mlx5dv_devx_umem_export / mlx5dv_devx_umem_import / mlx5dv_devx_umem_unimport(3)

NAME
mlx5dv_devx_umem_export - Export DEVX UMEM attributes for cross-process sharing

mlx5dv_devx_umem_import - Import a DEVX UMEM from exported attributes

mlx5dv_devx_umem_unimport - Unimport a DEVX UMEM

SYNOPSIS

        #include <infiniband/mlx5dv.h>
        int mlx5dv_devx_umem_export(struct mlx5dv_devx_umem *umem, void *data);
        struct mlx5dv_devx_umem *
        mlx5dv_devx_umem_import(struct ibv_context *context, void *data);
        void mlx5dv_devx_umem_unimport(struct mlx5dv_devx_umem *umem);

DESCRIPTION
These functions enable cross-process sharing of DEVX UMEM objects.

mlx5dv_devx_umem_export() exports DEVX UMEM attributes into a data buffer. The buffer must be allocated by the caller with at least the size returned by mlx5dv_get_export_sizes() in the devx_umem_attrs_size field.

mlx5dv_devx_umem_import() returns a DEVX UMEM that is associated with the exported attributes in the given context. The data buffer must have been previously filled by mlx5dv_devx_umem_export().

The context can be the original UMEM registering context or any context sharing the same kernel resources (e.g., via ibv_import_device()).

mlx5dv_devx_umem_unimport() unimports a DEVX UMEM that was imported via mlx5dv_devx_umem_import(). Once the UMEM usage has ended, either mlx5dv_devx_umem_dereg() or mlx5dv_devx_umem_unimport() should be called. mlx5dv_devx_umem_dereg() deregisters the kernel object, while mlx5dv_devx_umem_unimport() only cleans up local resources without affecting the kernel object.

It is the responsibility of the application to coordinate between all contexts that use this UMEM. Once deregistration is done, no other process can use the object except for unimport. All users must collaborate to ensure this.

ARGUMENTS

  mlx5dv_devx_umem_export

umem
    The DEVX UMEM to export.

data
    Pointer to a buffer to be filled with the exported attributes. The buffer must be at least devx_umem_attrs_size bytes as returned by mlx5dv_get_export_sizes().

  mlx5dv_devx_umem_import

context
    RDMA device context to import the DEVX UMEM into.

data
    Pointer to a buffer previously filled by mlx5dv_devx_umem_export().

RETURN VALUE
mlx5dv_devx_umem_export() returns 0 on success, or the value of errno on error.

mlx5dv_devx_umem_import() returns a pointer to a struct mlx5dv_devx_umem on success, or NULL on error with errno set.

SEE ALSO
mlx5dv_devx_umem_reg, mlx5dv_get_export_sizes, mlx5dv_open_device

AUTHOR
Maher Sanalla msanalla@nvidia.com