Merge git://git.linux-nfs.org/pub/linux/nfs-2.6

[linux-2.6-omap-h63xx.git] / net / sched / sch_generic.c

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 95ae11956f35ebb931fc4bf20039df2c8ba1caf8..fa1a6f45dc416173f8b6d853f9ce0c5fa3565bc7 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -249,10 +249,11 @@ static void dev_watchdog_down(struct net_device *dev)
  */
 void netif_carrier_on(struct net_device *dev)
 {
-       if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state))
+       if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
                linkwatch_fire_event(dev);
-       if (netif_running(dev))
-               __netdev_watchdog_up(dev);
+               if (netif_running(dev))
+                       __netdev_watchdog_up(dev);
+       }
 }
 
 /**
@@ -555,6 +556,7 @@ void dev_deactivate(struct net_device *dev)
 {
        struct Qdisc *qdisc;
        struct sk_buff *skb;
+       int running;
 
        spin_lock_bh(&dev->queue_lock);
        qdisc = dev->qdisc;
@@ -570,12 +572,31 @@ void dev_deactivate(struct net_device *dev)
 
        dev_watchdog_down(dev);
 
-       /* Wait for outstanding dev_queue_xmit calls. */
+       /* Wait for outstanding qdisc-less dev_queue_xmit calls. */
        synchronize_rcu();
 
        /* Wait for outstanding qdisc_run calls. */
-       while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
-               yield();
+       do {
+               while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
+                       yield();
+
+               /*
+                * Double-check inside queue lock to ensure that all effects
+                * of the queue run are visible when we return.
+                */
+               spin_lock_bh(&dev->queue_lock);
+               running = test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state);
+               spin_unlock_bh(&dev->queue_lock);
+
+               /*
+                * The running flag should never be set at this point because
+                * we've already set dev->qdisc to noop_qdisc *inside* the same
+                * pair of spin locks.  That is, if any qdisc_run starts after
+                * our initial test it should see the noop_qdisc and then
+                * clear the RUNNING bit before dropping the queue lock.  So
+                * if it is set here then we've found a bug.
+                */
+       } while (WARN_ON_ONCE(running));
 }
 
 void dev_init_scheduler(struct net_device *dev)