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| author | Martin K. Petersen <martin.petersen@oracle.com> | 2010-01-11 03:21:49 -0500 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-01-11 14:29:20 +0100 |
| commit | 17be8c245054b9c7786545af3ba3ca4e54cd4ad9 (patch) | |
| tree | 563687812bbb1b08643dfcc25997e34eb22a71b5 /block | |
| parent | dd3d145d49c5816b79acc6761ebbd842bc50b0ee (diff) | |
| download | lwn-17be8c245054b9c7786545af3ba3ca4e54cd4ad9.tar.gz lwn-17be8c245054b9c7786545af3ba3ca4e54cd4ad9.zip | |
block: bdev_stack_limits wrapper
DM does not want to know about partition offsets. Add a partition-aware
wrapper that DM can use when stacking block devices.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-settings.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 127f82551855..5eeb9e0d256e 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -640,6 +640,28 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, EXPORT_SYMBOL(blk_stack_limits); /** + * bdev_stack_limits - adjust queue limits for stacked drivers + * @t: the stacking driver limits (top device) + * @bdev: the component block_device (bottom) + * @start: first data sector within component device + * + * Description: + * Merges queue limits for a top device and a block_device. Returns + * 0 if alignment didn't change. Returns -1 if adding the bottom + * device caused misalignment. + */ +int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, + sector_t start) +{ + struct request_queue *bq = bdev_get_queue(bdev); + + start += get_start_sect(bdev); + + return blk_stack_limits(t, &bq->limits, start << 9); +} +EXPORT_SYMBOL(bdev_stack_limits); + +/** * disk_stack_limits - adjust queue limits for stacked drivers * @disk: MD/DM gendisk (top) * @bdev: the underlying block device (bottom) |