| .\" -*- nroff -*- |
| .\" |
| .TH IBV_QUERY_QP 3 2006-10-31 libibverbs "Libibverbs Programmer's Manual" |
| .SH "NAME" |
| ibv_query_qp \- get the attributes of a queue pair (QP) |
| .SH "SYNOPSIS" |
| .nf |
| .B #include <infiniband/verbs.h> |
| .sp |
| .BI "int ibv_query_qp(struct ibv_qp " "*qp" ", struct ibv_qp_attr " "*attr" , |
| .BI " int " "attr_mask" , |
| .BI " struct ibv_qp_init_attr " "*init_attr" ); |
| .fi |
| .SH "DESCRIPTION" |
| .B ibv_query_qp() |
| gets the attributes specified in |
| .I attr_mask |
| for the QP |
| .I qp |
| and returns them through the pointers |
| .I attr |
| and |
| .I init_attr\fR. |
| The argument |
| .I attr |
| is an ibv_qp_attr struct, as defined in <infiniband/verbs.h>. |
| .PP |
| .nf |
| struct ibv_qp_attr { |
| .in +8 |
| 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 (valid only for RC/UC QPs) */ |
| uint32_t dest_qp_num; /* Destination QP number (valid only for RC/UC QPs) */ |
| 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) */ |
| .in -8 |
| }; |
| .fi |
| .PP |
| For details on struct ibv_qp_cap see the description of |
| .B ibv_create_qp()\fR. |
| For details on struct ibv_ah_attr see the description of |
| .B ibv_create_ah()\fR. |
| .SH "RETURN VALUE" |
| .B ibv_query_qp() |
| returns 0 on success, or the value of errno on failure (which indicates the failure reason). |
| .SH "NOTES" |
| The argument |
| .I attr_mask |
| is a hint that specifies the minimum list of attributes 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 |
| .B ibv_modify_qp()\fR. |
| .PP |
| Attribute values are valid if they have been set using |
| .B ibv_modify_qp()\fR. |
| The exact list of valid attributes depends on the QP state. |
| .PP |
| Multiple calls to |
| .B ibv_query_qp() |
| may yield some differences in the values returned for the following attributes: qp_state, path_mig_state, sq_draining, ah_attr (if APM is enabled). |
| .SH "SEE ALSO" |
| .BR ibv_create_qp (3), |
| .BR ibv_destroy_qp (3), |
| .BR ibv_modify_qp (3), |
| .BR ibv_create_ah (3) |
| .SH "AUTHORS" |
| .TP |
| Dotan Barak <dotanba@gmail.com> |