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From:   Daeho Jeong <daeho43@gmail.com>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
Cc:     Daeho Jeong <daehojeong@google.com>
Subject: [PATCH] f2fs: fix iostat related lock protection
Date:   Fri, 10 Jun 2022 11:32:40 -0700
Message-Id: <20220610183240.2269085-1-daeho43@gmail.com>
MIME-Version: 1.0
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Precedence: bulk

From: Daeho Jeong <daehojeong@google.com>

Made iostat related locks safe to be called from irq context again.

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)
-- 
2.36.1.476.g0c4daa206d-goog