NAME

       mlx5dv_reserved_qpn_alloc - Allocate a reserved QP number from device

       mlx5dv_reserved_qpn_dealloc - Release the reserved QP number

SYNOPSIS

              #include <infiniband/mlx5dv.h>

              int mlx5dv_reserved_qpn_alloc(struct ibv_context *ctx, uint32_t *qpn);

              int mlx5dv_reserved_qpn_dealloc(struct ibv_context *ctx, uint32_t qpn);

DESCRIPTION

       When  work  with RDMA_CM RDMA_TCP_PS + external QP support, a client node needs GUID level
       unique QP numbers to comply with the CM’s timewait logic.

       If a real unique QP is not allocated, a device global QPN value is  required  and  can  be
       allocated via this interface.

       The mlx5 DCI QP is such an example, which could connect to the remote DCT’s multiple times
       as long as the application provides unique QPN for each new RDMA_CM connection.

       These 2 APIs provide the allocation/deallocation of a unique  QP  number  from/to  device.
       This  qpn  can  be used with DC QPN in RDMA_CM connection establishment, which will comply
       with the CM timewait kernel logic.

ARGUMENTS

       ctx    The device context to issue the action on.

       qpn    The allocated QP number (for alloc API), or the QP number to  be  deallocated  (for
              dealloc API).

RETURN VALUE

       0 on success; EOPNOTSUPP if not supported, or other errno value on other failures.

AUTHOR

       Mark Zhang <markzhang@nvidia.com>

       Alex Rosenbaum <alexr@nvidia.com>