mtty_dev
memset(&mtty_dev, 0, sizeof(mtty_dev));
idr_init(&mtty_dev.vd_idr);
ret = alloc_chrdev_region(&mtty_dev.vd_devt, 0, MINORMASK + 1,
cdev_init(&mtty_dev.vd_cdev, &vd_fops);
cdev_add(&mtty_dev.vd_cdev, mtty_dev.vd_devt, MINORMASK + 1);
pr_info("major_number:%d\n", MAJOR(mtty_dev.vd_devt));
mtty_dev.dev.class = &mtty_class;
mtty_dev.dev.release = mtty_device_release;
dev_set_name(&mtty_dev.dev, "%s", MTTY_NAME);
ret = device_register(&mtty_dev.dev);
ret = mdev_register_parent(&mtty_dev.parent, &mtty_dev.dev,
device_del(&mtty_dev.dev);
put_device(&mtty_dev.dev);
cdev_del(&mtty_dev.vd_cdev);
unregister_chrdev_region(mtty_dev.vd_devt, MINORMASK + 1);
mtty_dev.dev.bus = NULL;
mdev_unregister_parent(&mtty_dev.parent);
device_unregister(&mtty_dev.dev);
idr_destroy(&mtty_dev.vd_idr);
cdev_del(&mtty_dev.vd_cdev);
unregister_chrdev_region(mtty_dev.vd_devt, MINORMASK + 1);
} mtty_dev;