RDMA/mlx5: Add support for dmabuf to devx umem

Bugzilla: https://bugzilla.redhat.com/2123401

commit 9af859c
Author: Jason Gunthorpe <jgg@ziepe.ca>
Date:   Thu Sep 1 11:20:55 2022 -0300

    RDMA/mlx5: Add support for dmabuf to devx umem

    This is modeled after the similar EFA enablement in commit
    66f4817 ("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.

    Link: https://lore.kernel.org/r/3-v1-bd147097458e+ede-umem_dmabuf_jgg@nvidia.com
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Signed-off-by: Kamal Heib <kheib@redhat.com>

Author: Kamalheib

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,

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 {