From: Johannes Weiner <hannes@cmpxchg.org>
Date: Tue, 29 May 2012 22:06:24 +0000 (-0700)
Subject: kernel: cgroup: push rcu read locking from css_is_ancestor() to callsite
X-Git-Tag: v3.5-rc1~49^2~160
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=91c63734f6908425903aed69c04035592f18d398;p=pandora-kernel.git

kernel: cgroup: push rcu read locking from css_is_ancestor() to callsite

Library functions should not grab locks when the callsites can do it,
even if the lock nests like the rcu read-side lock does.

Push the rcu_read_lock() from css_is_ancestor() to its single user,
mem_cgroup_same_or_subtree() in preparation for another user that may
already hold the rcu read-side lock.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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