ibv_dereg_mr(3) [centos man page]

IBV_REG_MR(3)						  Libibverbs Programmer's Manual					     IBV_REG_MR(3)

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)

IBV_POST_RECV(3)					  Libibverbs Programmer's Manual					  IBV_POST_RECV(3)

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 process-
       ing 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>

libibverbs							    2006-10-31							  IBV_POST_RECV(3)