diff options
Diffstat (limited to 'net/sched/sch_generic.c')
| -rw-r--r-- | net/sched/sch_generic.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 95ae11956f35..fa1a6f45dc41 100644 --- 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) |