BD_READ_ONLY
bdev_set_flag(bdev, BD_READ_ONLY);
bdev_clear_flag(bdev, BD_READ_ONLY);
bdev_set_flag(bdev, BD_READ_ONLY);
return bdev_test_flag(disk->part0, BD_READ_ONLY) ||
return bdev_test_flag(bdev, BD_READ_ONLY) || get_disk_ro(bdev->bd_disk);