From: Jason Wang Date: Wed, 5 Jun 2013 23:54:34 +0000 (+0000) Subject: macvtap: do not add self to waitqueue if doing a nonblock read X-Git-Tag: v3.11-rc1~16^2~140 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=89cee917deb5bf0dc9da269a38622588d06cb6be;p=profile%2Fcommon%2Fkernel-common.git macvtap: do not add self to waitqueue if doing a nonblock read There's no need to add self to waitqueue if doing a nonblock read. This could help to avoid the spinlock contention. Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 5e485e3..8949631 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -845,7 +845,9 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, ssize_t ret = 0; while (len) { - prepare_to_wait(sk_sleep(&q->sk), &wait, TASK_INTERRUPTIBLE); + if (!noblock) + prepare_to_wait(sk_sleep(&q->sk), &wait, + TASK_INTERRUPTIBLE); /* Read frames from the queue */ skb = skb_dequeue(&q->sk.sk_receive_queue); @@ -867,7 +869,8 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, break; } - finish_wait(sk_sleep(&q->sk), &wait); + if (!noblock) + finish_wait(sk_sleep(&q->sk), &wait); return ret; }