Register or deregister a memory region (mr)
#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);
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.
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).
ibv_dereg_mr() fails if any memory window is still bound to this MR.
Dotan Barak <[email protected]>