From 17be8c245054b9c7786545af3ba3ca4e54cd4ad9 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Mon, 11 Jan 2010 03:21:49 -0500 Subject: 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 Acked-by: Mike Snitzer Reviewed-by: Alasdair G Kergon Signed-off-by: Jens Axboe --- block/blk-settings.c | 22 ++++++++++++++++++++++ include/linux/blkdev.h | 2 ++ 2 files changed, 24 insertions(+) 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 @@ -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) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index a41bcc8e140f..5c8018977efa 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -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); -- cgit v1.2.3