blk-mq: cleanup blk_mq_get_driver_tag()

We never pass 'wait' as true to blk_mq_get_driver_tag(), and hence
we never change '**hctx' as well. The last use of these went away
with the flush cleanup, commit 0c2a6fe4.

So cleanup the usage and remove the two extra parameters.

Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Tested-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -964,17 +964,14 @@ static inline unsigned int queued_to_index(unsigned int queued)
 	return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
 }
 
-bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
-			   bool wait)
+bool blk_mq_get_driver_tag(struct request *rq)
 {
 	struct blk_mq_alloc_data data = {
 		.q = rq->q,
 		.hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu),
-		.flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
+		.flags = BLK_MQ_REQ_NOWAIT,
 	};
 
-	might_sleep_if(wait);
-
 	if (rq->tag != -1)
 		goto done;
 
@@ -991,8 +988,6 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
 	}
 
 done:
-	if (hctx)
-		*hctx = data.hctx;
 	return rq->tag != -1;
 }
 
@@ -1034,7 +1029,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
 		 * Don't clear RESTART here, someone else could have set it.
 		 * At most this will cost an extra queue run.
 		 */
-		return blk_mq_get_driver_tag(rq, hctx, false);
+		return blk_mq_get_driver_tag(rq);
 	}
 
 	wait = &this_hctx->dispatch_wait;
@@ -1055,7 +1050,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
 	 * allocation failure and adding the hardware queue to the wait
 	 * queue.
 	 */
-	ret = blk_mq_get_driver_tag(rq, hctx, false);
+	ret = blk_mq_get_driver_tag(rq);
 	if (!ret) {
 		spin_unlock(&this_hctx->lock);
 		return false;
@@ -1105,7 +1100,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 		if (!got_budget && !blk_mq_get_dispatch_budget(hctx))
 			break;
 
-		if (!blk_mq_get_driver_tag(rq, NULL, false)) {
+		if (!blk_mq_get_driver_tag(rq)) {
 			/*
 			 * The initial allocation attempt failed, so we need to
 			 * rerun the hardware queue when a tag is freed. The
@@ -1137,7 +1132,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 			bd.last = true;
 		else {
 			nxt = list_first_entry(list, struct request, queuelist);
-			bd.last = !blk_mq_get_driver_tag(nxt, NULL, false);
+			bd.last = !blk_mq_get_driver_tag(nxt);
 		}
 
 		ret = q->mq_ops->queue_rq(hctx, &bd);
@@ -1700,7 +1695,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 	if (!blk_mq_get_dispatch_budget(hctx))
 		goto insert;
 
-	if (!blk_mq_get_driver_tag(rq, NULL, false)) {
+	if (!blk_mq_get_driver_tag(rq)) {
 		blk_mq_put_dispatch_budget(hctx);
 		goto insert;
 	}

block/blk-mq.h

@@ -36,8 +36,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
 void blk_mq_wake_waiters(struct request_queue *q);
 bool blk_mq_dispatch_rq_list(struct request_queue *, struct list_head *, bool);
 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
-bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
-				bool wait);
+bool blk_mq_get_driver_tag(struct request *rq);
 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
 					struct blk_mq_ctx *start);