scm_blk: 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>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-28-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/s390/block/scm_blk.c

@@ -462,12 +462,12 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 	if (ret)
 		goto out;
 
-	rq = blk_mq_init_queue(&bdev->tag_set);
-	if (IS_ERR(rq)) {
-		ret = PTR_ERR(rq);
+	bdev->gendisk = blk_mq_alloc_disk(&bdev->tag_set, scmdev);
+	if (IS_ERR(bdev->gendisk)) {
+		ret = PTR_ERR(bdev->gendisk);
 		goto out_tag;
 	}
-	bdev->rq = rq;
+	rq = bdev->rq = bdev->gendisk->queue;
 	nr_max_blk = min(scmdev->nr_max_block,
 			 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));
 
@@ -477,17 +477,11 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, rq);
 	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, rq);
 
-	bdev->gendisk = alloc_disk(SCM_NR_PARTS);
-	if (!bdev->gendisk) {
-		ret = -ENOMEM;
-		goto out_queue;
-	}
-	rq->queuedata = scmdev;
 	bdev->gendisk->private_data = scmdev;
 	bdev->gendisk->fops = &scm_blk_devops;
-	bdev->gendisk->queue = rq;
 	bdev->gendisk->major = scm_major;
 	bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;
+	bdev->gendisk->minors = SCM_NR_PARTS;
 
 	len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
 	if (devindex > 25) {
@@ -504,8 +498,6 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 	device_add_disk(&scmdev->dev, bdev->gendisk, NULL);
 	return 0;
 
-out_queue:
-	blk_cleanup_queue(rq);
 out_tag:
 	blk_mq_free_tag_set(&bdev->tag_set);
 out:
@@ -516,9 +508,8 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
 {
 	del_gendisk(bdev->gendisk);
-	blk_cleanup_queue(bdev->gendisk->queue);
+	blk_cleanup_disk(bdev->gendisk);
 	blk_mq_free_tag_set(&bdev->tag_set);
-	put_disk(bdev->gendisk);
 }
 
 void scm_blk_set_available(struct scm_blk_dev *bdev)