[SCSI] block: add support for shared tag maps

The current block queue implementation already contains most of the
machinery for shared tag maps.  The only remaining pieces are a way to
allocate and destroy a tag map independently of the queues (so that
the maps can be managed on the life cycle of the overseeing entity)

Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index aafe82788b4e..427b0d61be6c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -746,6 +746,8 @@ extern void blk_queue_free_tags(request_queue_t *);
 extern int blk_queue_resize_tags(request_queue_t *, int);
 extern void blk_queue_invalidate_tags(request_queue_t *);
 extern long blk_congestion_wait(int rw, long timeout);
+extern struct blk_queue_tag *blk_init_tags(int);
+extern void blk_free_tags(struct blk_queue_tag *);
 
 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
 extern int blkdev_issue_flush(struct block_device *, sector_t *);