NAME
ibv_post_recv - post a list of work requests (WRs) to a receive queue
SYNOPSIS
#include <infiniband/verbs.h>
int ibv_post_recv(struct ibv_qp *qp, struct ibv_recv_wr *wr,
struct ibv_recv_wr **bad_wr);
DESCRIPTION
ibv_post_recv() posts the linked list of work requests (WRs) starting
with wr to the receive queue of the queue pair qp. It stops processing
WRs from this list at the first failure (that can be detected
immediately while requests are being posted), and returns this failing
WR through bad_wr.
The argument wr is an ibv_recv_wr struct, as defined in
<infiniband/verbs.h>.
struct ibv_recv_wr {
uint64_t wr_id; /* User defined WR ID */
struct ibv_recv_wr *next; /* Pointer to next WR in list, NULL if last WR */
struct ibv_sge *sg_list; /* Pointer to the s/g array */
int num_sge; /* Size of the s/g array */
};
struct ibv_sge {
uint64_t addr; /* Start address of the local memory buffer */
uint32_t length; /* Length of the buffer */
uint32_t lkey; /* Key of the local Memory Region */
};
RETURN VALUE
ibv_post_recv() returns 0 on success, or the value of errno on failure
(which indicates the failure reason).
NOTES
The buffers used by a WR can only be safely reused after WR the request
is fully executed and a work completion has been retrieved from the
corresponding completion queue (CQ).
If the QP qp is associated with a shared receive queue, you must use
the function ibv_post_srq_recv(), and not ibv_post_recv(), since the
QP’s own receive queue will not be used.
If a WR is being posted to a UD QP, the Global Routing Header (GRH) of
the incoming message will be placed in the first 40 bytes of the
buffer(s) in the scatter list. If no GRH is present in the incoming
message, then the first bytes will be undefined. This means that in
all cases, the actual data of the incoming message will start at an
offset of 40 bytes into the buffer(s) in the scatter list.
SEE ALSO
ibv_create_qp(3), ibv_post_send(3), ibv_post_srq_recv(3),
ibv_poll_cq(3)
AUTHORS
Dotan Barak <dotanba@gmail.com>