ibv_post_send(3) — Linux manual page


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

NAME         top

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

SYNOPSIS         top

       #include <infiniband/verbs.h>

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

DESCRIPTION         top

       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 immediately 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

       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 */
               unsigned int            send_flags;             /* Flags of the WR properties */
               union {
                       __be32                  imm_data;               /* Immediate data (in network byte order) */
                       uint32_t                invalidate_rkey;        /* Remote rkey to invalidate */
               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 */
               unsigned 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 or number of bytes from the
                                                                  start of the MR for MRs which are IBV_ACCESS_ZERO_BASED */
               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 either 0 or the bitwise OR of one or more of the following

       IBV_SEND_FENCE  Set the fence indicator. Valid only for QPs with
       Transport 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
              Valid only when device_cap_flags in device_attr indicates
              current QP is supported by checksum offload.

RETURN VALUE         top

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

NOTES         top

       The user should not alter or destroy AHs associated with WRs
       until request 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 returns.

       IBV_WR_DRIVER1 is an opcode that should be used to issue a
       specific driver operation.

SEE ALSO         top

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

AUTHORS         top

       Dotan Barak <dotanba@gmail.com>

       Majd Dibbiny <majd@mellanox.com>

       Yishai Hadas <yishaih@mellanox.com>

COLOPHON         top

       This page is part of the rdma-core (RDMA Core Userspace Libraries
       and Daemons) project.  Information about the project can be found
       at ⟨https://github.com/linux-rdma/rdma-core⟩.  If you have a bug
       report for this manual page, send it to
       linux-rdma@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2023-12-22.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2023-12-20.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

libibverbs                     2006-10-31               IBV_POST_SEND(3)

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