From: Vladimir Davydov <vdavydov@parallels.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 1/3] mm: memcontrol: remove bogus NULL check after mem_cgroup_from_task()
Date: Fri, 24 Oct 2014 18:41:01 +0400 [thread overview]
Message-ID: <20141024144101.GA28055@esperanza> (raw)
In-Reply-To: <1414158589-26094-1-git-send-email-hannes@cmpxchg.org>
On Fri, Oct 24, 2014 at 09:49:47AM -0400, Johannes Weiner wrote:
> 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>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
> ---
> 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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next prev parent reply other threads:[~2014-10-24 14:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-24 13:49 Johannes Weiner
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 ` Vladimir Davydov [this message]
2014-10-24 18:29 ` [patch 1/3] mm: memcontrol: remove bogus NULL check after mem_cgroup_from_task() Michal Hocko
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