Commit 17be8c24 authored by Martin K. Petersen's avatar Martin K. Petersen Committed by Jens Axboe

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: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
Reviewed-by: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent dd3d145d
......@@ -639,6 +639,28 @@ 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)
......
......@@ -938,6 +938,8 @@ extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
extern void blk_set_default_limits(struct queue_limits *lim);
extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
sector_t offset);
extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
sector_t offset);
extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
sector_t offset);
extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
......
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