We can use lock_sock_fast() instead of lock_sock() in order to get
speedup in peek_head_len().

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/net.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index c32a2e4..50b622a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -211,12 +211,12 @@ static int peek_head_len(struct sock *sk)
 {
 	struct sk_buff *head;
 	int len = 0;
+	bool slow = lock_sock_fast(sk);
 
-	lock_sock(sk);
 	head = skb_peek(&sk->sk_receive_queue);
 	if (head)
 		len = head->len;
-	release_sock(sk);
+	unlock_sock_fast(sk, slow);
 	return len;
 }