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 <[email protected]> Acked-by: KAMEZAWA Hiroyuki <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Glauber Costa <[email protected]> Cc: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
josf · Jul 9, 2013 · 5347e5a · 5347e5a
1 parent f37a969
commit 5347e5a
Showing 1 changed file with 4 additions and 4 deletions.
diff --git 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);
 	}
 }