[net-next,09/14] net: sched: check for frozen queue before skb_bad_txq check

Message ID 20171207175641.5771.42808.stgit@john-Precision-Tower-5810
State Accepted
Delegated to: David Miller
Headers show
Series
  • lockless qdisc series
Related show

Commit Message

John Fastabend Dec. 7, 2017, 5:56 p.m.
I can not think of any reason to pull the bad txq skb off the qdisc if
the txq we plan to send this on is still frozen. So check for frozen
queue first and abort before dequeuing either skb_bad_txq skb or
normal qdisc dequeue() skb.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 net/sched/sch_generic.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

Patch

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 84cef05..5ff93c2 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -204,7 +204,7 @@  static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 				   int *packets)
 {
 	const struct netdev_queue *txq = q->dev_queue;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 
 	*packets = 1;
 	if (unlikely(!skb_queue_empty(&q->gso_skb))) {
@@ -248,12 +248,15 @@  static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 	}
 validate:
 	*validate = true;
+
+	if ((q->flags & TCQ_F_ONETXQUEUE) &&
+	    netif_xmit_frozen_or_stopped(txq))
+		return skb;
+
 	skb = qdisc_dequeue_skb_bad_txq(q);
 	if (unlikely(skb))
 		goto bulk;
-	if (!(q->flags & TCQ_F_ONETXQUEUE) ||
-	    !netif_xmit_frozen_or_stopped(txq))
-		skb = q->dequeue(q);
+	skb = q->dequeue(q);
 	if (skb) {
 bulk:
 		if (qdisc_may_bulk(q))