1 files changed, 20 insertions, 15 deletions

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 9d32f25489c2..bf0b840645cc 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -315,6 +315,10 @@ static void dm_done(struct request *clone, blk_status_t error, bool mapped)
 		/* The target wants to requeue the I/O */
 		dm_requeue_original_request(tio, false);
 		break;
+	case DM_ENDIO_DELAY_REQUEUE:
+		/* The target wants to requeue the I/O after a delay */
+		dm_requeue_original_request(tio, true);
+		break;
 	default:
 		DMWARN("unimplemented target endio return value: %d", r);
 		BUG();
@@ -395,7 +399,7 @@ static void end_clone_request(struct request *clone, blk_status_t error)
 	dm_complete_request(tio->orig, error);
 }
 
-static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
+static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
 {
 	blk_status_t r;
 
@@ -404,9 +408,10 @@ static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
 
 	clone->start_time = jiffies;
 	r = blk_insert_cloned_request(clone->q, clone);
-	if (r)
+	if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE)
 		/* must complete clone in terms of original request */
 		dm_complete_request(rq, r);
+	return r;
 }
 
 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
@@ -476,8 +481,10 @@ static int map_request(struct dm_rq_target_io *tio)
 	struct mapped_device *md = tio->md;
 	struct request *rq = tio->orig;
 	struct request *clone = NULL;
+	blk_status_t ret;
 
 	r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
+check_again:
 	switch (r) {
 	case DM_MAPIO_SUBMITTED:
 		/* The target has taken the I/O to submit by itself later */
@@ -492,7 +499,17 @@ static int map_request(struct dm_rq_target_io *tio)
 		/* The target has remapped the I/O so dispatch it */
 		trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
 				     blk_rq_pos(rq));
-		dm_dispatch_clone_request(clone, rq);
+		ret = dm_dispatch_clone_request(clone, rq);
+		if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
+			blk_rq_unprep_clone(clone);
+			tio->ti->type->release_clone_rq(clone);
+			tio->clone = NULL;
+			if (!rq->q->mq_ops)
+				r = DM_MAPIO_DELAY_REQUEUE;
+			else
+				r = DM_MAPIO_REQUEUE;
+			goto check_again;
+		}
 		break;
 	case DM_MAPIO_REQUEUE:
 		/* The target wants to requeue the I/O */
@@ -700,7 +717,6 @@ int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
 	/* disable dm_old_request_fn's merge heuristic by default */
 	md->seq_rq_merge_deadline_usecs = 0;
 
-	dm_init_normal_md_queue(md);
 	blk_queue_softirq_done(md->queue, dm_softirq_done);
 
 	/* Initialize the request-based DM worker thread */
@@ -713,8 +729,6 @@ int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
 		return error;
 	}
 
-	elv_register_queue(md->queue);
-
 	return 0;
 }
 
@@ -758,7 +772,6 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 		/* Undo dm_start_request() before requeuing */
 		rq_end_stats(md, rq);
 		rq_completed(md, rq_data_dir(rq), false);
-		blk_mq_delay_run_hw_queue(hctx, 100/*ms*/);
 		return BLK_STS_RESOURCE;
 	}
 
@@ -810,17 +823,9 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
 		err = PTR_ERR(q);
 		goto out_tag_set;
 	}
-	dm_init_md_queue(md);
-
-	/* backfill 'mq' sysfs registration normally done in blk_register_queue */
-	err = blk_mq_register_dev(disk_to_dev(md->disk), q);
-	if (err)
-		goto out_cleanup_queue;
 
 	return 0;
 
-out_cleanup_queue:
-	blk_cleanup_queue(q);
 out_tag_set:
 	blk_mq_free_tag_set(md->tag_set);
 out_kfree_tag_set: