From 5c0c52c9102f90c9d5674fb6c5f4f23e3019dd9f Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 6 Oct 2013 21:25:12 +0300 Subject: [PATCH] tun: don't look at current when non-blocking We play with a wait queue even if socket is non blocking. This is an obvious waste. Besides, it will prevent calling the non blocking variant when current is not valid. Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 807815fc9968..7cb105c103fe 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1293,7 +1293,8 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, if (unlikely(!noblock)) add_wait_queue(&tfile->wq.wait, &wait); while (len) { - current->state = TASK_INTERRUPTIBLE; + if (unlikely(!noblock)) + current->state = TASK_INTERRUPTIBLE; /* Read frames from the queue */ if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) { @@ -1320,9 +1321,10 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, break; } - current->state = TASK_RUNNING; - if (unlikely(!noblock)) + if (unlikely(!noblock)) { + current->state = TASK_RUNNING; remove_wait_queue(&tfile->wq.wait, &wait); + } return ret; } -- 2.20.1