[PATCH v2] blk: avoid divide-by-zero with zero granularity

[Li Feng]

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 <fen...@smartx.com>
---
 include/linux/blkdev.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f94ee3089e01..ffffb04ad113 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1485,7 +1485,11 @@ 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);
-       unsigned int alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
+       unsigned int alignment;
+       if (granularity >> SECTOR_SHIFT == 0)
+               return 0;
+
+       alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
                << SECTOR_SHIFT;
 
        return (granularity + lim->alignment_offset - alignment) % granularity;
-- 
2.29.2