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net/irda: Fix port open counts

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Saving the port count bump is unsafe. If the tty is hung up while
this open was blocking, the port count is zeroed.

Explicitly check if the tty was hung up while blocking, and correct
the port count if not.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Peter Hurley 2013-03-05 06:09:04 +00:00 committed by David S. Miller
parent 0305d0689e
commit a4ed2e737c
1 changed files with 5 additions and 9 deletions
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14
net/irda/ircomm/ircomm_tty.c
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@ -280,7 +280,7 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
struct tty_port *port = &self->port; struct tty_port *port = &self->port;
DECLARE_WAITQUEUE(wait, current); DECLARE_WAITQUEUE(wait, current);
int retval; int retval;
int do_clocal = 0, extra_count = 0; int do_clocal = 0;
unsigned long flags; unsigned long flags;
IRDA_DEBUG(2, "%s()\n", __func__ ); IRDA_DEBUG(2, "%s()\n", __func__ );
@ -315,10 +315,8 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
__FILE__, __LINE__, tty->driver->name, port->count); __FILE__, __LINE__, tty->driver->name, port->count);
spin_lock_irqsave(&port->lock, flags); spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp)) { if (!tty_hung_up_p(filp))
extra_count = 1;
port->count--; port->count--;
}
spin_unlock_irqrestore(&port->lock, flags); spin_unlock_irqrestore(&port->lock, flags);
port->blocked_open++; port->blocked_open++;
@ -361,12 +359,10 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait); remove_wait_queue(&port->open_wait, &wait);
if (extra_count) { spin_lock_irqsave(&port->lock, flags);
/* ++ is not atomic, so this should be protected - Jean II */ if (!tty_hung_up_p(filp))
spin_lock_irqsave(&port->lock, flags);
port->count++; port->count++;
spin_unlock_irqrestore(&port->lock, flags); spin_unlock_irqrestore(&port->lock, flags);
}
port->blocked_open--; port->blocked_open--;
IRDA_DEBUG(1, "%s(%d):block_til_ready after blocking on %s open_count=%d\n", IRDA_DEBUG(1, "%s(%d):block_til_ready after blocking on %s open_count=%d\n",