Subject: Re: [PATCH] cpuset: Remove unused 'struct cpuset*' variable
To: Kirtika Ruchandani <kirtika@chromium.org>, <tj@kernel.org>
References: <kirtika@chromium.org>
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CC: <arnd@arndb.de>, <cgroups@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
From: Zefan Li <lizefan@huawei.com>
Message-ID: <5837D01C.1070803@huawei.com>
Date: Fri, 25 Nov 2016 13:46:04 +0800
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On 2016/11/25 12:55, Kirtika Ruchandani wrote:
> 'struct cpuset* cs' that is set but not used, was introduced in commit
> 1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling").
> cpuset_cancel_attach() uses css_cs(css) instead. Compiling with W=1
> gives the folllowing harmless warning, which we'd like to fix to
> reduce the noise with W=1 in the kernel.
> 
> kernel/cpuset.c: In function ‘cpuset_cancel_attach’:
> kernel/cpuset.c:1502:17: warning: variable ‘cs’ set but not used [-Wunused-but-set-variable]
>   struct cpuset *cs;
>                  ^
> 
> Fixes: 1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling").

This isn't a bug, so I don't think this tag is proper.

> Cc: Tejun Heo <tj@kernel.org>
> Signed-off-by: Kirtika Ruchandani <kirtika@chromium.org>

Acked-by: Zefan Li <lizefan@huawei.com>

> ---
>  kernel/cpuset.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 29f815d..af51460 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1499,10 +1499,8 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
>  static void cpuset_cancel_attach(struct cgroup_taskset *tset)
>  {
>  	struct cgroup_subsys_state *css;
> -	struct cpuset *cs;
>  
>  	cgroup_taskset_first(tset, &css);
> -	cs = css_cs(css);
>  
>  	mutex_lock(&cpuset_mutex);
>  	css_cs(css)->attach_in_progress--;
>