Lock down the network interface queues. The queue mutex must be obtained

before adding/removing packets from the queue.  Also, the if_obytes and
if_omcasts fields should only be manipulated under protection of the mutex.

IF_ENQUEUE, IF_PREPEND, and IF_DEQUEUE perform all necessary locking on
the queue.  An IF_LOCK macro is provided, as well as the old (mutex-less)
versions of the macros in the form _IF_ENQUEUE, _IF_QFULL, for code which
needs them, but their use is discouraged.

Two new macros are introduced: IF_DRAIN() to drain a queue, and IF_HANDOFF,
which takes care of locking/enqueue, and also statistics updating/start
if necessary.

19 files changed, 157 insertions, 251 deletions

diff --git a/sys/i4b/driver/i4b_bsdi_ibc.c b/sys/i4b/driver/i4b_bsdi_ibc.c
index 369d4aa..6fcfe4c 100644
--- a/sys/i4b/driver/i4b_bsdi_ibc.c
+++ b/sys/i4b/driver/i4b_bsdi_ibc.c
@@ -196,18 +196,11 @@ ibcattach(void *dummy)
 static struct mbuf *
 p2p_dequeue(struct p2pcom *pp)
 {
-	struct ifqueue *ifq;
 	struct mbuf *m;
 
-	ifq = &pp->p2p_isnd;
-	m = ifq->ifq_head;
-	if (m == 0) {
-		ifq = &pp->p2p_if.if_snd;
-		m = ifq->ifq_head;
-	}
+	IF_DEQUEUE(&pp->p2p_isnd, m);
 	if (m == 0)
-		return 0;
-	IF_DEQUEUE(ifq, m);
+		IF_DEQUEUE(&pp->p2p_if.if_snd, m);
 	return m;
 }
 
@@ -231,13 +224,16 @@ ibc_start(struct ifnet *ifp)
 
 	s = SPLI4B();
 
-	if (IF_QFULL(isdn_ibc_lt[unit]->tx_queue)) {
+	IF_LOCK(isdn_ibc_lt[unit]->tx_queue);
+	if (_IF_QFULL(isdn_ibc_lt[unit]->tx_queue)) {
+		IF_UNLOCK(isdn_ibc_lt[unit]->tx_queue);
 		splx(s);
 		return 0;
 	}
 
 	m = p2p_dequeue(pp);
 	if (m == NULL) {
+		IF_UNLOCK(isdn_ibc_lt[unit]->tx_queue);
 		splx(s);
 		return 0;
 	}
@@ -245,13 +241,14 @@ ibc_start(struct ifnet *ifp)
 	do {
 		microtime(&ifp->if_lastchange);
 
-		IF_ENQUEUE(isdn_ibc_lt[unit]->tx_queue, m);
-
 		ifp->if_obytes += m->m_pkthdr.len;
 		sc->sc_outb += m->m_pkthdr.len;
+		_IF_ENQUEUE(isdn_ibc_lt[unit]->tx_queue, m);
+
 		ifp->if_opackets++;
-	} while (!IF_QFULL(isdn_ibc_lt[unit]->tx_queue) &&
+	} while (!_IF_QFULL(isdn_ibc_lt[unit]->tx_queue) &&
 					(m = p2p_dequeue(pp)) != NULL);
+	IF_UNLOCK(isdn_ibc_lt[unit]->tx_queue);
 	isdn_ibc_lt[unit]->bch_tx_start(isdn_ibc_lt[unit]->unit,
 					 isdn_ibc_lt[unit]->channel);
 	splx(s);
diff --git a/sys/i4b/driver/i4b_ing.c b/sys/i4b/driver/i4b_ing.c
index 26a5b3b..50e1c4b 100644
--- a/sys/i4b/driver/i4b_ing.c
+++ b/sys/i4b/driver/i4b_ing.c
@@ -247,6 +247,7 @@ i4bingattach(void *dummy)
 		sc->sc_state = ST_IDLE;
 		
 		sc->sc_fastq.ifq_maxlen = I4BINGMAXQLEN;
+		mtx_init(&sc->sc_fastq.ifq_mtx, "i4b_ing_fastq", MTX_DEF);
 		
 #if I4BINGACCT
 		callout_handle_init(&sc->sc_callout);
@@ -278,6 +279,8 @@ i4bingattach(void *dummy)
 
 		sc->xmitq.ifq_maxlen = IFQ_MAXLEN;
 		sc->xmitq_hipri.ifq_maxlen = IFQ_MAXLEN;
+		mtx_init(&sc->xmitq.ifq_mtx, "i4b_ing_xmitq", MTX_DEF);
+		mtx_init(&sc->xmitq_hipri.ifq_mtx, "i4b_ing_hipri", MTX_DEF);
 				
 		/* name the netgraph node */
 
@@ -339,20 +342,11 @@ static void
 ingclearqueue(struct ifqueue *iq)
 {
 	int x;
-	struct mbuf *m;
 	
-	for(;;)
-	{
-		x = splimp();
-		IF_DEQUEUE(iq, m);
-		splx(x);
-
-		if(m)
-			m_freem(m);
-		else
-			break;
-	}
-}	
+	x = splimp();
+	IF_DRAIN(iq);
+	splx(x);
+}
 #endif
 
 /*===========================================================================*
@@ -517,14 +511,9 @@ ing_tx_queue_empty(int unit)
 
 		x = 1;
 
-		if(IF_QFULL(isdn_linktab[unit]->tx_queue))
+		if(! IF_HANDOFF(isdn_linktab[unit]->tx_queue, m, NULL))
 		{
 			NDBGL4(L4_INGDBG, "ing%d: tx queue full!", unit);
-			m_freem(m);
-		}
-		else
-		{
-			IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
 		}
 	}
 
@@ -794,15 +783,18 @@ ng_ing_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 
 	s = splimp();
 
-	if (IF_QFULL(xmitq_p))
+	IF_LOCK(xmitq_p);
+	if (_IF_QFULL(xmitq_p))
 	{
-		IF_DROP(xmitq_p);
+		_IF_DROP(xmitq_p);
+		IF_UNLOCK(xmitq_p);
 		splx(s);
 		NG_FREE_DATA(m, meta);
 		return(ENOBUFS);
 	}
 
-	IF_ENQUEUE(xmitq_p, m);
+	_IF_ENQUEUE(xmitq_p, m);
+	IF_UNLOCK(xmitq_p);
 
 	ing_tx_queue_empty(sc->sc_unit);
 
diff --git a/sys/i4b/driver/i4b_ipr.c b/sys/i4b/driver/i4b_ipr.c
index 4d76cb9..4aa074a 100644
--- a/sys/i4b/driver/i4b_ipr.c
+++ b/sys/i4b/driver/i4b_ipr.c
@@ -324,6 +324,7 @@ i4biprattach()
 
 		sc->sc_if.if_snd.ifq_maxlen = I4BIPRMAXQLEN;
 		sc->sc_fastq.ifq_maxlen = I4BIPRMAXQLEN;
+		mtx_init(&sc->sc_fastq.ifq_mtx, "i4b_ipr_fastq", MTX_DEF);
 		
 		sc->sc_if.if_ipackets = 0;
 		sc->sc_if.if_ierrors = 0;
@@ -509,11 +510,9 @@ i4biproutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 
 	/* check for space in choosen send queue */
 	
-	if(IF_QFULL(ifq))
+	if(! IF_HANDOFF(ifq, m, NULL))
 	{
 		NDBGL4(L4_IPRDBG, "ipr%d: send queue full!", unit);
-		IF_DROP(ifq);
-		m_freem(m);
 		splx(s);
 		sc->sc_if.if_oerrors++;
 		return(ENOBUFS);
@@ -521,8 +520,6 @@ i4biproutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 	
 	NDBGL4(L4_IPRDBG, "ipr%d: add packet to send queue!", unit);
 	
-	IF_ENQUEUE(ifq, m);
-
 	ipr_tx_queue_empty(unit);
 
 	splx(s);
@@ -648,31 +645,11 @@ static void
 iprclearqueues(struct ipr_softc *sc)
 {
 	int x;
-	struct mbuf *m;
 	
-	for(;;)
-	{
-		x = splimp();
-		IF_DEQUEUE(&sc->sc_fastq, m);
-		splx(x);
-
-		if(m)
-			m_freem(m);
-		else
-			break;
-	}
-
-	for(;;)
-	{
-		x = splimp();
-		IF_DEQUEUE(&sc->sc_if.if_snd, m);
-		splx(x);
-
-		if(m)
-			m_freem(m);
-		else
-			break;
-	}
+	x = splimp();
+	IF_DRAIN(&sc->sc_fastq);
+	IF_DRAIN(&sc->sc_if.if_snd);
+	splx(x);
 }
         
 #if I4BIPRACCT
@@ -1070,18 +1047,14 @@ error:
 	}
 #endif /* NBPFILTER > 0  || NBPF > 0 */
 
-	if(IF_QFULL(&ipintrq))
+	if(! IF_HANDOFF(&ipintrq, m, NULL))
 	{
 		NDBGL4(L4_IPRDBG, "ipr%d: ipintrq full!", unit);
-
-		IF_DROP(&ipintrq);
 		sc->sc_if.if_ierrors++;
 		sc->sc_if.if_iqdrops++;		
-		m_freem(m);
 	}
 	else
 	{
-		IF_ENQUEUE(&ipintrq, m);
 		schednetisr(NETISR_IP);
 	}
 }
@@ -1155,19 +1128,22 @@ ipr_tx_queue_empty(int unit)
 #endif
 		x = 1;
 
-		if(IF_QFULL(isdn_linktab[unit]->tx_queue))
+		IF_LOCK(isdn_linktab[unit]->tx_queue);
+		if(_IF_QFULL(isdn_linktab[unit]->tx_queue))
 		{
 			NDBGL4(L4_IPRDBG, "ipr%d: tx queue full!", unit);
 			m_freem(m);
 		}
 		else
 		{
-			IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
-
 			sc->sc_if.if_obytes += m->m_pkthdr.len;
 
 			sc->sc_if.if_opackets++;
+
+			_IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
+
 		}
+		IF_UNLOCK(isdn_linktab[unit]->tx_queue);
 	}
 
 	if(x)
diff --git a/sys/i4b/driver/i4b_isppp.c b/sys/i4b/driver/i4b_isppp.c
index f13c229..0be5efa 100644
--- a/sys/i4b/driver/i4b_isppp.c
+++ b/sys/i4b/driver/i4b_isppp.c
@@ -426,20 +426,23 @@ i4bisppp_start(struct ifnet *ifp)
 
 		microtime(&ifp->if_lastchange);
 
-		if(IF_QFULL(isdn_linktab[unit]->tx_queue))
+		IF_LOCK(isdn_linktab[unit]->tx_queue);
+		if(_IF_QFULL(isdn_linktab[unit]->tx_queue))
 		{
 			NDBGL4(L4_ISPDBG, "isp%d, tx queue full!", unit);
 			m_freem(m);
 		}
 		else
 		{
-			IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
 #if 0
 			sc->sc_if.if_obytes += m->m_pkthdr.len;
 #endif
 			sc->sc_outb += m->m_pkthdr.len;
 			sc->sc_if.if_opackets++;
+
+			_IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
 		}
+		IF_UNLOCK(isdn_linktab[unit]->tx_queue);
 	}
 	isdn_linktab[unit]->bch_tx_start(isdn_linktab[unit]->unit,
 					 isdn_linktab[unit]->channel);
diff --git a/sys/i4b/driver/i4b_ispppsubr.c b/sys/i4b/driver/i4b_ispppsubr.c
index 7b3a1f9..cbe45b6 100644
--- a/sys/i4b/driver/i4b_ispppsubr.c
+++ b/sys/i4b/driver/i4b_ispppsubr.c
@@ -665,17 +665,15 @@ isppp_input(struct ifnet *ifp, struct mbuf *m)
 
 	/* Check queue. */
 	s = splimp();
-	if (IF_QFULL (inq)) {
-		/* Queue overflow. */
-		IF_DROP(inq);
-		splx(s);
+	if (! IF_HANDOFF(inq, m, NULL)) {
+		++ifp->if_ierrors;
+		++ifp->if_iqdrops;
 		if (debug)
 			log(LOG_DEBUG, SPP_FMT "protocol queue overflow\n",
 				SPP_ARGS(ifp));
-		goto drop;
+	} else {
+		sp->pp_last_recv = time_second;
 	}
-	IF_ENQUEUE(inq, m);
-	sp->pp_last_recv = time_second;
 	splx(s);
 }
 
@@ -748,7 +746,7 @@ sppp_output(struct ifnet *ifp, struct mbuf *m,
 		 * Put low delay, telnet, rlogin and ftp control packets
 		 * in front of the queue.
 		 */
-		if (IF_QFULL (&sp->pp_fastq))
+		if (_IF_QFULL (&sp->pp_fastq))
 			;
 		else if (ip->ip_tos & IPTOS_LOWDELAY)
 			ifq = &sp->pp_fastq;
@@ -870,24 +868,17 @@ nosupport:
 	/*
 	 * Queue message on interface, and start output if interface
 	 * not yet active.
+	 *
+	 * Count output packets and bytes.
+	 * The packet length includes header, FCS and 1 flag,
+	 * according to RFC 1333.
 	 */
-	if (IF_QFULL (ifq)) {
-		IF_DROP (&ifp->if_snd);
-		m_freem (m);
+	if (! IF_HANDOFF_ADJ(ifq, m, ifp, 3)) {
 		++ifp->if_oerrors;
 		splx (s);
 		return (rv? rv: ENOBUFS);
 	}
-	IF_ENQUEUE (ifq, m);
-	if (! (ifp->if_flags & IFF_OACTIVE))
-		(*ifp->if_start) (ifp);
 
-	/*
-	 * Count output packets and bytes.
-	 * The packet length includes header, FCS and 1 flag,
-	 * according to RFC 1333.
-	 */
-	ifp->if_obytes += m->m_pkthdr.len + 3;
 	sp->pp_last_sent = time_second;
 	splx (s);
 	return (0);
@@ -921,6 +912,8 @@ isppp_attach(struct ifnet *ifp)
 
 	sp->pp_fastq.ifq_maxlen = 32;
 	sp->pp_cpq.ifq_maxlen = 20;
+	mtx_init(&sp->pp_fastq.ifq_mtx, "i4b_isppp_fastq", MTX_DEF);
+	mtx_init(&sp->pp_cpq.ifq_mtx, "i4b_isppp_cpq", MTX_DEF);
 	sp->pp_loopcnt = 0;
 	sp->pp_alivecnt = 0;
 	sp->pp_seq = 0;
@@ -1316,15 +1309,7 @@ sppp_cisco_send(struct sppp *sp, int type, long par1, long par2)
 			SPP_ARGS(ifp), (u_long)ntohl (ch->type), (u_long)ch->par1,
 			(u_long)ch->par2, (u_int)ch->rel, (u_int)ch->time0, (u_int)ch->time1);
 
-	if (IF_QFULL (&sp->pp_cpq)) {
-		IF_DROP (&sp->pp_fastq);
-		IF_DROP (&ifp->if_snd);
-		m_freem (m);
-	} else
-		IF_ENQUEUE (&sp->pp_cpq, m);
-	if (! (ifp->if_flags & IFF_OACTIVE))
-		(*ifp->if_start) (ifp);
-	ifp->if_obytes += m->m_pkthdr.len + 3;
+	(void) IF_HANDOFF_ADJ(&sp->pp_cpq, m, ifp, 3);
 }
 
 /*
@@ -1372,16 +1357,8 @@ sppp_cp_send(struct sppp *sp, u_short proto, u_char type,
 		sppp_print_bytes ((u_char*) (lh+1), len);
 		addlog(">\n");
 	}
-	if (IF_QFULL (&sp->pp_cpq)) {
-		IF_DROP (&sp->pp_fastq);
-		IF_DROP (&ifp->if_snd);
-		m_freem (m);
+	if (! IF_HANDOFF_ADJ(&sp->pp_cpq, m, ifp, 3))
 		++ifp->if_oerrors;
-	} else
-		IF_ENQUEUE (&sp->pp_cpq, m);
-	if (! (ifp->if_flags & IFF_OACTIVE))
-		(*ifp->if_start) (ifp);
-	ifp->if_obytes += m->m_pkthdr.len + 3;
 }
 
 /*
@@ -4035,16 +4012,8 @@ sppp_auth_send(const struct cp *cp, struct sppp *sp,
 		sppp_print_bytes((u_char*) (lh+1), len);
 		addlog(">\n");
 	}
-	if (IF_QFULL (&sp->pp_cpq)) {
-		IF_DROP (&sp->pp_fastq);
-		IF_DROP (&ifp->if_snd);
-		m_freem (m);
+	if (! IF_HANDOFF_ADJ(&sp->pp_cpq, m, NULL, 3))
 		++ifp->if_oerrors;
-	} else
-		IF_ENQUEUE (&sp->pp_cpq, m);
-	if (! (ifp->if_flags & IFF_OACTIVE))
-		(*ifp->if_start) (ifp);
-	ifp->if_obytes += m->m_pkthdr.len + 3;
 }
 
 /*
diff --git a/sys/i4b/driver/i4b_rbch.c b/sys/i4b/driver/i4b_rbch.c
index 59247c2..9e7db6a 100644
--- a/sys/i4b/driver/i4b_rbch.c
+++ b/sys/i4b/driver/i4b_rbch.c
@@ -327,6 +327,7 @@ i4brbchattach()
 		rbch_softc[i].sc_unit = i;
 		rbch_softc[i].sc_devstate = ST_IDLE;
 		rbch_softc[i].sc_hdlcq.ifq_maxlen = I4BRBCHMAXQLEN;
+		mtx_init(&rbch_softc[i].sc_hdlcq.ifq_mtx, "i4b_rbch", MTX_DEF);
 		rbch_softc[i].it_in.c_ispeed = rbch_softc[i].it_in.c_ospeed = 64000;
 		termioschars(&rbch_softc[i].it_in);
 		rbch_init_linktab(i);
@@ -510,7 +511,7 @@ i4brbchwrite(dev_t dev, struct uio * uio, int ioflag)
 			CRIT_END;
 			return(EWOULDBLOCK);
 		}
-		if(IF_QFULL(isdn_linktab[unit]->tx_queue) && (sc->sc_devstate & ST_ISOPEN)) {
+		if(_IF_QFULL(isdn_linktab[unit]->tx_queue) && (sc->sc_devstate & ST_ISOPEN)) {
 			CRIT_END;
 			return(EWOULDBLOCK);
 	}
@@ -543,7 +544,7 @@ i4brbchwrite(dev_t dev, struct uio * uio, int ioflag)
 			tsleep((caddr_t) &rbch_softc[unit], TTIPRI | PCATCH, "xrbch", (hz*1));
 		}
 
-		while(IF_QFULL(isdn_linktab[unit]->tx_queue) && (sc->sc_devstate & ST_ISOPEN))
+		while(_IF_QFULL(isdn_linktab[unit]->tx_queue) && (sc->sc_devstate & ST_ISOPEN))
 		{
 			sc->sc_devstate |= ST_WRWAITEMPTY;
 
@@ -589,15 +590,7 @@ i4brbchwrite(dev_t dev, struct uio * uio, int ioflag)
 		
 		error = uiomove(m->m_data, m->m_len, uio);
 
-		if(IF_QFULL(isdn_linktab[unit]->tx_queue))
-		{
-			m_freem(m);			
-		}
-		else
-		{
-			IF_ENQUEUE(isdn_linktab[unit]->tx_queue, m);
-		}
-
+		(void) IF_HANDOFF(isdn_linktab[unit]->tx_queue, m, NULL);
 		(*isdn_linktab[unit]->bch_tx_start)(isdn_linktab[unit]->unit, isdn_linktab[unit]->channel);
 	}
 
@@ -733,7 +726,7 @@ i4brbchpoll(dev_t dev, int events, struct proc *p)
 	 
 	if((events & (POLLOUT|POLLWRNORM)) &&
 	   (sc->sc_devstate & ST_CONNECTED) &&
-	   !IF_QFULL(isdn_linktab[unit]->tx_queue))
+	   !_IF_QFULL(isdn_linktab[unit]->tx_queue))
 	{
 		revents |= (events & (POLLOUT|POLLWRNORM));
 	}
@@ -802,7 +795,7 @@ i4brbchselect(dev_t dev, int rw, struct proc *p)
 				break;
 
 			case FWRITE:
-				if(!IF_QFULL(isdn_linktab[unit]->rx_queue))
+				if(!_IF_QFULL(isdn_linktab[unit]->rx_queue))
 				{
 					splx(s);
 					return(1);
@@ -962,16 +955,11 @@ rbch_rx_data_rdy(int unit)
 
 		m->m_pkthdr.len = m->m_len;
 
-		if(IF_QFULL(&(rbch_softc[unit].sc_hdlcq)))
+		if (! IF_HANDOFF(&(rbch_softc[unit].sc_hdlcq), m, NULL))
 		{
 			NDBGL4(L4_RBCHDBG, "unit %d: hdlc rx queue full!", unit);
-			m_freem(m);
 		}
-		else
-		{
-			IF_ENQUEUE(&(rbch_softc[unit].sc_hdlcq), m);
-		}
-	}				
+	}
 
 	if(rbch_softc[unit].sc_devstate & ST_RDWAITDATA)
 	{
@@ -1025,20 +1013,11 @@ rbch_activity(int unit, int rxtx)
 static void
 rbch_clrq(int unit)
 {
-	struct mbuf *m;
 	CRIT_VAR;
 	
-	for(;;)
-	{
-		CRIT_BEG;
-		IF_DEQUEUE(&rbch_softc[unit].sc_hdlcq, m);
-		CRIT_END;
-		
-		if(m)
-			m_freem(m);
-		else
-			break;
-	}
+	CRIT_BEG;
+	IF_DRAIN(&rbch_softc[unit].sc_hdlcq);
+	CRIT_END;
 }
 				
 /*---------------------------------------------------------------------------*
diff --git a/sys/i4b/driver/i4b_tel.c b/sys/i4b/driver/i4b_tel.c
index 1652b20..b34ec16 100644
--- a/sys/i4b/driver/i4b_tel.c
+++ b/sys/i4b/driver/i4b_tel.c
@@ -573,6 +573,7 @@ i4btelread(dev_t dev, struct uio *uio, int ioflag)
 	if(func == FUNCTEL)
 	{
 		s = splimp();
+		IF_LOCK(sc->isdn_linktab->rx_queue);
 		while(IF_QEMPTY(sc->isdn_linktab->rx_queue) &&
 			(sc->devstate & ST_ISOPEN)          &&
 			(sc->devstate & ST_CONNECTED))		
@@ -581,11 +582,13 @@ i4btelread(dev_t dev, struct uio *uio, int ioflag)
 
 			NDBGL4(L4_TELDBG, "i4btel%d, queue empty!", unit);
 			
-			if((error = tsleep((caddr_t) &sc->isdn_linktab->rx_queue,
+			if((error = msleep((caddr_t) &sc->isdn_linktab->rx_queue,
+						&sc->isdn_linktab->rx_queue->ifq_mtx,
 						TTIPRI | PCATCH,
 						"rtel", 0 )) != 0)
 			{
 				sc->devstate &= ~ST_RDWAITDATA;
+				IF_UNLOCK(sc->isdn_linktab->rx_queue);
 				splx(s);
 				return(error);
 			}
@@ -593,18 +596,21 @@ i4btelread(dev_t dev, struct uio *uio, int ioflag)
 	
 		if(!(sc->devstate & ST_ISOPEN))
 		{
+			IF_UNLOCK(sc->isdn_linktab->rx_queue);
 			splx(s);
 			return(EIO);
 		}
 	
 		if(!(sc->devstate & ST_CONNECTED))
 		{
+			IF_UNLOCK(sc->isdn_linktab->rx_queue);
 			splx(s);
 			return(EIO);
 		}
 		
 	
-		IF_DEQUEUE(sc->isdn_linktab->rx_queue, m);
+		_IF_DEQUEUE(sc->isdn_linktab->rx_queue, m);
+		IF_UNLOCK(sc->isdn_linktab->rx_queue);
 		
 		if(m && m->m_len > 0)
 		{
@@ -700,19 +706,23 @@ i4btelwrite(dev_t dev, struct uio * uio, int ioflag)
 		}
 			
 		sc->devstate &= ~ST_TONE;		
-		while((IF_QFULL(sc->isdn_linktab->tx_queue)) &&
+		IF_LOCK(sc->isdn_linktab->tx_queue);
+		while((_IF_QFULL(sc->isdn_linktab->tx_queue)) &&
 		      (sc->devstate & ST_ISOPEN))
 		{
 			sc->devstate |= ST_WRWAITEMPTY;
 	
-			if((error = tsleep((caddr_t) &sc->isdn_linktab->tx_queue,
+			if((error = msleep((caddr_t) &sc->isdn_linktab->tx_queue,
+					&sc->isdn_linktab->tx_queue->ifq_mtx,
 					TTIPRI | PCATCH, "wtel", 0)) != 0)
 			{
 				sc->devstate &= ~ST_WRWAITEMPTY;			
+				IF_UNLOCK(sc->isdn_linktab->tx_queue);
 				splx(s);
 				return(error);
 			}
 		}
+		IF_UNLOCK(sc->isdn_linktab->tx_queue);
 	
 		if(!(sc->devstate & ST_ISOPEN))
 		{
@@ -744,15 +754,7 @@ i4btelwrite(dev_t dev, struct uio * uio, int ioflag)
 				mtod(m,u_char *)[i] = bitreverse[mtod(m,u_char *)[i]];
 			}
 			
-			if(IF_QFULL(sc->isdn_linktab->tx_queue))
-			{
-				m_freem(m);			
-			}
-			else
-			{
-				IF_ENQUEUE(sc->isdn_linktab->tx_queue, m);
-			}
-	
+			(void) IF_HANDOFF(sc->isdn_linktab->tx_queue, m, NULL);
 			(*sc->isdn_linktab->bch_tx_start)(sc->isdn_linktab->unit, sc->isdn_linktab->channel);
 		}
 	
@@ -867,7 +869,7 @@ i4btelpoll(dev_t dev, int events, struct proc *p)
 		if((events & (POLLOUT|POLLWRNORM))	&&
 			(sc->devstate & ST_CONNECTED)	&&
 			(sc->isdn_linktab != NULL)	&&
-			(!IF_QFULL(sc->isdn_linktab->tx_queue)))
+			(!_IF_QFULL(sc->isdn_linktab->tx_queue)))
 		{
 			NDBGL4(L4_TELDBG, "i4btel%d, POLLOUT", unit);
 			revents |= (events & (POLLOUT|POLLWRNORM));
@@ -958,7 +960,7 @@ i4btelsel(dev_t dev, int rw, struct proc *p)
 		}
 		else if (rw == FWRITE)
 		{
-			if (!IF_QFULL(sc->isdn_linktab->tx_queue))
+			if (!_IF_QFULL(sc->isdn_linktab->tx_queue))
 			{
 				NDBGL4(L4_TELDBG, "i4btel%d, FWRITE", unit);
 				splx(s);
diff --git a/sys/i4b/driver/i4b_trace.c b/sys/i4b/driver/i4b_trace.c
index 0d10771..ff29c01 100644
--- a/sys/i4b/driver/i4b_trace.c
+++ b/sys/i4b/driver/i4b_trace.c
@@ -245,6 +245,7 @@ i4btrcattach()
 #endif
 #endif
 		trace_queue[i].ifq_maxlen = IFQ_MAXLEN;
+		mtx_init(&trace_queue[i].ifq_mtx, "i4b_trace", MTX_DEF);
 		device_state[i] = ST_IDLE;
 	}
 }
@@ -317,12 +318,13 @@ get_trace_data_from_l1(i4b_trace_hdr_t *hdr, int len, char *buf)
 		unit = outunit;			
 	}
 
-	if(IF_QFULL(&trace_queue[unit]))
+	IF_LOCK(&trace_queue[unit]);
+	if(_IF_QFULL(&trace_queue[unit]))
 	{
 		struct mbuf *m1;
 
 		x = SPLI4B();
-		IF_DEQUEUE(&trace_queue[unit], m1);
+		_IF_DEQUEUE(&trace_queue[unit], m1);
 		splx(x);		
 
 		i4b_Bfreembuf(m1);
@@ -339,7 +341,8 @@ get_trace_data_from_l1(i4b_trace_hdr_t *hdr, int len, char *buf)
 
 	x = SPLI4B();
 	
-	IF_ENQUEUE(&trace_queue[unit], m);
+	_IF_ENQUEUE(&trace_queue[unit], m);
+	IF_UNLOCK(&trace_queue[unit]);
 	
 	if(device_state[unit] & ST_WAITDATA)
 	{
@@ -441,21 +444,25 @@ i4btrcread(dev_t dev, struct uio * uio, int ioflag)
 
 	x = SPLI4B();
 	
+	IF_LOCK(&trace_queue[unit]);
 	while(IF_QEMPTY(&trace_queue[unit]) && (device_state[unit] & ST_ISOPEN))
 	{
 		device_state[unit] |= ST_WAITDATA;
 		
-		if((error = tsleep((caddr_t) &trace_queue[unit],
+		if((error = msleep((caddr_t) &trace_queue[unit],
+					&trace_queue[unit].ifq_mtx,
 					TTIPRI | PCATCH,
 					"bitrc", 0 )) != 0)
 		{
 			device_state[unit] &= ~ST_WAITDATA;
+			IF_UNLOCK(&trace_queue[unit]);
 			splx(x);
 			return(error);
 		}
 	}
 
-	IF_DEQUEUE(&trace_queue[unit], m);
+	_IF_DEQUEUE(&trace_queue[unit], m);
+	IF_UNLOCK(&trace_queue[unit]);
 
 	if(m && m->m_len)
 		error = uiomove(m->m_data, m->m_len, uio);
diff --git a/sys/i4b/layer1/ifpi/i4b_ifpi_pci.c b/sys/i4b/layer1/ifpi/i4b_ifpi_pci.c
index a59e07d..6fb3c11 100644
--- a/sys/i4b/layer1/ifpi/i4b_ifpi_pci.c
+++ b/sys/i4b/layer1/ifpi/i4b_ifpi_pci.c
@@ -863,14 +863,7 @@ avma1pp_hscx_intr(int h_chan, u_int stat, struct l1_softc *sc)
 				
 					  /* move rx'd data to rx queue */
 
-					  if (!(IF_QFULL(&chan->rx_queue)))
-					  {
-					  	IF_ENQUEUE(&chan->rx_queue, chan->in_mbuf);
-					  }
-					  else
-				       	  {
-						i4b_Bfreembuf(chan->in_mbuf);
-				          }
+					  (void) IF_HANDOFF(&chan->rx_queue, chan->in_mbuf, NULL);
 
 					  /* signal upper layer that data are available */
 					  (*chan->isic_drvr_linktab->bch_rx_data_ready)(chan->isic_drvr_linktab->unit);
@@ -1124,9 +1117,10 @@ avma1pp_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 
 	/* receiver part */
 
-	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
-
 	chan->rx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->rx_queue.ifq_mtx, "i4b_avma1pp_rx", MTX_DEF);
+
+	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
 
 	chan->rxcount = 0;		/* reset rx counter */
 	
@@ -1138,10 +1132,11 @@ avma1pp_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 	
 	/* transmitter part */
 
-	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
-
 	chan->tx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->tx_queue.ifq_mtx, "i4b_avma1pp_tx", MTX_DEF);
 	
+	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
+
 	chan->txcount = 0;		/* reset tx counter */
 	
 	i4b_Bfreembuf(chan->out_mbuf_head);	/* clean tx mbuf */
diff --git a/sys/i4b/layer1/ifpnp/i4b_ifpnp_avm.c b/sys/i4b/layer1/ifpnp/i4b_ifpnp_avm.c
index 401a19d..bc69399 100644
--- a/sys/i4b/layer1/ifpnp/i4b_ifpnp_avm.c
+++ b/sys/i4b/layer1/ifpnp/i4b_ifpnp_avm.c
@@ -799,14 +799,7 @@ avm_pnp_hscx_intr(int h_chan, u_int stat, u_int cnt, struct l1_softc *sc)
 				
 					  /* move rx'd data to rx queue */
 
-					  if (!(IF_QFULL(&chan->rx_queue)))
-					  {
-					  	IF_ENQUEUE(&chan->rx_queue, chan->in_mbuf);
-					  }
-					  else
-				       	  {
-						i4b_Bfreembuf(chan->in_mbuf);
-				          }
+					  (void) IF_HANDOFF(&chan->rx_queue, chan->in_mbuf, NULL);
 
 					  /* signal upper layer that data are available */
 					  (*chan->isic_drvr_linktab->bch_rx_data_ready)(chan->isic_drvr_linktab->unit);
@@ -1044,9 +1037,10 @@ avm_pnp_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 
 	/* receiver part */
 
-	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
-
 	chan->rx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->rx_queue.ifq_mtx, "i4b_avm_pnp_rx", MTX_DEF);
+
+	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
 
 	chan->rxcount = 0;		/* reset rx counter */
 	
@@ -1058,10 +1052,11 @@ avm_pnp_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 	
 	/* transmitter part */
 
+	chan->tx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->tx_queue.ifq_mtx, "i4b_avm_pnp_tx", MTX_DEF);
+
 	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
 
-	chan->tx_queue.ifq_maxlen = IFQ_MAXLEN;
-	
 	chan->txcount = 0;		/* reset tx counter */
 	
 	i4b_Bfreembuf(chan->out_mbuf_head);	/* clean tx mbuf */
diff --git a/sys/i4b/layer1/ihfc/i4b_ihfc_drv.c b/sys/i4b/layer1/ihfc/i4b_ihfc_drv.c
index 814a40a..7a01014 100644
--- a/sys/i4b/layer1/ihfc/i4b_ihfc_drv.c
+++ b/sys/i4b/layer1/ihfc/i4b_ihfc_drv.c
@@ -351,13 +351,14 @@ ihfc_init (ihfc_sc_t *sc, u_char chan, int prot, int activate)
 	do
 	{	if (chan < 2)			/* D-Channel */
 		{
+			S_IFQUEUE.ifq_maxlen = IFQ_MAXLEN;
+			mtx_init(&S_IFQUEUE.ifq_mtx, "i4b_ihfc", MTX_DEF);
+
 			i4b_Dfreembuf(S_MBUF);
 			i4b_Dcleanifq(&S_IFQUEUE);
 
 			RESET_SOFT_CHAN(sc, chan);
 
-			S_IFQUEUE.ifq_maxlen = IFQ_MAXLEN;
-
 			if (!activate) continue;
 
 			if (S_HFC & HFC_1)
@@ -373,13 +374,15 @@ ihfc_init (ihfc_sc_t *sc, u_char chan, int prot, int activate)
 		}
 		else				/* B-Channel */
 		{
+			S_IFQUEUE.ifq_maxlen = IFQ_MAXLEN;
+			mtx_init(&S_IFQUEUE.ifq_mtx, "i4b_ihfc", MTX_DEF);
+
 			i4b_Bfreembuf(S_MBUF);
 			i4b_Bcleanifq(&S_IFQUEUE);
 
 			RESET_SOFT_CHAN(sc, chan);
 
 			S_PROT = prot;
-			S_IFQUEUE.ifq_maxlen = IFQ_MAXLEN;
 
 			if (!activate) continue;
 
diff --git a/sys/i4b/layer1/ihfc/i4b_ihfc_l1if.c b/sys/i4b/layer1/ihfc/i4b_ihfc_l1if.c
index 5b9e6cf..4bb59f0 100644
--- a/sys/i4b/layer1/ihfc/i4b_ihfc_l1if.c
+++ b/sys/i4b/layer1/ihfc/i4b_ihfc_l1if.c
@@ -127,7 +127,7 @@ ihfc_ph_data_req(int unit, struct mbuf *m, int freeflag)
 
 	if (freeflag == MBUF_DONTFREE)	m = m_copypacket(m, M_DONTWAIT);
 
-	if (!IF_QFULL(&S_IFQUEUE) && m)
+	if (!_IF_QFULL(&S_IFQUEUE) && m)
 	{
 		IF_ENQUEUE(&S_IFQUEUE, m);
 
@@ -300,7 +300,7 @@ ihfc_putmbuf (ihfc_sc_t *sc, u_char chan, struct mbuf *m)
 				S_BDRVLINK->bch_activity(S_BDRVLINK->unit, ACT_RX);
 			}
 
-			if (!IF_QFULL(&S_IFQUEUE))
+			if (!_IF_QFULL(&S_IFQUEUE))
 			{
 				S_BYTES += m->m_len;
 				IF_ENQUEUE(&S_IFQUEUE, m);
diff --git a/sys/i4b/layer1/isic/i4b_bchan.c b/sys/i4b/layer1/isic/i4b_bchan.c
index f1db0ea..c937790 100644
--- a/sys/i4b/layer1/isic/i4b_bchan.c
+++ b/sys/i4b/layer1/isic/i4b_bchan.c
@@ -91,9 +91,10 @@ isic_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 
 	/* receiver part */
 
-	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
-
 	chan->rx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->rx_queue.ifq_mtx, "i4b_isic_rx", MTX_DEF);
+
+	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
 
 	chan->rxcount = 0;		/* reset rx counter */
 	
@@ -105,10 +106,11 @@ isic_bchannel_setup(int unit, int h_chan, int bprot, int activate)
 	
 	/* transmitter part */
 
-	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
-
 	chan->tx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->tx_queue.ifq_mtx, "i4b_isic_tx", MTX_DEF);
 	
+	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
+
 	chan->txcount = 0;		/* reset tx counter */
 	
 	i4b_Bfreembuf(chan->out_mbuf_head);	/* clean tx mbuf */
diff --git a/sys/i4b/layer1/isic/i4b_hscx.c b/sys/i4b/layer1/isic/i4b_hscx.c
index 121b8c5..79e74b8 100644
--- a/sys/i4b/layer1/isic/i4b_hscx.c
+++ b/sys/i4b/layer1/isic/i4b_hscx.c
@@ -270,14 +270,7 @@ isic_hscx_irq(register struct l1_softc *sc, u_char ista, int h_chan, u_char ex_i
 				if(!(i4b_l1_bchan_tel_silence(chan->in_mbuf->m_data, chan->in_mbuf->m_len)))
 					activity = ACT_RX;
 
-				if(!(IF_QFULL(&chan->rx_queue)))
-				{
-					IF_ENQUEUE(&chan->rx_queue, chan->in_mbuf);
-				}
-				else
-				{
-					i4b_Bfreembuf(chan->in_mbuf);
-				}
+				(void) IF_HANDOFF(&chan->rx_queue, chan->in_mbuf, NULL);
 
 				/* signal upper driver that data is available */
 
diff --git a/sys/i4b/layer1/iwic/i4b_iwic_bchan.c b/sys/i4b/layer1/iwic/i4b_iwic_bchan.c
index e836f78..0b8fa26 100644
--- a/sys/i4b/layer1/iwic/i4b_iwic_bchan.c
+++ b/sys/i4b/layer1/iwic/i4b_iwic_bchan.c
@@ -239,14 +239,7 @@ iwic_bchan_xirq(struct iwic_softc *sc, int chan_no)
 				if(!(i4b_l1_bchan_tel_silence(chan->in_mbuf->m_data, chan->in_mbuf->m_len)))
 					activity = ACT_RX;
 
-				if(!(IF_QFULL(&chan->rx_queue)))
-				{
-					IF_ENQUEUE(&chan->rx_queue, chan->in_mbuf);
-				}
-				else
-				{
-					i4b_Bfreembuf(chan->in_mbuf);
-				}
+				(void) IF_HANDOFF(&chan->rx_queue, chan->in_mbuf, NULL);
 
 				/* signal upper driver that data is available */
 
@@ -416,9 +409,10 @@ iwic_bchannel_setup(int unit, int chan_no, int bprot, int activate)
 		
 	/* receiver part */
 
-	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
-
 	chan->rx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->rx_queue.ifq_mtx, "i4b_iwic_rx", MTX_DEF);
+
+	i4b_Bcleanifq(&chan->rx_queue);	/* clean rx queue */
 
 	chan->rxcount = 0;		/* reset rx counter */
 	
@@ -430,9 +424,10 @@ iwic_bchannel_setup(int unit, int chan_no, int bprot, int activate)
 	
 	/* transmitter part */
 
-	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
-
 	chan->tx_queue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&chan->tx_queue.ifq_mtx, "i4b_iwic_tx", MTX_DEF);
+
+	i4b_Bcleanifq(&chan->tx_queue);	/* clean tx queue */
 	
 	chan->txcount = 0;		/* reset tx counter */
 	
diff --git a/sys/i4b/layer2/i4b_l2.c b/sys/i4b/layer2/i4b_l2.c
index 59a09ba..b3f79a6 100644
--- a/sys/i4b/layer2/i4b_l2.c
+++ b/sys/i4b/layer2/i4b_l2.c
@@ -163,7 +163,7 @@ int i4b_dl_data_req(int unit, struct mbuf *m)
 		case ST_MULTIFR:
 		case ST_TIMREC:
 		
-		        if(IF_QFULL(&l2sc->i_queue))
+		        if(_IF_QFULL(&l2sc->i_queue))
 		        {
 		        	NDBGL2(L2_ERROR, "i_queue full!!");
 		        	i4b_Dfreembuf(m);
@@ -277,6 +277,7 @@ i4b_mph_status_ind(int unit, int status, int parm)
 		case STI_ATTACH:
 			l2sc->unit = unit;
 			l2sc->i_queue.ifq_maxlen = IQUEUE_MAXLEN;
+			mtx_init(&l2sc->i_queue.ifq_mtx, "i4b_l2sc", MTX_DEF);
 			l2sc->ua_frame = NULL;
 			bzero(&l2sc->stat, sizeof(lapdstat_t));			
 			i4b_l2_unit_init(unit);
diff --git a/sys/i4b/layer2/i4b_mbuf.c b/sys/i4b/layer2/i4b_mbuf.c
index a0f1013..0537a5e 100644
--- a/sys/i4b/layer2/i4b_mbuf.c
+++ b/sys/i4b/layer2/i4b_mbuf.c
@@ -140,15 +140,9 @@ i4b_Dfreembuf(struct mbuf *m)
 void
 i4b_Dcleanifq(struct ifqueue *ifq)
 {
-	struct mbuf *m;
 	int x = splimp();
 	
-	while(!IF_QEMPTY(ifq))
-	{
-		IF_DEQUEUE(ifq, m);
-		i4b_Dfreembuf(m);
-	}
-
+	IF_DRAIN(ifq);
 	splx(x);
 }
 
@@ -222,15 +216,9 @@ i4b_Bfreembuf(struct mbuf *m)
 void
 i4b_Bcleanifq(struct ifqueue *ifq)
 {
-	struct mbuf *m;
 	int x = splimp();
 	
-	while(!IF_QEMPTY(ifq))
-	{
-		IF_DEQUEUE(ifq, m);
-		i4b_Bfreembuf(m);
-	}
-
+	IF_DRAIN(ifq);
 	splx(x);
 }
 
diff --git a/sys/i4b/layer2/i4b_util.c b/sys/i4b/layer2/i4b_util.c
index 982760d..0569a84 100644
--- a/sys/i4b/layer2/i4b_util.c
+++ b/sys/i4b/layer2/i4b_util.c
@@ -182,7 +182,7 @@ i4b_invoke_retransmission(l2_softc_t *l2sc, int nr)
 
 		if((l2sc->ua_num != UA_EMPTY) && (l2sc->vs == l2sc->ua_num))
 		{
-			if(IF_QFULL(&l2sc->i_queue))
+			if(_IF_QFULL(&l2sc->i_queue))
 			{
 				NDBGL2(L2_ERROR, "ERROR, I-queue full!");
 			}
diff --git a/sys/i4b/layer4/i4b_i4bdrv.c b/sys/i4b/layer4/i4b_i4bdrv.c
index d02a159..118926d 100644
--- a/sys/i4b/layer4/i4b_i4bdrv.c
+++ b/sys/i4b/layer4/i4b_i4bdrv.c
@@ -262,6 +262,7 @@ i4battach()
 	printf("i4b: ISDN call control device attached\n");
 #endif
 	i4b_rdqueue.ifq_maxlen = IFQ_MAXLEN;
+	mtx_init(&i4b_rdqueue.ifq_mtx, "i4b_rdqueue", MTX_DEF);
 
 #if defined(__FreeBSD__)
 #if __FreeBSD__ == 3
@@ -328,17 +329,21 @@ i4bread(dev_t dev, struct uio *uio, int ioflag)
 		return(ENODEV);
 
 	x = splimp();
+	IF_LOCK(&i4b_rdqueue);
 	while(IF_QEMPTY(&i4b_rdqueue))
 	{
 		readflag = 1;
-		error = tsleep((caddr_t) &i4b_rdqueue, (PZERO + 1) | PCATCH, "bird", 0);
+		error = msleep((caddr_t) &i4b_rdqueue, &i4b_rdqueue.ifq_mtx,
+		    (PZERO + 1) | PCATCH, "bird", 0);
 		if (error != 0) {
-		splx(x);
+			IF_UNLOCK(&i4b_rdqueue);
+			splx(x);
 			return error;
 		}
 	}
 
-	IF_DEQUEUE(&i4b_rdqueue, m);
+	_IF_DEQUEUE(&i4b_rdqueue, m);
+	IF_UNLOCK(&i4b_rdqueue);
 
 	splx(x);
 		
@@ -978,15 +983,17 @@ i4bputqueue(struct mbuf *m)
 
 	x = splimp();
 	
-	if(IF_QFULL(&i4b_rdqueue))
+	IF_LOCK(&i4b_rdqueue);
+	if(_IF_QFULL(&i4b_rdqueue))
 	{
 		struct mbuf *m1;
-		IF_DEQUEUE(&i4b_rdqueue, m1);
+		_IF_DEQUEUE(&i4b_rdqueue, m1);
 		i4b_Dfreembuf(m1);
 		NDBGL4(L4_ERR, "ERROR, queue full, removing entry!");
 	}
 
-	IF_ENQUEUE(&i4b_rdqueue, m);
+	_IF_ENQUEUE(&i4b_rdqueue, m);
+	IF_UNLOCK(&i4b_rdqueue);
 
 	splx(x);	
 
@@ -1019,15 +1026,17 @@ i4bputqueue_hipri(struct mbuf *m)
 
 	x = splimp();
 	
-	if(IF_QFULL(&i4b_rdqueue))
+	IF_LOCK(&i4b_rdqueue);
+	if(_IF_QFULL(&i4b_rdqueue))
 	{
 		struct mbuf *m1;
-		IF_DEQUEUE(&i4b_rdqueue, m1);
+		_IF_DEQUEUE(&i4b_rdqueue, m1);
 		i4b_Dfreembuf(m1);
 		NDBGL4(L4_ERR, "ERROR, queue full, removing entry!");
 	}
 
-	IF_PREPEND(&i4b_rdqueue, m);
+	_IF_PREPEND(&i4b_rdqueue, m);
+	IF_UNLOCK(&i4b_rdqueue);
 
 	splx(x);