NAME
ibv_reg_mr, ibv_dereg_mr - register or deregister a memory region (MR)
SYNOPSIS
#include <infiniband/verbs.h>
struct ibv_mr *ibv_reg_mr(struct ibv_pd *pd, void *addr,
size_t length, int access);
int ibv_dereg_mr(struct ibv_mr *mr);
DESCRIPTION
ibv_reg_mr() registers a memory region (MR) associated with the
protection domain pd. The MR’s starting address is addr and its size
is length. The argument access describes the desired memory protection
attributes; it is either 0 or the bitwise OR of one or more of the
following flags:
IBV_ACCESS_LOCAL_WRITE Enable Local Write Access
IBV_ACCESS_REMOTE_WRITE Enable Remote Write Access
IBV_ACCESS_REMOTE_READ Enable Remote Read Access
IBV_ACCESS_REMOTE_ATOMIC Enable Remote Atomic Operation Access (if
supported)
IBV_ACCESS_MW_BIND Enable Memory Window Binding
If IBV_ACCESS_REMOTE_WRITE or IBV_ACCESS_REMOTE_ATOMIC is set, then
IBV_ACCESS_LOCAL_WRITE must be set too.
Local read access is always enabled for the MR.
ibv_dereg_mr() deregisters the MR mr.
RETURN VALUE
ibv_reg_mr() returns a pointer to the registered MR, or NULL if the
request fails. The local key (L_Key) field lkey is used as the lkey
field of struct ibv_sge when posting buffers with ibv_post_* verbs, and
the the remote key (R_Key) field rkey is used by remote processes to
perform Atomic and RDMA operations. The remote process places this
rkey as the rkey field of struct ibv_send_wr passed to the
ibv_post_send function.
ibv_dereg_mr() returns 0 on success, or the value of errno on failure
(which indicates the failure reason).
NOTES
ibv_dereg_mr() fails if any memory window is still bound to this MR.
SEE ALSO
ibv_alloc_pd(3), ibv_post_send(3), ibv_post_recv(3),
ibv_post_srq_recv(3)
AUTHORS
Dotan Barak <dotanba@gmail.com>