block: Introduce helper to reset queue limits to default values

DM reuses the request queue when swapping in a new device table
Introduce blk_set_default_limits() which can be used to reset the the
queue_limits prior to stacking devices.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0b1a6cae9de..8963d9149b5 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -926,6 +926,7 @@ extern void blk_queue_alignment_offset(struct request_queue *q,
                                        unsigned int alignment);
 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 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 void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,