netdev - [PATCH] tun: fix blocking read

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Date:   Sat, 23 Feb 2019 12:53:13 +0100
From:   Timur Celik <mail@...urcelik.de>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Timur Celik <mail@...urcelik.de>
Subject: [PATCH] tun: fix blocking read

This patch moves setting of the current state into the loop. Otherwise
the task may end up in a busy wait loop if none of the break conditions
are met.

Signed-off-by: Timur Celik <mail@...urcelik.de>
---
 drivers/net/tun.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index fed298c0cb39..d291762b9e9d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2167,9 +2167,9 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
 	}
 
 	add_wait_queue(&tfile->wq.wait, &wait);
-	current->state = TASK_INTERRUPTIBLE;
 
 	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
 		ptr = ptr_ring_consume(&tfile->tx_ring);
 		if (ptr)
 			break;
@@ -2185,7 +2185,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
 		schedule();
 	}
 
-	current->state = TASK_RUNNING;
+	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&tfile->wq.wait, &wait);
 
 out:
-- 
2.20.1