Merge tag 'block-6.13-20241228' of git://git.kernel.dk/linux

Pull block fix from Jens Axboe:
 "Just a single fix for ublk setup error handling"

* tag 'block-6.13-20241228' of git://git.kernel.dk/linux:
  ublk: detach gendisk from ublk device if add_disk() fails

Author: torvalds

drivers/block/ublk_drv.c

@@ -1618,6 +1618,21 @@ static void ublk_unquiesce_dev(struct ublk_device *ub)
 	blk_mq_kick_requeue_list(ub->ub_disk->queue);
 }
 
+static struct gendisk *ublk_detach_disk(struct ublk_device *ub)
+{
+	struct gendisk *disk;
+
+	/* Sync with ublk_abort_queue() by holding the lock */
+	spin_lock(&ub->lock);
+	disk = ub->ub_disk;
+	ub->dev_info.state = UBLK_S_DEV_DEAD;
+	ub->dev_info.ublksrv_pid = -1;
+	ub->ub_disk = NULL;
+	spin_unlock(&ub->lock);
+
+	return disk;
+}
+
 static void ublk_stop_dev(struct ublk_device *ub)
 {
 	struct gendisk *disk;
@@ -1631,14 +1646,7 @@ static void ublk_stop_dev(struct ublk_device *ub)
 		ublk_unquiesce_dev(ub);
 	}
 	del_gendisk(ub->ub_disk);
-
-	/* Sync with ublk_abort_queue() by holding the lock */
-	spin_lock(&ub->lock);
-	disk = ub->ub_disk;
-	ub->dev_info.state = UBLK_S_DEV_DEAD;
-	ub->dev_info.ublksrv_pid = -1;
-	ub->ub_disk = NULL;
-	spin_unlock(&ub->lock);
+	disk = ublk_detach_disk(ub);
 	put_disk(disk);
  unlock:
 	mutex_unlock(&ub->mutex);
@@ -2336,7 +2344,7 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
 
 out_put_cdev:
 	if (ret) {
-		ub->dev_info.state = UBLK_S_DEV_DEAD;
+		ublk_detach_disk(ub);
 		ublk_put_device(ub);
 	}
 	if (ret)