Re: [PATCH v4 2/2] block: Ensure that a request queue is dissociated from the cgroup controller

[Bart Van Assche]

On Wed, 2018-08-08 at 08:41 -0600, Jens Axboe wrote:
> On 7/30/18 3:10 PM, Bart Van Assche wrote:
> > +#ifdef CONFIG_BLK_CGROUP
> > +   {
> > +           struct blkcg_gq *blkg;
> > +
> > +           rcu_read_lock();
> > +           blkg = blkg_lookup(&blkcg_root, q);
> > +           rcu_read_unlock();
> > +
> > +           WARN(blkg,
> > +                "request queue %p is being released but it has not yet 
> > been removed from the blkcg controller\n",
> > +                q);
> > +   }
> > +#endif
> 
> This last hunk should go in the cgroup code.

Hello Jens,

How about leaving out the #ifdef CONFIG_BLK_CGROUP / #endif? Would that be
sufficient? I just noticed that blkg_lookup() returns NULL anyway if cgroup 
support
is disabled in the kernel config.

Thanks,

Bart.