Commit d616e09a authored Jun 25, 2006 by Andrew Morton Committed by Linus Torvalds Jun 25, 2006

[PATCH] pdflush: handle resume wakeups

pdflush is carefully designed to ensure that all wakeups have some
corresponding work to do - if a woken-up pdflush thread discovers that it
hasn't been given any work to do then this is considered an error.

That all broke when swsusp came along - because a timer-delivered wakeup to a
frozen pdflush thread will just get lost. This causes the pdflush thread to
get lost as well: the writeback timer is supposed to be re-armed by pdflush in
process context, but pdflush doesn't execute the callout which does this.

Fix that up by ignoring the return value from try_to_freeze(): jsut proceed,
see if we have any work pending and only go back to sleep if that is not the
case.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent bc648638

mm/pdflush.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -104,21 +104,20 @@ static int __pdflush(struct pdflush_work *my_work)
		list_move(&my_work->list, &pdflush_list);
		my_work->when_i_went_to_sleep = jiffies;
		spin_unlock_irq(&pdflush_lock);

		schedule();
		if (try_to_freeze()) {
		spin_lock_irq(&pdflush_lock);
		continue;
		}

		try_to_freeze();
		spin_lock_irq(&pdflush_lock);
		if (!list_empty(&my_work->list)) {
		printk("pdflush: bogus wakeup!\n");
		/*
		* Someone woke us up, but without removing our control
		* structure from the global list. swsusp will do this
		* in try_to_freeze()->refrigerator(). Handle it.
		*/
		my_work->fn = NULL;
		continue;
		}
		if (my_work->fn == NULL) {
		printk("pdflush: NULL work function\n");
		printk("pdflush: bogus wakeup\n");
		continue;
		}
		spin_unlock_irq(&pdflush_lock);