device_to_minor
idr_remove(&drbd_devices, device_to_minor(device));
((1 << device_to_minor(device)) & drbd_fault_devs) != 0) &&
snprintf(mb, 14, "minor-%d", device_to_minor(device));
dh->minor = device_to_minor(device);
d_out->minor = device_to_minor(device);