[PATCH 3.13 035/212] slip: fix spinlock variant

Kamal Mostafa
2014-06-17T21:42:09Z

From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit ddcde142bed44490e338ed1124cb149976d355bb ]

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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/net/slip/slip.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index cc70ecf..ad4a94e 100644
--- 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)
--
1.9.1