linux-kernel - [PATCH] blk: avoid divide-by-zero with zero granularity

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Date:   Tue, 12 Jan 2021 23:29:51 +0800
From:   Li Feng <fengli@...rtx.com>
To:     Jens Axboe <axboe@...nel.dk>,
        linux-block@...r.kernel.org (open list:BLOCK LAYER),
        linux-kernel@...r.kernel.org (open list)
Cc:     lifeng1519@...il.com, Li Feng <fengli@...rtx.com>
Subject: [PATCH] blk: avoid divide-by-zero with zero granularity

If the physical_block_size and io_min is less than a sector, the
'granularity >> SECTOR_SHIFT' will be zero.

Signed-off-by: Li Feng <fengli@...rtx.com>
---
 include/linux/blkdev.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f94ee3089e01..4d029e95adb4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1485,6 +1485,10 @@ static inline int queue_alignment_offset(const struct request_queue *q)
 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
 {
 	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
+	granularity = granularity >> SECTOR_SHIFT;
+	if (!granularity)
+		return 0;
+
 	unsigned int alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
 		<< SECTOR_SHIFT;
 
-- 
2.29.2