slip: fix spinlock variant

With commit cc9fa74e2a ("slip/slcan: added locking in wakeup function") a
formerly missing locking was added to slip.c and slcan.c by Andre Naujoks.

Alexander Stein contributed the fix 367525c8c2 ("can: slcan: Fix spinlock
variant") as the kernel lock debugging advised to use spin_lock_bh() instead
of just using spin_lock().

This fix has to be applied to the same code section in slip.c for the same
reason too.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index cc70ecf..ad4a94e 100644 (file)
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -429,13 +429,13 @@ static void slip_write_wakeup(struct tty_struct *tty)
        if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
                return;
 
-       spin_lock(&sl->lock);
+       spin_lock_bh(&sl->lock);
        if (sl->xleft <= 0)  {
                /* Now serial buffer is almost free & we can start
                 * transmission of another packet */
                sl->dev->stats.tx_packets++;
                clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-               spin_unlock(&sl->lock);
+               spin_unlock_bh(&sl->lock);
                sl_unlock(sl);
                return;
        }
@@ -443,7 +443,7 @@ static void slip_write_wakeup(struct tty_struct *tty)
        actual = tty->ops->write(tty, sl->xhead, sl->xleft);
        sl->xleft -= actual;
        sl->xhead += actual;
-       spin_unlock(&sl->lock);
+       spin_unlock_bh(&sl->lock);
 }
 
 static void sl_tx_timeout(struct net_device *dev)