1 files changed, 34 insertions, 54 deletions

diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index d7a4874543de..c6551578f1cf 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * Codel - The Controlled-Delay Active Queue Management algorithm
  *
@@ -7,37 +8,6 @@
  *  Implemented on linux by :
  *  Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net>
  *  Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions, and the following disclaimer,
- *    without modification.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. The names of the authors may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * Alternatively, provided that this notice is retained in full, this
- * software may be distributed under the terms of the GNU General
- * Public License ("GPL") version 2, in which case the provisions of the
- * GPL apply INSTEAD OF those given above.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
- * DAMAGE.
- *
  */
 
 #include <linux/module.h>
@@ -82,7 +52,7 @@ static void drop_func(struct sk_buff *skb, void *ctx)
 {
 	struct Qdisc *sch = ctx;
 
-	kfree_skb(skb);
+	qdisc_dequeue_drop(sch, skb, SKB_DROP_REASON_QDISC_CONGESTED);
 	qdisc_qstats_drop(sch);
 }
 
@@ -95,10 +65,7 @@ static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch)
 			    &q->stats, qdisc_pkt_len, codel_get_enqueue_time,
 			    drop_func, dequeue_func);
 
-	/* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
-	 * or HTB crashes. Defer it for next round.
-	 */
-	if (q->stats.drop_count && sch->q.qlen) {
+	if (q->stats.drop_count) {
 		qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len);
 		q->stats.drop_count = 0;
 		q->stats.drop_len = 0;
@@ -119,7 +86,8 @@ static int codel_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	}
 	q = qdisc_priv(sch);
 	q->drop_overlimit++;
-	return qdisc_drop(skb, sch, to_free);
+	return qdisc_drop_reason(skb, sch, to_free,
+				 SKB_DROP_REASON_QDISC_OVERLIMIT);
 }
 
 static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = {
@@ -133,9 +101,9 @@ static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = {
 static int codel_change(struct Qdisc *sch, struct nlattr *opt,
 			struct netlink_ext_ack *extack)
 {
+	unsigned int dropped_pkts = 0, dropped_bytes = 0;
 	struct codel_sched_data *q = qdisc_priv(sch);
 	struct nlattr *tb[TCA_CODEL_MAX + 1];
-	unsigned int qlen, dropped = 0;
 	int err;
 
 	err = nla_parse_nested_deprecated(tb, TCA_CODEL_MAX, opt,
@@ -148,36 +116,43 @@ static int codel_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_CODEL_TARGET]) {
 		u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
 
-		q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.target,
+			   ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_CE_THRESHOLD]) {
 		u64 val = nla_get_u32(tb[TCA_CODEL_CE_THRESHOLD]);
 
-		q->params.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.ce_threshold,
+			   (val * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_INTERVAL]) {
 		u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
 
-		q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.interval,
+			   ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]);
+		WRITE_ONCE(sch->limit,
+			   nla_get_u32(tb[TCA_CODEL_LIMIT]));
 
 	if (tb[TCA_CODEL_ECN])
-		q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
+		WRITE_ONCE(q->params.ecn,
+			   !!nla_get_u32(tb[TCA_CODEL_ECN]));
 
-	qlen = sch->q.qlen;
 	while (sch->q.qlen > sch->limit) {
-		struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
+		struct sk_buff *skb = qdisc_dequeue_internal(sch, true);
+
+		if (!skb)
+			break;
 
-		dropped += qdisc_pkt_len(skb);
-		qdisc_qstats_backlog_dec(sch, skb);
+		dropped_pkts++;
+		dropped_bytes += qdisc_pkt_len(skb);
 		rtnl_qdisc_drop(skb, sch);
 	}
-	qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
+	qdisc_tree_reduce_backlog(sch, dropped_pkts, dropped_bytes);
 
 	sch_tree_unlock(sch);
 	return 0;
@@ -207,12 +182,15 @@ static int codel_init(struct Qdisc *sch, struct nlattr *opt,
 	else
 		sch->flags &= ~TCQ_F_CAN_BYPASS;
 
+	sch->flags |= TCQ_F_DEQUEUE_DROPS;
+
 	return 0;
 }
 
 static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct codel_sched_data *q = qdisc_priv(sch);
+	codel_time_t ce_threshold;
 	struct nlattr *opts;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
@@ -220,17 +198,18 @@ static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CODEL_TARGET,
-			codel_time_to_us(q->params.target)) ||
+			codel_time_to_us(READ_ONCE(q->params.target))) ||
 	    nla_put_u32(skb, TCA_CODEL_LIMIT,
-			sch->limit) ||
+			READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_CODEL_INTERVAL,
-			codel_time_to_us(q->params.interval)) ||
+			codel_time_to_us(READ_ONCE(q->params.interval))) ||
 	    nla_put_u32(skb, TCA_CODEL_ECN,
-			q->params.ecn))
+			READ_ONCE(q->params.ecn)))
 		goto nla_put_failure;
-	if (q->params.ce_threshold != CODEL_DISABLED_THRESHOLD &&
+	ce_threshold = READ_ONCE(q->params.ce_threshold);
+	if (ce_threshold != CODEL_DISABLED_THRESHOLD &&
 	    nla_put_u32(skb, TCA_CODEL_CE_THRESHOLD,
-			codel_time_to_us(q->params.ce_threshold)))
+			codel_time_to_us(ce_threshold)))
 		goto nla_put_failure;
 	return nla_nest_end(skb, opts);
 
@@ -287,6 +266,7 @@ static struct Qdisc_ops codel_qdisc_ops __read_mostly = {
 	.dump_stats	=	codel_dump_stats,
 	.owner		=	THIS_MODULE,
 };
+MODULE_ALIAS_NET_SCH("codel");
 
 static int __init codel_module_init(void)
 {