From 89cee917deb5bf0dc9da269a38622588d06cb6be Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 5 Jun 2013 23:54:34 +0000 Subject: [PATCH] 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 --- drivers/net/macvtap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 5e485e307424..8949631c080c 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; } -- 2.20.1