cmac_instance
cmac_instance *instance;
cmac = kzalloc(sizeof(*cmac) + sizeof(cmac_instance), GFP_KERNEL);
cmac->instance = (cmac_instance *) (cmac + 1);
mac = kzalloc(sizeof(*mac) + sizeof(cmac_instance), GFP_KERNEL);
mac->instance = (cmac_instance *)(mac + 1);