Re: [f2fs-dev] [PATCH] f2fs: fix iostat related lock protection

[Chao Yu <chao@kernel.org>]

On 2022/6/16 0:54, Jaegeuk Kim wrote:
> On 06/15, Chao Yu wrote:
>> On 2022/6/11 2:32, Daeho Jeong wrote:
>>> From: Daeho Jeong <daehojeong@google.com>
>>>
>>> Made iostat related locks safe to be called from irq context again.
>>>
>>
>> Will be better to add a 'Fixes' line?
> 
> Added some tags. Thanks,
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=f8ed39ad779fbc5d37d08e83643384fc06e4bae4

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

> 
> 
>>
>> Thanks,
>>
>>> Signed-off-by: Daeho Jeong <daehojeong@google.com>
>>> ---
>>>    fs/f2fs/iostat.c | 31 ++++++++++++++++++-------------
>>>    1 file changed, 18 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
>>> index be599f31d3c4..d84c5f6cc09d 100644
>>> --- a/fs/f2fs/iostat.c
>>> +++ b/fs/f2fs/iostat.c
>>> @@ -91,8 +91,9 @@ static inline void __record_iostat_latency(struct f2fs_sb_info *sbi)
>>>    	unsigned int cnt;
>>>    	struct f2fs_iostat_latency iostat_lat[MAX_IO_TYPE][NR_PAGE_TYPE];
>>>    	struct iostat_lat_info *io_lat = sbi->iostat_io_lat;
>>> +	unsigned long flags;
>>> -	spin_lock_bh(&sbi->iostat_lat_lock);
>>> +	spin_lock_irqsave(&sbi->iostat_lat_lock, flags);
>>>    	for (idx = 0; idx < MAX_IO_TYPE; idx++) {
>>>    		for (io = 0; io < NR_PAGE_TYPE; io++) {
>>>    			cnt = io_lat->bio_cnt[idx][io];
>>> @@ -106,7 +107,7 @@ static inline void __record_iostat_latency(struct f2fs_sb_info *sbi)
>>>    			io_lat->bio_cnt[idx][io] = 0;
>>>    		}
>>>    	}
>>> -	spin_unlock_bh(&sbi->iostat_lat_lock);
>>> +	spin_unlock_irqrestore(&sbi->iostat_lat_lock, flags);
>>>    	trace_f2fs_iostat_latency(sbi, iostat_lat);
>>>    }
>>> @@ -115,14 +116,15 @@ static inline void f2fs_record_iostat(struct f2fs_sb_info *sbi)
>>>    {
>>>    	unsigned long long iostat_diff[NR_IO_TYPE];
>>>    	int i;
>>> +	unsigned long flags;
>>>    	if (time_is_after_jiffies(sbi->iostat_next_period))
>>>    		return;
>>>    	/* Need double check under the lock */
>>> -	spin_lock_bh(&sbi->iostat_lock);
>>> +	spin_lock_irqsave(&sbi->iostat_lock, flags);
>>>    	if (time_is_after_jiffies(sbi->iostat_next_period)) {
>>> -		spin_unlock_bh(&sbi->iostat_lock);
>>> +		spin_unlock_irqrestore(&sbi->iostat_lock, flags);
>>>    		return;
>>>    	}
>>>    	sbi->iostat_next_period = jiffies +
>>> @@ -133,7 +135,7 @@ static inline void f2fs_record_iostat(struct f2fs_sb_info *sbi)
>>>    				sbi->prev_rw_iostat[i];
>>>    		sbi->prev_rw_iostat[i] = sbi->rw_iostat[i];
>>>    	}
>>> -	spin_unlock_bh(&sbi->iostat_lock);
>>> +	spin_unlock_irqrestore(&sbi->iostat_lock, flags);
>>>    	trace_f2fs_iostat(sbi, iostat_diff);
>>> @@ -145,25 +147,27 @@ void f2fs_reset_iostat(struct f2fs_sb_info *sbi)
>>>    	struct iostat_lat_info *io_lat = sbi->iostat_io_lat;
>>>    	int i;
>>> -	spin_lock_bh(&sbi->iostat_lock);
>>> +	spin_lock_irq(&sbi->iostat_lock);
>>>    	for (i = 0; i < NR_IO_TYPE; i++) {
>>>    		sbi->rw_iostat[i] = 0;
>>>    		sbi->prev_rw_iostat[i] = 0;
>>>    	}
>>> -	spin_unlock_bh(&sbi->iostat_lock);
>>> +	spin_unlock_irq(&sbi->iostat_lock);
>>> -	spin_lock_bh(&sbi->iostat_lat_lock);
>>> +	spin_lock_irq(&sbi->iostat_lat_lock);
>>>    	memset(io_lat, 0, sizeof(struct iostat_lat_info));
>>> -	spin_unlock_bh(&sbi->iostat_lat_lock);
>>> +	spin_unlock_irq(&sbi->iostat_lat_lock);
>>>    }
>>>    void f2fs_update_iostat(struct f2fs_sb_info *sbi,
>>>    			enum iostat_type type, unsigned long long io_bytes)
>>>    {
>>> +	unsigned long flags;
>>> +
>>>    	if (!sbi->iostat_enable)
>>>    		return;
>>> -	spin_lock_bh(&sbi->iostat_lock);
>>> +	spin_lock_irqsave(&sbi->iostat_lock, flags);
>>>    	sbi->rw_iostat[type] += io_bytes;
>>>    	if (type == APP_BUFFERED_IO || type == APP_DIRECT_IO)
>>> @@ -172,7 +176,7 @@ void f2fs_update_iostat(struct f2fs_sb_info *sbi,
>>>    	if (type == APP_BUFFERED_READ_IO || type == APP_DIRECT_READ_IO)
>>>    		sbi->rw_iostat[APP_READ_IO] += io_bytes;
>>> -	spin_unlock_bh(&sbi->iostat_lock);
>>> +	spin_unlock_irqrestore(&sbi->iostat_lock, flags);
>>>    	f2fs_record_iostat(sbi);
>>>    }
>>> @@ -185,6 +189,7 @@ static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
>>>    	struct f2fs_sb_info *sbi = iostat_ctx->sbi;
>>>    	struct iostat_lat_info *io_lat = sbi->iostat_io_lat;
>>>    	int idx;
>>> +	unsigned long flags;
>>>    	if (!sbi->iostat_enable)
>>>    		return;
>>> @@ -202,12 +207,12 @@ static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
>>>    			idx = WRITE_ASYNC_IO;
>>>    	}
>>> -	spin_lock_bh(&sbi->iostat_lat_lock);
>>> +	spin_lock_irqsave(&sbi->iostat_lat_lock, flags);
>>>    	io_lat->sum_lat[idx][iotype] += ts_diff;
>>>    	io_lat->bio_cnt[idx][iotype]++;
>>>    	if (ts_diff > io_lat->peak_lat[idx][iotype])
>>>    		io_lat->peak_lat[idx][iotype] = ts_diff;
>>> -	spin_unlock_bh(&sbi->iostat_lat_lock);
>>> +	spin_unlock_irqrestore(&sbi->iostat_lat_lock, flags);
>>>    }
>>>    void iostat_update_and_unbind_ctx(struct bio *bio, int rw)
>>
>>
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