From: Li Zefan <lizf@cn.fujitsu.com>
Date: Tue, 2 Sep 2008 21:35:52 +0000 (-0700)
Subject: devcgroup: fix race against rmdir()
X-Git-Tag: v2.6.27-rc6~64
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=36fd71d293898a59b14e49da1f6e81c1a58f2035;p=pandora-kernel.git

devcgroup: fix race against rmdir()

During the use of a dev_cgroup, we should guarantee the corresponding
cgroup won't be deleted (i.e.  via rmdir).  This can be done through
css_get(&dev_cgroup->css), but here we can just get and use the dev_cgroup
under rcu_read_lock.

And also remove checking NULL dev_cgroup, it won't be NULL since a task
always belongs to a cgroup.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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