blk-mq: add shallow depth option for blk_mq_get_tag()

Wire up the sbitmap_get_shallow() operation to the tag code so that a
caller can limit the number of tags available to it.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/block/blk-mq.h b/block/blk-mq.h
index 7e6f2e467696..524f44742816 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -141,6 +141,7 @@ struct blk_mq_alloc_data {
 	/* input parameter */
 	struct request_queue *q;
 	unsigned int flags;
+	unsigned int shallow_depth;
 
 	/* input & output parameter */
 	struct blk_mq_ctx *ctx;