Man page - ibv_post_send(3)

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Manual

IBV_POST_SEND

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
NOTES
SEE ALSO
AUTHORS

NAME

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

SYNOPSIS

#include <infiniband/verbs.h>

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

DESCRIPTION

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 <infiniband/verbs.h>.

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:

OPCODE | IBV_QPT_UD | IBV_QPT_UC | IBV_QPT_RC | IBV_QPT_XRC_SEND | IBV_QPT_RAW_PACKET
----------------------------+------------+------------+------------+------------------+--------------------
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 flags:
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 calculation.

Valid only when device_cap_flags in device_attr indicates current QP is supported by checksum offload.

RETURN VALUE

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

NOTES

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

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

AUTHORS

Dotan Barak <dotanba@gmail.com>
Majd Dibbiny <majd@mellanox.com>
Yishai Hadas <yishaih@mellanox.com>