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Date:   Tue, 30 Mar 2021 10:32:47 +0200
From:   Michal Hocko <mhocko@suse.com>
To:     Wan Jiabing <wanjiabing@vivo.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Shakeel Butt <shakeelb@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Alex Shi <alex.shi@linux.alibaba.com>,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>,
        Chris Down <chris@chrisdown.name>,
        Yafang Shao <laoar.shao@gmail.com>,
        Wei Yang <richard.weiyang@gmail.com>,
        linux-kernel@vger.kernel.org, kael_w@yeah.net
Subject: Re: [PATCH] linux/memcontrol.h: Remove duplicate struct declaration
Message-ID: <YGLiL4CTvLQRSXy/@dhcp22.suse.cz>
References: <20210330020246.2265371-1-wanjiabing@vivo.com>
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On Tue 30-03-21 10:02:36, Wan Jiabing wrote:
> struct mem_cgroup is declared twice. One has been declared
> at forward struct declaration. Remove the duplicate.

Duplicate declaration shouldn't really cause any problems. You are right
that there is one which is independent on CONFIG_MEMCG so the below one
is not needed though. It would be great if the changelog mentioned that
so that.

> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  include/linux/memcontrol.h | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 0c04d39a7967..f0ae33a0f175 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1068,8 +1068,6 @@ void split_page_memcg(struct page *head, unsigned int nr);
>  #define MEM_CGROUP_ID_SHIFT	0
>  #define MEM_CGROUP_ID_MAX	0
>  
> -struct mem_cgroup;
> -
>  static inline struct mem_cgroup *page_memcg(struct page *page)
>  {
>  	return NULL;
> -- 
> 2.25.1

-- 
Michal Hocko
SUSE Labs