From: Andrew Morton <akpm@linux-foundation.org>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: "Paul Menage" <menage@google.com>,
"David Rientjes" <rientjes@google.com>,
"缪 勰" <miaox@cn.fujitsu.com>, LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH] cpuset: Add a missing unlock in cpuset_write_resmask()
Date: Mon, 28 Feb 2011 15:55:24 -0800 [thread overview]
Message-ID: <20110228155524.6d7563e0.akpm@linux-foundation.org> (raw)
In-Reply-To: <4D6601B2.1090207@cn.fujitsu.com>
On Thu, 24 Feb 2011 14:58:58 +0800
Li Zefan <lizf@cn.fujitsu.com> wrote:
> Don't forget to release cgroup_mutex if alloc_trial_cpuset() fails.
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> ---
> kernel/cpuset.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 1ca786a..6272503 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1561,8 +1561,10 @@ static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
> return -ENODEV;
>
> trialcs = alloc_trial_cpuset(cs);
> - if (!trialcs)
> + if (!trialcs) {
> + cgroup_unlock();
> return -ENOMEM;
> + }
>
> switch (cft->private) {
> case FILE_CPULIST:
It would be better to avoid multiple returns - it leads to more
maintainable code and often shorter code:
--- a/kernel/cpuset.c~cpuset-add-a-missing-unlock-in-cpuset_write_resmask-fix
+++ a/kernel/cpuset.c
@@ -1562,8 +1562,8 @@ static int cpuset_write_resmask(struct c
trialcs = alloc_trial_cpuset(cs);
if (!trialcs) {
- cgroup_unlock();
- return -ENOMEM;
+ retval = -ENOMEM;
+ goto out;
}
switch (cft->private) {
@@ -1579,6 +1579,7 @@ static int cpuset_write_resmask(struct c
}
free_trial_cpuset(trialcs);
+out:
cgroup_unlock();
return retval;
}
_
also, alloc_trial_cpuset() is a fairly slow-looking function.
cpuset_write_resmask() could run alloc_trial_cpuset() before running
cgroup_lock_live_group(), thereby reducing lock hold times.
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next prev parent reply other threads:[~2011-02-28 23:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-24 6:58 Li Zefan
2011-02-24 7:05 ` David Rientjes
2011-02-28 23:55 ` Andrew Morton [this message]
2011-03-01 1:05 ` Li Zefan
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