Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <2e41d6e0-13bb-fa5d-00aa-75865b8e7c34@kernel.org>
Date:   Thu, 13 Apr 2023 23:18:21 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.8.0
Content-Language: en-US
To:     Yangtao Li <frank.li@vivo.com>, Jaegeuk Kim <jaegeuk@kernel.org>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
References: <20230406191629.63024-1-frank.li@vivo.com>
From:   Chao Yu <chao@kernel.org>
Subject: Re: [PATCH] f2fs: remove bulk remove_proc_entry() and unnecessary
 kobject_del()
In-Reply-To: <20230406191629.63024-1-frank.li@vivo.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2023/4/7 3:16, Yangtao Li wrote:
> Convert to use remove_proc_subtree() and kill kobject_del() directly.
> kobject_put() actually covers kobject removal automatically, which is
> single stage removal.
> 
> Signed-off-by: Yangtao Li <frank.li@vivo.com>
> ---
>   fs/f2fs/sysfs.c | 15 ++-------------
>   1 file changed, 2 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index dfbd17802549..3aad3500a701 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -1461,25 +1461,14 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
>   
>   void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
>   {
> -	if (sbi->s_proc) {
> -#ifdef CONFIG_F2FS_IOSTAT
> -		remove_proc_entry("iostat_info", sbi->s_proc);
> -#endif
> -		remove_proc_entry("segment_info", sbi->s_proc);
> -		remove_proc_entry("segment_bits", sbi->s_proc);
> -		remove_proc_entry("victim_bits", sbi->s_proc);
> -		remove_proc_entry("discard_plist_info", sbi->s_proc);
> -		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
> -	}
> +	if (sbi->s_proc)
> +		remove_proc_subtree(sbi->sb->s_id, f2fs_proc_root);
>   
> -	kobject_del(&sbi->s_stat_kobj);

- f2fs_register_sysfs
  - kobject_init_and_add(&sbi->s_stat_kobj, ..)

/**
  * kobject_init_and_add() - Initialize a kobject structure and add it to
  *                          the kobject hierarchy.
...
  *
  * This function combines the call to kobject_init() and kobject_add().
...
  */

/**
  * kobject_del() - Unlink kobject from hierarchy.
  * @kobj: object.
  *
  * This is the function that should be called to delete an object
  * successfully added via kobject_add().
  */

Am I missing something?

Thanks,

>   	kobject_put(&sbi->s_stat_kobj);
>   	wait_for_completion(&sbi->s_stat_kobj_unregister);
> -	kobject_del(&sbi->s_feature_list_kobj);
>   	kobject_put(&sbi->s_feature_list_kobj);
>   	wait_for_completion(&sbi->s_feature_list_kobj_unregister);
>   
> -	kobject_del(&sbi->s_kobj);
>   	kobject_put(&sbi->s_kobj);
>   	wait_for_completion(&sbi->s_kobj_unregister);
>   }