[PATCHv4 2/3] block: Add blk_mq_make_unique_tag()

[Hannes Reinecke <hare@suse.de>]

Implement blk_mq_make_unique_tag() to generate a unique tag
value from a given hardware queue and tag value.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 block/blk-mq-tag.c     | 3 +--
 include/linux/blk-mq.h | 5 +++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index dcf5ce3..2df6d35 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -450,8 +450,7 @@ u32 blk_mq_unique_tag(struct request *rq)
 		hwq = hctx->queue_num;
 	}
 
-	return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
-		(rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
+	return blk_mq_make_unique_tag(hwq, rq->tag);
 }
 EXPORT_SYMBOL(blk_mq_unique_tag);
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 4a2ab5d9..1442c34 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -212,6 +212,11 @@ static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
 	return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
 }
 
+static inline u32 blk_mq_make_unique_tag(u16 hwq, u16 tag)
+{
+	return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
+		(tag & BLK_MQ_UNIQUE_TAG_MASK);
+}
 
 int blk_mq_request_started(struct request *rq);
 void blk_mq_start_request(struct request *rq);
-- 
1.8.5.6