2.6.16 needs this. It was merged into 2.6.18-rc1 in
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d616e09ab33aa4d013a93c9b393efd5cebf78521 .

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>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>