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[3/3] iw_cxgb4: handing draining an idle qp

Message ID 20160412143041.51965E08CA@smtp.ogc.us (mailing list archive)
State Accepted
Headers show

Commit Message

Steve Wise April 12, 2016, 1:55 p.m. UTC 
In c4iw_drain_sq/rq(), if the particular queue is already empty
then don't block.

Fixes: ce4af14d94aa ('iw_cxgb4: add queue drain functions')
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
---
 drivers/infiniband/hw/cxgb4/qp.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
index e17fb5d5..8aa2e52 100644
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -1895,13 +1895,27 @@  int c4iw_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 void c4iw_drain_sq(struct ib_qp *ibqp)
 {
 	struct c4iw_qp *qp = to_c4iw_qp(ibqp);
+	unsigned long flag;
+	bool need_to_wait;
+
+	spin_lock_irqsave(&qp->lock, flag);
+	need_to_wait = !t4_sq_empty(&qp->wq);
+	spin_unlock_irqrestore(&qp->lock, flag);
 
-	wait_for_completion(&qp->sq_drained);
+	if (need_to_wait)
+		wait_for_completion(&qp->sq_drained);
 }
 
 void c4iw_drain_rq(struct ib_qp *ibqp)
 {
 	struct c4iw_qp *qp = to_c4iw_qp(ibqp);
+	unsigned long flag;
+	bool need_to_wait;
+
+	spin_lock_irqsave(&qp->lock, flag);
+	need_to_wait = !t4_rq_empty(&qp->wq);
+	spin_unlock_irqrestore(&qp->lock, flag);
 
-	wait_for_completion(&qp->rq_drained);
+	if (need_to_wait)
+		wait_for_completion(&qp->rq_drained);
 }