[dm-devel] [PATCH 1/7] blk-mq: fix use of incorrect goto label in blk_mq_init_queue error path

[Mike Snitzer]

On Thu, Mar 12 2015 at  3:48am -0400,
Ming Lei <tom.leiming at gmail.com> wrote:

> On Thu, Mar 12, 2015 at 11:56 AM, Mike Snitzer <snitzer at redhat.com> wrote:
> > If percpu_ref_init() fails the 'err_hctxs' label should be used instead
> > of 'err_map'.
> >
> > Signed-off-by: Mike Snitzer <snitzer at redhat.com>
> > ---
> >  block/blk-mq.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block/blk-mq.c b/block/blk-mq.c
> > index 4f4bea2..459840c 100644
> > --- a/block/blk-mq.c
> > +++ b/block/blk-mq.c
> > @@ -1938,7 +1938,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
> >          */
> >         if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release,
> >                             PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
> > -               goto err_map;
> > +               goto err_hctxs;
> 
> If it is changed to 'goto err_hctxs', percpu_ref_init() need to
> move before blk_alloc_queue_node(), otherwise just 'goto err_hw'
> is enough, but the former is better.

Yes, you're correct.  Patch 2 happened to eliminate this problem.  But
I'll get it fixed up and post v2.

The reason this thinko happened is I noticed the problem after I moved
the blk_alloc_queue_node() out in patch 2 and when I rebased to reorder
the fix before that patch 2 context got lost in the shuffle.

Thanks for your review!