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authorShaohua Li <shli@kernel.org>2012-12-14 11:15:36 +0800
committerJens Axboe <axboe@kernel.dk>2012-12-14 20:46:04 +0100
commit8dd2cb7e880d2f77fba53b523c99133ad5054cfd (patch)
treeea51e89f8c8bf9ca8e888d68ecf6732a52e8e99d /include/linux/blkdev.h
parent75274551c81796b636c5acb0c2597dec7ec2e6c4 (diff)
downloadvexpress-lsk-8dd2cb7e880d2f77fba53b523c99133ad5054cfd.tar.gz
block: discard granularity might not be power of 2
In MD raid case, discard granularity might not be power of 2, for example, a 4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for such cases. Reported-by: Neil Brown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r--include/linux/blkdev.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c9d233e727f..acb4f7bbbd3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1188,13 +1188,14 @@ static inline int queue_discard_alignment(struct request_queue *q)
static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
{
- unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
+ sector_t alignment = sector << 9;
+ alignment = sector_div(alignment, lim->discard_granularity);
if (!lim->max_discard_sectors)
return 0;
- return (lim->discard_granularity + lim->discard_alignment - alignment)
- & (lim->discard_granularity - 1);
+ alignment = lim->discard_granularity + lim->discard_alignment - alignment;
+ return sector_div(alignment, lim->discard_granularity);
}
static inline int bdev_discard_alignment(struct block_device *bdev)