linux-kernel - Re: [PATCH] f2fs: remove bulk remove_proc_entry() and unnecessary kobject

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Date:   Thu, 13 Apr 2023 08:54:52 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <chao@...nel.org>
Cc:     Yangtao Li <frank.li@...o.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: remove bulk remove_proc_entry() and unnecessary
 kobject_del()

On 04/13, Chao Yu wrote:
> 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@...o.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?

kobject_put -> kobject_cleanup was supposed to do it?

> 
> 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);
> >   }