iw_cxgb4: add queue drain functions

Add completion objects, named sq_drained and rq_drained, to the c4iw_qp
struct.  The queue-specific completion object is signaled when the last
CQE is drained from the CQ for that queue.

Add c4iw_drain_sq() to block until qp->rq_drained is completed.

Add c4iw_drain_rq() to block until qp->sq_drained is completed.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/cxgb4/cq.c

@@ -815,8 +815,15 @@ static int c4iw_poll_cq_one(struct c4iw_cq *chp, struct ib_wc *wc)
 		}
 	}
 out:
-	if (wq)
+	if (wq) {
+		if (unlikely(qhp->attr.state != C4IW_QP_STATE_RTS)) {
+			if (t4_sq_empty(wq))
+				complete(&qhp->sq_drained);
+			if (t4_rq_empty(wq))
+				complete(&qhp->rq_drained);
+		}
 		spin_unlock(&qhp->lock);
+	}
 	return ret;
 }
 

drivers/infiniband/hw/cxgb4/iw_cxgb4.h

@@ -476,6 +476,8 @@ struct c4iw_qp {
 	wait_queue_head_t wait;
 	struct timer_list timer;
 	int sq_sig_all;
+	struct completion rq_drained;
+	struct completion sq_drained;
 };
 
 static inline struct c4iw_qp *to_c4iw_qp(struct ib_qp *ibqp)
@@ -1016,6 +1018,8 @@ extern int c4iw_wr_log;
 extern int db_fc_threshold;
 extern int db_coalescing_threshold;
 extern int use_dsgl;
+void c4iw_drain_rq(struct ib_qp *qp);
+void c4iw_drain_sq(struct ib_qp *qp);
 
 
 #endif

drivers/infiniband/hw/cxgb4/provider.c

@@ -564,6 +564,8 @@ int c4iw_register_device(struct c4iw_dev *dev)
 	dev->ibdev.get_protocol_stats = c4iw_get_mib;
 	dev->ibdev.uverbs_abi_ver = C4IW_UVERBS_ABI_VERSION;
 	dev->ibdev.get_port_immutable = c4iw_port_immutable;
+	dev->ibdev.drain_sq = c4iw_drain_sq;
+	dev->ibdev.drain_rq = c4iw_drain_rq;
 
 	dev->ibdev.iwcm = kmalloc(sizeof(struct iw_cm_verbs), GFP_KERNEL);
 	if (!dev->ibdev.iwcm)

drivers/infiniband/hw/cxgb4/qp.c

@@ -1697,6 +1697,8 @@ struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
 	qhp->attr.max_ird = 0;
 	qhp->sq_sig_all = attrs->sq_sig_type == IB_SIGNAL_ALL_WR;
 	spin_lock_init(&qhp->lock);
+	init_completion(&qhp->sq_drained);
+	init_completion(&qhp->rq_drained);
 	mutex_init(&qhp->mutex);
 	init_waitqueue_head(&qhp->wait);
 	atomic_set(&qhp->refcnt, 1);
@@ -1888,3 +1890,17 @@ int c4iw_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 	init_attr->sq_sig_type = qhp->sq_sig_all ? IB_SIGNAL_ALL_WR : 0;
 	return 0;
 }
+
+void c4iw_drain_sq(struct ib_qp *ibqp)
+{
+	struct c4iw_qp *qp = to_c4iw_qp(ibqp);
+
+	wait_for_completion(&qp->sq_drained);
+}
+
+void c4iw_drain_rq(struct ib_qp *ibqp)
+{
+	struct c4iw_qp *qp = to_c4iw_qp(ibqp);
+
+	wait_for_completion(&qp->rq_drained);
+}