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| author |   Martin K. Petersen <martin.petersen@oracle.com> | 2009-12-29 08:35:35 +0100 |
|---|---|---|
| committer |   Jens Axboe <jens.axboe@oracle.com> | 2009-12-29 08:35:35 +0100 |
| commit | 81744ee44ab2845c16ffd7d6f762f7b4a49a4750 (patch) | |
| tree | c3d0cca0e71080ecd8423cef8af1c632fc444764 /include | |
| parent | cfq-iosched: don't regard requests with long distance as close (diff) | |
| download | linux-dev-81744ee44ab2845c16ffd7d6f762f7b4a49a4750.tar.xz linux-dev-81744ee44ab2845c16ffd7d6f762f7b4a49a4750.zip | |
block: Fix incorrect alignment offset reporting and update documentation
queue_sector_alignment_offset returned the wrong value which caused
partitions to report an incorrect alignment_offset. Since offset
alignment calculation is needed several places it has been split into a
separate helper function. The topology stacking function has been
updated accordingly.
Furthermore, comments have been added to clarify how the stacking
function works.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 784a919aa0d0..59b832be3044 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1116,11 +1116,18 @@ static inline int queue_alignment_offset(struct request_queue *q) return q->limits.alignment_offset; } +static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t offset) +{ + unsigned int granularity = max(lim->physical_block_size, lim->io_min); + + offset &= granularity - 1; + return (granularity + lim->alignment_offset - offset) & (granularity - 1); +} + static inline int queue_sector_alignment_offset(struct request_queue *q, sector_t sector) { - return ((sector << 9) - q->limits.alignment_offset) - & (q->limits.io_min - 1); + return queue_limit_alignment_offset(&q->limits, sector << 9); } static inline int bdev_alignment_offset(struct block_device *bdev) |