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, 40 insertions, 36 deletions

diff --git a/sys/pci/if_rl.c b/sys/pci/if_rl.c
index c0e42e9..a35e999 100644
--- a/sys/pci/if_rl.c
+++ b/sys/pci/if_rl.c
@@ -195,10 +195,8 @@ static int rl_miibus_readreg(device_t, int, int);
 static void rl_miibus_statchg(device_t);
 static int rl_miibus_writereg(device_t, int, int, int);
 #ifdef DEVICE_POLLING
-static void rl_poll(struct ifnet *ifp, enum poll_cmd cmd,
-				 int count);
-static void rl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd,
-				 int count);
+static void rl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count);
+static void rl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count);
 #endif
 static int rl_probe(device_t);
 static void rl_read_eeprom(struct rl_softc *, uint8_t *, int, int, int);
@@ -956,10 +954,10 @@ rl_attach(device_t dev)
 	ifp->if_init = rl_init;
 	ifp->if_baudrate = 10000000;
 	ifp->if_capabilities = IFCAP_VLAN_MTU;
+	ifp->if_capenable = ifp->if_capabilities;
 #ifdef DEVICE_POLLING
 	ifp->if_capabilities |= IFCAP_POLLING;
 #endif
-	ifp->if_capenable = ifp->if_capabilities;
 	IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN);
 	ifp->if_snd.ifq_drv_maxlen = IFQ_MAXLEN;
 	IFQ_SET_READY(&ifp->if_snd);
@@ -1002,6 +1000,10 @@ rl_detach(device_t dev)
 
 	KASSERT(mtx_initialized(&sc->rl_mtx), ("rl mutex not initialized"));
 
+#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)) {
 		RL_LOCK(sc);
@@ -1115,12 +1117,12 @@ rl_rxeof(struct rl_softc *sc)
 
 	while((CSR_READ_1(sc, RL_COMMAND) & RL_CMD_EMPTY_RXBUF) == 0) {
 #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
 		rxbufpos = sc->rl_cdata.rl_rx_buf + cur_rx;
 		rxstat = le32toh(*(uint32_t *)rxbufpos);
 
@@ -1283,7 +1285,8 @@ rl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
 	struct rl_softc *sc = ifp->if_softc;
 
 	RL_LOCK(sc);
-	rl_poll_locked(ifp, cmd, count);
+	if (ifp->if_drv_flags & IFF_DRV_RUNNING)
+		rl_poll_locked(ifp, cmd, count);
 	RL_UNLOCK(sc);
 }
 
@@ -1294,17 +1297,6 @@ rl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count)
 
 	RL_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, RL_IMR, RL_INTRS);
-		return;
-	}
-
 	sc->rxcycles = count;
 	rl_rxeof(sc);
 	rl_txeof(sc);
@@ -1345,17 +1337,9 @@ rl_intr(void *arg)
 		goto done_locked;
 
 #ifdef DEVICE_POLLING
-	if  (ifp->if_flags & IFF_POLLING)
+	if  (ifp->if_capenable & IFCAP_POLLING)
 		goto done_locked;
-
-	if ((ifp->if_capenable & IFCAP_POLLING) &&
-	    ether_poll_register(rl_poll, ifp)) {
-		/* Disable interrupts. */
-		CSR_WRITE_2(sc, RL_IMR, 0x0000);
-		rl_poll_locked(ifp, 0, 1);
-		goto done_locked;
-	}
-#endif /* DEVICE_POLLING */
+#endif
 
 	for (;;) {
 		status = CSR_READ_2(sc, RL_ISR);
@@ -1574,10 +1558,10 @@ rl_init_locked(struct rl_softc *sc)
 
 #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, RL_IMR, 0);
 	else
-#endif /* DEVICE_POLLING */
+#endif
 	/* Enable interrupts. */
 	CSR_WRITE_2(sc, RL_IMR, RL_INTRS);
 
@@ -1669,8 +1653,31 @@ rl_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
 		error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
 		break;
 	case SIOCSIFCAP:
-		ifp->if_capenable &= ~IFCAP_POLLING;
-		ifp->if_capenable |= ifr->ifr_reqcap & IFCAP_POLLING;
+#ifdef DEVICE_POLLING
+		if (ifr->ifr_reqcap & IFCAP_POLLING &&
+		    !(ifp->if_capenable & IFCAP_POLLING)) {
+			error = ether_poll_register(rl_poll, ifp);
+			if (error)
+				return(error);
+			RL_LOCK(sc);
+			/* Disable interrupts */
+			CSR_WRITE_2(sc, RL_IMR, 0x0000);
+			ifp->if_capenable |= IFCAP_POLLING;
+			RL_UNLOCK(sc);
+			return (error);
+			
+		}
+		if (!(ifr->ifr_reqcap & IFCAP_POLLING) &&
+		    ifp->if_capenable & IFCAP_POLLING) {
+			error = ether_poll_deregister(ifp);
+			/* Enable interrupts. */
+			RL_LOCK(sc);
+			CSR_WRITE_2(sc, RL_IMR, RL_INTRS);
+			ifp->if_capenable &= ~IFCAP_POLLING;
+			RL_UNLOCK(sc);
+			return (error);
+		}
+#endif /* DEVICE_POLLING */
 		break;
 	default:
 		error = ether_ioctl(ifp, command, data);
@@ -1712,9 +1719,6 @@ rl_stop(struct rl_softc *sc)
 	ifp->if_timer = 0;
 	callout_stop(&sc->rl_stat_callout);
 	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
-#ifdef DEVICE_POLLING
-	ether_poll_deregister(ifp);
-#endif /* DEVICE_POLLING */
 
 	CSR_WRITE_1(sc, RL_COMMAND, 0x00);
 	CSR_WRITE_2(sc, RL_IMR, 0x0000);