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authorMartin K. Petersen <martin.petersen@oracle.com>2010-01-11 03:21:49 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-01-25 10:49:40 -0800
commitfbe2992083cc1e865a91a4a101e97c2c35667acf (patch)
tree2d850de5691209926fdb6e9b8d9c0ad77d5b4767 /block
parented0cd89c7333b17d50812201602f436b57ef1482 (diff)
block: bdev_stack_limits wrapper
commit 17be8c245054b9c7786545af3ba3ca4e54cd4ad9 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'block')
-rw-r--r--block/blk-settings.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 66d4aa8799b7..d5aa8865c644 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -560,6 +560,28 @@ 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)