【RDMA】ibv_create_qp, ibv_destroy_qp

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Description

ibv_create_qp() creates a queue pair (QP) associated with the protection domain pd. The argument qp_init_attr is an ibv_qp_init_attr struct, as defined in <rdma/verbs.h>.

	struct ibv_qp_init_attr {
	void	*qp_context;	/*Associated context of the QP*/
	struct ibv_cq	*send_cq;	/*CQ to be associated with the Send Queue (SQ)*/
	struct ibv_cq	*recv_cq;	/*CQ to be associated with the Receive Queue (RQ)*/
	struct ibv_srq	*srq;	/*Not Supported*/
	struct ibv_qp_cap	cap;	/*QP capabilities*/
	enum ibv_qp_type	qp_type;	/*QP Transport Service Type: IBV_QPT_RC,*/
	int	sq_sig_all;	/*If set, each Work Request (WR) submitted to the SQ*/
			/*generates a completion entry */
	struct ibv_xrc_domain	xrc_domain;	/*Not supported*/
struct ibv_qp_cap {
	uint32_t	max_send_wr;	/*Requested max number of outstanding*/
			/*WRs in the SQ*/
	uint32_t	max_recv_wr;	/*Requested max number of outstanding*/
			/*WRs in the RQ*/
	uint32_t	max_send_sge;	/*Requested max number of scatter/gather*/
			/*(s/g) elements in*/
			/*a WR in the SQ*/
	uint32_t	max_recv_sge;	/*Requested max number of s/g elements*/
			/*in a WR in the SQ*/
	uint32_t	max_inline_data;	/*Requested max number of data (bytes)*/
			/*that can be posted*/
			/*inline to the SQ, otherwise 0*/

 

    qp_type: The desired QP type (see enum ibv_qp_type)

     qp_context: Associated QP context

    scq: Send CQ to be used for this QP

      rcq: Receive CQ to be used for this QP

  srq: Shared receive queue to be used as RQ in QP

     cap: A QPCap object

    sq_sig_all: If set, each send WR will generate a completion

     entry

     :return: A QpInitAttr object

     

 

 

The function ibv_create_qp() updates the qp_init_attr->cap struct with the actual QP values of the QP that was created; the values will be greater than or equal to the values requested. ibv_destroy_qp() destroys the QP qp.

 

 

Input Parameters

pd	struct ibv_pd from ibv_alloc_pd.
qp_init_attr	Initial attributes of queue pair.

Output Parameters

qp_init_attr

Actual values are filled in.

Return Value

ibv_create_qp() returns a pointer to the created QP on success, or NULL if the request fails.

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