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Char: moxa, fix locking in moxa_write 

moxa_write can be called from atomic context with irqs disabled (from
ppp_async_push). Don't enable interrupts by spin_unlock_bh as this
might cause deadlocks in the ppp layer.

Instead, use irqsave/irqrestore spin_lock functions.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
Jiri Slaby 2011-04-20 10:43:15 +02:00 committed by Greg Kroah-Hartman
parent 7fdc289311
commit 0ad7c9af3e
1 changed files with 3 additions and 2 deletions
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5
drivers/tty/moxa.c
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@ -1202,14 +1202,15 @@ static int moxa_write(struct tty_struct *tty,
const unsigned char *buf, int count)
{
struct moxa_port *ch = tty->driver_data;
unsigned long flags;
int len;
if (ch == NULL)
return 0;
spin_lock_bh(&moxa_lock);
spin_lock_irqsave(&moxa_lock, flags);
len = MoxaPortWriteData(tty, buf, count);
spin_unlock_bh(&moxa_lock);
spin_unlock_irqrestore(&moxa_lock, flags);
set_bit(LOWWAIT, &ch->statusflags);
return len;