net: Change handling of the __QDISC_STATE_SCHED flag in net_tx_action().

Change handling of the __QDISC_STATE_SCHED flag in net_tx_action() to
enable proper control in dev_deactivate(). Now, if this flag is seen
as unset under root_lock means a qdisc can't be netif_scheduled.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 15 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index d9e31f63aded..819f0175bdc9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1339,19 +1339,23 @@ static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 }
 
 
-void __netif_schedule(struct Qdisc *q)
+static inline void __netif_reschedule(struct Qdisc *q)
 {
-        if (!test_and_set_bit(__QDISC_STATE_SCHED, &q->state)) {
-                struct softnet_data *sd;
-                unsigned long flags;
+        struct softnet_data *sd;
+        unsigned long flags;
 
-                local_irq_save(flags);
-                sd = &__get_cpu_var(softnet_data);
-                q->next_sched = sd->output_queue;
-                sd->output_queue = q;
-                raise_softirq_irqoff(NET_TX_SOFTIRQ);
-                local_irq_restore(flags);
-        }
+        local_irq_save(flags);
+        sd = &__get_cpu_var(softnet_data);
+        q->next_sched = sd->output_queue;
+        sd->output_queue = q;
+        raise_softirq_irqoff(NET_TX_SOFTIRQ);
+        local_irq_restore(flags);
+}
+
+void __netif_schedule(struct Qdisc *q)
+{
+        if (!test_and_set_bit(__QDISC_STATE_SCHED, &q->state))
+                __netif_reschedule(q);
 }
 EXPORT_SYMBOL(__netif_schedule);
 
@@ -1980,15 +1984,15 @@ static void net_tx_action(struct softirq_action *h)
 
                         head = head->next_sched;
 
-                        smp_mb__before_clear_bit();
-                        clear_bit(__QDISC_STATE_SCHED, &q->state);
-
                         root_lock = qdisc_lock(q);
                         if (spin_trylock(root_lock)) {
+                                smp_mb__before_clear_bit();
+                                clear_bit(__QDISC_STATE_SCHED,
+                                          &q->state);
                                 qdisc_run(q);
                                 spin_unlock(root_lock);
                         } else {
-                                __netif_schedule(q);
+                                __netif_reschedule(q);
                         }
                 }
         }