Make arl(4) MPSAFE:

- Add a mutex to the softc and use it to protect the softc and device
  hardware.
- Setup interrupt handler after ether_ifattach().
- Use a private timer instead of if_timer/if_watchdog.
- Retire arl_unit from the softc and use if_printf() and device_printf()
  instead.

Note that the unpatched driver in 6.x and later does not work with the
hardware, so the one person who had volunteered to test the patch wasn't
able to test it.

3 files changed, 149 insertions, 130 deletions

diff --git a/sys/dev/arl/if_arl.c b/sys/dev/arl/if_arl.c
index 8be9bda..6ebf3bf 100644
--- a/sys/dev/arl/if_arl.c
+++ b/sys/dev/arl/if_arl.c
@@ -76,7 +76,7 @@ __FBSDID("$FreeBSD$");
 
 /*#define DEBUG */
 #ifdef DEBUG
-#define D(x)	{printf("arl%d: ", sc->arl_unit); printf x; }
+#define D(x)	{device_printf(sc->arl_dev, "%s", ""); printf x; }
 #else
 #define D(x)
 #endif
@@ -98,30 +98,19 @@ __FBSDID("$FreeBSD$");
 #define GET_ARL_PARAM(name) (arcfg.name = ar->name)
 #define SET_ARL_PARAM(name) (ar->name = arcfg.name)
 
-#ifndef BPF_MTAP
-#define BPF_MTAP(_ifp,_m)					\
-	do {							\
-		if ((_ifp)->if_bpf)				\
-			bpf_mtap((_ifp), (_m));			\
-	} while (0)
-#endif
-
-#if __FreeBSD_version < 500100
-#define BROADCASTADDR	(etherbroadcastaddr)
-#define _ARL_CURPROC	(curproc)
-#else
 #define BROADCASTADDR	(sc->arl_ifp->if_broadcastaddr)
 #define _ARL_CURPROC	(curthread)
-#endif
 
 static void	arl_hwreset	(struct arl_softc *);
 static void	arl_reset	(struct arl_softc *);
 static int	arl_ioctl	(struct ifnet *, u_long, caddr_t);
 static void	arl_init	(void *);
+static void	arl_init_locked	(struct arl_softc *);
 static void	arl_start	(struct ifnet *);
+static void	arl_start_locked(struct ifnet *);
 
-static void	arl_watchdog	(struct ifnet *);
-static void	arl_waitreg	(struct ifnet *);
+static void	arl_watchdog	(void *);
+static void	arl_waitreg	(void *);
 
 static void	arl_enable	(struct arl_softc *);
 static void	arl_config	(struct arl_softc *);
@@ -190,7 +179,7 @@ arl_attach(dev)
 {
 	struct arl_softc* sc = device_get_softc(dev);
 	struct ifnet *ifp;
-	int		attached, configured = 0;
+	int		configured = 0, error;
 
 	D(("attach\n"));
 
@@ -198,8 +187,11 @@ arl_attach(dev)
 	if (ifp == NULL)
 		return (ENOSPC);
 
+	mtx_init(&sc->arl_lock, device_get_nameunit(dev), MTX_NETWORK_LOCK,
+	    MTX_DEF);
+	callout_init_mtx(&sc->arl_timer, &sc->arl_lock, 0);
+	ARL_LOCK(sc);
 	configured = ar->configuredStatusFlag;
-	attached = (ifp->if_softc != 0);
 
 	if (!configured && bootverbose)
 		device_printf(dev, "card is not configured\n");
@@ -211,25 +203,18 @@ arl_attach(dev)
 	/* Read config for default values if card was not configured */
 	if (!configured)
 		arl_read_config(sc);
+	ARL_UNLOCK(sc);
 
 	/* Initialize ifnet structure. */
 	ifp->if_softc = sc;
-#if __FreeBSD_version < 502000
-	ifp->if_unit = sc->arl_unit;
-	ifp->if_name = "arl";
-#else
 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
-#endif
 	ifp->if_mtu = ETHERMTU;
-	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST |
-	    IFF_NEEDSGIANT;
+	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
 	ifp->if_start = arl_start;
 	ifp->if_ioctl = arl_ioctl;
-	ifp->if_watchdog = arl_watchdog;
 	ifp->if_init = arl_init;
-	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
+	IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN);
 	ifp->if_baudrate = 2000000;
-	ifp->if_timer = 0;
 
 	ifmedia_init(&sc->arl_ifmedia, 0, arl_media_change, arl_media_status);
 #define ADD(s, o)	ifmedia_add(&sc->arl_ifmedia, \
@@ -249,12 +234,16 @@ arl_attach(dev)
 	/*
 	 * Attach the interface
 	 */
-	if (!attached) {
-#if __FreeBSD_version < 500100
-		ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
-#else
-		ether_ifattach(ifp, ar->lanCardNodeId);
-#endif
+	ether_ifattach(ifp, ar->lanCardNodeId);
+
+	error = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_NET | INTR_MPSAFE,
+			       NULL, arl_intr, sc, &sc->irq_handle);
+	if (error) {
+		ether_ifdetach(ifp);
+		mtx_destroy(&sc->arl_lock);
+		if_free(sc->arl_ifp);
+		arl_release_resources(dev);
+		return (error);
 	}
 
 	return (0);
@@ -270,6 +259,7 @@ arl_hwreset(sc)
 {
 	D(("hw reset\n"));
 
+	ARL_LOCK_ASSERT(sc);
 	ar->controlRegister = 1;
 	DELAY(ARDELAY1);
 
@@ -328,6 +318,7 @@ arl_reset(sc)
 	struct arl_softc *sc;
 {
 	D(("reset\n"));
+	ARL_LOCK_ASSERT(sc);
 	arl_hwreset(sc);
 
 	ar->resetFlag1 = 1;
@@ -351,7 +342,7 @@ arl_reset(sc)
 			DELAY(delay);
 
 		if (cnt == 0) {
-			printf("arl%d: reset timeout\n", sc->arl_unit);
+			if_printf(sc->arl_ifp, "reset timeout\n");
 			return;
 		}
 
@@ -360,7 +351,7 @@ arl_reset(sc)
 #endif
 
 	if (ar->diagnosticInfo != 0xff) {
-		printf("arl%d: reset error\n", sc->arl_unit);
+		if_printf(sc->arl_ifp, "reset error\n");
 		return;
 	}
 	arl_config(sc);
@@ -438,14 +429,15 @@ arl_ioctl(ifp, cmd, data)
 	struct ieee80211req *ireq = (struct ieee80211req *)data;
 	d_thread_t *td = _ARL_CURPROC;
 	struct arl_req arlan_io;
-	int count, s, error = 0;
+	int error = 0;
+	struct arl_sigcache *arl_cache;
+	struct arl_stats *arl_stats;
 	u_int8_t tmpstr[IEEE80211_NWID_LEN*2];
+	u_int8_t tmpname[ARLAN_NAME_SIZE];
 	u_int8_t *tmpptr;
 	u_int32_t newsid;
-	caddr_t user;
 
 	D(("ioctl %lx\n", cmd));
-	s = splimp();
 
 	switch (cmd) {
 	case SIOCSIFADDR:
@@ -455,13 +447,15 @@ arl_ioctl(ifp, cmd, data)
 		break;
 
 	case SIOCSIFFLAGS:
+		ARL_LOCK(sc);
 		if (ifp->if_flags & IFF_UP) {
 			if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
-				arl_init(sc);
+				arl_init_locked(sc);
 		} else {
 			if (ifp->if_drv_flags & IFF_DRV_RUNNING)
 				arl_stop(sc);
 		}
+		ARL_UNLOCK(sc);
 		break;
 	case SIOCSIFMEDIA:
 	case SIOCGIFMEDIA:
@@ -476,27 +470,35 @@ arl_ioctl(ifp, cmd, data)
 				break;
 			}
 			bzero(tmpstr, IEEE80211_NWID_LEN);
+			ARL_LOCK(sc);
 			snprintf(tmpstr, IEEE80211_NWID_LEN - 1, "0x%08x",
 					*(int *)arcfg.sid);
+			ARL_UNLOCK(sc);
 			ireq->i_len = IEEE80211_NWID_LEN;
 			error = copyout(tmpstr, ireq->i_data,
 				IEEE80211_NWID_LEN);
 			break;
 		case IEEE80211_IOC_STATIONNAME:
 			ireq->i_len = sizeof(arcfg.name);
+			ARL_LOCK(sc);
 			tmpptr = arcfg.name;
 			bzero(tmpstr, IEEE80211_NWID_LEN);
 			bcopy(tmpptr, tmpstr, ireq->i_len);
+			ARL_UNLOCK(sc);
 			error = copyout(tmpstr, ireq->i_data,
 				IEEE80211_NWID_LEN);
 			break;
 		case IEEE80211_IOC_CHANNEL:
+			ARL_LOCK(sc);
 			ireq->i_val = arcfg.channelNumber;
+			ARL_UNLOCK(sc);
 			break;
 		case IEEE80211_IOC_POWERSAVE:
+			ARL_LOCK(sc);
 			ireq->i_val = (arcfg.registrationMode == 2 ?
 				IEEE80211_POWERSAVE_PSP :
 				IEEE80211_POWERSAVE_OFF);
+			ARL_UNLOCK(sc);
 			break;
 		default:
 			error = EINVAL;
@@ -527,6 +529,7 @@ arl_ioctl(ifp, cmd, data)
 				break;
 			}
 
+			ARL_LOCK(sc);
 			bcopy(&newsid, arcfg.sid, sizeof(arcfg.sid));
 			break;
 		case IEEE80211_IOC_STATIONNAME:
@@ -534,24 +537,31 @@ arl_ioctl(ifp, cmd, data)
 				error = EINVAL;
 				break;
 			}
+			error = copyin(ireq->i_data, tmpname, ireq->i_len);
+			if (error)
+				break;
+			ARL_LOCK(sc);
 			bzero(arcfg.name, ARLAN_NAME_SIZE);
-			error = copyin(ireq->i_data, arcfg.name, ireq->i_len);
+			bcopy(tmpname, arcfg.name, ireq->i_len);
 			break;
 		case IEEE80211_IOC_CHANNEL:
 			if (ireq->i_val < 0 || ireq->i_val > 5) {
 				error = EINVAL;
 				break;
 			}
+			ARL_LOCK(sc);
 			arcfg.channelNumber = ireq->i_val;
 			break;
 		case IEEE80211_IOC_POWERSAVE:
 			switch (ireq->i_val) {
 			case IEEE80211_POWERSAVE_OFF:
+				ARL_LOCK(sc);
 				if (arcfg.registrationMode == 2)
 					arcfg.registrationMode = 1;
 				break;
 			case IEEE80211_POWERSAVE_ON:
 			case IEEE80211_POWERSAVE_PSP:
+				ARL_LOCK(sc);
 				arcfg.registrationMode = 2;
 				break;
 			default:
@@ -564,8 +574,16 @@ arl_ioctl(ifp, cmd, data)
 			break;
 		}
 
-		if (!error)
+		if (!error) {
+			/*
+			 * XXX: Somewhat gross: we require that if the
+			 * clauses in the switch statement above
+			 * didn't encounter an error they leave the
+			 * softc locked.
+			 */
 			arl_config(sc);
+			ARL_UNLOCK(sc);
+		}
 
 		break;
 
@@ -578,6 +596,7 @@ arl_ioctl(ifp, cmd, data)
 	}
 	case SIOCGARLALL:
 		bzero(&arlan_io, sizeof(arlan_io));
+		ARL_LOCK(sc);
 		if (!priv_check(td, PRIV_DRIVER)) {
 			bcopy(ar->systemId, arlan_io.cfg.sid, 4);
 		}
@@ -596,11 +615,9 @@ arl_ioctl(ifp, cmd, data)
 		GET_PARAM(priority);
 		GET_PARAM(receiveMode);
 		GET_PARAM(txRetry);
+		ARL_UNLOCK(sc);
 
-		user = (void *)ifr->ifr_data;
-		for (count = 0; count < sizeof(arlan_io); count++)
-			if (subyte(user + count, ((char *)&arlan_io)[count]))
-				return (EFAULT);
+		error = copyout(&arlan_io, ifr->ifr_data, sizeof(arlan_io));
 		break;
 
 #define SET_PARAM(name)							\
@@ -620,17 +637,14 @@ arl_ioctl(ifp, cmd, data)
 		if (priv_check(td, PRIV_DRIVER))
 			break;
 
-		user = (void *)ifr->ifr_data;
-		for (count = 0; count < sizeof(arlan_io); count++) {
-			if (fubyte(user + count) < 0)
-				return (EFAULT);
-		}
-
-		bcopy(user, (char *)&arlan_io, sizeof(arlan_io));
+		error = copyin(ifr->ifr_data, &arlan_io, sizeof(arlan_io));
+		if (error)
+			break;
 
 		D(("need set 0x%04x\n", arlan_io.what_set));
 
 		if (arlan_io.what_set) {
+			ARL_LOCK(sc);
 			SET_COPY_PARAM(name);
 			SET_COPY_PARAM(sid);
 			SET_COPY_PARAM(specifiedRouter);
@@ -644,6 +658,7 @@ arl_ioctl(ifp, cmd, data)
 			SET_PARAM(txRetry);
 
 			arl_config(sc);
+			ARL_UNLOCK(sc);
 		}
 #undef SET_COPY_PARAM
 #undef SET_PARAM
@@ -652,34 +667,35 @@ arl_ioctl(ifp, cmd, data)
 		break;
 #ifdef ARLCACHE
 	case SIOCGARLQLT:
-		user = (void *)ifr->ifr_data;
-		for (count = 0; count < sizeof(sc->arl_sigcache); count++) {
-			if (fubyte(user + count) < 0)
-				return (EFAULT);
-		}
+		arl_cache = malloc(sizeof(sc->arl_sigcache), M_DEVBUF,
+		    M_WAITOK);
+		ARL_LOCK(sc);
 		while (ar->interruptInProgress) ; /* wait */
-		bcopy(&(sc->arl_sigcache), (void *)ifr->ifr_data, sizeof(sc->arl_sigcache));
+		bcopy(&(sc->arl_sigcache), arl_cache, sizeof(sc->arl_sigcache));
+		ARL_UNLOCK(sc);
+		error = copyout(arl_cache, ifr->ifr_data,
+		    sizeof(sc->arl_sigcache));
+		free(arl_cache, M_DEVBUF);
 		break;
 #endif
 	case SIOCGARLSTB:
-		user = (void *)ifr->ifr_data;
-		for (count = 0; count < sizeof(struct arl_stats); count++) {
-			if (fubyte(user + count) < 0)
-				return (EFAULT);
-		}
-
+		arl_stats = malloc(sizeof(struct arl_stats), M_DEVBUF,
+		    M_WAITOK);
+		ARL_LOCK(sc);
 		while (ar->lancpuLock) ;
 		ar->hostcpuLock = 1;
-		bcopy(&(ar->stat), (void *)ifr->ifr_data, sizeof(struct arl_stats));
+		bcopy(&(ar->stat), arl_stats, sizeof(struct arl_stats));
 		ar->hostcpuLock  = 0;
+		ARL_UNLOCK(sc);
+		error = copyout(arl_stats, ifr->ifr_data,
+		    sizeof(struct arl_stats));
+		free(arl_stats, M_DEVBUF);
 		break;
 
 	default:
 		error = EINVAL;
 	}
 
-	splx(s);
-
 	return (error);
 }
 
@@ -687,24 +703,22 @@ arl_ioctl(ifp, cmd, data)
  * Wait registration
  */
 static void
-arl_waitreg(ifp)
-	struct ifnet		*ifp;
+arl_waitreg(void *arg)
 {
-	struct arl_softc	*sc = ifp->if_softc;
+	struct arl_softc	*sc = arg;
 
 	D(("wait reg\n"));
 
-	if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
+	ARL_LOCK_ASSERT(sc);
+	if (sc->arl_ifp->if_drv_flags & IFF_DRV_RUNNING) {
 		if (ARL_CHECKREG(sc)) {
 			/* wait registration */
 			D(("wait registration\n"));
-			ifp->if_watchdog = arl_waitreg;
-			ifp->if_timer = 2;
+			callout_reset(&sc->arl_timer, hz * 2, arl_waitreg, sc);
 		} else {
 			/* registration restored */
 			D(("registration restored\n"));
-			ifp->if_timer = 0;
-			arl_init(sc);
+			arl_init_locked(sc);
 		}
 	}
 }
@@ -713,12 +727,12 @@ arl_waitreg(ifp)
  * Handle transmit timeouts.
  */
 static void
-arl_watchdog(ifp)
-	struct ifnet		*ifp;
+arl_watchdog(void *arg)
 {
-	struct arl_softc        *sc = ifp->if_softc;
+	struct arl_softc        *sc = arg;
 
-	if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
+	ARL_LOCK_ASSERT(sc);
+	if (!(sc->arl_ifp->if_drv_flags & IFF_DRV_RUNNING))
 		return;
 
 	D(("device timeout\n"));
@@ -726,8 +740,7 @@ arl_watchdog(ifp)
 	if (ARL_CHECKREG(sc)) {
 		/* Lost registratoin */
 		D(("timeout lost registration\n"));
-		ifp->if_watchdog = arl_waitreg;
-		ifp->if_timer = 2;
+		callout_reset(&sc->arl_timer, hz * 2, arl_waitreg, sc);
 	}
 }
 
@@ -739,13 +752,19 @@ arl_init(xsc)
 	void *xsc;
 {
 	struct arl_softc *sc = xsc;
+
+	ARL_LOCK(sc);
+	arl_init_locked(sc);
+	ARL_UNLOCK(sc);
+}
+
+static void
+arl_init_locked(struct arl_softc *sc)
+{
 	struct ifnet *ifp = sc->arl_ifp;
-	int s;
 
 	D(("init\n"));
 
-	s = splimp();
-
 	if (ARL_CHECKREG(sc))
 		arl_reset(sc);
 
@@ -756,9 +775,8 @@ arl_init(xsc)
 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
 
-	arl_start(ifp);
+	arl_start_locked(ifp);
 
-	splx(s);
 	D(("init done\n"));
 }
 
@@ -818,6 +836,18 @@ arl_start(ifp)
 	struct ifnet		*ifp;
 {
 	struct arl_softc	*sc;
+
+	sc = ifp->if_softc;
+	ARL_LOCK(sc);
+	arl_start_locked(ifp);
+	ARL_UNLOCK(sc);
+}
+
+static void
+arl_start_locked(ifp)
+	struct ifnet		*ifp;
+{
+	struct arl_softc	*sc;
 	struct mbuf		*m;
 	struct mbuf		*m0 = NULL;
 
@@ -859,10 +889,10 @@ arl_start(ifp)
 		m_freem(m0);
 
 		/* Now transmit the datagram */
-		ifp->if_timer = 1;        /* wait 1 sec */
-
-		ifp->if_watchdog = arl_watchdog;
 		arl_put(sc);
+
+		/* wait 1 sec */
+		callout_reset(&sc->arl_timer, hz * 1, arl_watchdog, sc);
 	}
 }
 
@@ -874,21 +904,16 @@ arl_stop(sc)
 	struct arl_softc *sc;
 {
 	struct ifnet	*ifp;
-	int		s;
-
-	s = splimp();
 
 	ifp = sc->arl_ifp;
 
-	ifp->if_timer = 0;        /* disable timer */
+	callout_stop(&sc->arl_timer);        /* disable timer */
 	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING|IFF_DRV_OACTIVE);
 	/*  arl_hwreset(unit);  */
 	sc->rx_len = 0;
 	sc->tx_len = 0;
 	/* disable interrupt */
 	ar->controlRegister = 0;
-
-	splx(s);
 }
 
 /*
@@ -998,10 +1023,6 @@ arl_read(sc, buf, len)
 	/*
 	 * Pull packet off interface.
 	 */
-#if __FreeBSD_version < 500100
-	buf += sizeof(struct ether_header);
-	len -= sizeof(struct ether_header);
-#endif
 	m = arl_get(buf, len, 0, ifp);
 	if (m == 0)
 		return;
@@ -1011,11 +1032,9 @@ arl_read(sc, buf, len)
 			(ar->rxQuality & 0xf0) >> 4, ARLCACHE_RX);
 #endif
 
-#if __FreeBSD_version < 500100
-	ether_input(ifp, eh, m);
-#else
+	ARL_UNLOCK(sc);
 	(*ifp->if_input)(ifp, m);
-#endif
+	ARL_LOCK(sc);
 }
 
 /*
@@ -1056,6 +1075,7 @@ arl_intr(arg)
 	register struct arl_softc *sc = (struct arl_softc *) arg;
 	struct ifnet *ifp = sc->arl_ifp;
 
+	ARL_LOCK(sc);
 	/* enable interrupt */
 	ar->controlRegister = (sc->arl_control & ~ARL_CLEAR_INTERRUPT);
 	ar->controlRegister = (sc->arl_control | ARL_CLEAR_INTERRUPT);
@@ -1063,9 +1083,9 @@ arl_intr(arg)
 	if (ar->txStatusVector) {
 		if (ar->txStatusVector != 1)
 			sc->arl_ifp->if_collisions++;
-		ifp->if_timer = 0;     /* disable timer */
+		callout_stop(&sc->arl_timer);     /* disable timer */
 		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
-		arl_start(ifp);
+		arl_start_locked(ifp);
 		ar->txStatusVector = 0;
 #ifdef ARLCACHE
 		arl_cache_store(sc,
@@ -1089,6 +1109,7 @@ arl_intr(arg)
 		if (arl_command(sc))
 			ifp->if_ierrors++;
 	}
+	ARL_UNLOCK(sc);
 
 	return;
 }
@@ -1113,7 +1134,7 @@ arl_wait_reset(sc, cnt, delay)
 	D(("reset done. %d cycles left\n", cnt));
 
 	if (cnt == 0)
-		printf("arl%d: reset failed\n", sc->arl_unit);
+		if_printf(sc->arl_ifp, "reset failed\n");
 
 	return (cnt == 0);
 }
@@ -1235,6 +1256,7 @@ arl_media_change(ifp)
 	int orate = arcfg.spreadingCode;
 	int nrate, i;
 
+	ARL_LOCK(sc);
 	nrate = IFM_SUBTYPE(sc->arl_ifmedia.ifm_cur->ifm_media);
 
 	for(i = 1; i <= 4; i++) {
@@ -1242,8 +1264,10 @@ arl_media_change(ifp)
 			break;
 	}
 
-	if (i == 5)
+	if (i == 5) {
+		ARL_UNLOCK(sc);
 		return (EINVAL);
+	}
 
 	arcfg.spreadingCode = i;
 
@@ -1256,6 +1280,7 @@ arl_media_change(ifp)
 	if (otype != arcfg.registrationMode ||
 	    orate != arcfg.spreadingCode)
 		arl_config(sc);
+	ARL_UNLOCK(sc);
 
 	return (0);
 }
@@ -1269,6 +1294,7 @@ arl_media_status(ifp, imr)
 
 	imr->ifm_active = IFM_IEEE80211;
 
+	ARL_LOCK(sc);
 	if (arcfg.registrationMode == 0)
 		imr->ifm_active |= IFM_IEEE80211_ADHOC;
 
@@ -1277,4 +1303,5 @@ arl_media_status(ifp, imr)
 	imr->ifm_status = IFM_AVALID;
 	if (!ARL_CHECKREG(sc))
 		imr->ifm_status |= IFM_ACTIVE;
+	ARL_UNLOCK(sc);
 }
diff --git a/sys/dev/arl/if_arl_isa.c b/sys/dev/arl/if_arl_isa.c
index 11cbf5f..91b6e41 100644
--- a/sys/dev/arl/if_arl_isa.c
+++ b/sys/dev/arl/if_arl_isa.c
@@ -214,13 +214,10 @@ arl_isa_probe (device_t dev)
 	if (isa_get_vendorid(dev))
 		return (ENXIO);
 
+	sc->arl_dev = dev;
 	if (bootverbose)
 		device_printf(dev, "in probe\n");
 
-	bzero(sc, sizeof(struct arl_softc));
-
-	sc->arl_unit = device_get_unit(dev);
-
 	error = arl_alloc_memory(dev, 0, ARL_BASE_STEP);
 	if (error) {
 		if (bootverbose)
@@ -294,25 +291,14 @@ static int
 arl_isa_attach (device_t dev)
 {
 	struct arl_softc *sc = device_get_softc(dev);
-	int error;
 
+	sc->arl_dev = dev;
 	if (bootverbose)
 		device_printf(dev, "in attach\n");
 
 	arl_alloc_memory(dev, sc->mem_rid, ARL_BASE_STEP);
 	arl_alloc_irq(dev, sc->irq_rid, 0);
 
-	error = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_NET,
-			       NULL, arl_intr, sc, &sc->irq_handle);
-	if (error) {
-		arl_release_resources(dev);
-		return (error);
-	}
-
-#if __FreeBSD_version < 502108
-	device_printf(dev, "Ethernet address %6D\n", IFP2ENADDR(sc->arl_ifp), ":");
-#endif
-
 	return arl_attach(dev);
 }
 
@@ -321,16 +307,16 @@ arl_isa_detach(device_t dev)
 {
 	struct arl_softc *sc = device_get_softc(dev);
 
+	ARL_LOCK(sc);
 	arl_stop(sc);
+	ARL_UNLOCK(sc);
+	callout_drain(&sc->arl_timer);
+	ether_ifdetach(sc->arl_ifp);
 	ifmedia_removeall(&sc->arl_ifmedia);
 	bus_teardown_intr(dev, sc->irq_res, sc->irq_handle);
-#if __FreeBSD_version < 500100
-	ether_ifdetach(sc->arl_ifp, ETHER_BPF_SUPPORTED);
-#else
-	ether_ifdetach(sc->arl_ifp);
 	if_free(sc->arl_ifp);
-#endif
 	arl_release_resources(dev);
+	mtx_destroy(&sc->arl_lock);
 
 	return (0);
 }
diff --git a/sys/dev/arl/if_arlreg.h b/sys/dev/arl/if_arlreg.h
index 161ee46..34f05a9 100644
--- a/sys/dev/arl/if_arlreg.h
+++ b/sys/dev/arl/if_arlreg.h
@@ -282,8 +282,8 @@ struct arl_sigcache {
 #ifdef _KERNEL
 struct arl_softc {
 	struct ifnet		*arl_ifp;
+	device_t		arl_dev;
 
-	int			arl_unit;
 	struct arl_private *	arl_mem;	/* arlan data */
 
 	struct arl_cfg_param	arl_cfg;	/* arlan vars in our mem */
@@ -304,7 +304,13 @@ struct arl_softc {
 	struct arl_sigcache	arl_sigcache[MAXARLCACHE];
 #endif
 	struct ifmedia		arl_ifmedia;
+	struct callout		arl_timer;
+	struct mtx		arl_lock;
 };
+
+#define	ARL_LOCK(sc)		mtx_lock(&(sc)->arl_lock)
+#define	ARL_UNLOCK(sc)		mtx_unlock(&(sc)->arl_lock)
+#define	ARL_LOCK_ASSERT(sc)	mtx_assert(&(sc)->arl_lock, MA_OWNED)
 #endif
 
 #define	ARLAN_SIGN		"TELESYSTEM"