Messages in this thread | | | Date | Thu, 26 Mar 2009 07:39:09 +0000 | From | Jarek Poplawski <> | Subject | Re: Revert "gro: Fix legacy path napi_complete crash", |
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On Thu, Mar 26, 2009 at 10:41:29AM +0800, Herbert Xu wrote: ... > Yes this is why my original patch that started all this is broken. > However, this doesn't apply to my patch that open-codes __napi_complete. ... > This should work too. However, the fact that the following patch > is broken means that we have bigger problems.
I agree. This should be effectively equal to the revert, so I guess Ingo probably hit some other bug btw.
Jarek P.
> > net: Fix netpoll lockup in legacy receive path > > When I fixed the GRO crash in the legacy receive path I used > napi_complete to replace __napi_complete. Unfortunately they're > not the same when NETPOLL is enabled, which may result in us > not calling __napi_complete at all. > > What's more, we really do need to keep the __napi_complete call > within the IRQ-off section since in theory an IRQ can occur in > between and fill up the backlog to the maximum, causing us to > lock up. > > This patch fixes this by essentially open-coding __napi_complete. > > Note we no longer need the memory barrier because this function > is per-cpu. > > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> > > diff --git a/net/core/dev.c b/net/core/dev.c > index e3fe5c7..2a7f6b3 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -2588,9 +2588,10 @@ static int process_backlog(struct napi_struct *napi, int quota) > local_irq_disable(); > skb = __skb_dequeue(&queue->input_pkt_queue); > if (!skb) { > + list_del(&napi->poll_list); > + clear_bit(NAPI_STATE_SCHED, &napi->state); > local_irq_enable(); > - napi_complete(napi); > - goto out; > + break; > } > local_irq_enable(); > > @@ -2599,7 +2600,6 @@ static int process_backlog(struct napi_struct *napi, int quota) > > napi_gro_flush(napi); > > -out: > return work; > } > > Thanks, > -- > Visit Openswan at http://www.openswan.org/ > Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> > Home Page: http://gondor.apana.org.au/~herbert/ > PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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