[PATCH] memcg: don't do cleanup manually if mem_cgroup_css_online() fails

[Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>]

If memcg_init_kmem() returns -errno when a memcg is being created,
mem_cgroup_css_online() will decrement memcg and its parent's refcnt,
(but strangely there's no mem_cgroup_put() for mem_cgroup_get() called
in memcg_propagate_kmem()).

But then cgroup core will call mem_cgroup_css_free() to do cleanup...

Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
 mm/memcontrol.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e80504e..e927fc6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6247,16 +6247,7 @@ mem_cgroup_css_online(struct cgroup *cont)
 
 	error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
 	mutex_unlock(&memcg_create_mutex);
-	if (error) {
-		/*
-		 * We call put now because our (and parent's) refcnts
-		 * are already in place. mem_cgroup_put() will internally
-		 * call __mem_cgroup_free, so return directly
-		 */
-		mem_cgroup_put(memcg);
-		if (parent->use_hierarchy)
-			mem_cgroup_put(parent);
-	}
+
 	return error;
 }
 
-- 
1.8.0.2