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 <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
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 @@
break;
}
- finish_wait(sk_sleep(&q->sk), &wait);
+ if (!noblock)
+ finish_wait(sk_sleep(&q->sk), &wait);
return ret;
}