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From: Johannes Weiner <hannes@cmpxchg.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>,
	Vladimir Davydov <vdavydov@parallels.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [patch 1/3] mm: memcontrol: remove bogus NULL check after mem_cgroup_from_task()
Date: Fri, 24 Oct 2014 09:49:47 -0400	[thread overview]
Message-ID: <1414158589-26094-1-git-send-email-hannes@cmpxchg.org> (raw)

That function acts like a typecast - unless NULL is passed in, no NULL
can come out.  task_in_mem_cgroup() callers don't pass NULL tasks.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
 mm/memcontrol.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 23cf27cca370..bdf8520979cf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1335,7 +1335,7 @@ static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
 bool task_in_mem_cgroup(struct task_struct *task,
 			const struct mem_cgroup *memcg)
 {
-	struct mem_cgroup *curr = NULL;
+	struct mem_cgroup *curr;
 	struct task_struct *p;
 	bool ret;
 
@@ -1351,8 +1351,7 @@ bool task_in_mem_cgroup(struct task_struct *task,
 		 */
 		rcu_read_lock();
 		curr = mem_cgroup_from_task(task);
-		if (curr)
-			css_get(&curr->css);
+		css_get(&curr->css);
 		rcu_read_unlock();
 	}
 	/*
-- 
2.1.2

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             reply	other threads:[~2014-10-24 13:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-24 13:49 Johannes Weiner [this message]
2014-10-24 13:49 ` [patch 2/3] mm: memcontrol: pull the NULL check from __mem_cgroup_same_or_subtree() Johannes Weiner
2014-10-24 14:49   ` Vladimir Davydov
2014-10-24 18:30   ` Michal Hocko
2014-10-24 13:49 ` [patch 3/3] mm: memcontrol: drop bogus RCU locking from mem_cgroup_same_or_subtree() Johannes Weiner
2014-10-24 15:22   ` Vladimir Davydov
2014-10-24 18:41   ` Michal Hocko
2014-10-24 14:41 ` [patch 1/3] mm: memcontrol: remove bogus NULL check after mem_cgroup_from_task() Vladimir Davydov
2014-10-24 18:29 ` Michal Hocko

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