[PATCH 3/4] RDMA/mlx5: Add support for dmabuf to devx umem

[Jason Gunthorpe]

This is modeled after the similar EFA enablement in commit
66f4817b5712 ("RDMA/efa: Add support for dmabuf memory regions").

Like EFA there is no support for revocation so we simply call the
ib_umem_dmabuf_get_pinned() to obtain a umem instead of the normal
ib_umem_get().  Everything else stays the same.

Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
---
 drivers/infiniband/hw/mlx5/devx.c        | 24 +++++++++++++++++++++---
 include/uapi/rdma/mlx5_user_ioctl_cmds.h |  1 +
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/devx.c 
b/drivers/infiniband/hw/mlx5/devx.c
index 2a2a9e9afc9dad..291e73d7928276 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -2181,9 +2181,25 @@ static int devx_umem_get(struct mlx5_ib_dev *dev, struct 
ib_ucontext *ucontext,
        if (err)
                return err;
 
-       obj->umem = ib_umem_get(&dev->ib_dev, addr, size, access);
-       if (IS_ERR(obj->umem))
-               return PTR_ERR(obj->umem);
+       if (uverbs_attr_is_valid(attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_DMABUF_FD)) {
+               struct ib_umem_dmabuf *umem_dmabuf;
+               int dmabuf_fd;
+
+               err = uverbs_get_raw_fd(&dmabuf_fd, attrs,
+                                       MLX5_IB_ATTR_DEVX_UMEM_REG_DMABUF_FD);
+               if (err)
+                       return -EFAULT;
+
+               umem_dmabuf = ib_umem_dmabuf_get_pinned(
+                       &dev->ib_dev, addr, size, dmabuf_fd, access);
+               if (IS_ERR(umem_dmabuf))
+                       return PTR_ERR(umem_dmabuf);
+               obj->umem = &umem_dmabuf->umem;
+       } else {
+               obj->umem = ib_umem_get(&dev->ib_dev, addr, size, access);
+               if (IS_ERR(obj->umem))
+                       return PTR_ERR(obj->umem);
+       }
        return 0;
 }
 
@@ -2833,6 +2849,8 @@ DECLARE_UVERBS_NAMED_METHOD(
        UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_LEN,
                           UVERBS_ATTR_TYPE(u64),
                           UA_MANDATORY),
+       UVERBS_ATTR_RAW_FD(MLX5_IB_ATTR_DEVX_UMEM_REG_DMABUF_FD,
+                          UA_OPTIONAL),
        UVERBS_ATTR_FLAGS_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS,
                             enum ib_access_flags),
        UVERBS_ATTR_CONST_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_PGSZ_BITMAP,
diff --git a/include/uapi/rdma/mlx5_user_ioctl_cmds.h 
b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
index 3bee490eb5857f..595edad03dfe54 100644
--- a/include/uapi/rdma/mlx5_user_ioctl_cmds.h
+++ b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
@@ -174,6 +174,7 @@ enum mlx5_ib_devx_umem_reg_attrs {
        MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS,
        MLX5_IB_ATTR_DEVX_UMEM_REG_OUT_ID,
        MLX5_IB_ATTR_DEVX_UMEM_REG_PGSZ_BITMAP,
+       MLX5_IB_ATTR_DEVX_UMEM_REG_DMABUF_FD,
 };
 
 enum mlx5_ib_devx_umem_dereg_attrs {
-- 
2.37.2