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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.

Obtained from:  NetBSD (joerg@)
MFC after:      2 weeks
This commit is contained in:
damien 2005-11-13 17:16:06 +00:00
parent 44b90b5b5f
commit 47b7157310
1 changed files with 40 additions and 20 deletions
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60
sys/dev/iwi/if_iwi.c
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@ -1158,7 +1158,7 @@ iwi_frame_intr(struct iwi_softc *sc, struct iwi_rx_data *data, int i,
{
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;
int error;
@ -1169,10 +1169,48 @@ iwi_frame_intr(struct iwi_softc *sc, struct iwi_rx_data *data, int i,
if (le16toh(frame->len) < sizeof (struct ieee80211_frame))
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_unload(sc->rxq.data_dmat, data->map);
/* finalize mbuf */
error = bus_dmamap_load(sc->rxq.data_dmat, data->map,
mtod(mnew, void *), MCLBYTES, iwi_dma_map_addr, &data->physaddr,
0);
if (error != 0) {
m_freem(mnew);
/* try to reload the old mbuf */
error = bus_dmamap_load(sc->rxq.data_dmat, data->map,
mtod(data->m, void *), MCLBYTES, iwi_dma_map_addr,
&data->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 = data->m;
data->m = mnew;
CSR_WRITE_4(sc, data->reg, data->physaddr);
/* finalize mbuf */
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.len = m->m_len = sizeof (struct iwi_hdr) +
sizeof (struct iwi_frame) + le16toh(frame->len);
@ -1205,24 +1243,6 @@ iwi_frame_intr(struct iwi_softc *sc, struct iwi_rx_data *data, int i,
/* node is no longer needed */
ieee80211_free_node(ni);
data->m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
if (data->m == NULL) {
device_printf(sc->sc_dev, "could not allocate rx mbuf\n");
return;
}
error = bus_dmamap_load(sc->rxq.data_dmat, data->map,
mtod(data->m, void *), MCLBYTES, iwi_dma_map_addr, &data->physaddr,
0);
if (error != 0) {
device_printf(sc->sc_dev, "could not load rx buf DMA map\n");
m_freem(data->m);
data->m = NULL;
return;
}
CSR_WRITE_4(sc, data->reg, data->physaddr);
}
static void