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

       IBV_ACCESS_ON_DEMAND Create an on-demand paging MR

       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>