#include <infiniband/verbs.h>
int ibv_post_send(struct ibv_qp *qp, struct ibv_send_wr *wr,
struct ibv_send_wr **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 */
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;
};
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:
OPCODE | IBV_QPT_UD | IBV_QPT_UC | IBV_QPT_RC ----------------------------+------------+------------+----------- IBV_WR_SEND | X | X | X IBV_WR_SEND_WITH_IMM | X | X | X IBV_WR_RDMA_WRITE | | X | X IBV_WR_RDMA_WRITE_WITH_IMM | | X | X IBV_WR_RDMA_READ | | | X IBV_WR_ATOMIC_CMP_AND_SWP | | | X IBV_WR_ATOMIC_FETCH_AND_ADD | | | 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:
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.