1 files changed, 12 insertions, 22 deletions

diff --git a/net/sched/sch_skbprio.c b/net/sched/sch_skbprio.c
index 52c0b6d8f1d7..f485f62ab721 100644
--- a/net/sched/sch_skbprio.c
+++ b/net/sched/sch_skbprio.c
@@ -1,11 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * net/sched/sch_skbprio.c  SKB Priority Queue.
  *
- *		This program is free software; you can redistribute it and/or
- *		modify it under the terms of the GNU General Public License
- *		as published by the Free Software Foundation; either version
- *		2 of the License, or (at your option) any later version.
- *
  * Authors:	Nishanth Devarajan, <ndev2021@gmail.com>
  *		Cody Doucette, <doucette@bu.edu>
  *	        original idea by Michel Machado, Cody Doucette, and Qiaobin Fu
@@ -83,7 +79,9 @@ static int skbprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	prio = min(skb->priority, max_priority);
 
 	qdisc = &q->qdiscs[prio];
-	if (sch->q.qlen < sch->limit) {
+
+	/* sch->limit can change under us from skbprio_change() */
+	if (sch->q.qlen < READ_ONCE(sch->limit)) {
 		__skb_queue_tail(qdisc, skb);
 		qdisc_qstats_backlog_inc(sch, skb);
 		q->qstats[prio].backlog += qdisc_pkt_len(skb);
@@ -125,8 +123,6 @@ static int skbprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	/* Check to update highest and lowest priorities. */
 	if (skb_queue_empty(lp_qdisc)) {
 		if (q->lowest_prio == q->highest_prio) {
-			/* The incoming packet is the only packet in queue. */
-			BUG_ON(sch->q.qlen != 1);
 			q->lowest_prio = prio;
 			q->highest_prio = prio;
 		} else {
@@ -158,7 +154,6 @@ static struct sk_buff *skbprio_dequeue(struct Qdisc *sch)
 	/* Update highest priority field. */
 	if (skb_queue_empty(hpq)) {
 		if (q->lowest_prio == q->highest_prio) {
-			BUG_ON(sch->q.qlen);
 			q->highest_prio = 0;
 			q->lowest_prio = SKBPRIO_MAX_PRIORITY - 1;
 		} else {
@@ -173,7 +168,10 @@ static int skbprio_change(struct Qdisc *sch, struct nlattr *opt,
 {
 	struct tc_skbprio_qopt *ctl = nla_data(opt);
 
-	sch->limit = ctl->limit;
+	if (opt->nla_len != nla_attr_size(sizeof(*ctl)))
+		return -EINVAL;
+
+	WRITE_ONCE(sch->limit, ctl->limit);
 	return 0;
 }
 
@@ -201,7 +199,7 @@ static int skbprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct tc_skbprio_qopt opt;
 
-	opt.limit = sch->limit;
+	opt.limit = READ_ONCE(sch->limit);
 
 	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 		return -1;
@@ -214,9 +212,6 @@ static void skbprio_reset(struct Qdisc *sch)
 	struct skbprio_sched_data *q = qdisc_priv(sch);
 	int prio;
 
-	sch->qstats.backlog = 0;
-	sch->q.qlen = 0;
-
 	for (prio = 0; prio < SKBPRIO_MAX_PRIORITY; prio++)
 		__skb_queue_purge(&q->qdiscs[prio]);
 
@@ -269,15 +264,8 @@ static void skbprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 		return;
 
 	for (i = 0; i < SKBPRIO_MAX_PRIORITY; i++) {
-		if (arg->count < arg->skip) {
-			arg->count++;
-			continue;
-		}
-		if (arg->fn(sch, i + 1, arg) < 0) {
-			arg->stop = 1;
+		if (!tc_qdisc_stats_dump(sch, i + 1, arg))
 			break;
-		}
-		arg->count++;
 	}
 }
 
@@ -303,6 +291,7 @@ static struct Qdisc_ops skbprio_qdisc_ops __read_mostly = {
 	.destroy	=	skbprio_destroy,
 	.owner		=	THIS_MODULE,
 };
+MODULE_ALIAS_NET_SCH("skbprio");
 
 static int __init skbprio_module_init(void)
 {
@@ -318,3 +307,4 @@ module_init(skbprio_module_init)
 module_exit(skbprio_module_exit)
 
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SKB priority based scheduling qdisc");