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, 41 deletions

diff --git a/sys/pci/if_xl.c b/sys/pci/if_xl.c
index 520f668..e49997a 100644
--- a/sys/pci/if_xl.c
+++ b/sys/pci/if_xl.c
@@ -249,7 +249,7 @@ static int xl_resume(device_t);
 #ifdef DEVICE_POLLING
 static void xl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count);
 static void xl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count);
-#endif /* DEVICE_POLLING */
+#endif
 
 static int xl_ifmedia_upd(struct ifnet *);
 static void xl_ifmedia_sts(struct ifnet *, struct ifmediareq *);
@@ -1487,9 +1487,10 @@ xl_attach(device_t dev)
 		ifp->if_capabilities |= IFCAP_HWCSUM;
 #endif
 	}
+	ifp->if_capenable = ifp->if_capabilities;
 #ifdef DEVICE_POLLING
 	ifp->if_capabilities |= IFCAP_POLLING;
-#endif /* DEVICE_POLLING */
+#endif
 	ifp->if_start = xl_start;
 	ifp->if_watchdog = xl_watchdog;
 	ifp->if_init = xl_init;
@@ -1497,7 +1498,6 @@ xl_attach(device_t dev)
 	IFQ_SET_MAXLEN(&ifp->if_snd, XL_TX_LIST_CNT - 1);
 	ifp->if_snd.ifq_drv_maxlen = XL_TX_LIST_CNT - 1;
 	IFQ_SET_READY(&ifp->if_snd);
-	ifp->if_capenable = ifp->if_capabilities;
 
 	/*
 	 * Now we have to see what sort of media we have.
@@ -1690,6 +1690,11 @@ xl_detach(device_t dev)
 
 	KASSERT(mtx_initialized(&sc->xl_mtx), ("xl mutex not initialized"));
 
+#ifdef DEVICE_POLLING
+	if (ifp->if_capenable & IFCAP_POLLING)
+		ether_poll_deregister(ifp);
+#endif
+
 	if (sc->xl_flags & XL_FLAG_USE_MMIO) {
 		rid = XL_PCI_LOMEM;
 		res = SYS_RES_MEMORY;
@@ -1960,12 +1965,12 @@ again:
 	    BUS_DMASYNC_POSTREAD);
 	while ((rxstat = le32toh(sc->xl_cdata.xl_rx_head->xl_ptr->xl_status))) {
 #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->xl_cdata.xl_rx_head;
 		sc->xl_cdata.xl_rx_head = cur_rx->xl_next;
 		total_len = rxstat & XL_RXSTAT_LENMASK;
@@ -2275,24 +2280,11 @@ xl_intr(void *arg)
 	XL_LOCK(sc);
 
 #ifdef DEVICE_POLLING
-	if (ifp->if_flags & IFF_POLLING) {
+	if (ifp->if_capenable & IFCAP_POLLING) {
 		XL_UNLOCK(sc);
 		return;
 	}
-
-	if ((ifp->if_capenable & IFCAP_POLLING) &&
-	    ether_poll_register(xl_poll, ifp)) {
-		/* Disable interrupts. */
-		CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
-		CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK|0xFF);
-		if (sc->xl_flags & XL_FLAG_FUNCREG)
-			bus_space_write_4(sc->xl_ftag, sc->xl_fhandle,
-			    4, 0x8000);
-		xl_poll_locked(ifp, 0, 1);
-		XL_UNLOCK(sc);
-		return;
-	}
-#endif /* DEVICE_POLLING */
+#endif
 
 	while ((status = CSR_READ_2(sc, XL_STATUS)) & XL_INTRS &&
 	    status != 0xFFFF) {
@@ -2351,7 +2343,8 @@ xl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
 	struct xl_softc *sc = ifp->if_softc;
 
 	XL_LOCK(sc);
-	xl_poll_locked(ifp, cmd, count);
+	if (ifp->if_drv_flags & IFF_DRV_RUNNING)
+		xl_poll_locked(ifp, cmd, count);
 	XL_UNLOCK(sc);
 }
 
@@ -2362,21 +2355,6 @@ xl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count)
 
 	XL_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_2(sc, XL_COMMAND, XL_CMD_INTR_ACK|0xFF);
-		CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|XL_INTRS);
-		if (sc->xl_flags & XL_FLAG_FUNCREG)
-			bus_space_write_4(sc->xl_ftag, sc->xl_fhandle,
-			    4, 0x8000);
-		return;
-	}
-
 	sc->rxcycles = count;
 	xl_rxeof(sc);
 	if (sc->xl_type == XL_TYPE_905B)
@@ -2989,10 +2967,10 @@ xl_init_locked(struct xl_softc *sc)
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STAT_ENB|XL_INTRS);
 #ifdef DEVICE_POLLING
 	/* Disable interrupts if we are polling. */
-	if (ifp->if_flags & IFF_POLLING)
+	if (ifp->if_capenable & IFCAP_POLLING)
 		CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
 	else
-#endif /* DEVICE_POLLING */
+#endif
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|XL_INTRS);
 	if (sc->xl_flags & XL_FLAG_FUNCREG)
 	    bus_space_write_4(sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);
@@ -3204,6 +3182,35 @@ xl_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
 			    &mii->mii_media, command);
 		break;
 	case SIOCSIFCAP:
+#ifdef DEVICE_POLLING
+		if (ifr->ifr_reqcap & IFCAP_POLLING &&
+		    !(ifp->if_capenable & IFCAP_POLLING)) {
+			error = ether_poll_register(xl_poll, ifp);
+			if (error)
+				return(error);
+			XL_LOCK(sc);
+			/* Disable interrupts */
+			CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
+			ifp->if_capenable |= IFCAP_POLLING;
+			XL_UNLOCK(sc);
+			return (error);
+			
+		}
+		if (!(ifr->ifr_reqcap & IFCAP_POLLING) &&
+		    ifp->if_capenable & IFCAP_POLLING) {
+			error = ether_poll_deregister(ifp);
+			/* Enable interrupts. */
+			XL_LOCK(sc);
+			CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK|0xFF);
+			CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|XL_INTRS);
+			if (sc->xl_flags & XL_FLAG_FUNCREG)
+				bus_space_write_4(sc->xl_ftag, sc->xl_fhandle,
+				    4, 0x8000);
+			ifp->if_capenable &= ~IFCAP_POLLING;
+			XL_UNLOCK(sc);
+			return (error);
+		}
+#endif /* DEVICE_POLLING */
 		XL_LOCK(sc);
 		ifp->if_capenable = ifr->ifr_reqcap;
 		if (ifp->if_capenable & IFCAP_TXCSUM)
@@ -3268,9 +3275,6 @@ xl_stop(struct xl_softc *sc)
 	XL_LOCK_ASSERT(sc);
 
 	ifp->if_timer = 0;
-#ifdef DEVICE_POLLING
-	ether_poll_deregister(ifp);
-#endif /* DEVICE_POLLING */
 
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_DISABLE);
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STATS_DISABLE);