net: add a noref bit on skb dst
[safe/jmp/linux-2.6] / net / sched / sch_generic.c
index 3d53e92..a63029e 100644 (file)
 #include <linux/init.h>
 #include <linux/rcupdate.h>
 #include <linux/list.h>
+#include <linux/slab.h>
 #include <net/pkt_sched.h>
+#include <net/dst.h>
 
 /* Main transmission queue. */
 
 /* Modifications to data participating in scheduling must be protected with
- * qdisc_root_lock(qdisc) spinlock.
+ * qdisc_lock(qdisc) spinlock.
  *
  * The idea is the following:
  * - enqueue, dequeue are serialized via qdisc root lock
  * - updates to tree and tree walking are only done under the rtnl mutex.
  */
 
-static inline int qdisc_qlen(struct Qdisc *q)
-{
-       return q->q.qlen;
-}
-
 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);
-
+       skb_dst_force(skb);
+       q->gso_skb = skb;
+       q->qstats.requeues++;
+       q->q.qlen++;    /* it's still part of the queue */
        __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;
+                       q->q.qlen--;
+               } else
+                       skb = NULL;
+       } else {
                skb = q->dequeue(q);
+       }
 
        return skb;
 }
@@ -88,7 +96,7 @@ static inline int handle_dev_cpu_collision(struct sk_buff *skb,
                 * Another cpu is holding lock, requeue & delay xmits for
                 * some time.
                 */
-               __get_cpu_var(netdev_rx_stat).cpu_collision++;
+               __get_cpu_var(softnet_data).cpu_collision++;
                ret = dev_requeue_skb(skb, q);
        }
 
@@ -96,78 +104,91 @@ static inline int handle_dev_cpu_collision(struct sk_buff *skb,
 }
 
 /*
- * NOTE: Called under queue->lock with locally disabled BH.
- *
- * __QDISC_STATE_RUNNING guarantees only one CPU can process
- * this qdisc at a time. queue->lock serializes queue accesses for
- * this queue AND txq->qdisc pointer itself.
- *
- *  netif_tx_lock serializes accesses to device driver.
- *
- *  queue->lock and netif_tx_lock are mutually exclusive,
- *  if one is grabbed, another must be free.
- *
- * Note, that this procedure can be called by a watchdog timer
+ * Transmit one skb, and handle the return status as required. Holding the
+ * __QDISC_STATE_RUNNING bit guarantees that only one CPU can execute this
+ * function.
  *
  * Returns to the caller:
  *                             0  - queue is empty or throttled.
  *                             >0 - queue is not empty.
- *
  */
-static inline int qdisc_restart(struct Qdisc *q)
+int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
+                   struct net_device *dev, struct netdev_queue *txq,
+                   spinlock_t *root_lock)
 {
-       struct netdev_queue *txq;
        int ret = NETDEV_TX_BUSY;
-       struct net_device *dev;
-       spinlock_t *root_lock;
-       struct sk_buff *skb;
-
-       /* Dequeue packet */
-       if (unlikely((skb = dequeue_skb(q)) == NULL))
-               return 0;
-
-       root_lock = qdisc_root_lock(q);
 
        /* And release qdisc */
        spin_unlock(root_lock);
 
-       dev = qdisc_dev(q);
-       txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
-
        HARD_TX_LOCK(dev, txq, smp_processor_id());
-       if (!netif_subqueue_stopped(dev, skb))
+       if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
                ret = dev_hard_start_xmit(skb, dev, txq);
+
        HARD_TX_UNLOCK(dev, txq);
 
        spin_lock(root_lock);
 
-       switch (ret) {
-       case NETDEV_TX_OK:
-               /* Driver sent out skb successfully */
+       if (dev_xmit_complete(ret)) {
+               /* Driver sent out skb successfully or skb was consumed */
                ret = qdisc_qlen(q);
-               break;
-
-       case NETDEV_TX_LOCKED:
+       } else if (ret == NETDEV_TX_LOCKED) {
                /* Driver try lock failed */
                ret = handle_dev_cpu_collision(skb, txq, q);
-               break;
-
-       default:
+       } else {
                /* Driver returned NETDEV_TX_BUSY - requeue skb */
                if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
                        printk(KERN_WARNING "BUG %s code %d qlen %d\n",
                               dev->name, ret, q->q.qlen);
 
                ret = dev_requeue_skb(skb, q);
-               break;
        }
 
-       if (ret && netif_tx_queue_stopped(txq))
+       if (ret && (netif_tx_queue_stopped(txq) ||
+                   netif_tx_queue_frozen(txq)))
                ret = 0;
 
        return ret;
 }
 
+/*
+ * NOTE: Called under qdisc_lock(q) with locally disabled BH.
+ *
+ * __QDISC_STATE_RUNNING guarantees only one CPU can process
+ * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
+ * this queue.
+ *
+ *  netif_tx_lock serializes accesses to device driver.
+ *
+ *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
+ *  if one is grabbed, another must be free.
+ *
+ * Note, that this procedure can be called by a watchdog timer
+ *
+ * Returns to the caller:
+ *                             0  - queue is empty or throttled.
+ *                             >0 - queue is not empty.
+ *
+ */
+static inline int qdisc_restart(struct Qdisc *q)
+{
+       struct netdev_queue *txq;
+       struct net_device *dev;
+       spinlock_t *root_lock;
+       struct sk_buff *skb;
+
+       /* Dequeue packet */
+       skb = dequeue_skb(q);
+       if (unlikely(!skb))
+               return 0;
+       WARN_ON_ONCE(skb_dst_is_noref(skb));
+       root_lock = qdisc_lock(q);
+       dev = qdisc_dev(q);
+       txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
+
+       return sch_direct_xmit(skb, q, dev, txq, root_lock);
+}
+
 void __qdisc_run(struct Qdisc *q)
 {
        unsigned long start_time = jiffies;
@@ -187,6 +208,21 @@ void __qdisc_run(struct Qdisc *q)
        clear_bit(__QDISC_STATE_RUNNING, &q->state);
 }
 
+unsigned long dev_trans_start(struct net_device *dev)
+{
+       unsigned long val, res = dev->trans_start;
+       unsigned int i;
+
+       for (i = 0; i < dev->num_tx_queues; i++) {
+               val = netdev_get_tx_queue(dev, i)->trans_start;
+               if (val && time_after(val, res))
+                       res = val;
+       }
+       dev->trans_start = res;
+       return res;
+}
+EXPORT_SYMBOL(dev_trans_start);
+
 static void dev_watchdog(unsigned long arg)
 {
        struct net_device *dev = (struct net_device *)arg;
@@ -196,27 +232,31 @@ static void dev_watchdog(unsigned long arg)
                if (netif_device_present(dev) &&
                    netif_running(dev) &&
                    netif_carrier_ok(dev)) {
-                       int some_queue_stopped = 0;
+                       int some_queue_timedout = 0;
                        unsigned int i;
+                       unsigned long trans_start;
 
                        for (i = 0; i < dev->num_tx_queues; i++) {
                                struct netdev_queue *txq;
 
                                txq = netdev_get_tx_queue(dev, i);
-                               if (netif_tx_queue_stopped(txq)) {
-                                       some_queue_stopped = 1;
+                               /*
+                                * old device drivers set dev->trans_start
+                                */
+                               trans_start = txq->trans_start ? : dev->trans_start;
+                               if (netif_tx_queue_stopped(txq) &&
+                                   time_after(jiffies, (trans_start +
+                                                        dev->watchdog_timeo))) {
+                                       some_queue_timedout = 1;
                                        break;
                                }
                        }
 
-                       if (some_queue_stopped &&
-                           time_after(jiffies, (dev->trans_start +
-                                                dev->watchdog_timeo))) {
-                               printk(KERN_INFO "NETDEV WATCHDOG: %s: "
-                                      "transmit timed out\n",
-                                      dev->name);
-                               dev->tx_timeout(dev);
-                               WARN_ON_ONCE(1);
+                       if (some_queue_timedout) {
+                               char drivername[64];
+                               WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
+                                      dev->name, netdev_drivername(dev, drivername, 64), i);
+                               dev->netdev_ops->ndo_tx_timeout(dev);
                        }
                        if (!mod_timer(&dev->watchdog_timer,
                                       round_jiffies(jiffies +
@@ -231,7 +271,7 @@ static void dev_watchdog(unsigned long arg)
 
 void __netdev_watchdog_up(struct net_device *dev)
 {
-       if (dev->tx_timeout) {
+       if (dev->netdev_ops->ndo_tx_timeout) {
                if (dev->watchdog_timeo <= 0)
                        dev->watchdog_timeo = 5*HZ;
                if (!mod_timer(&dev->watchdog_timer,
@@ -262,6 +302,8 @@ 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 (dev->reg_state == NETREG_UNINITIALIZED)
+                       return;
                linkwatch_fire_event(dev);
                if (netif_running(dev))
                        __netdev_watchdog_up(dev);
@@ -277,8 +319,11 @@ EXPORT_SYMBOL(netif_carrier_on);
  */
 void netif_carrier_off(struct net_device *dev)
 {
-       if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state))
+       if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
+               if (dev->reg_state == NETREG_UNINITIALIZED)
+                       return;
                linkwatch_fire_event(dev);
+       }
 }
 EXPORT_SYMBOL(netif_carrier_off);
 
@@ -298,27 +343,18 @@ static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
        return NULL;
 }
 
-static int noop_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
-{
-       if (net_ratelimit())
-               printk(KERN_DEBUG "%s deferred output. It is buggy.\n",
-                      skb->dev->name);
-       kfree_skb(skb);
-       return NET_XMIT_CN;
-}
-
 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
        .id             =       "noop",
        .priv_size      =       0,
        .enqueue        =       noop_enqueue,
        .dequeue        =       noop_dequeue,
-       .requeue        =       noop_requeue,
+       .peek           =       noop_dequeue,
        .owner          =       THIS_MODULE,
 };
 
 static struct netdev_queue noop_netdev_queue = {
-       .lock           =       __SPIN_LOCK_UNLOCKED(noop_netdev_queue.lock),
        .qdisc          =       &noop_qdisc,
+       .qdisc_sleeping =       &noop_qdisc,
 };
 
 struct Qdisc noop_qdisc = {
@@ -327,6 +363,7 @@ struct Qdisc noop_qdisc = {
        .flags          =       TCQ_F_BUILTIN,
        .ops            =       &noop_qdisc_ops,
        .list           =       LIST_HEAD_INIT(noop_qdisc.list),
+       .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
        .dev_queue      =       &noop_netdev_queue,
 };
 EXPORT_SYMBOL(noop_qdisc);
@@ -336,16 +373,24 @@ static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
        .priv_size      =       0,
        .enqueue        =       noop_enqueue,
        .dequeue        =       noop_dequeue,
-       .requeue        =       noop_requeue,
+       .peek           =       noop_dequeue,
        .owner          =       THIS_MODULE,
 };
 
+static struct Qdisc noqueue_qdisc;
+static struct netdev_queue noqueue_netdev_queue = {
+       .qdisc          =       &noqueue_qdisc,
+       .qdisc_sleeping =       &noqueue_qdisc,
+};
+
 static struct Qdisc noqueue_qdisc = {
        .enqueue        =       NULL,
        .dequeue        =       noop_dequeue,
        .flags          =       TCQ_F_BUILTIN,
        .ops            =       &noqueue_qdisc_ops,
        .list           =       LIST_HEAD_INIT(noqueue_qdisc.list),
+       .q.lock         =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
+       .dev_queue      =       &noqueue_netdev_queue,
 };
 
 
@@ -358,18 +403,38 @@ static const u8 prio2band[TC_PRIO_MAX+1] =
 
 #define PFIFO_FAST_BANDS 3
 
-static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
-                                            struct Qdisc *qdisc)
+/*
+ * Private data for a pfifo_fast scheduler containing:
+ *     - queues for the three band
+ *     - bitmap indicating which of the bands contain skbs
+ */
+struct pfifo_fast_priv {
+       u32 bitmap;
+       struct sk_buff_head q[PFIFO_FAST_BANDS];
+};
+
+/*
+ * Convert a bitmap to the first band number where an skb is queued, where:
+ *     bitmap=0 means there are no skbs on any band.
+ *     bitmap=1 means there is an skb on band 0.
+ *     bitmap=7 means there are skbs on all 3 bands, etc.
+ */
+static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
+
+static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
+                                            int band)
 {
-       struct sk_buff_head *list = qdisc_priv(qdisc);
-       return list + prio2band[skb->priority & TC_PRIO_MAX];
+       return priv->q + band;
 }
 
 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
 {
-       struct sk_buff_head *list = prio2list(skb, qdisc);
+       if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
+               int band = prio2band[skb->priority & TC_PRIO_MAX];
+               struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+               struct sk_buff_head *list = band2list(priv, band);
 
-       if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
+               priv->bitmap |= (1 << band);
                qdisc->q.qlen++;
                return __qdisc_enqueue_tail(skb, qdisc, list);
        }
@@ -379,33 +444,46 @@ static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
 
 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
 {
-       int prio;
-       struct sk_buff_head *list = qdisc_priv(qdisc);
+       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+       int band = bitmap2band[priv->bitmap];
 
-       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
-               if (!skb_queue_empty(list + prio)) {
-                       qdisc->q.qlen--;
-                       return __qdisc_dequeue_head(qdisc, list + prio);
-               }
+       if (likely(band >= 0)) {
+               struct sk_buff_head *list = band2list(priv, band);
+               struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
+
+               qdisc->q.qlen--;
+               if (skb_queue_empty(list))
+                       priv->bitmap &= ~(1 << band);
+
+               return skb;
        }
 
        return NULL;
 }
 
-static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
+static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc)
 {
-       qdisc->q.qlen++;
-       return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
+       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+       int band = bitmap2band[priv->bitmap];
+
+       if (band >= 0) {
+               struct sk_buff_head *list = band2list(priv, band);
+
+               return skb_peek(list);
+       }
+
+       return NULL;
 }
 
 static void pfifo_fast_reset(struct Qdisc* qdisc)
 {
        int prio;
-       struct sk_buff_head *list = qdisc_priv(qdisc);
+       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 
        for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
-               __qdisc_reset_queue(qdisc, list + prio);
+               __qdisc_reset_queue(qdisc, band2list(priv, prio));
 
+       priv->bitmap = 0;
        qdisc->qstats.backlog = 0;
        qdisc->q.qlen = 0;
 }
@@ -425,20 +503,20 @@ nla_put_failure:
 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
 {
        int prio;
-       struct sk_buff_head *list = qdisc_priv(qdisc);
+       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 
        for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
-               skb_queue_head_init(list + prio);
+               skb_queue_head_init(band2list(priv, prio));
 
        return 0;
 }
 
-static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
+struct Qdisc_ops pfifo_fast_ops __read_mostly = {
        .id             =       "pfifo_fast",
-       .priv_size      =       PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
+       .priv_size      =       sizeof(struct pfifo_fast_priv),
        .enqueue        =       pfifo_fast_enqueue,
        .dequeue        =       pfifo_fast_dequeue,
-       .requeue        =       pfifo_fast_requeue,
+       .peek           =       pfifo_fast_peek,
        .init           =       pfifo_fast_init,
        .reset          =       pfifo_fast_reset,
        .dump           =       pfifo_fast_dump,
@@ -453,7 +531,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
        unsigned int size;
        int err = -ENOBUFS;
 
-       /* ensure that the Qdisc and the private data are 32-byte aligned */
+       /* ensure that the Qdisc and the private data are 64-byte aligned */
        size = QDISC_ALIGN(sizeof(*sch));
        size += ops->priv_size + (QDISC_ALIGNTO - 1);
 
@@ -498,7 +576,7 @@ errout:
 }
 EXPORT_SYMBOL(qdisc_create_dflt);
 
-/* Under queue->lock and BH! */
+/* Under qdisc_lock(qdisc) and BH! */
 
 void qdisc_reset(struct Qdisc *qdisc)
 {
@@ -506,17 +584,35 @@ void qdisc_reset(struct Qdisc *qdisc)
 
        if (ops->reset)
                ops->reset(qdisc);
+
+       if (qdisc->gso_skb) {
+               kfree_skb(qdisc->gso_skb);
+               qdisc->gso_skb = NULL;
+               qdisc->q.qlen = 0;
+       }
 }
 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_rcu_free(struct rcu_head *head)
+{
+       struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
 
-static void __qdisc_destroy(struct rcu_head *head)
+       kfree((char *) qdisc - qdisc->padded);
+}
+
+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);
        if (ops->reset)
                ops->reset(qdisc);
@@ -526,38 +622,38 @@ static void __qdisc_destroy(struct rcu_head *head)
        module_put(ops->owner);
        dev_put(qdisc_dev(qdisc));
 
-       kfree((char *) qdisc - qdisc->padded);
+       kfree_skb(qdisc->gso_skb);
+       /*
+        * gen_estimator est_timer() might access qdisc->q.lock,
+        * wait a RCU grace period before freeing qdisc.
+        */
+       call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
 }
+EXPORT_SYMBOL(qdisc_destroy);
 
-/* Under queue->lock and BH! */
-
-void qdisc_destroy(struct Qdisc *qdisc)
+/* Attach toplevel qdisc to device queue. */
+struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
+                             struct Qdisc *qdisc)
 {
-       struct net_device *dev = qdisc_dev(qdisc);
-
-       if (qdisc->flags & TCQ_F_BUILTIN ||
-           !atomic_dec_and_test(&qdisc->refcnt))
-               return;
+       struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
+       spinlock_t *root_lock;
 
-       spin_lock_bh(&dev->qdisc_list_lock);
-       list_del(&qdisc->list);
-       spin_unlock_bh(&dev->qdisc_list_lock);
+       root_lock = qdisc_lock(oqdisc);
+       spin_lock_bh(root_lock);
 
-       call_rcu(&qdisc->q_rcu, __qdisc_destroy);
-}
-EXPORT_SYMBOL(qdisc_destroy);
+       /* Prune old scheduler */
+       if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
+               qdisc_reset(oqdisc);
 
-static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)
-{
-       unsigned int i;
+       /* ... and graft new one */
+       if (qdisc == NULL)
+               qdisc = &noop_qdisc;
+       dev_queue->qdisc_sleeping = qdisc;
+       rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
 
-       for (i = 0; i < dev->num_tx_queues; i++) {
-               struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+       spin_unlock_bh(root_lock);
 
-               if (txq->qdisc_sleeping != &noop_qdisc)
-                       return false;
-       }
-       return true;
+       return oqdisc;
 }
 
 static void attach_one_default_qdisc(struct net_device *dev,
@@ -573,26 +669,50 @@ static void attach_one_default_qdisc(struct net_device *dev,
                        printk(KERN_INFO "%s: activation failed\n", dev->name);
                        return;
                }
-               spin_lock_bh(&dev->qdisc_list_lock);
-               list_add_tail(&qdisc->list, &dev->qdisc_list);
-               spin_unlock_bh(&dev->qdisc_list_lock);
+
+               /* Can by-pass the queue discipline for default qdisc */
+               qdisc->flags |= TCQ_F_CAN_BYPASS;
        } else {
                qdisc =  &noqueue_qdisc;
        }
        dev_queue->qdisc_sleeping = qdisc;
 }
 
+static void attach_default_qdiscs(struct net_device *dev)
+{
+       struct netdev_queue *txq;
+       struct Qdisc *qdisc;
+
+       txq = netdev_get_tx_queue(dev, 0);
+
+       if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
+               netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+               dev->qdisc = txq->qdisc_sleeping;
+               atomic_inc(&dev->qdisc->refcnt);
+       } else {
+               qdisc = qdisc_create_dflt(dev, txq, &mq_qdisc_ops, TC_H_ROOT);
+               if (qdisc) {
+                       qdisc->ops->attach(qdisc);
+                       dev->qdisc = qdisc;
+               }
+       }
+}
+
 static void transition_one_qdisc(struct net_device *dev,
                                 struct netdev_queue *dev_queue,
                                 void *_need_watchdog)
 {
+       struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
        int *need_watchdog_p = _need_watchdog;
 
-       spin_lock_bh(&dev_queue->lock);
-       rcu_assign_pointer(dev_queue->qdisc, dev_queue->qdisc_sleeping);
-       if (dev_queue->qdisc != &noqueue_qdisc)
+       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) {
+               dev_queue->trans_start = 0;
                *need_watchdog_p = 1;
-       spin_unlock_bh(&dev_queue->lock);
+       }
 }
 
 void dev_activate(struct net_device *dev)
@@ -605,8 +725,8 @@ void dev_activate(struct net_device *dev)
           virtual interfaces
         */
 
-       if (dev_all_qdisc_sleeping_noop(dev))
-               netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+       if (dev->qdisc == &noop_qdisc)
+               attach_default_qdiscs(dev);
 
        if (!netif_carrier_ok(dev))
                /* Delay activation until next carrier-on event */
@@ -614,6 +734,7 @@ void dev_activate(struct net_device *dev)
 
        need_watchdog = 0;
        netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
+       transition_one_qdisc(dev, &dev->rx_queue, NULL);
 
        if (need_watchdog) {
                dev->trans_start = jiffies;
@@ -626,26 +747,23 @@ static void dev_deactivate_queue(struct net_device *dev,
                                 void *_qdisc_default)
 {
        struct Qdisc *qdisc_default = _qdisc_default;
-       struct sk_buff *skb = NULL;
        struct Qdisc *qdisc;
 
-       spin_lock_bh(&dev_queue->lock);
-
        qdisc = dev_queue->qdisc;
        if (qdisc) {
-               dev_queue->qdisc = qdisc_default;
-               qdisc_reset(qdisc);
+               spin_lock_bh(qdisc_lock(qdisc));
 
-               skb = qdisc->gso_skb;
-               qdisc->gso_skb = NULL;
-       }
+               if (!(qdisc->flags & TCQ_F_BUILTIN))
+                       set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
 
-       spin_unlock_bh(&dev_queue->lock);
+               rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
+               qdisc_reset(qdisc);
 
-       kfree_skb(skb);
+               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;
 
@@ -656,16 +774,15 @@ 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;
-               root_lock = qdisc_root_lock(q);
+               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;
@@ -675,9 +792,8 @@ 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);
 
        dev_watchdog_down(dev);
 
@@ -685,25 +801,8 @@ 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,
@@ -718,8 +817,9 @@ static void dev_init_scheduler_queue(struct net_device *dev,
 
 void dev_init_scheduler(struct net_device *dev)
 {
+       dev->qdisc = &noop_qdisc;
        netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
-       dev_init_scheduler_queue(dev, &dev->rx_queue, NULL);
+       dev_init_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
 
        setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
 }
@@ -732,20 +832,19 @@ static void shutdown_scheduler_queue(struct net_device *dev,
        struct Qdisc *qdisc_default = _qdisc_default;
 
        if (qdisc) {
-               spinlock_t *root_lock = qdisc_root_lock(qdisc);
-
-               dev_queue->qdisc = qdisc_default;
+               rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
                dev_queue->qdisc_sleeping = qdisc_default;
 
-               spin_lock(root_lock);
                qdisc_destroy(qdisc);
-               spin_unlock(root_lock);
        }
 }
 
 void dev_shutdown(struct net_device *dev)
 {
        netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
-       shutdown_scheduler_queue(dev, &dev->rx_queue, NULL);
-       BUG_TRAP(!timer_pending(&dev->watchdog_timer));
+       shutdown_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
+       qdisc_destroy(dev->qdisc);
+       dev->qdisc = &noop_qdisc;
+
+       WARN_ON(timer_pending(&dev->watchdog_timer));
 }