From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH v2] cgroup: protect modifications to cgroup->idr with
 cgroup_mutex
Date: Wed, 12 Feb 2014 01:37:13 -0500
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To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>

Hello, Li.

On Wed, Feb 12, 2014 at 02:28:53PM +0800, Li Zefan wrote:
> v2:
> - Don't call deactivate_super() inside cgroup_mutex, as cgroup_kill_sb()
> will be called if sb refcnt reaches 0. I don't think this can happen,
> as cgroup_create() is called through vfs, so vfs should guarantee the
> superblock won't disappear. Still better not depend on it even my guess
> is probably correct.

If the deadlock can't actually happen, I don't really care either way
as the code goes away after kernfs conversion anyway.  I've already
applied v1, so if you think this change is important, can you send an
incremental patch?

Thanks!

-- 
tejun