mlx5dv_reserved_qpn_alloc /mlx5lProgrammmlx5dvareserved_qpn_alloc / dealloc(3)
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 re-
quired 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 oth-
er failures.
AUTHOR
Mark Zhang <markzhang@nvidia.com>
Alex Rosenbaum <alexr@nvidia.com>
mlx5 2020-1mlx5dv_reserved_qpn_alloc / dealloc(3)
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