Re: blk_throtl_exit taking q->queue_lock is problematic

From: NeilBrown
Date: Mon Feb 21 2011 - 02:24:34 EST


On Fri, 18 Feb 2011 10:04:29 -0500 Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:

> On Fri, Feb 18, 2011 at 02:33:25PM +1100, NeilBrown wrote:
> > On Thu, 17 Feb 2011 22:19:52 -0500 Mike Snitzer <snitzer@xxxxxxxxxx> wrote:

> > > Noticed an inconsistency, raid10.c's additional locking also protects
> > > the bio_list_add() whereas raid1.c's doesn't. Seems the additional
> > > protection in raid10 isn't needed?
> >
> > Correct - not needed at all.
> > I put it there because it felt a little cleaner keeping the two 'lock's
> > together like the two 'unlock's. Probably confusing though...
>
> I guess you could use blk_plug_device_unlocked() to get rid of ugliness
> and this routine will take care of taking queue lock.
>

Yep, that gets rid of some ugliness.
I've made that change and will submit it in due course.
So blk_throtl doesn't need any change to avoid the problem with md - that
changes are made in md instead.

Thanks,
NeilBrown

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/