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From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	containers@lists.linux-foundation.org
Subject: Re: [PATCH 1/8] blkcg: kill blkio_list and replace blkio_list_lock with a mutex
Date: Fri, 13 Apr 2012 09:55:19 -0700	[thread overview]
Message-ID: <20120413165519.GA12233@google.com> (raw)
In-Reply-To: <20120413133226.GB26383@redhat.com>

On Fri, Apr 13, 2012 at 09:32:26AM -0400, Vivek Goyal wrote:
> On Thu, Apr 12, 2012 at 04:29:33PM -0700, Tejun Heo wrote:
> 
> Hi Tejun,
> 
> > @@ -732,20 +732,21 @@ void blkio_policy_register(struct blkio_policy_type *blkiop)
> >  {
> >  	struct request_queue *q;
> >  
> > +	mutex_lock(&blkcg_pol_mutex);
> > +
> >  	blkcg_bypass_start();
> > -	spin_lock(&blkio_list_lock);
> >  
> >  	BUG_ON(blkio_policy[blkiop->plid]);
> 
> A minor nit. It might be a good idea to check that blkiop->plid is not
> greater than BLKIO_NR_POLICIES for both registration and unresitration
> functions to avoid touching memory beyond blkio_policy[] array.

I'm making ->plid to be dynamically allocated on registration anyway,
so I don't think it really matters.  The updated unregistration
function does BUG_ON(blkio_policy[pol->plid] != pol) which should
catch stray plid.

Thanks.

-- 
tejun

  reply	other threads:[~2012-04-13 16:55 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-12 23:29 [PATCHSET] block: per-queue policy activation Tejun Heo
2012-04-12 23:29 ` [PATCH 1/8] blkcg: kill blkio_list and replace blkio_list_lock with a mutex Tejun Heo
2012-04-13 13:32   ` Vivek Goyal
2012-04-13 16:55     ` Tejun Heo [this message]
2012-04-12 23:29 ` [PATCH 2/8] blkcg: use @pol instead of @plid in update_root_blkg_pd() and blkcg_print_blkgs() Tejun Heo
2012-04-12 23:29 ` [PATCH 3/8] blkcg: remove static policy ID enums Tejun Heo
2012-04-12 23:29 ` [PATCH 4/8] blkcg: make blkg_conf_prep() take @pol and return with queue lock held Tejun Heo
2012-04-12 23:29 ` [PATCH 5/8] blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing Tejun Heo
2012-04-13 16:00   ` Vivek Goyal
2012-04-13 17:03     ` Tejun Heo
2012-04-13 17:23       ` Vivek Goyal
2012-04-13 17:28         ` Tejun Heo
2012-04-16 22:41         ` Paul E. McKenney
2012-04-12 23:29 ` [PATCH 6/8] blkcg: add request_queue->root_blkg Tejun Heo
2012-04-12 23:29 ` [PATCH 7/8] blkcg: implement per-queue policy activation Tejun Heo
2012-04-13 15:21   ` Vivek Goyal
2012-04-13 15:23     ` Vivek Goyal
2012-04-13 18:12   ` Vivek Goyal
2012-04-13 18:17     ` Tejun Heo
2012-04-12 23:29 ` [PATCH 8/8] blkcg: drop stuff unused after per-queue policy activation update Tejun Heo

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