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From: Johannes Weiner <hannes@cmpxchg.org>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Vladimir Davydov <vdavydov@virtuozzo.com>,
	Michal Hocko <mhocko@suse.cz>, Li Zefan <lizefan@huawei.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 2/3] cgroup: remove unnecessary 0 check from css_from_id()
Date: Fri, 17 Jun 2016 12:24:27 -0400
Message-ID: <20160617162427.GC19084@cmpxchg.org> (raw)
In-Reply-To: <20160617162310.GA19084@cmpxchg.org>

css_idr allocation starts at 1, so index 0 will never point to an
item. css_from_id() currently filters that before asking idr_find(),
but idr_find() would also just return NULL, so this is not needed.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
 kernel/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 36fc0ff506c3..78f6d18ff0af 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6162,7 +6162,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
 {
 	WARN_ON_ONCE(!rcu_read_lock_held());
-	return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
+	return idr_find(&ss->css_idr, id);
 }
 
 /**
-- 
2.8.3

--
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  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-16  3:42 [PATCH] mm: memcontrol: fix cgroup creation failure after many small jobs Johannes Weiner
2016-06-16 20:06 ` Tejun Heo
2016-06-17 16:23   ` Johannes Weiner
2016-06-17 16:23     ` [PATCH 1/3] cgroup: fix idr leak for the first cgroup root Johannes Weiner
2016-06-17 16:24     ` Johannes Weiner [this message]
2016-06-17 18:17       ` [PATCH 2/3] cgroup: remove unnecessary 0 check from css_from_id() Tejun Heo
2016-06-17 16:25     ` [PATCH 3/3] mm: memcontrol: fix cgroup creation failure after many small jobs Johannes Weiner
2016-06-17 18:18       ` Tejun Heo
2016-06-20  6:14       ` Nikolay Borisov
2016-06-21 10:16       ` Vladimir Davydov
2016-06-21 15:46         ` Johannes Weiner
2016-06-17  9:06 ` [PATCH] " Vladimir Davydov
2016-06-17 16:40   ` Johannes Weiner
2016-07-14 15:37 ` Johannes Weiner

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