drbd: convert to blk_alloc_disk/blk_cleanup_disk

Convert the drbd 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/20210521055116.1053587-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/drbd/drbd_main.c

@@ -2231,8 +2231,7 @@ void drbd_destroy_device(struct kref *kref)
 	if (device->bitmap) /* should no longer be there. */
 		drbd_bm_cleanup(device);
 	__free_page(device->md_io.page);
-	put_disk(device->vdisk);
-	blk_cleanup_queue(device->rq_queue);
+	blk_cleanup_disk(device->vdisk);
 	kfree(device->rs_plan_s);
 
 	/* not for_each_connection(connection, resource):
@@ -2701,7 +2700,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	struct drbd_device *device;
 	struct drbd_peer_device *peer_device, *tmp_peer_device;
 	struct gendisk *disk;
-	struct request_queue *q;
 	int id;
 	int vnr = adm_ctx->volume;
 	enum drbd_ret_code err = ERR_NOMEM;
@@ -2723,29 +2721,26 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 
 	drbd_init_set_defaults(device);
 
-	q = blk_alloc_queue(NUMA_NO_NODE);
-	if (!q)
-		goto out_no_q;
-	device->rq_queue = q;
-
-	disk = alloc_disk(1);
+	disk = blk_alloc_disk(NUMA_NO_NODE);
 	if (!disk)
 		goto out_no_disk;
+
 	device->vdisk = disk;
+	device->rq_queue = disk->queue;
 
 	set_disk_ro(disk, true);
 
-	disk->queue = q;
 	disk->major = DRBD_MAJOR;
 	disk->first_minor = minor;
+	disk->minors = 1;
 	disk->fops = &drbd_ops;
 	sprintf(disk->disk_name, "drbd%d", minor);
 	disk->private_data = device;
 
-	blk_queue_write_cache(q, true, true);
+	blk_queue_write_cache(disk->queue, true, true);
 	/* Setting the max_hw_sectors to an odd value of 8kibyte here
 	   This triggers a max_bio_size message upon first attach or connect */
-	blk_queue_max_hw_sectors(q, DRBD_MAX_BIO_SIZE_SAFE >> 8);
+	blk_queue_max_hw_sectors(disk->queue, DRBD_MAX_BIO_SIZE_SAFE >> 8);
 
 	device->md_io.page = alloc_page(GFP_KERNEL);
 	if (!device->md_io.page)
@@ -2834,10 +2829,8 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 out_no_bitmap:
 	__free_page(device->md_io.page);
 out_no_io_page:
-	put_disk(disk);
+	blk_cleanup_disk(disk);
 out_no_disk:
-	blk_cleanup_queue(q);
-out_no_q:
 	kref_put(&resource->kref, drbd_destroy_resource);
 	kfree(device);
 	return err;