1 files changed, 25 insertions, 16 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index c3ed4d44fc14..7b5572d6beb5 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -44,23 +44,30 @@ static inline int qdisc_qlen(struct Qdisc *q)
 
 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
 {
-        if (unlikely(skb->next))
-                q->gso_skb = skb;
-        else
-                q->ops->requeue(skb, q);
-
+        q->gso_skb = skb;
+        q->qstats.requeues++;
         __netif_schedule(q);
+
         return 0;
 }
 
 static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
 {
-        struct sk_buff *skb;
+        struct sk_buff *skb = q->gso_skb;
+
+        if (unlikely(skb)) {
+                struct net_device *dev = qdisc_dev(q);
+                struct netdev_queue *txq;
 
-        if ((skb = q->gso_skb))
-                q->gso_skb = NULL;
-        else
+                /* check the reason of requeuing without tx lock first */
+                txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
+                if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
+                        q->gso_skb = NULL;
+                else
+                        skb = NULL;
+        } else {
                 skb = q->dequeue(q);
+        }
 
         return skb;
 }
@@ -215,10 +222,9 @@ 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 +
@@ -328,6 +334,7 @@ struct Qdisc noop_qdisc = {
         .flags          =       TCQ_F_BUILTIN,
         .ops            =       &noop_qdisc_ops,
         .list           =       LIST_HEAD_INIT(noop_qdisc.list),
+        .requeue.lock   =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
         .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
         .dev_queue      =       &noop_netdev_queue,
 };
@@ -353,6 +360,7 @@ static struct Qdisc noqueue_qdisc = {
         .flags          =       TCQ_F_BUILTIN,
         .ops            =       &noqueue_qdisc_ops,
         .list           =       LIST_HEAD_INIT(noqueue_qdisc.list),
+        .requeue.lock   =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
         .q.lock         =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
         .dev_queue      =       &noqueue_netdev_queue,
 };
@@ -473,6 +481,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
         sch->padded = (char *) sch - (char *) p;
 
         INIT_LIST_HEAD(&sch->list);
+        skb_queue_head_init(&sch->requeue);
         skb_queue_head_init(&sch->q);
         sch->ops = ops;
         sch->enqueue = ops->enqueue;
@@ -526,10 +535,9 @@ void qdisc_destroy(struct Qdisc *qdisc)
             !atomic_dec_and_test(&qdisc->refcnt))
                 return;
 
-        if (qdisc->parent)
-                list_del(&qdisc->list);
-
 #ifdef CONFIG_NET_SCHED
+        qdisc_list_del(qdisc);
+
         qdisc_put_stab(qdisc->stab);
 #endif
         gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
@@ -542,6 +550,7 @@ void qdisc_destroy(struct Qdisc *qdisc)
         dev_put(qdisc_dev(qdisc));
 
         kfree_skb(qdisc->gso_skb);
+        __skb_queue_purge(&qdisc->requeue);
 
         kfree((char *) qdisc - qdisc->padded);
 }
@@ -635,7 +644,7 @@ static void dev_deactivate_queue(struct net_device *dev,
                 if (!(qdisc->flags & TCQ_F_BUILTIN))
                         set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
 
-                dev_queue->qdisc = qdisc_default;
+                rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
                 qdisc_reset(qdisc);
 
                 spin_unlock_bh(qdisc_lock(qdisc));
@@ -710,7 +719,7 @@ static void shutdown_scheduler_queue(struct net_device *dev,
         struct Qdisc *qdisc_default = _qdisc_default;
 
         if (qdisc) {
-                dev_queue->qdisc = qdisc_default;
+                rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
                 dev_queue->qdisc_sleeping = qdisc_default;
 
                 qdisc_destroy(qdisc);