ifb: use the lockless variants of skb_queue

rq and tq are both protected by tx queue lock, so we can simply use
the lockless variants of skb_queue.

skb_queue_splice_tail_init() is used instead of the open coded and slow
one.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ifb.c

@@ -63,9 +63,7 @@ static void ri_tasklet(unsigned long dev)
 	txq = netdev_get_tx_queue(_dev, 0);
 	if ((skb = skb_peek(&dp->tq)) == NULL) {
 		if (__netif_tx_trylock(txq)) {
-			while ((skb = skb_dequeue(&dp->rq)) != NULL) {
-				skb_queue_tail(&dp->tq, skb);
-			}
+			skb_queue_splice_tail_init(&dp->rq, &dp->tq);
 			__netif_tx_unlock(txq);
 		} else {
 			/* reschedule */
@@ -163,7 +161,7 @@ static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 		netif_stop_queue(dev);
 	}
 
-	skb_queue_tail(&dp->rq, skb);
+	__skb_queue_tail(&dp->rq, skb);
 	if (!dp->tasklet_pending) {
 		dp->tasklet_pending = 1;
 		tasklet_schedule(&dp->ifb_tasklet);
@@ -178,8 +176,8 @@ static int ifb_close(struct net_device *dev)
 
 	tasklet_kill(&dp->ifb_tasklet);
 	netif_stop_queue(dev);
-	skb_queue_purge(&dp->rq);
-	skb_queue_purge(&dp->tq);
+	__skb_queue_purge(&dp->rq);
+	__skb_queue_purge(&dp->tq);
 	return 0;
 }
 
@@ -188,8 +186,8 @@ static int ifb_open(struct net_device *dev)
 	struct ifb_private *dp = netdev_priv(dev);
 
 	tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
-	skb_queue_head_init(&dp->rq);
-	skb_queue_head_init(&dp->tq);
+	__skb_queue_head_init(&dp->rq);
+	__skb_queue_head_init(&dp->tq);
 	netif_start_queue(dev);
 
 	return 0;