vserver 1.9.3

[linux-2.6.git] / net / sched / sch_generic.c

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 82117f9..2516dd9 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -97,46 +97,71 @@ int qdisc_restart(struct net_device *dev)
 
        /* Dequeue packet */
        if ((skb = q->dequeue(q)) != NULL) {
-               if (spin_trylock(&dev->xmit_lock)) {
+               unsigned nolock = (dev->features & NETIF_F_LLTX);
+               /*
+                * When the driver has LLTX set it does its own locking
+                * in start_xmit. No need to add additional overhead by
+                * locking again. These checks are worth it because
+                * even uncongested locks can be quite expensive.
+                * The driver can do trylock like here too, in case
+                * of lock congestion it should return -1 and the packet
+                * will be requeued.
+                */
+               if (!nolock) {
+                       if (!spin_trylock(&dev->xmit_lock)) {
+                       collision:
+                               /* So, someone grabbed the driver. */
+                               
+                               /* It may be transient configuration error,
+                                  when hard_start_xmit() recurses. We detect
+                                  it by checking xmit owner and drop the
+                                  packet when deadloop is detected.
+                               */
+                               if (dev->xmit_lock_owner == smp_processor_id()) {
+                                       kfree_skb(skb);
+                                       if (net_ratelimit())
+                                               printk(KERN_DEBUG "Dead loop on netdevice %s, fix it urgently!\n", dev->name);
+                                       return -1;
+                               }
+                               __get_cpu_var(netdev_rx_stat).cpu_collision++;
+                               goto requeue;
+                       }
                        /* Remember that the driver is grabbed by us. */
                        dev->xmit_lock_owner = smp_processor_id();
-
+               }
+               
+               {
                        /* And release queue */
                        spin_unlock(&dev->queue_lock);
 
                        if (!netif_queue_stopped(dev)) {
+                               int ret;
                                if (netdev_nit)
                                        dev_queue_xmit_nit(skb, dev);
 
-                               if (dev->hard_start_xmit(skb, dev) == 0) {
-                                       dev->xmit_lock_owner = -1;
-                                       spin_unlock(&dev->xmit_lock);
-
+                               ret = dev->hard_start_xmit(skb, dev);
+                               if (ret == NETDEV_TX_OK) { 
+                                       if (!nolock) {
+                                               dev->xmit_lock_owner = -1;
+                                               spin_unlock(&dev->xmit_lock);
+                                       }
                                        spin_lock(&dev->queue_lock);
                                        return -1;
                                }
+                               if (ret == NETDEV_TX_LOCKED && nolock) {
+                                       spin_lock(&dev->queue_lock);
+                                       goto collision; 
+                               }
                        }
 
+                       /* NETDEV_TX_BUSY - we need to requeue */
                        /* Release the driver */
-                       dev->xmit_lock_owner = -1;
-                       spin_unlock(&dev->xmit_lock);
+                       if (!nolock) { 
+                               dev->xmit_lock_owner = -1;
+                               spin_unlock(&dev->xmit_lock);
+                       } 
                        spin_lock(&dev->queue_lock);
                        q = dev->qdisc;
-               } else {
-                       /* So, someone grabbed the driver. */
-
-                       /* It may be transient configuration error,
-                          when hard_start_xmit() recurses. We detect
-                          it by checking xmit owner and drop the
-                          packet when deadloop is detected.
-                        */
-                       if (dev->xmit_lock_owner == smp_processor_id()) {
-                               kfree_skb(skb);
-                               if (net_ratelimit())
-                                       printk(KERN_DEBUG "Dead loop on netdevice %s, fix it urgently!\n", dev->name);
-                               return -1;
-                       }
-                       __get_cpu_var(netdev_rx_stat).cpu_collision++;
                }
 
                /* Device kicked us out :(
@@ -149,6 +174,7 @@ int qdisc_restart(struct net_device *dev)
                   3. device is buggy (ppp)
                 */
 
+requeue:
                q->ops->requeue(skb, q);
                netif_schedule(dev);
                return 1;
@@ -415,6 +441,7 @@ struct Qdisc * qdisc_create_dflt(struct net_device *dev, struct Qdisc_ops *ops)
        if (!ops->init || ops->init(sch, NULL) == 0)
                return sch;
 
+       dev_put(dev);
        kfree(p);
        return NULL;
 }