net/sched: Add drop reasons for AQM-based qdiscs

Now that we have generic QDISC_CONGESTED and QDISC_OVERLIMIT drop
reasons, let's have all the qdiscs that contain an AQM apply them
consistently when dropping packets.

Signed-off-by: Toke Høiland-Jørgensen <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

net/sched/sch_codel.c

···
 {
 	struct Qdisc *sch = ctx;
 
-	kfree_skb(skb);
+	kfree_skb_reason(skb, SKB_DROP_REASON_QDISC_CONGESTED);
 	qdisc_qstats_drop(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] = {

net/sched/sch_fq_codel.c

···
 		skb = dequeue_head(flow);
 		len += qdisc_pkt_len(skb);
 		mem += get_codel_cb(skb)->mem_usage;
+		tcf_set_drop_reason(skb, SKB_DROP_REASON_QDISC_OVERLIMIT);
 		__qdisc_drop(skb, to_free);
 	} while (++i < max_packets && len < threshold);
 
···
 {
 	struct Qdisc *sch = ctx;
 
-	kfree_skb(skb);
+	kfree_skb_reason(skb, SKB_DROP_REASON_QDISC_CONGESTED);
 	qdisc_qstats_drop(sch);
 }
 

net/sched/sch_fq_pie.c

···
 static int fq_pie_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 				struct sk_buff **to_free)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_QDISC_OVERLIMIT;
 	struct fq_pie_sched_data *q = qdisc_priv(sch);
 	struct fq_pie_flow *sel_flow;
 	int ret;
···
 	} else if (unlikely(memory_limited)) {
 		q->overmemory++;
 	}
+
+	reason = SKB_DROP_REASON_QDISC_CONGESTED;
 
 	if (!pie_drop_early(sch, &q->p_params, &sel_flow->vars,
 			    sel_flow->backlog, skb->len)) {
···
 out:
 	q->stats.dropped++;
 	sel_flow->vars.accu_prob = 0;
-	__qdisc_drop(skb, to_free);
-	qdisc_qstats_drop(sch);
+	qdisc_drop_reason(skb, sch, to_free, reason);
 	return NET_XMIT_CN;
 }
 

net/sched/sch_gred.c

···
 
 	q->stats.pdrop++;
 drop:
-	return qdisc_drop(skb, sch, to_free);
+	return qdisc_drop_reason(skb, sch, to_free, SKB_DROP_REASON_QDISC_OVERLIMIT);
 
 congestion_drop:
-	qdisc_drop(skb, sch, to_free);
+	qdisc_drop_reason(skb, sch, to_free, SKB_DROP_REASON_QDISC_CONGESTED);
 	return NET_XMIT_CN;
 }
 

net/sched/sch_pie.c

···
 static int pie_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 			     struct sk_buff **to_free)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_QDISC_OVERLIMIT;
 	struct pie_sched_data *q = qdisc_priv(sch);
 	bool enqueue = false;
 
···
 		q->stats.overlimit++;
 		goto out;
 	}
+
+	reason = SKB_DROP_REASON_QDISC_CONGESTED;
 
 	if (!pie_drop_early(sch, &q->params, &q->vars, sch->qstats.backlog,
 			    skb->len)) {
···
 out:
 	q->stats.dropped++;
 	q->vars.accu_prob = 0;
-	return qdisc_drop(skb, sch, to_free);
+	return qdisc_drop_reason(skb, sch, to_free, reason);
 }
 
 static const struct nla_policy pie_policy[TCA_PIE_MAX + 1] = {

net/sched/sch_red.c

···
 static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		       struct sk_buff **to_free)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_QDISC_CONGESTED;
 	struct red_sched_data *q = qdisc_priv(sch);
 	struct Qdisc *child = q->qdisc;
 	unsigned int len;
···
 		break;
 
 	case RED_HARD_MARK:
+		reason = SKB_DROP_REASON_QDISC_OVERLIMIT;
 		qdisc_qstats_overlimit(sch);
 		if (red_use_harddrop(q) || !red_use_ecn(q)) {
 			q->stats.forced_drop++;
···
 	if (!skb)
 		return NET_XMIT_CN | ret;
 
-	qdisc_drop(skb, sch, to_free);
+	qdisc_drop_reason(skb, sch, to_free, reason);
 	return NET_XMIT_CN;
 }
 

net/sched/sch_sfb.c

···
 		       struct sk_buff **to_free)
 {
 
+	enum skb_drop_reason reason = SKB_DROP_REASON_QDISC_OVERLIMIT;
 	struct sfb_sched_data *q = qdisc_priv(sch);
 	unsigned int len = qdisc_pkt_len(skb);
 	struct Qdisc *child = q->qdisc;
···
 	}
 
 	r = get_random_u16() & SFB_MAX_PROB;
+	reason = SKB_DROP_REASON_QDISC_CONGESTED;
 
 	if (unlikely(r < p_min)) {
 		if (unlikely(p_min > SFB_MAX_PROB / 2)) {
···
 	return ret;
 
 drop:
-	qdisc_drop(skb, sch, to_free);
+	qdisc_drop_reason(skb, sch, to_free, reason);
 	return NET_XMIT_CN;
 other_drop:
 	if (ret & __NET_XMIT_BYPASS)