dm: remove dm_dispatch_clone_request

Fold dm_dispatch_clone_request into it's only caller, and use a switch
statement to single dispatch for the handling of the different return
values from blk_insert_cloned_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/dm-rq.c

@@ -303,17 +303,6 @@ static void end_clone_request(struct request *clone, blk_status_t error)
 	dm_complete_request(tio->orig, error);
 }
 
-static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
-{
-	blk_status_t r;
-
-	r = blk_insert_cloned_request(clone);
-	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,
 				 void *data)
 {
@@ -394,13 +383,20 @@ 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, disk_devt(dm_disk(md)),
 				     blk_rq_pos(rq));
-		ret = dm_dispatch_clone_request(clone, rq);
-		if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
+		ret = blk_insert_cloned_request(clone);
+		switch (ret) {
+		case BLK_STS_OK:
+			break;
+		case BLK_STS_RESOURCE:
+		case BLK_STS_DEV_RESOURCE:
 			blk_rq_unprep_clone(clone);
 			blk_mq_cleanup_rq(clone);
 			tio->ti->type->release_clone_rq(clone, &tio->info);
 			tio->clone = NULL;
 			return DM_MAPIO_REQUEUE;
+		default:
+			/* must complete clone in terms of original request */
+			dm_complete_request(rq, ret);
 		}
 		break;
 	case DM_MAPIO_REQUEUE: