[NETPOLL]: Make sure TX lock is taken with BH disabled.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -242,10 +242,12 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 
 	/* don't get messages out of order, and no recursion */
 	if (skb_queue_len(&npinfo->txq) == 0 &&
-	    npinfo->poll_owner != smp_processor_id() &&
-	    netif_tx_trylock(dev)) {
+		    npinfo->poll_owner != smp_processor_id()) {
+		local_bh_disable();	/* Where's netif_tx_trylock_bh()? */
+		if (netif_tx_trylock(dev)) {
 			/* try until next clock tick */
-		for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; tries > 0; --tries) {
+			for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
+					tries > 0; --tries) {
 				if (!netif_queue_stopped(dev))
 					status = dev->hard_start_xmit(skb, dev);
 
@@ -259,6 +261,8 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 			}
 			netif_tx_unlock(dev);
 		}
+		local_bh_enable();
+	}
 
 	if (status != NETDEV_TX_OK) {
 		skb_queue_tail(&npinfo->txq, skb);