ataflop: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-30-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/ataflop.c

@@ -1968,22 +1968,14 @@ static const struct blk_mq_ops ataflop_mq_ops = {
 static int ataflop_alloc_disk(unsigned int drive, unsigned int type)
 {
 	struct gendisk *disk;
-	int ret;
-
-	disk = alloc_disk(1);
-	if (!disk)
-		return -ENOMEM;
 
-	disk->queue = blk_mq_init_queue(&unit[drive].tag_set);
-	if (IS_ERR(disk->queue)) {
-		ret = PTR_ERR(disk->queue);
-		disk->queue = NULL;
-		put_disk(disk);
-		return ret;
-	}
+	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL);
+	if (IS_ERR(disk))
+		return PTR_ERR(disk);
 
 	disk->major = FLOPPY_MAJOR;
 	disk->first_minor = drive + (type << 2);
+	disk->minors = 1;
 	sprintf(disk->disk_name, "fd%d", drive);
 	disk->fops = &floppy_fops;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;