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Fix one race and one fence post error. When the TX buffer was

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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
This commit is contained in:
Warner Losh 2013-12-11 05:32:29 +00:00
parent e53c69c1f5
commit 19dab280cc
1 changed files with 23 additions and 14 deletions
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37
sys/arm/at91/if_ate.c
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@ -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],