warn: Turn the netdev timeout WARN_ON() into a WARN()

[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 7cf83b37459d0f08926baf49c07ce1ad9882b433..ec0a0839ce512620231997be5f5c233b4bea423a 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -215,10 +215,9 @@ static void dev_watchdog(unsigned long arg)
                            time_after(jiffies, (dev->trans_start +
                                                 dev->watchdog_timeo))) {
                                char drivername[64];
-                               printk(KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit timed out\n",
+                               WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit timed out\n",
                                       dev->name, netdev_drivername(dev, drivername, 64));
                                dev->tx_timeout(dev);
-                               WARN_ON_ONCE(1);
                        }
                        if (!mod_timer(&dev->watchdog_timer,
                                       round_jiffies(jiffies +
@@ -518,15 +517,17 @@ void qdisc_reset(struct Qdisc *qdisc)
 }
 EXPORT_SYMBOL(qdisc_reset);
 
-/* this is the rcu callback function to clean up a qdisc when there
- * are no further references to it */
-
-static void __qdisc_destroy(struct rcu_head *head)
+void qdisc_destroy(struct Qdisc *qdisc)
 {
-       struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
        const struct Qdisc_ops  *ops = qdisc->ops;
 
+       if (qdisc->flags & TCQ_F_BUILTIN ||
+           !atomic_dec_and_test(&qdisc->refcnt))
+               return;
+
 #ifdef CONFIG_NET_SCHED
+       qdisc_list_del(qdisc);
+
        qdisc_put_stab(qdisc->stab);
 #endif
        gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
@@ -542,20 +543,6 @@ static void __qdisc_destroy(struct rcu_head *head)
 
        kfree((char *) qdisc - qdisc->padded);
 }
-
-/* Under qdisc_lock(qdisc) and BH! */
-
-void qdisc_destroy(struct Qdisc *qdisc)
-{
-       if (qdisc->flags & TCQ_F_BUILTIN ||
-           !atomic_dec_and_test(&qdisc->refcnt))
-               return;
-
-       if (qdisc->parent)
-               list_del(&qdisc->list);
-
-       call_rcu(&qdisc->q_rcu, __qdisc_destroy);
-}
 EXPORT_SYMBOL(qdisc_destroy);
 
 static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)
@@ -597,6 +584,9 @@ static void transition_one_qdisc(struct net_device *dev,
        struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
        int *need_watchdog_p = _need_watchdog;
 
+       if (!(new_qdisc->flags & TCQ_F_BUILTIN))
+               clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
+
        rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
        if (need_watchdog_p && new_qdisc != &noqueue_qdisc)
                *need_watchdog_p = 1;
@@ -640,14 +630,17 @@ static void dev_deactivate_queue(struct net_device *dev,
        if (qdisc) {
                spin_lock_bh(qdisc_lock(qdisc));
 
-               dev_queue->qdisc = qdisc_default;
+               if (!(qdisc->flags & TCQ_F_BUILTIN))
+                       set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
+
+               rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
                qdisc_reset(qdisc);
 
                spin_unlock_bh(qdisc_lock(qdisc));
        }
 }
 
-static bool some_qdisc_is_running(struct net_device *dev, int lock)
+static bool some_qdisc_is_busy(struct net_device *dev)
 {
        unsigned int i;
 
@@ -658,16 +651,15 @@ static bool some_qdisc_is_running(struct net_device *dev, int lock)
                int val;
 
                dev_queue = netdev_get_tx_queue(dev, i);
-               q = dev_queue->qdisc;
+               q = dev_queue->qdisc_sleeping;
                root_lock = qdisc_lock(q);
 
-               if (lock)
-                       spin_lock_bh(root_lock);
+               spin_lock_bh(root_lock);
 
-               val = test_bit(__QDISC_STATE_RUNNING, &q->state);
+               val = (test_bit(__QDISC_STATE_RUNNING, &q->state) ||
+                      test_bit(__QDISC_STATE_SCHED, &q->state));
 
-               if (lock)
-                       spin_unlock_bh(root_lock);
+               spin_unlock_bh(root_lock);
 
                if (val)
                        return true;
@@ -677,8 +669,6 @@ static bool some_qdisc_is_running(struct net_device *dev, int lock)
 
 void dev_deactivate(struct net_device *dev)
 {
-       bool running;
-
        netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc);
        dev_deactivate_queue(dev, &dev->rx_queue, &noop_qdisc);
 
@@ -688,25 +678,8 @@ void dev_deactivate(struct net_device *dev)
        synchronize_rcu();
 
        /* Wait for outstanding qdisc_run calls. */
-       do {
-               while (some_qdisc_is_running(dev, 0))
-                       yield();
-
-               /*
-                * Double-check inside queue lock to ensure that all effects
-                * of the queue run are visible when we return.
-                */
-               running = some_qdisc_is_running(dev, 1);
-
-               /*
-                * 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));
+       while (some_qdisc_is_busy(dev))
+               yield();
 }
 
 static void dev_init_scheduler_queue(struct net_device *dev,
@@ -735,14 +708,10 @@ static void shutdown_scheduler_queue(struct net_device *dev,
        struct Qdisc *qdisc_default = _qdisc_default;
 
        if (qdisc) {
-               spinlock_t *root_lock = qdisc_lock(qdisc);
-
-               dev_queue->qdisc = qdisc_default;
+               rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
                dev_queue->qdisc_sleeping = qdisc_default;
 
-               spin_lock_bh(root_lock);
                qdisc_destroy(qdisc);
-               spin_unlock_bh(root_lock);
        }
 }