[RFC PATCH v3 0/2] RDMA/rxe: Add dma-buf support

[RFC PATCH v3 0/2] RDMA/rxe: Add dma-buf support

[Shunsuke Mie]

This patch series add a dma-buf support for rxe driver.

A dma-buf based memory registering has beed introduced to use the memory
region that lack of associated page structures (e.g. device memory and CMA
managed memory) [1]. However, to use the dma-buf based memory, each rdma
device drivers require add some implementation. The rxe driver has not
support yet.

[1] https://www.spinics.net/lists/linux-rdma/msg98592.html

To enable to use the dma-buf memory in rxe rdma device, add some changes
and implementation in this patch series.

This series consists of two patches. The first patch changes the IB core
to support for rdma drivers that has not dma device. The secound patch adds
the dma-buf support to rxe driver.

Related user space RDMA library changes are provided as a separate patch.

v3:
* Rebase to the latest linux-rdma 'for-next' branch (5.15.0-rc6+)
* Fix to use dma-buf-map helpers
v2: https://www.spinics.net/lists/linux-rdma/msg105928.html
* Rebase to the latest linux-rdma 'for-next' branch (5.15.0-rc1+)
* Instead of using a dummy dma_device to attach dma-buf, just store
  dma-buf to use software RDMA driver
* Use dma-buf vmap() interface
* Check to pass tests of rdma-core
v1: https://www.spinics.net/lists/linux-rdma/msg105376.html
* The initial patch set
* Use ib_device as dma_device.
* Use dma-buf dynamic attach interface
* Add dma-buf support to rxe device

Shunsuke Mie (2):
  RDMA/umem: Change for rdma devices has not dma device
  RDMA/rxe: Add dma-buf support

 drivers/infiniband/core/umem_dmabuf.c |  20 ++++-
 drivers/infiniband/sw/rxe/rxe_loc.h   |   2 +
 drivers/infiniband/sw/rxe/rxe_mr.c    | 113 ++++++++++++++++++++++++++
 drivers/infiniband/sw/rxe/rxe_verbs.c |  34 ++++++++
 include/rdma/ib_umem.h                |   1 +
 5 files changed, 166 insertions(+), 4 deletions(-)

-- 
2.17.1

[RFC PATCH v3 1/2] RDMA/umem: Change for rdma devices has not dma device

[Shunsuke Mie]

Current implementation requires a dma device for RDMA driver to use
dma-buf memory space as RDMA buffer. However, software RDMA drivers has
not dma device and copy RDMA data using CPU instead of hardware.

This patch changes to be hold a dma-buf on struct ib_umem_dmabuf. This
allows the software RDMA driver to map dma-buf memory for CPU memory
accessing.

Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
---
 drivers/infiniband/core/umem_dmabuf.c | 20 ++++++++++++++++----
 include/rdma/ib_umem.h                |  1 +
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
index e824baf4640d..ebbb0a259fd4 100644
--- a/drivers/infiniband/core/umem_dmabuf.c
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -117,9 +117,6 @@ struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
 	if (check_add_overflow(offset, (unsigned long)size, &end))
 		return ret;
 
-	if (unlikely(!ops || !ops->move_notify))
-		return ret;
-
 	dmabuf = dma_buf_get(fd);
 	if (IS_ERR(dmabuf))
 		return ERR_CAST(dmabuf);
@@ -133,6 +130,8 @@ struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
 		goto out_release_dmabuf;
 	}
 
+	umem_dmabuf->dmabuf = dmabuf;
+
 	umem = &umem_dmabuf->umem;
 	umem->ibdev = device;
 	umem->length = size;
@@ -143,6 +142,13 @@ struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
 	if (!ib_umem_num_pages(umem))
 		goto out_free_umem;
 
+	/* Software RDMA drivers has not dma device. Just get dmabuf from fd */
+	if (!device->dma_device)
+		goto done;
+
+	if (unlikely(!ops || !ops->move_notify))
+		goto out_free_umem;
+
 	umem_dmabuf->attach = dma_buf_dynamic_attach(
 					dmabuf,
 					device->dma_device,
@@ -152,6 +158,7 @@ struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
 		ret = ERR_CAST(umem_dmabuf->attach);
 		goto out_free_umem;
 	}
+done:
 	return umem_dmabuf;
 
 out_free_umem:
@@ -165,13 +172,18 @@ EXPORT_SYMBOL(ib_umem_dmabuf_get);
 
 void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
 {
-	struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
+	struct dma_buf *dmabuf = umem_dmabuf->dmabuf;
+
+	if (!umem_dmabuf->attach)
+		goto free_dmabuf;
 
 	dma_resv_lock(dmabuf->resv, NULL);
 	ib_umem_dmabuf_unmap_pages(umem_dmabuf);
 	dma_resv_unlock(dmabuf->resv);
 
 	dma_buf_detach(dmabuf, umem_dmabuf->attach);
+
+free_dmabuf:
 	dma_buf_put(dmabuf);
 	kfree(umem_dmabuf);
 }
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 5ae9dff74dac..11c0cf7e0dd8 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -32,6 +32,7 @@ struct ib_umem {
 struct ib_umem_dmabuf {
 	struct ib_umem umem;
 	struct dma_buf_attachment *attach;
+	struct dma_buf *dmabuf;
 	struct sg_table *sgt;
 	struct scatterlist *first_sg;
 	struct scatterlist *last_sg;
-- 
2.17.1

[RFC PATCH v3 2/2] RDMA/rxe: Add dma-buf support

[Shunsuke Mie]

Implement a ib device operation ‘reg_user_mr_dmabuf’. Generate a
rxe_map from the memory space linked the passed dma-buf.

Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
---
 drivers/infiniband/sw/rxe/rxe_loc.h   |   2 +
 drivers/infiniband/sw/rxe/rxe_mr.c    | 113 ++++++++++++++++++++++++++
 drivers/infiniband/sw/rxe/rxe_verbs.c |  34 ++++++++
 3 files changed, 149 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 1ca43b859d80..8bc19ea1a376 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -75,6 +75,8 @@ u8 rxe_get_next_key(u32 last_key);
 void rxe_mr_init_dma(struct rxe_pd *pd, int access, struct rxe_mr *mr);
 int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 		     int access, struct rxe_mr *mr);
+int rxe_mr_dmabuf_init_user(struct rxe_pd *pd, int fd, u64 start, u64 length,
+			    u64 iova, int access, struct rxe_mr *mr);
 int rxe_mr_init_fast(struct rxe_pd *pd, int max_pages, struct rxe_mr *mr);
 int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 		enum rxe_mr_copy_dir dir);
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 53271df10e47..ba1282b99772 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -4,6 +4,8 @@
  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
  */
 
+#include <linux/dma-buf.h>
+#include <linux/dma-buf-map.h>
 #include "rxe.h"
 #include "rxe_loc.h"
 
@@ -245,6 +247,114 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 	return err;
 }
 
+static int rxe_map_dmabuf_mr(struct rxe_mr *mr,
+			     struct ib_umem_dmabuf *umem_dmabuf)
+{
+	struct rxe_map_set *set;
+	struct rxe_phys_buf *buf = NULL;
+	struct rxe_map **map;
+	void *vaddr, *vaddr_end;
+	int num_buf = 0;
+	int err;
+	size_t remain;
+	struct dma_buf_map dmabuf_map;
+
+	err = dma_buf_vmap(umem_dmabuf->dmabuf, &dmabuf_map);
+	if (err || dmabuf_map.is_iomem)
+		goto err_out;
+
+	set = mr->cur_map_set;
+	set->page_shift = PAGE_SHIFT;
+	set->page_mask = PAGE_SIZE - 1;
+
+	map = set->map;
+	buf = map[0]->buf;
+
+	vaddr = dmabuf_map.vaddr;
+	vaddr_end = vaddr + umem_dmabuf->dmabuf->size;
+	remain = umem_dmabuf->dmabuf->size;
+
+	for (; remain; vaddr += PAGE_SIZE) {
+		if (num_buf >= RXE_BUF_PER_MAP) {
+			map++;
+			buf = map[0]->buf;
+			num_buf = 0;
+		}
+
+		buf->addr = (uintptr_t)vaddr;
+		if (remain >= PAGE_SIZE)
+			buf->size = PAGE_SIZE;
+		else
+			buf->size = remain;
+		remain -= buf->size;
+
+		num_buf++;
+		buf++;
+	}
+
+	return 0;
+
+err_out:
+	return err;
+}
+
+static void rxe_unmap_dmabuf_mr(struct rxe_mr *mr)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(mr->umem);
+	struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(
+		(void *)mr->cur_map_set->map[0]->buf->addr);
+
+	dma_buf_vunmap(umem_dmabuf->dmabuf, &map);
+}
+
+int rxe_mr_dmabuf_init_user(struct rxe_pd *pd, int fd, u64 start, u64 length,
+			    u64 iova, int access, struct rxe_mr *mr)
+{
+	struct ib_umem_dmabuf *umem_dmabuf;
+	struct rxe_map_set *set;
+	int err;
+
+	umem_dmabuf = ib_umem_dmabuf_get(pd->ibpd.device, start, length, fd,
+					 access, NULL);
+	if (IS_ERR(umem_dmabuf)) {
+		err = PTR_ERR(umem_dmabuf);
+		goto err_out;
+	}
+
+	rxe_mr_init(access, mr);
+
+	err = rxe_mr_alloc(mr, ib_umem_num_pages(&umem_dmabuf->umem), 0);
+	if (err) {
+		pr_warn("%s: Unable to allocate memory for map\n", __func__);
+		goto err_release_umem;
+	}
+
+	mr->ibmr.pd = &pd->ibpd;
+	mr->umem = &umem_dmabuf->umem;
+	mr->access = access;
+	mr->state = RXE_MR_STATE_VALID;
+	mr->type = IB_MR_TYPE_USER;
+
+	set = mr->cur_map_set;
+	set->length = length;
+	set->iova = iova;
+	set->va = start;
+	set->offset = ib_umem_offset(mr->umem);
+
+	err = rxe_map_dmabuf_mr(mr, umem_dmabuf);
+	if (err)
+		goto err_free_map_set;
+
+	return 0;
+
+err_free_map_set:
+	rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
+err_release_umem:
+	ib_umem_release(&umem_dmabuf->umem);
+err_out:
+	return err;
+}
+
 int rxe_mr_init_fast(struct rxe_pd *pd, int max_pages, struct rxe_mr *mr)
 {
 	int err;
@@ -703,6 +813,9 @@ void rxe_mr_cleanup(struct rxe_pool_entry *arg)
 {
 	struct rxe_mr *mr = container_of(arg, typeof(*mr), pelem);
 
+	if (mr->umem && mr->umem->is_dmabuf)
+		rxe_unmap_dmabuf_mr(mr);
+
 	ib_umem_release(mr->umem);
 
 	if (mr->cur_map_set)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 0aa0d7e52773..dc7d27b3cb90 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -940,6 +940,39 @@ static struct ib_mr *rxe_reg_user_mr(struct ib_pd *ibpd,
 	return ERR_PTR(err);
 }
 
+static struct ib_mr *rxe_reg_user_mr_dmabuf(struct ib_pd *ibpd, u64 start,
+					    u64 length, u64 iova, int fd,
+					    int access, struct ib_udata *udata)
+{
+	int err;
+	struct rxe_dev *rxe = to_rdev(ibpd->device);
+	struct rxe_pd *pd = to_rpd(ibpd);
+	struct rxe_mr *mr;
+
+	mr = rxe_alloc(&rxe->mr_pool);
+	if (!mr) {
+		err = -ENOMEM;
+		goto err2;
+	}
+
+	rxe_add_index(mr);
+
+	rxe_add_ref(pd);
+
+	err = rxe_mr_dmabuf_init_user(pd, fd, start, length, iova, access, mr);
+	if (err)
+		goto err3;
+
+	return &mr->ibmr;
+
+err3:
+	rxe_drop_ref(pd);
+	rxe_drop_index(mr);
+	rxe_drop_ref(mr);
+err2:
+	return ERR_PTR(err);
+}
+
 static struct ib_mr *rxe_alloc_mr(struct ib_pd *ibpd, enum ib_mr_type mr_type,
 				  u32 max_num_sg)
 {
@@ -1105,6 +1138,7 @@ static const struct ib_device_ops rxe_dev_ops = {
 	.query_qp = rxe_query_qp,
 	.query_srq = rxe_query_srq,
 	.reg_user_mr = rxe_reg_user_mr,
+	.reg_user_mr_dmabuf = rxe_reg_user_mr_dmabuf,
 	.req_notify_cq = rxe_req_notify_cq,
 	.resize_cq = rxe_resize_cq,
 
-- 
2.17.1

Re: [RFC PATCH v3 2/2] RDMA/rxe: Add dma-buf support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4239 bytes --]

Hi Shunsuke,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on rdma/for-next]
[also build test WARNING on v5.15-rc7 next-20211029]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Shunsuke-Mie/RDMA-rxe-Add-dma-buf-support/20211029-150351
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
config: riscv-randconfig-r042-20211029 (attached as .config)
compiler: riscv32-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/132b40bb2550f801c5e94fcde19f28b29b0852e2
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Shunsuke-Mie/RDMA-rxe-Add-dma-buf-support/20211029-150351
        git checkout 132b40bb2550f801c5e94fcde19f28b29b0852e2
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/infiniband/sw/rxe/rxe_mr.c: In function 'rxe_map_dmabuf_mr':
>> drivers/infiniband/sw/rxe/rxe_mr.c:256:23: warning: variable 'vaddr_end' set but not used [-Wunused-but-set-variable]
     256 |         void *vaddr, *vaddr_end;
         |                       ^~~~~~~~~
   In file included from include/linux/dma-buf.h:16,
                    from drivers/infiniband/sw/rxe/rxe_mr.c:7:
   drivers/infiniband/sw/rxe/rxe_mr.c: In function 'rxe_unmap_dmabuf_mr':
>> drivers/infiniband/sw/rxe/rxe_mr.c:305:17: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     305 |                 (void *)mr->cur_map_set->map[0]->buf->addr);
         |                 ^
   include/linux/dma-buf-map.h:129:27: note: in definition of macro 'DMA_BUF_MAP_INIT_VADDR'
     129 |                 .vaddr = (vaddr_), \
         |                           ^~~~~~


vim +/vaddr_end +256 drivers/infiniband/sw/rxe/rxe_mr.c

   249	
   250	static int rxe_map_dmabuf_mr(struct rxe_mr *mr,
   251				     struct ib_umem_dmabuf *umem_dmabuf)
   252	{
   253		struct rxe_map_set *set;
   254		struct rxe_phys_buf *buf = NULL;
   255		struct rxe_map **map;
 > 256		void *vaddr, *vaddr_end;
   257		int num_buf = 0;
   258		int err;
   259		size_t remain;
   260		struct dma_buf_map dmabuf_map;
   261	
   262		err = dma_buf_vmap(umem_dmabuf->dmabuf, &dmabuf_map);
   263		if (err || dmabuf_map.is_iomem)
   264			goto err_out;
   265	
   266		set = mr->cur_map_set;
   267		set->page_shift = PAGE_SHIFT;
   268		set->page_mask = PAGE_SIZE - 1;
   269	
   270		map = set->map;
   271		buf = map[0]->buf;
   272	
   273		vaddr = dmabuf_map.vaddr;
   274		vaddr_end = vaddr + umem_dmabuf->dmabuf->size;
   275		remain = umem_dmabuf->dmabuf->size;
   276	
   277		for (; remain; vaddr += PAGE_SIZE) {
   278			if (num_buf >= RXE_BUF_PER_MAP) {
   279				map++;
   280				buf = map[0]->buf;
   281				num_buf = 0;
   282			}
   283	
   284			buf->addr = (uintptr_t)vaddr;
   285			if (remain >= PAGE_SIZE)
   286				buf->size = PAGE_SIZE;
   287			else
   288				buf->size = remain;
   289			remain -= buf->size;
   290	
   291			num_buf++;
   292			buf++;
   293		}
   294	
   295		return 0;
   296	
   297	err_out:
   298		return err;
   299	}
   300	
   301	static void rxe_unmap_dmabuf_mr(struct rxe_mr *mr)
   302	{
   303		struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(mr->umem);
   304		struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(
 > 305			(void *)mr->cur_map_set->map[0]->buf->addr);
   306	
   307		dma_buf_vunmap(umem_dmabuf->dmabuf, &map);
   308	}
   309	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 37499 bytes --]

Re: [RFC PATCH v3 2/2] RDMA/rxe: Add dma-buf support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3314 bytes --]

Hi Shunsuke,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on rdma/for-next]
[also build test ERROR on v5.15 next-20211111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Shunsuke-Mie/RDMA-rxe-Add-dma-buf-support/20211029-150351
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
config: s390-allyesconfig (attached as .config)
compiler: s390-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/132b40bb2550f801c5e94fcde19f28b29b0852e2
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Shunsuke-Mie/RDMA-rxe-Add-dma-buf-support/20211029-150351
        git checkout 132b40bb2550f801c5e94fcde19f28b29b0852e2
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/infiniband/sw/rxe/rxe_mr.c: In function 'rxe_map_dmabuf_mr':
>> drivers/infiniband/sw/rxe/rxe_mr.c:256:23: error: variable 'vaddr_end' set but not used [-Werror=unused-but-set-variable]
     256 |         void *vaddr, *vaddr_end;
         |                       ^~~~~~~~~
   cc1: all warnings being treated as errors


vim +/vaddr_end +256 drivers/infiniband/sw/rxe/rxe_mr.c

   249	
   250	static int rxe_map_dmabuf_mr(struct rxe_mr *mr,
   251				     struct ib_umem_dmabuf *umem_dmabuf)
   252	{
   253		struct rxe_map_set *set;
   254		struct rxe_phys_buf *buf = NULL;
   255		struct rxe_map **map;
 > 256		void *vaddr, *vaddr_end;
   257		int num_buf = 0;
   258		int err;
   259		size_t remain;
   260		struct dma_buf_map dmabuf_map;
   261	
   262		err = dma_buf_vmap(umem_dmabuf->dmabuf, &dmabuf_map);
   263		if (err || dmabuf_map.is_iomem)
   264			goto err_out;
   265	
   266		set = mr->cur_map_set;
   267		set->page_shift = PAGE_SHIFT;
   268		set->page_mask = PAGE_SIZE - 1;
   269	
   270		map = set->map;
   271		buf = map[0]->buf;
   272	
   273		vaddr = dmabuf_map.vaddr;
   274		vaddr_end = vaddr + umem_dmabuf->dmabuf->size;
   275		remain = umem_dmabuf->dmabuf->size;
   276	
   277		for (; remain; vaddr += PAGE_SIZE) {
   278			if (num_buf >= RXE_BUF_PER_MAP) {
   279				map++;
   280				buf = map[0]->buf;
   281				num_buf = 0;
   282			}
   283	
   284			buf->addr = (uintptr_t)vaddr;
   285			if (remain >= PAGE_SIZE)
   286				buf->size = PAGE_SIZE;
   287			else
   288				buf->size = remain;
   289			remain -= buf->size;
   290	
   291			num_buf++;
   292			buf++;
   293		}
   294	
   295		return 0;
   296	
   297	err_out:
   298		return err;
   299	}
   300	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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