blk-mq: don't run the hw_queue from blk_mq_request_bypass_insert

blk_mq_request_bypass_insert takes a bool parameter to control how to run
the queue at the end of the function.  Move the blk_mq_run_hw_queue call
to the callers that want it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-flush.c

@@ -389,6 +389,7 @@ void blk_insert_flush(struct request *rq)
 	unsigned long fflags = q->queue_flags;	/* may change, cache */
 	unsigned int policy = blk_flush_policy(fflags, rq);
 	struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx);
+	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
 
 	/*
 	 * @policy now records what operations need to be done.  Adjust
@@ -425,7 +426,8 @@ void blk_insert_flush(struct request *rq)
 	 */
 	if ((policy & REQ_FSEQ_DATA) &&
 	    !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) {
-		blk_mq_request_bypass_insert(rq, false, true);
+		blk_mq_request_bypass_insert(rq, false);
+		blk_mq_run_hw_queue(hctx, false);
 		return;
 	}
 

block/blk-mq.c

@@ -1442,7 +1442,7 @@ static void blk_mq_requeue_work(struct work_struct *work)
 		if (rq->rq_flags & RQF_DONTPREP) {
 			rq->rq_flags &= ~RQF_SOFTBARRIER;
 			list_del_init(&rq->queuelist);
-			blk_mq_request_bypass_insert(rq, false, false);
+			blk_mq_request_bypass_insert(rq, false);
 		} else if (rq->rq_flags & RQF_SOFTBARRIER) {
 			rq->rq_flags &= ~RQF_SOFTBARRIER;
 			list_del_init(&rq->queuelist);
@@ -2457,13 +2457,11 @@ static void blk_mq_run_work_fn(struct work_struct *work)
  * blk_mq_request_bypass_insert - Insert a request at dispatch list.
  * @rq: Pointer to request to be inserted.
  * @at_head: true if the request should be inserted at the head of the list.
- * @run_queue: If we should run the hardware queue after inserting the request.
  *
  * Should only be used carefully, when the caller knows we want to
  * bypass a potential IO scheduler on the target device.
  */
-void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
-				  bool run_queue)
+void blk_mq_request_bypass_insert(struct request *rq, bool at_head)
 {
 	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
 
@@ -2473,9 +2471,6 @@ void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
 	else
 		list_add_tail(&rq->queuelist, &hctx->dispatch);
 	spin_unlock(&hctx->lock);
-
-	if (run_queue)
-		blk_mq_run_hw_queue(hctx, false);
 }
 
 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
@@ -2530,7 +2525,7 @@ static void blk_mq_insert_request(struct request *rq, bool at_head)
 		 * and it is added to the scheduler queue, there is no chance to
 		 * dispatch it given we prioritize requests in hctx->dispatch.
 		 */
-		blk_mq_request_bypass_insert(rq, at_head, false);
+		blk_mq_request_bypass_insert(rq, at_head);
 	} else if (rq->rq_flags & RQF_FLUSH_SEQ) {
 		/*
 		 * Firstly normal IO request is inserted to scheduler queue or
@@ -2553,7 +2548,7 @@ static void blk_mq_insert_request(struct request *rq, bool at_head)
 		 * Simply queue flush rq to the front of hctx->dispatch so that
 		 * intensive flush workloads can benefit in case of NCQ HW.
 		 */
-		blk_mq_request_bypass_insert(rq, true, false);
+		blk_mq_request_bypass_insert(rq, true);
 	} else if (q->elevator) {
 		LIST_HEAD(list);
 
@@ -2673,7 +2668,8 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 		break;
 	case BLK_STS_RESOURCE:
 	case BLK_STS_DEV_RESOURCE:
-		blk_mq_request_bypass_insert(rq, false, true);
+		blk_mq_request_bypass_insert(rq, false);
+		blk_mq_run_hw_queue(hctx, false);
 		break;
 	default:
 		blk_mq_end_request(rq, ret);
@@ -2720,7 +2716,8 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug)
 			break;
 		case BLK_STS_RESOURCE:
 		case BLK_STS_DEV_RESOURCE:
-			blk_mq_request_bypass_insert(rq, false, true);
+			blk_mq_request_bypass_insert(rq, false);
+			blk_mq_run_hw_queue(hctx, false);
 			goto out;
 		default:
 			blk_mq_end_request(rq, ret);
@@ -2838,8 +2835,9 @@ static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 			break;
 		case BLK_STS_RESOURCE:
 		case BLK_STS_DEV_RESOURCE:
-			blk_mq_request_bypass_insert(rq, false,
-						     list_empty(list));
+			blk_mq_request_bypass_insert(rq, false);
+			if (list_empty(list))
+				blk_mq_run_hw_queue(hctx, false);
 			goto out;
 		default:
 			blk_mq_end_request(rq, ret);

block/blk-mq.h

@@ -65,8 +65,7 @@ void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
 /*
  * Internal helpers for request insertion into sw queues
  */
-void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
-				  bool run_queue);
+void blk_mq_request_bypass_insert(struct request *rq, bool at_head);
 
 /*
  * CPU -> queue mappings