md: convert to blk_alloc_disk/blk_cleanup_disk

Convert the md driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-15-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/md.c

@@ -5598,12 +5598,10 @@ static void md_free(struct kobject *ko)
 	if (mddev->sysfs_level)
 		sysfs_put(mddev->sysfs_level);
 
-	if (mddev->gendisk)
+	if (mddev->gendisk) {
 		del_gendisk(mddev->gendisk);
-	if (mddev->queue)
-		blk_cleanup_queue(mddev->queue);
-	if (mddev->gendisk)
-		put_disk(mddev->gendisk);
+		blk_cleanup_disk(mddev->gendisk);
+	}
 	percpu_ref_exit(&mddev->writes_pending);
 
 	bioset_exit(&mddev->bio_set);
@@ -5711,20 +5709,13 @@ static int md_alloc(dev_t dev, char *name)
 		goto abort;
 
 	error = -ENOMEM;
-	mddev->queue = blk_alloc_queue(NUMA_NO_NODE);
-	if (!mddev->queue)
+	disk = blk_alloc_disk(NUMA_NO_NODE);
+	if (!disk)
 		goto abort;
 
-	blk_set_stacking_limits(&mddev->queue->limits);
-
-	disk = alloc_disk(1 << shift);
-	if (!disk) {
-		blk_cleanup_queue(mddev->queue);
-		mddev->queue = NULL;
-		goto abort;
-	}
 	disk->major = MAJOR(mddev->unit);
 	disk->first_minor = unit << shift;
+	disk->minors = 1 << shift;
 	if (name)
 		strcpy(disk->disk_name, name);
 	else if (partitioned)
@@ -5733,7 +5724,9 @@ static int md_alloc(dev_t dev, char *name)
 		sprintf(disk->disk_name, "md%d", unit);
 	disk->fops = &md_fops;
 	disk->private_data = mddev;
-	disk->queue = mddev->queue;
+
+	mddev->queue = disk->queue;
+	blk_set_stacking_limits(&mddev->queue->limits);
 	blk_queue_write_cache(mddev->queue, true, true);
 	/* Allow extended partitions.  This makes the
 	 * 'mdp' device redundant, but we can't really