1 files changed, 20 insertions, 30 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 6ab4a2f92ca0..0fc4a18fd96f 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -97,10 +97,9 @@ static int tclass_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 
    Auxiliary routines:
 
-   ---requeue
+   ---peek
 
-   requeues once dequeued packet. It is used for non-standard or
-   just buggy devices, which can defer output even if netif_queue_stopped()=0.
+   like dequeue but without removing a packet from the queue
 
    ---reset
 
@@ -147,8 +146,14 @@ int register_qdisc(struct Qdisc_ops *qops)
 
         if (qops->enqueue == NULL)
                 qops->enqueue = noop_qdisc_ops.enqueue;
-        if (qops->requeue == NULL)
-                qops->requeue = noop_qdisc_ops.requeue;
+        if (qops->peek == NULL) {
+                if (qops->dequeue == NULL) {
+                        qops->peek = noop_qdisc_ops.peek;
+                } else {
+                        rc = -EINVAL;
+                        goto out;
+                }
+        }
         if (qops->dequeue == NULL)
                 qops->dequeue = noop_qdisc_ops.dequeue;
 
@@ -184,7 +189,7 @@ EXPORT_SYMBOL(unregister_qdisc);
    (root qdisc, all its children, children of children etc.)
  */
 
-struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
+static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
 {
         struct Qdisc *q;
 
@@ -199,28 +204,16 @@ struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
         return NULL;
 }
 
-/*
- * This lock is needed until some qdiscs stop calling qdisc_tree_decrease_qlen()
- * without rtnl_lock(); currently hfsc_dequeue(), netem_dequeue(), tbf_dequeue()
- */
-static DEFINE_SPINLOCK(qdisc_list_lock);
-
 static void qdisc_list_add(struct Qdisc *q)
 {
-        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
-                spin_lock_bh(&qdisc_list_lock);
+        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
                 list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);
-                spin_unlock_bh(&qdisc_list_lock);
-        }
 }
 
 void qdisc_list_del(struct Qdisc *q)
 {
-        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
-                spin_lock_bh(&qdisc_list_lock);
+        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
                 list_del(&q->list);
-                spin_unlock_bh(&qdisc_list_lock);
-        }
 }
 EXPORT_SYMBOL(qdisc_list_del);
 
@@ -229,22 +222,17 @@ struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
         unsigned int i;
         struct Qdisc *q;
 
-        spin_lock_bh(&qdisc_list_lock);
-
         for (i = 0; i < dev->num_tx_queues; i++) {
                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
                 struct Qdisc *txq_root = txq->qdisc_sleeping;
 
                 q = qdisc_match_from_root(txq_root, handle);
                 if (q)
-                        goto unlock;
+                        goto out;
         }
 
         q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
-
-unlock:
-        spin_unlock_bh(&qdisc_list_lock);
-
+out:
         return q;
 }
 
@@ -462,7 +450,6 @@ static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
                                                  timer);
 
         wd->qdisc->flags &= ~TCQ_F_THROTTLED;
-        smp_wmb();
         __netif_schedule(qdisc_root(wd->qdisc));
 
         return HRTIMER_NORESTART;
@@ -892,9 +879,12 @@ static int qdisc_change(struct Qdisc *sch, struct nlattr **tca)
         sch->stab = stab;
 
         if (tca[TCA_RATE])
+                /* NB: ignores errors from replace_estimator
+                   because change can't be undone. */
                 gen_replace_estimator(&sch->bstats, &sch->rate_est,
-                                      qdisc_root_sleeping_lock(sch),
-                                      tca[TCA_RATE]);
+                                            qdisc_root_sleeping_lock(sch),
+                                            tca[TCA_RATE]);
+
         return 0;
 }