blk-mq: remove blk_qc_t_to_tag and blk_qc_t_is_internal

Merge both functions into their only caller to keep the blk-mq tag to
blk_qc_t mapping as private as possible in blk-mq.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6367730..24a10c9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -74,9 +74,11 @@ static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q,
 static inline struct request *blk_qc_to_rq(struct blk_mq_hw_ctx *hctx,
 		blk_qc_t qc)
 {
-	if (blk_qc_t_is_internal(qc))
-		return blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(qc));
-	return blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(qc));
+	unsigned int tag = qc & ((1U << BLK_QC_T_SHIFT) - 1);
+
+	if (qc & BLK_QC_T_INTERNAL)
+		return blk_mq_tag_to_rq(hctx->sched_tags, tag);
+	return blk_mq_tag_to_rq(hctx->tags, tag);
 }
 
 /*