IBV_QUERY_QP(3) Libibverbs Programmer's Manual IBV_QUERY_QP(3)
NAME
ibv_query_qp - get the attributes of a queue pair (QP)
SYNOPSIS
#include <infiniband/verbs.h>
int ibv_query_qp(struct ibv_qp *qp, struct ibv_qp_attr *attr,
int attr_mask,
struct ibv_qp_init_attr *init_attr);
DESCRIPTION
ibv_query_qp() gets the attributes specified in attr_mask for the QP qp
and returns them through the pointers attr and init_attr. The argument
attr is an ibv_qp_attr struct, as defined in <infiniband/verbs.h>.
struct ibv_qp_attr {
enum ibv_qp_state qp_state; /* Current QP state */
enum ibv_qp_state cur_qp_state; /* Current QP state - irrelevant for ibv_query_qp */
enum ibv_mtu path_mtu; /* Path MTU (valid only for RC/UC QPs) */
enum ibv_mig_state path_mig_state; /* Path migration state (valid if HCA supports APM) */
uint32_t qkey; /* Q_Key of the QP (valid only for UD QPs) */
uint32_t rq_psn; /* PSN for receive queue (valid only for RC/UC QPs) */
uint32_t sq_psn; /* PSN for send queue */
uint32_t dest_qp_num; /* Destination QP number (valid only for RC/UC QPs) */
unsigned int qp_access_flags; /* Mask of enabled remote access operations (valid only for RC/UC QPs) */
struct ibv_qp_cap cap; /* QP capabilities */
struct ibv_ah_attr ah_attr; /* Primary path address vector (valid only for RC/UC QPs) */
struct ibv_ah_attr alt_ah_attr; /* Alternate path address vector (valid only for RC/UC QPs) */
uint16_t pkey_index; /* Primary P_Key index */
uint16_t alt_pkey_index; /* Alternate P_Key index */
uint8_t en_sqd_async_notify; /* Enable SQD.drained async notification - irrelevant for ibv_query_qp */
uint8_t sq_draining; /* Is the QP draining? (Valid only if qp_state is SQD) */
uint8_t max_rd_atomic; /* Number of outstanding RDMA reads & atomic operations on the destination QP (valid only for RC QPs) */
uint8_t max_dest_rd_atomic; /* Number of responder resources for handling incoming RDMA reads & atomic operations (valid only for RC QPs) */
uint8_t min_rnr_timer; /* Minimum RNR NAK timer (valid only for RC QPs) */
uint8_t port_num; /* Primary port number */
uint8_t timeout; /* Local ack timeout for primary path (valid only for RC QPs) */
uint8_t retry_cnt; /* Retry count (valid only for RC QPs) */
uint8_t rnr_retry; /* RNR retry (valid only for RC QPs) */
uint8_t alt_port_num; /* Alternate port number */
uint8_t alt_timeout; /* Local ack timeout for alternate path (valid only for RC QPs) */
};
For details on struct ibv_qp_cap see the description of ibv_cre-
ate_qp(). For details on struct ibv_ah_attr see the description of
ibv_create_ah().
RETURN VALUE
ibv_query_qp() returns 0 on success, or the value of errno on failure
(which indicates the failure reason).
NOTES
The argument attr_mask is a hint that specifies the minimum list of at-
tributes to retrieve. Some RDMA devices may return extra attributes
not requested, for example if the value can be returned cheaply. This
has the same form as in ibv_modify_qp().
Attribute values are valid if they have been set using ibv_modify_qp().
The exact list of valid attributes depends on the QP state.
Multiple calls to ibv_query_qp() may yield some differences in the val-
ues returned for the following attributes: qp_state, path_mig_state,
sq_draining, ah_attr (if APM is enabled).
SEE ALSO
ibv_create_qp(3), ibv_destroy_qp(3), ibv_modify_qp(3), ibv_create_ah(3)
AUTHORS
Dotan Barak <dotanba@gmail.com>
libibverbs 2006-10-31 IBV_QUERY_QP(3)
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