Re: [PATCH 2.6.11-rc2 11/29] ide: add ide_drive_t.sleeping

Jens Axboe
2005-02-03T13:33:06Z

On Thu, Feb 03 2005, Bartlomiej Zolnierkiewicz wrote:
> On Thu, 3 Feb 2005 12:37:10 +0100, Jens Axboe <axboe@suse.de> wrote:
> > On Thu, Feb 03 2005, Bartlomiej Zolnierkiewicz wrote:
> > > On Wed, 2 Feb 2005 11:54:48 +0900, Tejun Heo <tj@home-tj.org> wrote:
> > > > > 11_ide_drive_sleeping_fix.patch
> > > > >
> > > > > ide_drive_t.sleeping field added. 0 in sleep field used to
> > > > > indicate inactive sleeping but because 0 is a valid jiffy
> > > > > value, though slim, there's a chance that something can go
> > > > > weird. And while at it, explicit jiffy comparisons are
> > > > > converted to use time_{after|before} macros.
> > >
> > > Same question as for "add ide_hwgroup_t.polling" patch.
> > > AFAICS drive->sleep is either '0' or 'timeout + jiffies' (always > 0)
> >
> > Hmm, what if jiffies + timeout == 0?
>
> Hm, jiffies is unsigned and timeout is always > 0
> but this is still possible if jiffies + timeout wraps, right?

Precisely, if jiffies is exactly 'timeout' away from wrapping to 0 it
could happen. So I think the fix looks sane.

--
Jens Axboe