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

       ibv_post_send - post a list of work requests (WRs) to a send queue

       #include	<infiniband/verbs.h>

       int ibv_post_send(struct	ibv_qp *qp, struct ibv_send_wr *wr,
			 struct	ibv_send_wr **bad_wr);

       ibv_post_send()	posts  the linked list of work requests	(WRs) starting
       with wr to the send queue of the	queue pair qp.	 It  stops  processing
       WRs  from  this list at the first failure (that can be detected immedi-
       ately while requests are	being posted), and  returns  this  failing  WR
       through bad_wr.

       The  argument  wr  is  an  ibv_send_wr  struct,	as defined in <infini-

       struct ibv_send_wr {
	       uint64_t		       wr_id;		       /* User defined WR ID */
	       struct ibv_send_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	*/
	       enum ibv_wr_opcode      opcode;		       /* Operation type */
	       int		       send_flags;	       /* Flags	of the WR properties */
	       uint32_t		       imm_data;	       /* Immediate data (in network byte order) */
	       union {
		       struct {
			       uint64_t	       remote_addr;    /* Start	address	of remote memory buffer	*/
			       uint32_t	       rkey;	       /* Key of the remote Memory Region */
		       } rdma;
		       struct {
			       uint64_t	       remote_addr;    /* Start	address	of remote memory buffer	*/
			       uint64_t	       compare_add;    /* Compare operand */
			       uint64_t	       swap;	       /* Swap operand */
			       uint32_t	       rkey;	       /* Key of the remote Memory Region */
		       } atomic;
		       struct {
			       struct ibv_ah  *ah;	       /* Address handle (AH) for the remote node address */
			       uint32_t	       remote_qpn;     /* QP number of the destination QP */
			       uint32_t	       remote_qkey;    /* Q_Key	number of the destination QP */
		       } ud;
	       } wr;
	       union {
		       struct {
			       uint32_t	remote_srqn;		/* Number of the remote	SRQ */
		       } xrc;
	       } qp_type;
	       union {
		       struct {
			       struct ibv_mw		*mw;		 /* Memory window (MW) of type 2 to bind */
			       uint32_t			rkey;		 /* The	desired	new rkey of the	MW */
			       struct ibv_mw_bind_info	bind_info;	 /* MW additional bind information */
		       } bind_mw;
		       struct {
			       void	      *hdr;	/* Pointer address of inline header */
			       uint16_t	      hdr_sz;	/* Inline header size */
			       uint16_t	      mss; /* Maximum segment size for each TSO	fragment */
		       } tso;

       struct ibv_mw_bind_info {
	       struct ibv_mr		*mr;		 /* The	Memory region (MR) to bind the MW to */
	       uint64_t			addr;		/* The address the MW should start at */
	       uint64_t			length;		 /* The	length (in bytes) the MW should	span */
	       int			mw_access_flags; /* Access flags to the	MW. Use	ibv_access_flags */

       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 */

       Each QP Transport Service Type supports a specific set of  opcodes,  as
       shown in	the following table:

       IBV_WR_SEND		   |	 X	|     X	     |	   X	  |	    X	     |	       X
       IBV_WR_SEND_WITH_IMM	   |	 X	|     X	     |	   X	  |	    X	     |
       IBV_WR_RDMA_WRITE	   |		|     X	     |	   X	  |	    X	     |
       IBV_WR_RDMA_WRITE_WITH_IMM  |		|     X	     |	   X	  |	    X	     |
       IBV_WR_RDMA_READ		   |		|	     |	   X	  |	    X	     |
       IBV_WR_ATOMIC_CMP_AND_SWP   |		|	     |	   X	  |	    X	     |
       IBV_WR_ATOMIC_FETCH_AND_ADD |		|	     |	   X	  |	    X	     |
       IBV_WR_LOCAL_INV		   |		|     X	     |	   X	  |	    X	     |
       IBV_WR_BIND_MW		   |		|     X	     |	   X	  |	    X	     |
       IBV_WR_SEND_WITH_INV	   |		|     X	     |	   X	  |	    X	     |
       IBV_WR_TSO		   |	 X	|	     |		  |		     |	       X

       The  attribute send_flags describes the properties of the WR. It	is ei-
       ther 0 or the bitwise OR	of one or more of the following	flags:

       IBV_SEND_FENCE  Set the fence indicator.	Valid only for QPs with	Trans-
       port Service Type IBV_QPT_RC

       IBV_SEND_SIGNALED   Set the completion notification indicator. Relevant
       only if QP was created with sq_sig_all=0

       IBV_SEND_SOLICITED  Set the solicited event indicator. Valid  only  for
       Send and	RDMA Write with	immediate

       IBV_SEND_INLINE	Send data in given gather list as inline data
	      in  a  send WQE.	Valid only for Send and	RDMA Write.  The L_Key
	      will not be checked.

       IBV_SEND_IP_CSUM	 Offload the IPv4 and TCP/UDP checksum calculation.
	      Valid only when device_cap_flags in device_attr  indicates  cur-
	      rent QP is supported by checksum offload.

       ibv_post_send()	returns	0 on success, or the value of errno on failure
       (which indicates	the failure reason).

       The user	should not alter or destroy AHs	associated with	WRs until  re-
       quest  is  fully	executed and a work completion has been	retrieved from
       the corresponding completion queue (CQ) to avoid	unexpected behavior.

       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). However,  if  the  IBV_SEND_INLINE
       flag  was  set, the buffer can be reused	immediately after the call re-

       ibv_create_qp(3),	  ibv_create_ah(3),	     ibv_post_recv(3),
       ibv_post_srq_recv(3), ibv_poll_cq(3)

       Dotan Barak <>

       Majd Dibbiny <>

       Yishai Hadas <>

libibverbs			  2006-10-31		      IBV_POST_SEND(3)


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