linux-kernel - Re: [PATCH 1/2] f2fs: remove folio_detach_private() in .invalidate_folio and .release

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Message-ID: <b05d7ce8-ef98-a7ef-9873-4403ec0858c1@kernel.org>
Date:   Tue, 11 Apr 2023 16:34:05 +0800
From:   Chao Yu <chao@...nel.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] f2fs: remove folio_detach_private() in
 .invalidate_folio and .release_folio

On 2023/4/11 2:33, Jaegeuk Kim wrote:
> On 04/10, Chao Yu wrote:
>> We have maintain PagePrivate and page_private and page reference
>> w/ {set,clear}_page_private_*, it doesn't need to call
>> folio_detach_private() in the end of .invalidate_folio and
>> .release_folio, remove it and use f2fs_bug_on instead.
>>
>> Signed-off-by: Chao Yu <chao@...nel.org>
>> ---
>>   fs/f2fs/data.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 4946df6dd253..8b179b4bdc03 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -3737,7 +3737,8 @@ void f2fs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
>>   			inode->i_ino == F2FS_COMPRESS_INO(sbi))
>>   		clear_page_private_data(&folio->page);
>>   
>> -	folio_detach_private(folio);
>> +	f2fs_bug_on(sbi, PagePrivate(&folio->page));
>> +	f2fs_bug_on(sbi, page_private(&folio->page));
> 
> I think we can just check page_private() only.

Why? how about the case PagePrivate was set, but page_private was't? It must
be a bug as well?

Thanks,

> 
>>   }
>>   
>>   bool f2fs_release_folio(struct folio *folio, gfp_t wait)
>> @@ -3759,7 +3760,9 @@ bool f2fs_release_folio(struct folio *folio, gfp_t wait)
>>   	clear_page_private_reference(&folio->page);
>>   	clear_page_private_gcing(&folio->page);
>>   
>> -	folio_detach_private(folio);
>> +	f2fs_bug_on(sbi, PagePrivate(&folio->page));
>> +	f2fs_bug_on(sbi, page_private(&folio->page));
>> +
>>   	return true;
>>   }
>>   
>> -- 
>> 2.25.1