datapath: Fix race against workqueue in dp_dev and simplify code.

[sliver-openvswitch.git] / datapath / dp_dev.c

diff --git a/datapath/dp_dev.c b/datapath/dp_dev.c
index 34a102a..0284f96 100644 (file)
--- a/datapath/dp_dev.c
+++ b/datapath/dp_dev.c
@@ -56,6 +56,8 @@ static int dp_dev_mac_addr(struct net_device *dev, void *p)
        return 0;
 }
 
+/* Not reentrant (because it is called with BHs disabled), but may be called
+ * simultaneously on different CPUs. */
 static int dp_dev_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
        struct dp_dev *dp_dev = dp_dev_priv(netdev);
@@ -66,10 +68,7 @@ static int dp_dev_xmit(struct sk_buff *skb, struct net_device *netdev)
         * harder to predict when. */
        skb_orphan(skb);
 
-       /* We are going to modify 'skb', by sticking it on &dp_dev->xmit_queue,
-        * so we need to have our own clone.  (At any rate, fwd_port_input()
-        * will need its own clone, so there's no benefit to queuing any other
-        * way.) */
+       /* dp_process_received_packet() needs its own clone. */
        skb = skb_share_check(skb, GFP_ATOMIC);
        if (!skb)
                return 0;
@@ -77,37 +76,14 @@ static int dp_dev_xmit(struct sk_buff *skb, struct net_device *netdev)
        dp_dev->stats.tx_packets++;
        dp_dev->stats.tx_bytes += skb->len;
 
-       if (skb_queue_len(&dp_dev->xmit_queue) >= netdev->tx_queue_len) {
-               /* Queue overflow.  Stop transmitter. */
-               netif_stop_queue(netdev);
-
-               /* We won't see all dropped packets individually, so overrun
-                * error is appropriate. */
-               dp_dev->stats.tx_fifo_errors++;
-       }
-       skb_queue_tail(&dp_dev->xmit_queue, skb);
-       netdev->trans_start = jiffies;
-
-       schedule_work(&dp_dev->xmit_work);
+       skb_reset_mac_header(skb);
+       rcu_read_lock_bh();
+       dp_process_received_packet(skb, dp_dev->dp->ports[dp_dev->port_no]);
+       rcu_read_unlock_bh();
 
        return 0;
 }
 
-static void dp_dev_do_xmit(struct work_struct *work)
-{
-       struct dp_dev *dp_dev = container_of(work, struct dp_dev, xmit_work);
-       struct datapath *dp = dp_dev->dp;
-       struct sk_buff *skb;
-
-       while ((skb = skb_dequeue(&dp_dev->xmit_queue)) != NULL) {
-               skb_reset_mac_header(skb);
-               rcu_read_lock_bh();
-               dp_process_received_packet(skb, dp->ports[dp_dev->port_no]);
-               rcu_read_unlock_bh();
-       }
-       netif_wake_queue(dp_dev->dev);
-}
-
 static int dp_dev_open(struct net_device *netdev)
 {
        netif_start_queue(netdev);
@@ -146,10 +122,12 @@ do_setup(struct net_device *netdev)
        netdev->open = dp_dev_open;
        SET_ETHTOOL_OPS(netdev, &dp_ethtool_ops);
        netdev->stop = dp_dev_stop;
-       netdev->tx_queue_len = 100;
+       netdev->tx_queue_len = 0;
        netdev->set_mac_address = dp_dev_mac_addr;
+       netdev->destructor = free_netdev;
 
        netdev->flags = IFF_BROADCAST | IFF_MULTICAST;
+       netdev->features = NETIF_F_LLTX; /* XXX other features? */
 
        random_ether_addr(netdev->dev_addr);
 
@@ -195,19 +173,12 @@ struct net_device *dp_dev_create(struct datapath *dp, const char *dp_name, int p
        dp_dev->dp = dp;
        dp_dev->port_no = port_no;
        dp_dev->dev = netdev;
-       skb_queue_head_init(&dp_dev->xmit_queue);
-       INIT_WORK(&dp_dev->xmit_work, dp_dev_do_xmit);
        return netdev;
 }
 
 /* Called with RTNL lock and dp_mutex.*/
 void dp_dev_destroy(struct net_device *netdev)
 {
-       struct dp_dev *dp_dev = dp_dev_priv(netdev);
-
-       netif_tx_disable(netdev);
-       synchronize_net();
-       skb_queue_purge(&dp_dev->xmit_queue);
        unregister_netdevice(netdev);
 }