xen-netback: Disable NAPI after disabling interrupts

Otherwise the interrupt handler still calls napi_complete. Although it
won't schedule NAPI again as either NAPI_STATE_DISABLE or
NAPI_STATE_SCHED is set, it is just unnecessary, and it makes more
sense to do this way.
Signed-off-by: NZoltan Kiss <zoltan.kiss@linaro.org>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/xen-netback/interface.c

@@ -281,10 +281,10 @@ static void xenvif_down(struct xenvif *vif)
 
 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
 		queue = &vif->queues[queue_index];
-		napi_disable(&queue->napi);
 		disable_irq(queue->tx_irq);
 		if (queue->tx_irq != queue->rx_irq)
 			disable_irq(queue->rx_irq);
+		napi_disable(&queue->napi);
 		del_timer_sync(&queue->credit_timeout);
 	}
 }