blk-mq: Add a kick_requeue_list argument to blk_mq_requeue_request()

Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
are followed by kicking the requeue list. Hence add an argument to
these two functions that allows to kick the requeue list. This was
proposed by Christoph Hellwig.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-flush.c b/block/blk-flush.c
index d35beca..c486b7a 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -134,10 +134,7 @@
 static bool blk_flush_queue_rq(struct request *rq, bool add_front)
 {
 	if (rq->q->mq_ops) {
-		struct request_queue *q = rq->q;
-
-		blk_mq_add_to_requeue_list(rq, add_front);
-		blk_mq_kick_requeue_list(q);
+		blk_mq_add_to_requeue_list(rq, add_front, true);
 		return false;
 	} else {
 		if (add_front)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3dc3235..8d3de5b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -492,12 +492,12 @@
 	}
 }
 
-void blk_mq_requeue_request(struct request *rq)
+void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
 {
 	__blk_mq_requeue_request(rq);
 
 	BUG_ON(blk_queued_rq(rq));
-	blk_mq_add_to_requeue_list(rq, true);
+	blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
 }
 EXPORT_SYMBOL(blk_mq_requeue_request);
 
@@ -531,7 +531,8 @@
 	blk_mq_run_hw_queues(q, false);
 }
 
-void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
+void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
+				bool kick_requeue_list)
 {
 	struct request_queue *q = rq->q;
 	unsigned long flags;
@@ -550,6 +551,9 @@
 		list_add_tail(&rq->queuelist, &q->requeue_list);
 	}
 	spin_unlock_irqrestore(&q->requeue_lock, flags);
+
+	if (kick_requeue_list)
+		blk_mq_kick_requeue_list(q);
 }
 EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
 
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 71ca36e..c000fdf 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2043,7 +2043,7 @@
 		/* Requeue pending requests (flush or discard) */
 		list_del_init(&req->queuelist);
 		BUG_ON(req->nr_phys_segments > segs);
-		blk_mq_requeue_request(req);
+		blk_mq_requeue_request(req, false);
 	}
 	blk_mq_start_stopped_hw_queues(info->rq, true);
 	blk_mq_kick_requeue_list(info->rq);
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 060ccc5..3152579 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -347,7 +347,7 @@
 
 static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
 {
-	blk_mq_requeue_request(rq);
+	blk_mq_requeue_request(rq, false);
 	__dm_mq_kick_requeue_list(rq->q, msecs);
 }
 
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index a764c2a..e8070e3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -203,7 +203,7 @@
 {
 	unsigned long flags;
 
-	blk_mq_requeue_request(req);
+	blk_mq_requeue_request(req, false);
 	spin_lock_irqsave(req->q->queue_lock, flags);
 	if (!blk_queue_stopped(req->q))
 		blk_mq_kick_requeue_list(req->q);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2b78ff1..2e35132 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -86,10 +86,8 @@
 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
 {
 	struct scsi_device *sdev = cmd->device;
-	struct request_queue *q = cmd->request->q;
 
-	blk_mq_requeue_request(cmd->request);
-	blk_mq_kick_requeue_list(q);
+	blk_mq_requeue_request(cmd->request, true);
 	put_device(&sdev->sdev_gendev);
 }
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index ed20ac7..35a0af5 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -218,8 +218,9 @@
 void blk_mq_end_request(struct request *rq, int error);
 void __blk_mq_end_request(struct request *rq, int error);
 
-void blk_mq_requeue_request(struct request *rq);
-void blk_mq_add_to_requeue_list(struct request *rq, bool at_head);
+void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
+void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
+				bool kick_requeue_list);
 void blk_mq_kick_requeue_list(struct request_queue *q);
 void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
 void blk_mq_abort_requeue_list(struct request_queue *q);