Re: [PATCH] workqueue: cancel_rearming_delayed_work/workqueue usage warning

[Jarek Poplawski <jarkao2@o2.pl>]

On Fri, Apr 20, 2007 at 09:23:48PM +0400, Oleg Nesterov wrote:
> On 04/20, Jarek Poplawski wrote:
> > 
> > Here is my proposal to make things clearer:
> > (this time on 2.6.21-rc7)
> > 
> > CC: David Chinner <dgc@sgi.com>
> > CC: Oleg Nesterov <oleg@tv-sign.ru>
> > Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
> > 
> > ---
> > 
> > diff -Nurp 2.6.21-rc7-/kernel/workqueue.c 2.6.21-rc7/kernel/workqueue.c
> > --- 2.6.21-rc7-/kernel/workqueue.c	2007-04-18 10:14:16.000000000 +0200
> > +++ 2.6.21-rc7/kernel/workqueue.c	2007-04-20 13:56:51.000000000 +0200
> > @@ -662,6 +662,8 @@ EXPORT_SYMBOL(flush_scheduled_work);
> >   * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work.
> >   * @wq:   the controlling workqueue structure
> >   * @dwork: the delayed work struct
> > + *
> > + * WARNING: use only with handlers, which rearm unconditionally with delay > 0
> >   */
> 
> Nit: it is ok if the work re-arms itself with delay == 0 "sometimes". What we
> need is that the handler use delay > 0 eventually.

Probably it would be shorter to write it yourself, because I'm not sure
of your intentions: so, you think we can call this function with such
a work?

> 
> I'd suggest to re-diff against -mm tree. I don't think this patch can find its
> way to the soon to be released 2.6.21.

The current thread seems to confirm my initial fear, this function
is not explained enough, so it should help to remove errors as soon
as possible from the current code. And I hope this functions will
work other way soon...

Jarek P.