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Subject: Re: [PATCH 1/3] f2fs: avoid __GFP_NOFAIL in f2fs_bio_alloc
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>
References: <20200218102136.32150-1-yuchao0@huawei.com>
 <20200219024928.GA96609@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <52705a9b-306b-c6b0-0f48-c12149e7b915@huawei.com>
Date:   Wed, 19 Feb 2020 11:12:53 +0800
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On 2020/2/19 10:49, Jaegeuk Kim wrote:
> On 02/18, Chao Yu wrote:
>> __f2fs_bio_alloc() won't fail due to memory pool backend, remove unneeded
>> __GFP_NOFAIL flag in __f2fs_bio_alloc().
> 
> It it safe for old kernels as well when thinking backports?

^1da177e4c3f4 (Linus Torvalds     2005-04-16 15:20:36 -0700  134)       struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);

It looks if we have a backend mempool, we will never fail to allocate bio
for very long time, we don't need to backport to 2.6.x kernel, right?

Thanks,

> 
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>>  fs/f2fs/data.c | 12 ++++--------
>>  fs/f2fs/f2fs.h |  2 +-
>>  2 files changed, 5 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index baf12318ec64..3a4ece26928c 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -54,17 +54,13 @@ static inline struct bio *__f2fs_bio_alloc(gfp_t gfp_mask,
>>  	return bio_alloc_bioset(gfp_mask, nr_iovecs, &f2fs_bioset);
>>  }
>>  
>> -struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi, int npages, bool no_fail)
>> +struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi, int npages, bool noio)
>>  {
>> -	struct bio *bio;
>> -
>> -	if (no_fail) {
>> +	if (noio) {
>>  		/* No failure on bio allocation */
>> -		bio = __f2fs_bio_alloc(GFP_NOIO, npages);
>> -		if (!bio)
>> -			bio = __f2fs_bio_alloc(GFP_NOIO | __GFP_NOFAIL, npages);
>> -		return bio;
>> +		return __f2fs_bio_alloc(GFP_NOIO, npages);
>>  	}
>> +
>>  	if (time_to_inject(sbi, FAULT_ALLOC_BIO)) {
>>  		f2fs_show_injection_info(sbi, FAULT_ALLOC_BIO);
>>  		return NULL;
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 5316ac3eacdf..65f569949d42 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -3343,7 +3343,7 @@ void f2fs_destroy_checkpoint_caches(void);
>>   */
>>  int __init f2fs_init_bioset(void);
>>  void f2fs_destroy_bioset(void);
>> -struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi, int npages, bool no_fail);
>> +struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi, int npages, bool noio);
>>  int f2fs_init_bio_entry_cache(void);
>>  void f2fs_destroy_bio_entry_cache(void);
>>  void f2fs_submit_bio(struct f2fs_sb_info *sbi,
>> -- 
>> 2.18.0.rc1
> .
>