xen-netback: immediately wake tx queue when guest rx queue has space

When an skb is removed from the guest rx queue, immediately wake the
tx queue, instead of after processing them.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[re-based]
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>

diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index dd37de4f1ffe314eeffb846c3a6fb2d837845ab2..ea1473fca1182ffb220d96fcc74cc45084492147 100644 (file)
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -91,25 +91,19 @@ static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
        spin_lock_irq(&queue->rx_queue.lock);
 
        skb = __skb_dequeue(&queue->rx_queue);
-       if (skb)
+       if (skb) {
                queue->rx_queue_len -= skb->len;
+               if (queue->rx_queue_len < queue->rx_queue_max) {
+                       struct netdev_queue *txq;
 
-       spin_unlock_irq(&queue->rx_queue.lock);
-
-       return skb;
-}
-
-static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
-{
-       spin_lock_irq(&queue->rx_queue.lock);
-
-       if (queue->rx_queue_len < queue->rx_queue_max) {
-               struct net_device *dev = queue->vif->dev;
-
-               netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
+                       txq = netdev_get_tx_queue(queue->vif->dev, queue->id);
+                       netif_tx_wake_queue(txq);
+               }
        }
 
        spin_unlock_irq(&queue->rx_queue.lock);
+
+       return skb;
 }
 
 static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
@@ -581,8 +575,6 @@ int xenvif_kthread_guest_rx(void *data)
                 */
                xenvif_rx_queue_drop_expired(queue);
 
-               xenvif_rx_queue_maybe_wake(queue);
-
                cond_resched();
        }