add: TRACE(("close_port(id = %ld)\n", id));
context: close_port(port_id id){	cpu_status state;	int slot;	if (!sPortsActive || id < 0)		return B_BAD_PORT_ID;	slot = id % sMaxPorts;	// walk through the sem list, trying to match name	state = disable_interrupts();	GRAB_PORT_LOCK(sPorts[slot]);	if (sPorts[slot].id != id) {		RELEASE_PORT_LOCK(sPorts[slot]);		restore_interrupts(state);		dprintf("close_port: invalid port_id %ld\n", id);		return B_BAD_PORT_ID;	}	// mark port to disable writing	sPorts[slot].capacity = 0;	RELEASE_PORT_LOCK(sPorts[slot]);	restore_interrupts(state);	return B_NO_ERROR;}