rem: int err;
add: status_t err;
context: vm_delete_region(aspace_id aid, region_id rid){	vm_address_space *aspace;	int err;	aspace = vm_get_aspace_by_id(aid);	if (aspace == NULL)		return ERR_VM_INVALID_ASPACE;	err = _vm_delete_region(aspace, rid);	vm_put_aspace(aspace);	return err;}