(-)
> > 
> > -- 
> > 2.17.1
> > 

Re: [PATCH 0/5 v5] Fix virtio-blk issue with SWIOTLB

[Michael S. Tsirkin]

On Wed, Jan 30, 2019 at 01:35:13PM -0500, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 30, 2019 at 05:40:02PM +0100, Joerg Roedel wrote:
> > Hi,
> > 
> > here is the next version of this patch-set. Previous
> > versions can be found here:
> > 
> > 	V1: https://lore.kernel.org/lkml/20190110134433.15672-1-joro@8bytes.org/
> > 
> > 	V2: https://lore.kernel.org/lkml/20190115132257.6426-1-joro@8bytes.org/
> > 
> > 	V3: https://lore.kernel.org/lkml/20190123163049.24863-1-joro@8bytes.org/
> > 
> > 	V4: https://lore.kernel.org/lkml/20190129084342.26030-1-joro@8bytes.org/
> > 
> > The problem solved here is a limitation of the SWIOTLB implementation,
> > which does not support allocations larger than 256kb.  When the
> > virtio-blk driver tries to read/write a block larger than that, the
> > allocation of the dma-handle fails and an IO error is reported.
> > 
> > Changes to v4 are:
> > 
> > 	- Added Reviewed-by tags from Christoph
> > 
> > 	- Added missing EXPORT_SYMBOL(_GPL) lines
> > 
> > Please review.
> 
> I can put it in my tree and send it to Linus .. unless folks want
> to do it through a different tree?

I queued it in my tree as it seems virtio specific.

> 
> > 
> > Thanks,
> > 
> > 	Joerg
> > Joerg Roedel (5):
> >   swiotlb: Introduce swiotlb_max_mapping_size()
> >   swiotlb: Add is_swiotlb_active() function
> >   dma: Introduce dma_max_mapping_size()
> >   virtio: Introduce virtio_max_dma_size()
> >   virtio-blk: Consider virtio_max_dma_size() for maximum segment size
> > 
> >  Documentation/DMA-API.txt    |  8 ++++++++
> >  drivers/block/virtio_blk.c   | 10 ++++++----
> >  drivers/virtio/virtio_ring.c | 11 +++++++++++
> >  include/linux/dma-mapping.h  | 16 ++++++++++++++++
> >  include/linux/swiotlb.h      | 11 +++++++++++
> >  include/linux/virtio.h       |  2 ++
> >  kernel/dma/direct.c          | 12 ++++++++++++
> >  kernel/dma/swiotlb.c         | 14 ++++++++++++++
> >  8 files changed, 80 insertions(+), 4 deletions(-)
> > 
> > -- 
> > 2.17.1
> > 

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

> +static inline size_t dma_max_mapping_size(struct device *dev)
> +{
> +	const struct dma_map_ops *ops = get_dma_ops(dev);
> +	size_t size = SIZE_MAX;
> +
> +	if (dma_is_direct(ops))
> +		size = dma_direct_max_mapping_size(dev);
> +	else if (ops && ops->max_mapping_size)
> +		size = ops->max_mapping_size(dev);
> +
> +	return size;
> +}

Sorry for not noticing last time, but since 5.0 we keep all non-fast
path DMA mapping interfaces out of line, so this should move to
kernel/dma/mapping.c.

> +EXPORT_SYMBOL(dma_direct_max_mapping_size);

And then there is no need to export this one.

The dma_max_mapping_size export should be EXPORT_SYMBOL_GPL like all
new dma-mapping interfaces.

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

> +static inline size_t dma_max_mapping_size(struct device *dev)
> +{
> +	const struct dma_map_ops *ops = get_dma_ops(dev);
> +	size_t size = SIZE_MAX;
> +
> +	if (dma_is_direct(ops))
> +		size = dma_direct_max_mapping_size(dev);
> +	else if (ops && ops->max_mapping_size)
> +		size = ops->max_mapping_size(dev);
> +
> +	return size;
> +}

Sorry for not noticing last time, but since 5.0 we keep all non-fast
path DMA mapping interfaces out of line, so this should move to
kernel/dma/mapping.c.

> +EXPORT_SYMBOL(dma_direct_max_mapping_size);

And then there is no need to export this one.

The dma_max_mapping_size export should be EXPORT_SYMBOL_GPL like all
new dma-mapping interfaces.

[PATCH] dma: Uninline dma_max_mapping_size()

[Joerg Roedel]

On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> Sorry for not noticing last time, but since 5.0 we keep all non-fast
> path DMA mapping interfaces out of line, so this should move to
> kernel/dma/mapping.c.

Okay, attached patch does that. It applies on-top of this patch-set.

Michael, feel free to either apply this on-top of the patch-set or merge
the diff into patch 3, whatever you prefer.

From 2bb95d2136280c79de9553852ee3370f6d42d7b3 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Thu, 31 Jan 2019 13:55:27 +0100
Subject: [PATCH] dma: Uninline dma_max_mapping_size()

The function is not performance sensitive and doesn't need
to be inlined at every call-site. Move it out of the header
into the appropriate C source file.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/dma-mapping.h | 18 +++++-------------
 kernel/dma/direct.c         |  1 -
 kernel/dma/mapping.c        | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index a3ca8a71a704..5b21f14802e1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -443,19 +443,6 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
-static inline size_t dma_max_mapping_size(struct device *dev)
-{
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-	size_t size = SIZE_MAX;
-
-	if (dma_is_direct(ops))
-		size = dma_direct_max_mapping_size(dev);
-	else if (ops && ops->max_mapping_size)
-		size = ops->max_mapping_size(dev);
-
-	return size;
-}
-
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@@ -476,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
 u64 dma_get_required_mask(struct device *dev);
+size_t dma_max_mapping_size(struct device *dev);
 #else /* CONFIG_HAS_DMA */
 static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 		struct page *page, size_t offset, size_t size,
@@ -577,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
 {
 	return 0;
 }
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_HAS_DMA */
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 81ca8170b928..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -391,4 +391,3 @@ size_t dma_direct_max_mapping_size(struct device *dev)
 
 	return size;
 }
-EXPORT_SYMBOL(dma_direct_max_mapping_size);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
-- 
2.16.4

[PATCH] dma: Uninline dma_max_mapping_size()

[Joerg Roedel]

On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> Sorry for not noticing last time, but since 5.0 we keep all non-fast
> path DMA mapping interfaces out of line, so this should move to
> kernel/dma/mapping.c.

Okay, attached patch does that. It applies on-top of this patch-set.

Michael, feel free to either apply this on-top of the patch-set or merge
the diff into patch 3, whatever you prefer.

>From 2bb95d2136280c79de9553852ee3370f6d42d7b3 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Thu, 31 Jan 2019 13:55:27 +0100
Subject: [PATCH] dma: Uninline dma_max_mapping_size()

The function is not performance sensitive and doesn't need
to be inlined at every call-site. Move it out of the header
into the appropriate C source file.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/dma-mapping.h | 18 +++++-------------
 kernel/dma/direct.c         |  1 -
 kernel/dma/mapping.c        | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index a3ca8a71a704..5b21f14802e1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -443,19 +443,6 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
-static inline size_t dma_max_mapping_size(struct device *dev)
-{
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-	size_t size = SIZE_MAX;
-
-	if (dma_is_direct(ops))
-		size = dma_direct_max_mapping_size(dev);
-	else if (ops && ops->max_mapping_size)
-		size = ops->max_mapping_size(dev);
-
-	return size;
-}
-
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@@ -476,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
 u64 dma_get_required_mask(struct device *dev);
+size_t dma_max_mapping_size(struct device *dev);
 #else /* CONFIG_HAS_DMA */
 static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 		struct page *page, size_t offset, size_t size,
@@ -577,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
 {
 	return 0;
 }
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_HAS_DMA */
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 81ca8170b928..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -391,4 +391,3 @@ size_t dma_direct_max_mapping_size(struct device *dev)
 
 	return size;
 }
-EXPORT_SYMBOL(dma_direct_max_mapping_size);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
-- 
2.16.4

[PATCH] dma: Uninline dma_max_mapping_size()

[Joerg Roedel]

On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> Sorry for not noticing last time, but since 5.0 we keep all non-fast
> path DMA mapping interfaces out of line, so this should move to
> kernel/dma/mapping.c.

Okay, attached patch does that. It applies on-top of this patch-set.

Michael, feel free to either apply this on-top of the patch-set or merge
the diff into patch 3, whatever you prefer.

From 2bb95d2136280c79de9553852ee3370f6d42d7b3 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Thu, 31 Jan 2019 13:55:27 +0100
Subject: [PATCH] dma: Uninline dma_max_mapping_size()

The function is not performance sensitive and doesn't need
to be inlined at every call-site. Move it out of the header
into the appropriate C source file.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/dma-mapping.h | 18 +++++-------------
 kernel/dma/direct.c         |  1 -
 kernel/dma/mapping.c        | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index a3ca8a71a704..5b21f14802e1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -443,19 +443,6 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
-static inline size_t dma_max_mapping_size(struct device *dev)
-{
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-	size_t size = SIZE_MAX;
-
-	if (dma_is_direct(ops))
-		size = dma_direct_max_mapping_size(dev);
-	else if (ops && ops->max_mapping_size)
-		size = ops->max_mapping_size(dev);
-
-	return size;
-}
-
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@@ -476,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
 u64 dma_get_required_mask(struct device *dev);
+size_t dma_max_mapping_size(struct device *dev);
 #else /* CONFIG_HAS_DMA */
 static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 		struct page *page, size_t offset, size_t size,
@@ -577,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
 {
 	return 0;
 }
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_HAS_DMA */
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 81ca8170b928..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -391,4 +391,3 @@ size_t dma_direct_max_mapping_size(struct device *dev)
 
 	return size;
 }
-EXPORT_SYMBOL(dma_direct_max_mapping_size);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
-- 
2.16.4

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Christoph Hellwig]

On Thu, Jan 31, 2019 at 02:01:27PM +0100, Joerg Roedel wrote:
> On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> > Sorry for not noticing last time, but since 5.0 we keep all non-fast
> > path DMA mapping interfaces out of line, so this should move to
> > kernel/dma/mapping.c.
> 
> Okay, attached patch does that. It applies on-top of this patch-set.
> 
> Michael, feel free to either apply this on-top of the patch-set or merge
> the diff into patch 3, whatever you prefer.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

I'd prefer it to be squashed if possible.

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Christoph Hellwig]

On Thu, Jan 31, 2019 at 02:01:27PM +0100, Joerg Roedel wrote:
> On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> > Sorry for not noticing last time, but since 5.0 we keep all non-fast
> > path DMA mapping interfaces out of line, so this should move to
> > kernel/dma/mapping.c.
> 
> Okay, attached patch does that. It applies on-top of this patch-set.
> 
> Michael, feel free to either apply this on-top of the patch-set or merge
> the diff into patch 3, whatever you prefer.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

I'd prefer it to be squashed if possible.

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Michael S. Tsirkin]

On Thu, Jan 31, 2019 at 03:37:23PM +0100, Christoph Hellwig wrote:
> On Thu, Jan 31, 2019 at 02:01:27PM +0100, Joerg Roedel wrote:
> > On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> > > Sorry for not noticing last time, but since 5.0 we keep all non-fast
> > > path DMA mapping interfaces out of line, so this should move to
> > > kernel/dma/mapping.c.
> > 
> > Okay, attached patch does that. It applies on-top of this patch-set.
> > 
> > Michael, feel free to either apply this on-top of the patch-set or merge
> > the diff into patch 3, whatever you prefer.
> 
> Looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> I'd prefer it to be squashed if possible.

OK. Joerg can you repost the series with this squashed
and all acks applied?

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Michael S. Tsirkin]

On Thu, Jan 31, 2019 at 03:37:23PM +0100, Christoph Hellwig wrote:
> On Thu, Jan 31, 2019 at 02:01:27PM +0100, Joerg Roedel wrote:
> > On Thu, Jan 31, 2019 at 11:41:29AM +0100, Christoph Hellwig wrote:
> > > Sorry for not noticing last time, but since 5.0 we keep all non-fast
> > > path DMA mapping interfaces out of line, so this should move to
> > > kernel/dma/mapping.c.
> > 
> > Okay, attached patch does that. It applies on-top of this patch-set.
> > 
> > Michael, feel free to either apply this on-top of the patch-set or merge
> > the diff into patch 3, whatever you prefer.
> 
> Looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> I'd prefer it to be squashed if possible.

OK. Joerg can you repost the series with this squashed
and all acks applied?

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Joerg Roedel]

On Thu, Jan 31, 2019 at 09:43:51AM -0500, Michael S. Tsirkin wrote:
> OK. Joerg can you repost the series with this squashed
> and all acks applied?

Sure, sent out now as v6.

Regards,

	Joerg

Re: [PATCH] dma: Uninline dma_max_mapping_size()

[Joerg Roedel]

On Thu, Jan 31, 2019 at 09:43:51AM -0500, Michael S. Tsirkin wrote:
> OK. Joerg can you repost the series with this squashed
> and all acks applied?

Sure, sent out now as v6.

Regards,

	Joerg

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h |  8 ++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 kernel/dma/mapping.c        | 14 ++++++++++++++
 4 files changed, 41 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..5b21f14802e1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -460,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
 u64 dma_get_required_mask(struct device *dev);
+size_t dma_max_mapping_size(struct device *dev);
 #else /* CONFIG_HAS_DMA */
 static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 		struct page *page, size_t offset, size_t size,
@@ -561,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
 {
 	return 0;
 }
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_HAS_DMA */
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
-- 
2.17.1

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h |  8 ++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 kernel/dma/mapping.c        | 14 ++++++++++++++
 4 files changed, 41 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..5b21f14802e1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -460,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
 u64 dma_get_required_mask(struct device *dev);
+size_t dma_max_mapping_size(struct device *dev);
 #else /* CONFIG_HAS_DMA */
 static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 		struct page *page, size_t offset, size_t size,
@@ -561,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
 {
 	return 0;
 }
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_HAS_DMA */
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
-- 
2.17.1

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Lendacky, Thomas]

On 1/29/19 2:43 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The function returns the maximum size that can be mapped
> using DMA-API functions. The patch also adds the
> implementation for direct DMA and a new dma_map_ops pointer
> so that other implementations can expose their limit.
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  Documentation/DMA-API.txt   |  8 ++++++++
>  include/linux/dma-mapping.h | 16 ++++++++++++++++
>  kernel/dma/direct.c         | 11 +++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
> index e133ccd60228..acfe3d0f78d1 100644
> --- a/Documentation/DMA-API.txt
> +++ b/Documentation/DMA-API.txt
> @@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
>  wish to take advantage of it, you should issue a dma_set_mask()
>  call to set the mask to the value returned.
>  
> +::
> +
> +	size_t
> +	dma_direct_max_mapping_size(struct device *dev);
> +
> +Returns the maximum size of a mapping for the device. The size parameter
> +of the mapping functions like dma_map_single(), dma_map_page() and
> +others should not be larger than the returned value.
>  
>  Part Id - Streaming DMA mappings
>  --------------------------------
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index f6ded992c183..a3ca8a71a704 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -130,6 +130,7 @@ struct dma_map_ops {
>  			enum dma_data_direction direction);
>  	int (*dma_supported)(struct device *dev, u64 mask);
>  	u64 (*get_required_mask)(struct device *dev);
> +	size_t (*max_mapping_size)(struct device *dev);
>  };
>  
>  #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
> @@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
>  }
>  #endif
>  
> +size_t dma_direct_max_mapping_size(struct device *dev);
> +
>  #ifdef CONFIG_HAS_DMA
>  #include <asm/dma-mapping.h>
>  
> @@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>  	return 0;
>  }
>  
> +static inline size_t dma_max_mapping_size(struct device *dev)
> +{
> +	const struct dma_map_ops *ops = get_dma_ops(dev);
> +	size_t size = SIZE_MAX;
> +
> +	if (dma_is_direct(ops))
> +		size = dma_direct_max_mapping_size(dev);
> +	else if (ops && ops->max_mapping_size)
> +		size = ops->max_mapping_size(dev);
> +
> +	return size;
> +}
> +
>  void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  		gfp_t flag, unsigned long attrs);
>  void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 355d16acee6d..6310ad01f915 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
>  	 */
>  	return mask >= __phys_to_dma(dev, min_mask);
>  }
> +
> +size_t dma_direct_max_mapping_size(struct device *dev)
> +{
> +	size_t size = SIZE_MAX;
> +
> +	/* If SWIOTLB is active, use its maximum mapping size */
> +	if (is_swiotlb_active())
> +		size = swiotlb_max_mapping_size(dev);
> +
> +	return size;
> +}

When I build with these patches and with the virtio devices as modules I
get a build failure. Looks like this needs an EXPORT_SYMBOL() (I'm
assuming EXPORT_SYMBOL for DMA functions and not EXPORT_SYMBOL_GPL?).

Thanks,
Tom

> 

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Lendacky, Thomas]

On 1/29/19 2:43 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The function returns the maximum size that can be mapped
> using DMA-API functions. The patch also adds the
> implementation for direct DMA and a new dma_map_ops pointer
> so that other implementations can expose their limit.
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  Documentation/DMA-API.txt   |  8 ++++++++
>  include/linux/dma-mapping.h | 16 ++++++++++++++++
>  kernel/dma/direct.c         | 11 +++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
> index e133ccd60228..acfe3d0f78d1 100644
> --- a/Documentation/DMA-API.txt
> +++ b/Documentation/DMA-API.txt
> @@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
>  wish to take advantage of it, you should issue a dma_set_mask()
>  call to set the mask to the value returned.
>  
> +::
> +
> +	size_t
> +	dma_direct_max_mapping_size(struct device *dev);
> +
> +Returns the maximum size of a mapping for the device. The size parameter
> +of the mapping functions like dma_map_single(), dma_map_page() and
> +others should not be larger than the returned value.
>  
>  Part Id - Streaming DMA mappings
>  --------------------------------
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index f6ded992c183..a3ca8a71a704 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -130,6 +130,7 @@ struct dma_map_ops {
>  			enum dma_data_direction direction);
>  	int (*dma_supported)(struct device *dev, u64 mask);
>  	u64 (*get_required_mask)(struct device *dev);
> +	size_t (*max_mapping_size)(struct device *dev);
>  };
>  
>  #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
> @@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
>  }
>  #endif
>  
> +size_t dma_direct_max_mapping_size(struct device *dev);
> +
>  #ifdef CONFIG_HAS_DMA
>  #include <asm/dma-mapping.h>
>  
> @@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>  	return 0;
>  }
>  
> +static inline size_t dma_max_mapping_size(struct device *dev)
> +{
> +	const struct dma_map_ops *ops = get_dma_ops(dev);
> +	size_t size = SIZE_MAX;
> +
> +	if (dma_is_direct(ops))
> +		size = dma_direct_max_mapping_size(dev);
> +	else if (ops && ops->max_mapping_size)
> +		size = ops->max_mapping_size(dev);
> +
> +	return size;
> +}
> +
>  void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  		gfp_t flag, unsigned long attrs);
>  void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 355d16acee6d..6310ad01f915 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
>  	 */
>  	return mask >= __phys_to_dma(dev, min_mask);
>  }
> +
> +size_t dma_direct_max_mapping_size(struct device *dev)
> +{
> +	size_t size = SIZE_MAX;
> +
> +	/* If SWIOTLB is active, use its maximum mapping size */
> +	if (is_swiotlb_active())
> +		size = swiotlb_max_mapping_size(dev);
> +
> +	return size;
> +}

When I build with these patches and with the virtio devices as modules I
get a build failure. Looks like this needs an EXPORT_SYMBOL() (I'm
assuming EXPORT_SYMBOL for DMA functions and not EXPORT_SYMBOL_GPL?).

Thanks,
Tom

> 

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Lendacky, Thomas]

On 1/29/19 2:43 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The function returns the maximum size that can be mapped
> using DMA-API functions. The patch also adds the
> implementation for direct DMA and a new dma_map_ops pointer
> so that other implementations can expose their limit.
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  Documentation/DMA-API.txt   |  8 ++++++++
>  include/linux/dma-mapping.h | 16 ++++++++++++++++
>  kernel/dma/direct.c         | 11 +++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
> index e133ccd60228..acfe3d0f78d1 100644
> --- a/Documentation/DMA-API.txt
> +++ b/Documentation/DMA-API.txt
> @@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
>  wish to take advantage of it, you should issue a dma_set_mask()
>  call to set the mask to the value returned.
>  
> +::
> +
> +	size_t
> +	dma_direct_max_mapping_size(struct device *dev);
> +
> +Returns the maximum size of a mapping for the device. The size parameter
> +of the mapping functions like dma_map_single(), dma_map_page() and
> +others should not be larger than the returned value.
>  
>  Part Id - Streaming DMA mappings
>  --------------------------------
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index f6ded992c183..a3ca8a71a704 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -130,6 +130,7 @@ struct dma_map_ops {
>  			enum dma_data_direction direction);
>  	int (*dma_supported)(struct device *dev, u64 mask);
>  	u64 (*get_required_mask)(struct device *dev);
> +	size_t (*max_mapping_size)(struct device *dev);
>  };
>  
>  #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
> @@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
>  }
>  #endif
>  
> +size_t dma_direct_max_mapping_size(struct device *dev);
> +
>  #ifdef CONFIG_HAS_DMA
>  #include <asm/dma-mapping.h>
>  
> @@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>  	return 0;
>  }
>  
> +static inline size_t dma_max_mapping_size(struct device *dev)
> +{
> +	const struct dma_map_ops *ops = get_dma_ops(dev);
> +	size_t size = SIZE_MAX;
> +
> +	if (dma_is_direct(ops))
> +		size = dma_direct_max_mapping_size(dev);
> +	else if (ops && ops->max_mapping_size)
> +		size = ops->max_mapping_size(dev);
> +
> +	return size;
> +}
> +
>  void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  		gfp_t flag, unsigned long attrs);
>  void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 355d16acee6d..6310ad01f915 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
>  	 */
>  	return mask >= __phys_to_dma(dev, min_mask);
>  }
> +
> +size_t dma_direct_max_mapping_size(struct device *dev)
> +{
> +	size_t size = SIZE_MAX;
> +
> +	/* If SWIOTLB is active, use its maximum mapping size */
> +	if (is_swiotlb_active())
> +		size = swiotlb_max_mapping_size(dev);
> +
> +	return size;
> +}

When I build with these patches and with the virtio devices as modules I
get a build failure. Looks like this needs an EXPORT_SYMBOL() (I'm
assuming EXPORT_SYMBOL for DMA functions and not EXPORT_SYMBOL_GPL?).

Thanks,
Tom

> 

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

On Tue, Jan 29, 2019 at 09:43:40AM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The function returns the maximum size that can be mapped
> using DMA-API functions. The patch also adds the
> implementation for direct DMA and a new dma_map_ops pointer
> so that other implementations can expose their limit.
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

On Tue, Jan 29, 2019 at 09:43:40AM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> The function returns the maximum size that can be mapped
> using DMA-API functions. The patch also adds the
> implementation for direct DMA and a new dma_map_ops pointer
> so that other implementations can expose their limit.
> 
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 3 files changed, 35 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
-- 
2.17.1

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 Documentation/DMA-API.txt   |  8 ++++++++
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 3 files changed, 35 insertions(+)

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..acfe3d0f78d1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -195,6 +195,14 @@ Requesting the required mask does not alter the current mask.  If you
 wish to take advantage of it, you should issue a dma_set_mask()
 call to set the mask to the value returned.
 
+::
+
+	size_t
+	dma_direct_max_mapping_size(struct device *dev);
+
+Returns the maximum size of a mapping for the device. The size parameter
+of the mapping functions like dma_map_single(), dma_map_page() and
+others should not be larger than the returned value.
 
 Part Id - Streaming DMA mappings
 --------------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
-- 
2.17.1

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

This looks ok, but could really use some documentation in
Documentation/DMA-API.txt.

Re: [PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

This looks ok, but could really use some documentation in
Documentation/DMA-API.txt.

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
-- 
2.17.1

[PATCH 3/5] dma: Introduce dma_max_mapping_size()

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 kernel/dma/direct.c         | 11 +++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
 			enum dma_data_direction direction);
 	int (*dma_supported)(struct device *dev, u64 mask);
 	u64 (*get_required_mask)(struct device *dev);
+	size_t (*max_mapping_size)(struct device *dev);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
 }
 #endif
 
+size_t dma_direct_max_mapping_size(struct device *dev);
+
 #ifdef CONFIG_HAS_DMA
 #include <asm/dma-mapping.h>
 
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	 */
 	return mask >= __phys_to_dma(dev, min_mask);
 }
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	size_t size = SIZE_MAX;
+
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active())
+		size = swiotlb_max_mapping_size(dev);
+
+	return size;
+}
-- 
2.17.1