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

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Message-ID: <YqoOzdxeG78RniEK@google.com>
Date:   Wed, 15 Jun 2022 09:54:37 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <chao@...nel.org>
Cc:     Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
        Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix iostat related lock protection

On 06/15, Chao Yu wrote:
> On 2022/6/11 2:32, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@...gle.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


> 
> Thanks,
> 
> > Signed-off-by: Daeho Jeong <daehojeong@...gle.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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