VDCBLK_NAME
VDCBLK_NAME "%c%c",
VDCBLK_NAME "%c", 'a' + ((int)vdev->dev_no % 26));
err = register_blkdev(0, VDCBLK_NAME);
unregister_blkdev(vdc_major, VDCBLK_NAME);
unregister_blkdev(vdc_major, VDCBLK_NAME);