netpoll: drivers must not enable IRQ unconditionally in their NAPI handler

net/core/netpoll.c::netpoll_send_skb() calls the poll handler when
it is available. As netconsole can be used from almost any context,
IRQ must not be enabled blindly in the NAPI handler of a driver which
supports netpoll.

b57bd06655 fixed the issue for the
8139too.c driver.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/8139cp.c

@@ -617,13 +617,15 @@ rx_next:
 	 * this round of polling
 	 */
 	if (rx_work) {
+		unsigned long flags;
+
 		if (cpr16(IntrStatus) & cp_rx_intr_mask)
 			goto rx_status_loop;
 
-		local_irq_disable();
+		local_irq_save(flags);
 		cpw16_f(IntrMask, cp_intr_mask);
 		__netif_rx_complete(dev);
-		local_irq_enable();
+		local_irq_restore(flags);
 
 		return 0;	/* done */
 	}