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Be more robust when handling Rx interrupts. If we can't allocate and DMA map

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a new mbuf, just discard the received frame and reuse the old mbuf.
This should fix kernel panics on high network traffic.

MFC after:      2 weeks
This commit is contained in:
damien 2005-11-13 17:17:40 +00:00
parent 47b7157310
commit 7c8c64ed53
1 changed files with 42 additions and 24 deletions
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66
sys/dev/ipw/if_ipw.c
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@ -1010,21 +1010,61 @@ ipw_data_intr(struct ipw_softc *sc, struct ipw_status *status,
{
struct ieee80211com *ic = &sc->sc_ic;
struct ifnet *ifp = ic->ic_ifp;
struct mbuf *m;
struct mbuf *mnew, *m;
struct ieee80211_frame *wh;
struct ieee80211_node *ni;
bus_addr_t physaddr;
int error;
DPRINTFN(5, ("received frame len=%u, rssi=%u\n", le32toh(status->len),
status->rssi));
if (le32toh(status->len) < sizeof (struct ieee80211_frame_min) ||
le32toh(status->len) > MCLBYTES)
return;
/*
* Try to allocate a new mbuf for this ring element and load it before
* processing the current mbuf. If the ring element cannot be loaded,
* drop the received packet and reuse the old mbuf. In the unlikely
* case that the old mbuf can't be reloaded either, explicitly panic.
*/
mnew = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
if (mnew == NULL) {
ifp->if_ierrors++;
return;
}
bus_dmamap_sync(sc->rxbuf_dmat, sbuf->map, BUS_DMASYNC_POSTREAD);
bus_dmamap_unload(sc->rxbuf_dmat, sbuf->map);
/* finalize mbuf */
error = bus_dmamap_load(sc->rxbuf_dmat, sbuf->map, mtod(mnew, void *),
MCLBYTES, ipw_dma_map_addr, &physaddr, 0);
if (error != 0) {
m_freem(mnew);
/* try to reload the old mbuf */
error = bus_dmamap_load(sc->rxbuf_dmat, sbuf->map,
mtod(sbuf->m, void *), MCLBYTES, ipw_dma_map_addr,
&physaddr, 0);
if (error != 0) {
/* very unlikely that it will fail... */
panic("%s: could not load old rx mbuf",
device_get_name(sc->sc_dev));
}
ifp->if_ierrors++;
return;
}
/*
* New mbuf successfully loaded, update Rx ring and continue
* processing.
*/
m = sbuf->m;
sbuf->m = mnew;
sbd->bd->physaddr = htole32(physaddr);
/* finalize mbuf */
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.len = m->m_len = le32toh(status->len);
@ -1051,28 +1091,6 @@ ipw_data_intr(struct ipw_softc *sc, struct ipw_status *status,
/* node is no longer needed */
ieee80211_free_node(ni);
m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
if (m == NULL) {
device_printf(sc->sc_dev, "could not allocate rx mbuf\n");
sbuf->m = NULL;
return;
}
error = bus_dmamap_load(sc->rxbuf_dmat, sbuf->map, mtod(m, void *),
MCLBYTES, ipw_dma_map_addr, &physaddr, 0);
if (error != 0) {
device_printf(sc->sc_dev, "could not map rx DMA memory\n");
m_freem(m);
sbuf->m = NULL;
return;
}
sbuf->m = m;
sbd->bd->physaddr = htole32(physaddr);
DPRINTFN(5, ("received frame len=%u, rssi=%u\n", le32toh(status->len),
status->rssi));
bus_dmamap_sync(sc->rbd_dmat, sc->rbd_map, BUS_DMASYNC_PREWRITE);
}