NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | RETURN VALUE | SEE ALSO | COLOPHON |
|
|
mlx5dv_devx_ume...devx_umem_dereg(3) mlx5dv_devx_ume...devx_umem_dereg(3)
mlx5dv_devx_umem_reg - Register a user memory to be used by the devx interface mlx5dv_devx_umem_reg_ex - Register a user memory to be used by the devx interface mlx5dv_devx_umem_dereg - Deregister a devx umem object
#include <infiniband/mlx5dv.h> struct mlx5dv_devx_umem { uint32_t umem_id; }; struct mlx5dv_devx_umem * mlx5dv_devx_umem_reg(struct ibv_context *context, void *addr, size_t size, uint32_t access) struct mlx5dv_devx_umem_in { void *addr; size_t size; uint32_t access; uint64_t pgsz_bitmap; uint64_t comp_mask; int dmabuf_fd; }; struct mlx5dv_devx_umem * mlx5dv_devx_umem_reg_ex(struct ibv_context *ctx, struct mlx5dv_devx_umem_in *umem_in); int mlx5dv_devx_umem_dereg(struct mlx5dv_devx_umem *dv_devx_umem)
Register or deregister a user memory to be used by the devx interface. The register verb exposes a UMEM DEVX object for user memory registration for DMA. The API to register the user memory gets as input the user address, length and access flags, and provides to the user as output an object which holds the UMEM ID returned by the firmware to this registered memory. The user can ask for specific page sizes for the given address and length, in that case mlx5dv_devx_umem_reg_ex() should be used. In case the kernel couldn’t find a matching page size from the given umem_in->pgsz_bitmap bitmap the API will fail. The user will use that UMEM ID in device direct commands that use this memory instead of the physical addresses list, for example upon mlx5dv_devx_obj_create to create a QP.
context RDMA device context to create the action on. addr The memory start address to register. size The size of *addr* buffer. access The desired memory protection attributes; it is either 0 or the bitwise OR of one or more of enum ibv_access_flags. umem_in A structure holds the argument bundle. pgsz_bitmap Represents the required page sizes. umem creation will fail if it cannot be created with these page sizes. comp_mask Flags indicating the additional fields. dmabuf_fd If MLX5DV_UMEM_MASK_DMABUF is set in comp_mask then this value must be a FD of a dmabuf. In this mode the dmabuf is used as the backing memory to create the umem out of. The dmabuf must be pinnable. addr is interpreted as the starting offset of the dmabuf.
Upon success mlx5dv_devx_umem_reg / mlx5dv_devx_umem_reg_ex will return a new struct mlx5dv_devx_umem object, on error NULL will be returned and errno will be set. mlx5dv_devx_umem_dereg returns 0 on success, or the value of errno on failure (which indicates the failure reason).
mlx5dv_open_device(3), ibv_reg_mr(3), mlx5dv_devx_obj_create(3) #AUTHOR Yishai Hadas ⟨yishaih@mellanox.com⟩
This page is part of the rdma-core (RDMA Core Userspace Libraries
and Daemons) project. Information about the project can be found
at ⟨https://github.com/linux-rdma/rdma-core⟩. If you have a bug
report for this manual page, send it to
linux-rdma@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-04.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
mlx5dv_devx_ume...devx_umem_dereg(3)