1 files changed, 17 insertions, 20 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 17bd8f539bc7..5ab696efca95 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -382,13 +382,8 @@ void __qdisc_run(struct Qdisc *q)
 	int packets;
 
 	while (qdisc_restart(q, &packets)) {
-		/*
-		 * Ordered by possible occurrence: Postpone processing if
-		 * 1. we've exceeded packet quota
-		 * 2. another process needs the CPU;
-		 */
 		quota -= packets;
-		if (quota <= 0 || need_resched()) {
+		if (quota <= 0) {
 			__netif_schedule(q);
 			break;
 		}
@@ -657,7 +652,7 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
 	if (likely(skb)) {
 		qdisc_update_stats_at_dequeue(qdisc, skb);
 	} else {
-		qdisc->empty = true;
+		WRITE_ONCE(qdisc->empty, true);
 	}
 
 	return skb;
@@ -799,9 +794,6 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 };
 EXPORT_SYMBOL(pfifo_fast_ops);
 
-static struct lock_class_key qdisc_tx_busylock;
-static struct lock_class_key qdisc_running_key;
-
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack)
@@ -854,17 +846,9 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 	}
 
 	spin_lock_init(&sch->busylock);
-	lockdep_set_class(&sch->busylock,
-			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
-
 	/* seqlock has the same scope of busylock, for NOLOCK qdisc */
 	spin_lock_init(&sch->seqlock);
-	lockdep_set_class(&sch->busylock,
-			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
-
 	seqcount_init(&sch->running);
-	lockdep_set_class(&sch->running,
-			  dev->qdisc_running_key ?: &qdisc_running_key);
 
 	sch->ops = ops;
 	sch->flags = ops->static_flags;
@@ -875,6 +859,12 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 	dev_hold(dev);
 	refcount_set(&sch->refcnt, 1);
 
+	if (sch != &noop_qdisc) {
+		lockdep_set_class(&sch->busylock, &dev->qdisc_tx_busylock_key);
+		lockdep_set_class(&sch->seqlock, &dev->qdisc_tx_busylock_key);
+		lockdep_set_class(&sch->running, &dev->qdisc_running_key);
+	}
+
 	return sch;
 errout1:
 	kfree(p);
@@ -1043,6 +1033,8 @@ static void attach_one_default_qdisc(struct net_device *dev,
 
 	if (dev->priv_flags & IFF_NO_QUEUE)
 		ops = &noqueue_qdisc_ops;
+	else if(dev->type == ARPHRD_CAN)
+		ops = &pfifo_fast_ops;
 
 	qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
 	if (!qdisc) {
@@ -1217,8 +1209,13 @@ void dev_deactivate_many(struct list_head *head)
 
 	/* Wait for outstanding qdisc_run calls. */
 	list_for_each_entry(dev, head, close_list) {
-		while (some_qdisc_is_busy(dev))
-			yield();
+		while (some_qdisc_is_busy(dev)) {
+			/* wait_event() would avoid this sleep-loop but would
+			 * require expensive checks in the fast paths of packet
+			 * processing which isn't worth it.
+			 */
+			schedule_timeout_uninterruptible(1);
+		}
 		/* The new qdisc is assigned at this point so we can safely
 		 * unwind stale skb lists and qdisc statistics
 		 */