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>

libibverbs                                         2006-10-31                                      IBV_REG_MR(3)