Author: imp
Date: Wed Dec 11 05:32:29 2013
New Revision: 259212
URL: http://svnweb.freebsd.org/changeset/base/259212
Log:
Fix one race and one fence post error. When the TX buffer was
completely full, we'd not complete any of the mbufs due to the fence
post error (this creates a large leak). When this is fixed, we still
leak, but at a much smaller rate due to a race between ateintr and
atestart_locked as well as an asymmetry where atestart_locked is
called from elsewhere. Ensure that we free in-flight packets that
have completed there as well. Also remove needless check for NULL on
mb, checked earlier in the loop and simplify a redundant if.
MFC after: 3 days
Modified:
head/sys/arm/at91/if_ate.c
Modified: head/sys/arm/at91/if_ate.c
==============================================================================
--- head/sys/arm/at91/if_ate.c Wed Dec 11 04:31:40 2013 (r259211)
+++ head/sys/arm/at91/if_ate.c Wed Dec 11 05:32:29 2013 (r259212)
@@ -947,10 +947,8 @@ ate_intr(void *xsc)
} while (!done);
- if (mb != NULL) {
- ifp->if_ipackets++;
- (*ifp->if_input)(ifp, mb);
- }
+ ifp->if_ipackets++;
+ (*ifp->if_input)(ifp, mb);
}
}
@@ -974,16 +972,14 @@ ate_intr(void *xsc)
sc->tx_descs[sc->txtail + 1].status |=
ETHB_TX_USED;
}
- while (sc->txtail != sc->txhead &&
- sc->tx_descs[sc->txtail].status & ETHB_TX_USED ) {
-
+ while ((sc->tx_descs[sc->txtail].status & ETHB_TX_USED) &&
+ sc->sent_mbuf[sc->txtail] != NULL) {
bus_dmamap_sync(sc->mtag, sc->tx_map[sc->txtail],
BUS_DMASYNC_POSTWRITE);
bus_dmamap_unload(sc->mtag, sc->tx_map[sc->txtail]);
m_freem(sc->sent_mbuf[sc->txtail]);
sc->tx_descs[sc->txtail].addr = 0;
sc->sent_mbuf[sc->txtail] = NULL;
-
ifp->if_opackets++;
sc->txtail = NEXT_TX_IDX(sc, sc->txtail);
}
@@ -1118,12 +1114,10 @@ atestart_locked(struct ifnet *ifp)
* xmit packets. We use OACTIVE to indicate "we can stuff more
* into our buffers (clear) or not (set)."
*/
- if (!sc->is_emacb) {
- /* RM9200 has only two hardware entries */
- if (!sc->is_emacb && (RD4(sc, ETH_TSR) & ETH_TSR_BNQ)
== 0) {
- ifp->if_drv_flags |= IFF_DRV_OACTIVE;
- return;
- }
+ /* RM9200 has only two hardware entries */
+ if (!sc->is_emacb && (RD4(sc, ETH_TSR) & ETH_TSR_BNQ) == 0) {
+ ifp->if_drv_flags |= IFF_DRV_OACTIVE;
+ return;
}
IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
@@ -1146,6 +1140,21 @@ atestart_locked(struct ifnet *ifp)
m_freem(m);
continue;
}
+
+ /*
+ * There's a small race between the loop in ate_intr finishing
+ * and the check above to see if the packet was finished, as
well
+ * as when atestart gets called via other paths. Loose the race
+ * gracefully and free the mbuf...
+ */
+ if (sc->sent_mbuf[sc->txhead] != NULL) {
+ bus_dmamap_sync(sc->mtag, sc->tx_map[sc->txtail],
+ BUS_DMASYNC_POSTWRITE);
+ bus_dmamap_unload(sc->mtag, sc->tx_map[sc->txtail]);
+ m_free(sc->sent_mbuf[sc->txhead]);
+ ifp->if_opackets++;
+ }
+
sc->sent_mbuf[sc->txhead] = m;
bus_dmamap_sync(sc->mtag, sc->tx_map[sc->txhead],
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