Re: [PATCH] cgroups: remove redundant get/put of css_set from css_set_check_fetched()

[Li Zefan <lizf@cn.fujitsu.com>]

Mandeep Singh Baines wrote:
> We already have a reference to all elements in newcg_list.
> 

Indeed. The patch looks good to me.

Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>

> Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Li Zefan <lizf@cn.fujitsu.com>
> Cc: containers@lists.linux-foundation.org
> Cc: cgroups@vger.kernel.org
> Cc: Paul Menage <paul@paulmenage.org>
> ---
>  kernel/cgroup.c |   10 ++--------
>  1 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index d9d5648..a7e00b9 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1935,23 +1935,17 @@ static bool css_set_check_fetched(struct cgroup *cgrp,
>  
>  	read_lock(&css_set_lock);
>  	newcg = find_existing_css_set(cg, cgrp, template);
> -	if (newcg)
> -		get_css_set(newcg);
>  	read_unlock(&css_set_lock);
>  
>  	/* doesn't exist at all? */
>  	if (!newcg)
>  		return false;
>  	/* see if it's already in the list */
> -	list_for_each_entry(cg_entry, newcg_list, links) {
> -		if (cg_entry->cg == newcg) {
> -			put_css_set(newcg);
> +	list_for_each_entry(cg_entry, newcg_list, links)
> +		if (cg_entry->cg == newcg)
>  			return true;
> -		}
> -	}
>  
>  	/* not found */
> -	put_css_set(newcg);
>  	return false;
>  }
>