gro: Flush GRO packets in napi_disable_pending path

When NAPI is disabled while we're in net_rx_action, we end up
calling __napi_complete without flushing GRO packets.  This is
a bug as it would cause the GRO packets to linger, of course it
also literally BUGs to catch error like this :)

This patch changes it to napi_complete, with the obligatory IRQ
reenabling.  This should be safe because we've only just disabled
IRQs and it does not materially affect the test conditions in
between.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2823,9 +2823,11 @@ static void net_rx_action(struct softirq_action *h)
 		 * move the instance around on the list at-will.
 		 */
 		if (unlikely(work == weight)) {
-			if (unlikely(napi_disable_pending(n)))
-				__napi_complete(n);
-			else
+			if (unlikely(napi_disable_pending(n))) {
+				local_irq_enable();
+				napi_complete(n);
+				local_irq_disable();
+			} else
 				list_move_tail(&n->poll_list, list);
 		}