MSPRO_BLOCK_PART_SHIFT
msb->disk->first_minor = disk_id << MSPRO_BLOCK_PART_SHIFT;
msb->disk->minors = 1 << MSPRO_BLOCK_PART_SHIFT;
int disk_id = MINOR(disk_devt(disk)) >> MSPRO_BLOCK_PART_SHIFT;