From 5347e5ae13710420eebbbd0b22c045685704da80 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan@huawei.com>
Date: Mon, 8 Jul 2013 16:00:30 -0700
Subject: memcg: use css_get() in sock_update_memcg()

Use css_get/css_put instead of mem_cgroup_get/put.

Note, if at the same time someone is moving @current to a different
cgroup and removing the old cgroup, css_tryget() may return false, and
sock->sk_cgrp won't be initialized, which is fine.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/memcontrol.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

(limited to 'mm')

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bdeb82ca6c20..4c31a21a55be 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -551,15 +551,15 @@ void sock_update_memcg(struct sock *sk)
 		 */
 		if (sk->sk_cgrp) {
 			BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
-			mem_cgroup_get(sk->sk_cgrp->memcg);
+			css_get(&sk->sk_cgrp->memcg->css);
 			return;
 		}
 
 		rcu_read_lock();
 		memcg = mem_cgroup_from_task(current);
 		cg_proto = sk->sk_prot->proto_cgroup(memcg);
-		if (!mem_cgroup_is_root(memcg) && memcg_proto_active(cg_proto)) {
-			mem_cgroup_get(memcg);
+		if (!mem_cgroup_is_root(memcg) &&
+		    memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) {
 			sk->sk_cgrp = cg_proto;
 		}
 		rcu_read_unlock();
@@ -573,7 +573,7 @@ void sock_release_memcg(struct sock *sk)
 		struct mem_cgroup *memcg;
 		WARN_ON(!sk->sk_cgrp->memcg);
 		memcg = sk->sk_cgrp->memcg;
-		mem_cgroup_put(memcg);
+		css_put(&sk->sk_cgrp->memcg->css);
 	}
 }
 
-- 
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