GRO: Disable GRO on legacy netif_rx path

[ Upstream commit 8f1ead2d ]

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.

Since we can't seem to find a fix that works properly right now,
this patch reverts all the GRO support from the netif_rx path.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

net/core/dev.c

@@ -2588,18 +2588,15 @@ static int process_backlog(struct napi_struct *napi, int quota)
 		local_irq_disable();
 		skb = __skb_dequeue(&queue->input_pkt_queue);
 		if (!skb) {
+			__napi_complete(napi);
 			local_irq_enable();
-			napi_complete(napi);
-			goto out;
+			break;
 		}
 		local_irq_enable();
 
-		napi_gro_receive(napi, skb);
+		netif_receive_skb(skb);
 	} while (++work < quota && jiffies == start_time);
 
-	napi_gro_flush(napi);
-
-out:
 	return work;
 }