Author: marius
Date: Wed Jul 13 18:52:11 2011
New Revision: 223986
URL: http://svn.freebsd.org/changeset/base/223986

Log:
  - Expand the scope of the lock in the interrupt routine to close races with
    checking IFF_DRV_RUNNING and simplify the code. This also involves holding
    the driver lock in the rx_ch callout.
  - Just use ifp instead of sc->sc_ifp.
  
  Submitted by: jhb (mostly)

Modified:
  head/sys/dev/cas/if_cas.c

Modified: head/sys/dev/cas/if_cas.c
==============================================================================
--- head/sys/dev/cas/if_cas.c   Wed Jul 13 18:48:51 2011        (r223985)
+++ head/sys/dev/cas/if_cas.c   Wed Jul 13 18:52:11 2011        (r223986)
@@ -203,7 +203,7 @@ cas_attach(struct cas_softc *sc)
        IFQ_SET_READY(&ifp->if_snd);
 
        callout_init_mtx(&sc->sc_tick_ch, &sc->sc_mtx, 0);
-       callout_init(&sc->sc_rx_ch, 1);
+       callout_init_mtx(&sc->sc_rx_ch, &sc->sc_mtx, 0);
        /* Create local taskq. */
        TASK_INIT(&sc->sc_intr_task, 0, cas_intr_task, sc);
        TASK_INIT(&sc->sc_tx_task, 1, cas_tx_task, ifp);
@@ -1599,7 +1599,7 @@ cas_rint_timeout(void *arg)
 {
        struct cas_softc *sc = arg;
 
-       CAS_LOCK_ASSERT(sc, MA_NOTOWNED);
+       CAS_LOCK_ASSERT(sc, MA_OWNED);
 
        cas_rint(sc);
 }
@@ -1614,7 +1614,7 @@ cas_rint(struct cas_softc *sc)
        uint32_t rxhead;
        u_int idx, idx2, len, off, skip;
 
-       CAS_LOCK_ASSERT(sc, MA_NOTOWNED);
+       CAS_LOCK_ASSERT(sc, MA_OWNED);
 
        callout_stop(&sc->sc_rx_ch);
 
@@ -1742,7 +1742,9 @@ cas_rint(struct cas_softc *sc)
                                        cas_rxcksum(m, CAS_GET(word4,
                                            CAS_RC4_TCP_CSUM));
                                /* Pass it on. */
+                               CAS_UNLOCK(sc);
                                (*ifp->if_input)(ifp, m);
+                               CAS_LOCK(sc);
                        } else
                                ifp->if_iqdrops++;
 
@@ -1838,7 +1840,9 @@ cas_rint(struct cas_softc *sc)
                                        cas_rxcksum(m, CAS_GET(word4,
                                            CAS_RC4_TCP_CSUM));
                                /* Pass it on. */
+                               CAS_UNLOCK(sc);
                                (*ifp->if_input)(ifp, m);
+                               CAS_LOCK(sc);
                        } else
                                ifp->if_iqdrops++;
 
@@ -1876,7 +1880,7 @@ cas_free(void *arg1, void *arg2)
 {
        struct cas_rxdsoft *rxds;
        struct cas_softc *sc;
-       u_int idx;
+       u_int idx, locked;
 
 #if __FreeBSD_version < 800016
        rxds = arg2;
@@ -1894,17 +1898,18 @@ cas_free(void *arg1, void *arg2)
         * NB: this function can be called via m_freem(9) within
         * this driver!
         */
-
+       if ((locked = CAS_LOCK_OWNED(sc)) == 0)
+               CAS_LOCK(sc);
        cas_add_rxdesc(sc, idx);
+       if (locked == 0)
+               CAS_UNLOCK(sc);
 }
 
 static inline void
 cas_add_rxdesc(struct cas_softc *sc, u_int idx)
 {
-       u_int locked;
 
-       if ((locked = CAS_LOCK_OWNED(sc)) == 0)
-               CAS_LOCK(sc);
+       CAS_LOCK_ASSERT(sc, MA_OWNED);
 
        bus_dmamap_sync(sc->sc_rdmatag, sc->sc_rxdsoft[idx].rxds_dmamap,
            BUS_DMASYNC_PREREAD);
@@ -1922,9 +1927,6 @@ cas_add_rxdesc(struct cas_softc *sc, u_i
                CAS_WRITE_4(sc, CAS_RX_KICK,
                    (sc->sc_rxdptr + CAS_NRXDESC - 4) & CAS_NRXDESC_MASK);
        }
-
-       if (locked == 0)
-               CAS_UNLOCK(sc);
 }
 
 static void
@@ -1932,7 +1934,7 @@ cas_eint(struct cas_softc *sc, u_int sta
 {
        struct ifnet *ifp = sc->sc_ifp;
 
-       CAS_LOCK_ASSERT(sc, MA_NOTOWNED);
+       CAS_LOCK_ASSERT(sc, MA_OWNED);
 
        ifp->if_ierrors++;
 
@@ -1949,7 +1951,7 @@ cas_eint(struct cas_softc *sc, u_int sta
        printf("\n");
 
        ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
-       cas_init(sc);
+       cas_init_locked(sc);
        if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
                taskqueue_enqueue(sc->sc_tq, &sc->sc_tx_task);
 }
@@ -1986,6 +1988,7 @@ cas_intr_task(void *arg, int pending __u
        if (__predict_false((status & CAS_INTR_SUMMARY) == 0))
                goto done;
 
+       CAS_LOCK(sc);
 #ifdef CAS_DEBUG
        CTR4(KTR_CAS, "%s: %s: cplt %x, status %x",
            device_get_name(sc->sc_dev), __func__,
@@ -2025,6 +2028,7 @@ cas_intr_task(void *arg, int pending __u
            (CAS_INTR_TX_TAG_ERR | CAS_INTR_RX_TAG_ERR |
            CAS_INTR_RX_LEN_MMATCH | CAS_INTR_PCI_ERROR_INT)) != 0)) {
                cas_eint(sc, status);
+               CAS_UNLOCK(sc);
                return;
        }
 
@@ -2032,7 +2036,7 @@ cas_intr_task(void *arg, int pending __u
                status2 = CAS_READ_4(sc, CAS_MAC_TX_STATUS);
                if ((status2 &
                    (CAS_MAC_TX_UNDERRUN | CAS_MAC_TX_MAX_PKT_ERR)) != 0)
-                       sc->sc_ifp->if_oerrors++;
+                       ifp->if_oerrors++;
                else if ((status2 & ~CAS_MAC_TX_FRAME_XMTD) != 0)
                        device_printf(sc->sc_dev,
                            "MAC TX fault, status %x\n", status2);
@@ -2041,7 +2045,7 @@ cas_intr_task(void *arg, int pending __u
        if (__predict_false(status & CAS_INTR_RX_MAC_INT)) {
                status2 = CAS_READ_4(sc, CAS_MAC_RX_STATUS);
                if ((status2 & CAS_MAC_RX_OVERFLOW) != 0)
-                       sc->sc_ifp->if_ierrors++;
+                       ifp->if_ierrors++;
                else if ((status2 & ~CAS_MAC_RX_FRAME_RCVD) != 0)
                        device_printf(sc->sc_dev,
                            "MAC RX fault, status %x\n", status2);
@@ -2061,16 +2065,15 @@ cas_intr_task(void *arg, int pending __u
        }
 
        if ((status &
-           (CAS_INTR_TX_INT_ME | CAS_INTR_TX_ALL | CAS_INTR_TX_DONE)) != 0) {
-               CAS_LOCK(sc);
+           (CAS_INTR_TX_INT_ME | CAS_INTR_TX_ALL | CAS_INTR_TX_DONE)) != 0)
                cas_tint(sc);
-               CAS_UNLOCK(sc);
-       }
 
-       if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
+       if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
+               CAS_UNLOCK(sc);
                return;
-       else if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
+       } else if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
                taskqueue_enqueue(sc->sc_tq, &sc->sc_tx_task);
+       CAS_UNLOCK(sc);
 
        status = CAS_READ_4(sc, CAS_STATUS_ALIAS);
        if (__predict_false((status & CAS_INTR_SUMMARY) != 0)) {
@@ -2403,7 +2406,7 @@ cas_mii_statchg(device_t dev)
        CAS_WRITE_4(sc, CAS_MAC_XIF_CONF, v);
 
        sc->sc_mac_rxcfg = rxcfg;
-       if ((sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING) != 0 &&
+       if ((ifp->if_drv_flags & IFF_DRV_RUNNING) != 0 &&
            (sc->sc_flags & CAS_LINK) != 0) {
                CAS_WRITE_4(sc, CAS_MAC_TX_CONF,
                    txcfg | CAS_MAC_TX_CONF_EN);
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