diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2014-10-08 18:26:13 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-14 10:10:26 -0800 |
| commit | ab050e8e15aae8d949757a91348f8b1ebd9dfec0 (patch) | |
| tree | e15bd5491d1e1c3445e07737fc474c8d9a83dd03 /include | |
| parent | 3757dfbf653fdf9c9c9d391cbff089325ab374e2 (diff) | |
block: fix alignment_offset math that assumes io_min is a power-of-2
commit b8839b8c55f3fdd60dc36abcda7e0266aff7985c upstream.
The math in both blk_stack_limits() and queue_limit_alignment_offset()
assume that a block device's io_min (aka minimum_io_size) is always a
power-of-2. Fix the math such that it works for non-power-of-2 io_min.
This issue (of alignment_offset != 0) became apparent when testing
dm-thinp with a thinp blocksize that matches a RAID6 stripesize of
1280K. Commit fdfb4c8c1 ("dm thin: set minimum_io_size to pool's data
block size") unlocked the potential for alignment_offset != 0 due to
the dm-thin-pool's io_min possibly being a non-power-of-2.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 518b46555b80..bd8b1a4699b9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1285,10 +1285,9 @@ static inline int queue_alignment_offset(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 << 9) & (granularity - 1); + unsigned int alignment = sector_div(sector, granularity >> 9) << 9; - return (granularity + lim->alignment_offset - alignment) - & (granularity - 1); + return (granularity + lim->alignment_offset - alignment) % granularity; } static inline int bdev_alignment_offset(struct block_device *bdev) |