Big polling(4) cleanup.

o Axe poll in trap.

o Axe IFF_POLLING flag from if_flags.

o Rework revision 1.21 (Giant removal), in such a way that
  poll_mtx is not dropped during call to polling handler.
  This fixes problem with idle polling.

o Make registration and deregistration from polling in a
  functional way, insted of next tick/interrupt.

o Obsolete kern.polling.enable. Polling is turned on/off
  with ifconfig.

Detailed kern_poll.c changes:
  - Remove polling handler flags, introduced in 1.21. The are not
    needed now.
  - Forget and do not check if_flags, if_capenable and if_drv_flags.
  - Call all registered polling handlers unconditionally.
  - Do not drop poll_mtx, when entering polling handlers.
  - In ether_poll() NET_LOCK_GIANT prior to locking poll_mtx.
  - In netisr_poll() axe the block, where polling code asks drivers
    to unregister.
  - In netisr_poll() and ether_poll() do polling always, if any
    handlers are present.
  - In ether_poll_[de]register() remove a lot of error hiding code. Assert
    that arguments are correct, instead.
  - In ether_poll_[de]register() use standard return values in case of
    error or success.
  - Introduce poll_switch() that is a sysctl handler for kern.polling.enable.
    poll_switch() goes through interface list and enabled/disables polling.
    A message that kern.polling.enable is deprecated is printed.

Detailed driver changes:
  - On attach driver announces IFCAP_POLLING in if_capabilities, but
    not in if_capenable.
  - On detach driver calls ether_poll_deregister() if polling is enabled.
  - In polling handler driver obtains its lock and checks IFF_DRV_RUNNING
    flag. If there is no, then unlocks and returns.
  - In ioctl handler driver checks for IFCAP_POLLING flag requested to
    be set or cleared. Driver first calls ether_poll_[de]register(), then
    obtains driver lock and [dis/en]ables interrupts.
  - In interrupt handler driver checks IFCAP_POLLING flag in if_capenable.
    If present, then returns.This is important to protect from spurious
    interrupts.

Reviewed by:	ru, sam, jhb

1 files changed, 45 insertions, 44 deletions

diff --git a/sys/dev/sf/if_sf.c b/sys/dev/sf/if_sf.c
index fa7eb83..691a0f6 100644
--- a/sys/dev/sf/if_sf.c
+++ b/sys/dev/sf/if_sf.c
@@ -165,11 +165,9 @@ static int sf_miibus_readreg(device_t, int, int);
 static int sf_miibus_writereg(device_t, int, int, int);
 static void sf_miibus_statchg(device_t);
 #ifdef DEVICE_POLLING
-static void sf_poll(struct ifnet *ifp, enum poll_cmd cmd,
-				 int count);
-static void sf_poll_locked(struct ifnet *ifp, enum poll_cmd cmd,
-				 int count);
-#endif /* DEVICE_POLLING */
+static void sf_poll(struct ifnet *ifp, enum poll_cmd cmd, int count);
+static void sf_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count);
+#endif
 
 static u_int32_t csr_read_4(struct sf_softc *, int);
 static void csr_write_4(struct sf_softc *, int, u_int32_t);
@@ -560,10 +558,31 @@ sf_ioctl(ifp, command, data)
 		error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
 		break;
 	case SIOCSIFCAP:
-		SF_LOCK(sc);
-		ifp->if_capenable &= ~IFCAP_POLLING;
-		ifp->if_capenable |= ifr->ifr_reqcap & IFCAP_POLLING;
-		SF_UNLOCK(sc);
+#ifdef DEVICE_POLLING
+		if (ifr->ifr_reqcap & IFCAP_POLLING &&
+		    !(ifp->if_capenable & IFCAP_POLLING)) {
+			error = ether_poll_register(sf_poll, ifp);
+			if (error)
+				return(error);
+			SF_LOCK(sc);
+			/* Disable interrupts */
+			csr_write_4(sc, SF_IMR, 0x00000000);
+			ifp->if_capenable |= IFCAP_POLLING;
+			SF_UNLOCK(sc);
+			return (error);
+			
+		}
+		if (!(ifr->ifr_reqcap & IFCAP_POLLING) &&
+		    ifp->if_capenable & IFCAP_POLLING) {
+			error = ether_poll_deregister(ifp);
+			/* Enable interrupts. */
+			SF_LOCK(sc);
+			csr_write_4(sc, SF_IMR, SF_INTRS);
+			ifp->if_capenable &= ~IFCAP_POLLING;
+			SF_UNLOCK(sc);
+			return (error);
+		}
+#endif /* DEVICE_POLLING */
 		break;
 	default:
 		error = ether_ioctl(ifp, command, data);
@@ -749,10 +768,10 @@ sf_attach(dev)
 	IFQ_SET_MAXLEN(&ifp->if_snd, SF_TX_DLIST_CNT - 1);
 	ifp->if_snd.ifq_drv_maxlen = SF_TX_DLIST_CNT - 1;
 	IFQ_SET_READY(&ifp->if_snd);
+	ifp->if_capenable = ifp->if_capabilities;
 #ifdef DEVICE_POLLING
 	ifp->if_capabilities |= IFCAP_POLLING;
-#endif /* DEVICE_POLLING */
-	ifp->if_capenable = ifp->if_capabilities;
+#endif
 
 	/*
 	 * Call MI attach routine.
@@ -794,6 +813,11 @@ sf_detach(dev)
 	KASSERT(mtx_initialized(&sc->sf_mtx), ("sf mutex not initialized"));
 	ifp = sc->sf_ifp;
 
+#ifdef DEVICE_POLLING
+	if (ifp->if_capenable & IFCAP_POLLING)
+		ether_poll_deregister(ifp);
+#endif
+	
 	/* These should only be active if attach succeeded */
 	if (device_is_attached(dev)) {
 		SF_LOCK(sc);
@@ -946,12 +970,12 @@ sf_rxeof(sc)
 		struct mbuf		*m0;
 
 #ifdef DEVICE_POLLING
-		if (ifp->if_flags & IFF_POLLING) {
+		if (ifp->if_capenable & IFCAP_POLLING) {
 			if (sc->rxcycles <= 0)
 				break;
 			sc->rxcycles--;
 		}
-#endif /* DEVICE_POLLING */
+#endif
 
 		cur_rx = &sc->sf_ldata->sf_rx_clist[cmpconsidx];
 		desc = &sc->sf_ldata->sf_rx_dlist_big[cur_rx->sf_endidx];
@@ -1068,7 +1092,8 @@ sf_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
 	struct sf_softc *sc = ifp->if_softc;
 
 	SF_LOCK(sc);
-	sf_poll_locked(ifp, cmd, count);
+	if (ifp->if_drv_flags & IFF_DRV_RUNNING)
+		sf_poll_locked(ifp, cmd, count);
 	SF_UNLOCK(sc);
 }
 
@@ -1079,17 +1104,6 @@ sf_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count)
 
 	SF_LOCK_ASSERT(sc);
 
-	if (!(ifp->if_capenable & IFCAP_POLLING)) {
-		ether_poll_deregister(ifp);
-		cmd = POLL_DEREGISTER;
-	}
-
-	if (cmd == POLL_DEREGISTER) {
-		/* Final call, enable interrupts. */
-		csr_write_4(sc, SF_IMR, SF_INTRS);
-		return;
-	}
-
 	sc->rxcycles = count;
 	sf_rxeof(sc);
 	sf_txeof(sc);
@@ -1131,17 +1145,11 @@ sf_intr(arg)
 	ifp = sc->sf_ifp;
 
 #ifdef DEVICE_POLLING
-	if (ifp->if_flags & IFF_POLLING)
-		goto done_locked;
-
-	if ((ifp->if_capenable & IFCAP_POLLING) &&
-	    ether_poll_register(sf_poll, ifp)) {
-		/* OK, disable interrupts. */
-		csr_write_4(sc, SF_IMR, 0x00000000);
-		sf_poll_locked(ifp, 0, 1);
-		goto done_locked;
+	if (ifp->if_capenable & IFCAP_POLLING) {
+		SF_UNLOCK(sc);
+		return;
 	}
-#endif /* DEVICE_POLLING */
+#endif
 
 	if (!(csr_read_4(sc, SF_ISR_SHADOW) & SF_ISR_PCIINT_ASSERTED)) {
 		SF_UNLOCK(sc);
@@ -1185,9 +1193,6 @@ sf_intr(arg)
 	if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
 		sf_start_locked(ifp);
 
-#ifdef DEVICE_POLLING
-done_locked:
-#endif /* DEVICE_POLLING */
 	SF_UNLOCK(sc);
 }
 
@@ -1296,10 +1301,10 @@ sf_init_locked(sc)
 
 #ifdef DEVICE_POLLING
 	/* Disable interrupts if we are polling. */
-	if (ifp->if_flags & IFF_POLLING)
+	if (ifp->if_capenable & IFCAP_POLLING)
 		csr_write_4(sc, SF_IMR, 0x00000000);
 	else
-#endif /* DEVICE_POLLING */
+#endif
 
 	/* Enable interrupts. */
 	csr_write_4(sc, SF_IMR, SF_INTRS);
@@ -1478,10 +1483,6 @@ sf_stop(sc)
 
 	callout_stop(&sc->sf_stat_callout);
 
-#ifdef DEVICE_POLLING
-	ether_poll_deregister(ifp);
-#endif /* DEVICE_POLLING */
-	
 	csr_write_4(sc, SF_GEN_ETH_CTL, 0);
 	csr_write_4(sc, SF_CQ_CONSIDX, 0);
 	csr_write_4(sc, SF_CQ_PRODIDX, 0);