Re: down_timeout

[Andrew Morton <akpm@osdl.org>]

Matthew Wilcox <willy@debian.org> wrote:
>
> /* Returns -EINTR if the timeout expires */
> int down_timeout(struct semaphore *sem, long timeout)
> {
> 	struct timer_list timer;
> 	int result;
> 
> 	init_timer(&timer);
> 	timer.expires = timeout + jiffies;
> 	timer.data = (unsigned long) current;
> 	timer.function = process_timeout;
> 
> 	add_timer(&timer);
> 	result = down_interruptible(sem);
> 	del_timer_sync(&timer);
> 
> 	return result;
> }

down_interruptible() will only break out if signal_pending(current), so the
wakeup-on-expiry here will not work as desired.

New per-arch primitives would be needed to implement this, I think.