[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20090324.154743.200977253.davem@davemloft.net>
Date: Tue, 24 Mar 2009 15:47:43 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: herbert@...dor.apana.org.au
Cc: mingo@...e.hu, r.schwebel@...gutronix.de,
torvalds@...ux-foundation.org, blaschka@...ux.vnet.ibm.com,
tglx@...utronix.de, a.p.zijlstra@...llo.nl,
linux-kernel@...r.kernel.org, kernel@...gutronix.de
Subject: Re: Revert "gro: Fix legacy path napi_complete crash",
From: David Miller <davem@...emloft.net>
Date: Tue, 24 Mar 2009 14:36:22 -0700 (PDT)
> From: Herbert Xu <herbert@...dor.apana.org.au>
> Date: Tue, 24 Mar 2009 23:09:28 +0800
>
> > @@ -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();
>
> I think the problem is that we need to do the GRO flush before the
> list delete and clearing the NAPI_STATE_SCHED bit.
Ok Herbert, I'm even more sure of this because in your original commit
log message you mention:
This simply doesn't work since we need to flush the held
GRO packets first.
We are certainly in a pickle here, actually.
We can't run the GRO flush until we re-enable interrupts. But if we
re-enable interrupts, more packets get queued to the input_pkt_queue
and we end up back where we started.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists