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can: slcan: Fix spinlock variant 

slc_xmit is called within softirq context and locks sl->lock, but
slcan_write_wakeup is not softirq context, so we need to use
spin_[un]lock_bh!
Detected using kernel lock debugging mechanism.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
hifive-unleashed-5.1
Alexander Stein 2014-04-15 16:51:04 +02:00 committed by Marc Kleine-Budde
parent d482443244
commit 367525c8c2
1 changed files with 3 additions and 3 deletions
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6
drivers/net/can/slcan.c
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@ -322,13 +322,13 @@ static void slcan_write_wakeup(struct tty_struct *tty)
if (!sl || sl->magic != SLCAN_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);
netif_wake_queue(sl->dev);
return;
}
@ -336,7 +336,7 @@ static void slcan_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);
}
/* Send a can_frame to a TTY queue. */