blk-mq: factor out a blk_qc_to_hctx helper

Add a helper to get the hctx from a request_queue and cookie, and fold
the blk_qc_t_to_queue_num helper into it as no other callers are left.

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/20211012111226.760968-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -65,6 +65,12 @@ static int blk_mq_poll_stats_bkt(const struct request *rq)
 	return bucket;
 }
 
+static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q,
+		blk_qc_t qc)
+{
+	return q->queue_hw_ctx[(qc & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT];
+}
+
 /*
  * Check if any of the ctx, dispatch list or elevator
  * have pending work in this hardware queue.
@@ -4071,7 +4077,7 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 	if (current->plug)
 		blk_flush_plug_list(current->plug, false);
 
-	hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
+	hctx = blk_qc_to_hctx(q, cookie);
 
 	/*
 	 * If we sleep, have the caller restart the poll loop to reset

include/linux/blk_types.h

@@ -505,11 +505,6 @@ static inline bool blk_qc_t_valid(blk_qc_t cookie)
 	return cookie != BLK_QC_T_NONE;
 }
 
-static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
-{
-	return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
-}
-
 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 {
 	return cookie & ((1u << BLK_QC_T_SHIFT) - 1);