net/sched: sch_cake: Factor out config variables into separate struct

Factor out all the user-configurable variables into a separate struct
and embed it into struct cake_sched_data. This is done in preparation
for sharing the configuration across multiple instances of cake in an mq
setup.

No functional change is intended with this patch.

Reviewed-by: Jamal Hadi Salim <[e-mail]>
Reviewed-by: Willem de Bruijn <[e-mail]>
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_cake.c

···
 	u32	way_collisions;
 }; /* number of tins is small, so size of this struct doesn't matter much */
 
+struct cake_sched_config {
+	u64		rate_bps;
+	u64		interval;
+	u64		target;
+	u32		buffer_config_limit;
+	u32		fwmark_mask;
+	u16		fwmark_shft;
+	s16		rate_overhead;
+	u16		rate_mpu;
+	u16		rate_flags;
+	u8		tin_mode;
+	u8		flow_mode;
+	u8		atm_mode;
+	u8		ack_filter;
+};
+
 struct cake_sched_data {
 	struct tcf_proto __rcu *filter_list; /* optional external classifier */
 	struct tcf_block *block;
 	struct cake_tin_data *tins;
+	struct cake_sched_config *config;
 
 	struct cake_heap_entry overflow_heap[CAKE_QUEUES * CAKE_MAX_TINS];
-	u16		overflow_timeout;
-
-	u16		tin_cnt;
-	u8		tin_mode;
-	u8		flow_mode;
-	u8		ack_filter;
-	u8		atm_mode;
-
-	u32		fwmark_mask;
-	u16		fwmark_shft;
 
 	/* time_next = time_this + ((len * rate_ns) >> rate_shft) */
-	u16		rate_shft;
 	ktime_t		time_next_packet;
 	ktime_t		failsafe_next_packet;
 	u64		rate_ns;
-	u64		rate_bps;
-	u16		rate_flags;
-	s16		rate_overhead;
-	u16		rate_mpu;
-	u64		interval;
-	u64		target;
+	u16		rate_shft;
+	u16		overflow_timeout;
+	u16		tin_cnt;
 
 	/* resource tracking */
 	u32		buffer_used;
 	u32		buffer_max_used;
 	u32		buffer_limit;
-	u32		buffer_config_limit;
 
 	/* indices for dequeue */
 	u16		cur_tin;
···
 static struct sk_buff *cake_ack_filter(struct cake_sched_data *q,
 				       struct cake_flow *flow)
 {
-	bool aggressive = q->ack_filter == CAKE_ACK_AGGRESSIVE;
+	bool aggressive = q->config->ack_filter == CAKE_ACK_AGGRESSIVE;
 	struct sk_buff *elig_ack = NULL, *elig_ack_prev = NULL;
 	struct sk_buff *skb_check, *skb_prev = NULL;
 	const struct ipv6hdr *ipv6h, *ipv6h_check;
···
 	return avg;
 }
 
-static u32 cake_calc_overhead(struct cake_sched_data *q, u32 len, u32 off)
+static u32 cake_calc_overhead(struct cake_sched_data *qd, u32 len, u32 off)
 {
+	struct cake_sched_config *q = qd->config;
+
 	if (q->rate_flags & CAKE_FLAG_OVERHEAD)
 		len -= off;
 
-	if (q->max_netlen < len)
-		q->max_netlen = len;
-	if (q->min_netlen > len)
-		q->min_netlen = len;
+	if (qd->max_netlen < len)
+		qd->max_netlen = len;
+	if (qd->min_netlen > len)
+		qd->min_netlen = len;
 
 	len += q->rate_overhead;
 
···
 		len += (len + 63) / 64;
 	}
 
-	if (q->max_adjlen < len)
-		q->max_adjlen = len;
-	if (q->min_adjlen > len)
-		q->min_adjlen = len;
+	if (qd->max_adjlen < len)
+		qd->max_adjlen = len;
+	if (qd->min_adjlen > len)
+		qd->min_adjlen = len;
 
 	return len;
 }
···
 	flow->dropped++;
 	b->tin_dropped++;
 
-	if (q->rate_flags & CAKE_FLAG_INGRESS)
+	if (q->config->rate_flags & CAKE_FLAG_INGRESS)
 		cake_advance_shaper(q, b, skb, now, true);
 
 	qdisc_drop_reason(skb, sch, to_free, SKB_DROP_REASON_QDISC_OVERLIMIT);
···
 static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
 					     struct sk_buff *skb)
 {
-	struct cake_sched_data *q = qdisc_priv(sch);
+	struct cake_sched_data *qd = qdisc_priv(sch);
+	struct cake_sched_config *q = qd->config;
 	u32 tin, mark;
 	bool wash;
 	u8 dscp;
···
 	if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
 		tin = 0;
 
-	else if (mark && mark <= q->tin_cnt)
-		tin = q->tin_order[mark - 1];
+	else if (mark && mark <= qd->tin_cnt)
+		tin = qd->tin_order[mark - 1];
 
 	else if (TC_H_MAJ(skb->priority) == sch->handle &&
 		 TC_H_MIN(skb->priority) > 0 &&
-		 TC_H_MIN(skb->priority) <= q->tin_cnt)
-		tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
+		 TC_H_MIN(skb->priority) <= qd->tin_cnt)
+		tin = qd->tin_order[TC_H_MIN(skb->priority) - 1];
 
 	else {
 		if (!wash)
 			dscp = cake_handle_diffserv(skb, wash);
-		tin = q->tin_index[dscp];
+		tin = qd->tin_index[dscp];
 
-		if (unlikely(tin >= q->tin_cnt))
+		if (unlikely(tin >= qd->tin_cnt))
 			tin = 0;
 	}
 
-	return &q->tins[tin];
+	return &qd->tins[tin];
 }
 
 static u32 cake_classify(struct Qdisc *sch, struct cake_tin_data **t,
···
 	bool same_flow = false;
 
 	/* choose flow to insert into */
-	idx = cake_classify(sch, &b, skb, q->flow_mode, &ret);
+	idx = cake_classify(sch, &b, skb, q->config->flow_mode, &ret);
 	if (idx == 0) {
 		if (ret & __NET_XMIT_BYPASS)
 			qdisc_qstats_drop(sch);
···
 	if (unlikely(len > b->max_skblen))
 		b->max_skblen = len;
 
-	if (qdisc_pkt_segs(skb) > 1 && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
+	if (qdisc_pkt_segs(skb) > 1 && q->config->rate_flags & CAKE_FLAG_SPLIT_GSO) {
 		struct sk_buff *segs, *nskb;
 		netdev_features_t features = netif_skb_features(skb);
 		unsigned int slen = 0, numsegs = 0;
···
 		get_cobalt_cb(skb)->adjusted_len = cake_overhead(q, skb);
 		flow_queue_add(flow, skb);
 
-		if (q->ack_filter)
+		if (q->config->ack_filter)
 			ack = cake_ack_filter(q, flow);
 
 		if (ack) {
···
 			ack_pkt_len = qdisc_pkt_len(ack);
 			b->bytes += ack_pkt_len;
 			q->buffer_used += skb->truesize - ack->truesize;
-			if (q->rate_flags & CAKE_FLAG_INGRESS)
+			if (q->config->rate_flags & CAKE_FLAG_INGRESS)
 				cake_advance_shaper(q, b, ack, now, true);
 
 			qdisc_tree_reduce_backlog(sch, 1, ack_pkt_len);
···
 		cake_heapify_up(q, b->overflow_idx[idx]);
 
 	/* incoming bandwidth capacity estimate */
-	if (q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS) {
+	if (q->config->rate_flags & CAKE_FLAG_AUTORATE_INGRESS) {
 		u64 packet_interval = \
 			ktime_to_ns(ktime_sub(now, q->last_packet_time));
 
···
 			if (ktime_after(now,
 					ktime_add_ms(q->last_reconfig_time,
 						     250))) {
-				q->rate_bps = (q->avg_peak_bandwidth * 15) >> 4;
+				q->config->rate_bps = (q->avg_peak_bandwidth * 15) >> 4;
 				cake_reconfigure(sch);
 			}
 		}
···
 		flow->set = CAKE_SET_SPARSE;
 		b->sparse_flow_count++;
 
-		flow->deficit = cake_get_flow_quantum(b, flow, q->flow_mode);
+		flow->deficit = cake_get_flow_quantum(b, flow, q->config->flow_mode);
 	} else if (flow->set == CAKE_SET_SPARSE_WAIT) {
 		/* this flow was empty, accounted as a sparse flow, but actually
 		 * in the bulk rotation.
···
 		b->sparse_flow_count--;
 		b->bulk_flow_count++;
 
-		cake_inc_srchost_bulk_flow_count(b, flow, q->flow_mode);
-		cake_inc_dsthost_bulk_flow_count(b, flow, q->flow_mode);
+		cake_inc_srchost_bulk_flow_count(b, flow, q->config->flow_mode);
+		cake_inc_dsthost_bulk_flow_count(b, flow, q->config->flow_mode);
 	}
 
 	if (q->buffer_used > q->buffer_max_used)
···
 				b->sparse_flow_count--;
 				b->bulk_flow_count++;
 
-				cake_inc_srchost_bulk_flow_count(b, flow, q->flow_mode);
-				cake_inc_dsthost_bulk_flow_count(b, flow, q->flow_mode);
+				cake_inc_srchost_bulk_flow_count(b, flow, q->config->flow_mode);
+				cake_inc_dsthost_bulk_flow_count(b, flow, q->config->flow_mode);
 
 				flow->set = CAKE_SET_BULK;
 			} else {
···
 			}
 		}
 
-		flow->deficit += cake_get_flow_quantum(b, flow, q->flow_mode);
+		flow->deficit += cake_get_flow_quantum(b, flow, q->config->flow_mode);
 		list_move_tail(&flow->flowchain, &b->old_flows);
 
 		goto retry;
···
 				if (flow->set == CAKE_SET_BULK) {
 					b->bulk_flow_count--;
 
-					cake_dec_srchost_bulk_flow_count(b, flow, q->flow_mode);
-					cake_dec_dsthost_bulk_flow_count(b, flow, q->flow_mode);
+					cake_dec_srchost_bulk_flow_count(b, flow, q->config->flow_mode);
+					cake_dec_dsthost_bulk_flow_count(b, flow, q->config->flow_mode);
 
 					b->decaying_flow_count++;
 				} else if (flow->set == CAKE_SET_SPARSE ||
···
 				else if (flow->set == CAKE_SET_BULK) {
 					b->bulk_flow_count--;
 
-					cake_dec_srchost_bulk_flow_count(b, flow, q->flow_mode);
-					cake_dec_dsthost_bulk_flow_count(b, flow, q->flow_mode);
+					cake_dec_srchost_bulk_flow_count(b, flow, q->config->flow_mode);
+					cake_dec_dsthost_bulk_flow_count(b, flow, q->config->flow_mode);
 				} else
 					b->decaying_flow_count--;
 
···
 
 		reason = cobalt_should_drop(&flow->cvars, &b->cparams, now, skb,
 					    (b->bulk_flow_count *
-					     !!(q->rate_flags &
+					     !!(q->config->rate_flags &
 						CAKE_FLAG_INGRESS)));
 		/* Last packet in queue may be marked, shouldn't be dropped */
 		if (reason == SKB_NOT_DROPPED_YET || !flow->head)
 			break;
 
 		/* drop this packet, get another one */
-		if (q->rate_flags & CAKE_FLAG_INGRESS) {
+		if (q->config->rate_flags & CAKE_FLAG_INGRESS) {
 			len = cake_advance_shaper(q, b, skb,
 						  now, true);
 			flow->deficit -= len;
···
 		qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
 		qdisc_qstats_drop(sch);
 		qdisc_dequeue_drop(sch, skb, reason);
-		if (q->rate_flags & CAKE_FLAG_INGRESS)
+		if (q->config->rate_flags & CAKE_FLAG_INGRESS)
 			goto retry;
 	}
 
···
 	struct cake_sched_data *q = qdisc_priv(sch);
 	struct cake_tin_data *b = &q->tins[0];
 	u32 mtu = psched_mtu(qdisc_dev(sch));
-	u64 rate = q->rate_bps;
+	u64 rate = q->config->rate_bps;
 
 	q->tin_cnt = 1;
 
···
 	q->tin_order = normal_order;
 
 	cake_set_rate(b, rate, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	b->tin_quantum = 65535;
 
 	return 0;
···
 	/* convert high-level (user visible) parameters into internal format */
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 mtu = psched_mtu(qdisc_dev(sch));
-	u64 rate = q->rate_bps;
+	u64 rate = q->config->rate_bps;
 	u32 quantum = 256;
 	u32 i;
 
···
 	for (i = 0; i < q->tin_cnt; i++) {
 		struct cake_tin_data *b = &q->tins[i];
 
-		cake_set_rate(b, rate, mtu, us_to_ns(q->target),
-			      us_to_ns(q->interval));
+		cake_set_rate(b, rate, mtu, us_to_ns(q->config->target),
+			      us_to_ns(q->config->interval));
 
 		b->tin_quantum = max_t(u16, 1U, quantum);
 
···
 
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 mtu = psched_mtu(qdisc_dev(sch));
-	u64 rate = q->rate_bps;
+	u64 rate = q->config->rate_bps;
 	u32 quantum = 256;
 	u32 i;
 
···
 	for (i = 0; i < q->tin_cnt; i++) {
 		struct cake_tin_data *b = &q->tins[i];
 
-		cake_set_rate(b, rate, mtu, us_to_ns(q->target),
-			      us_to_ns(q->interval));
+		cake_set_rate(b, rate, mtu, us_to_ns(q->config->target),
+			      us_to_ns(q->config->interval));
 
 		b->tin_quantum = max_t(u16, 1U, quantum);
 
···
 
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 mtu = psched_mtu(qdisc_dev(sch));
-	u64 rate = q->rate_bps;
+	u64 rate = q->config->rate_bps;
 	u32 quantum = 1024;
 
 	q->tin_cnt = 4;
···
 
 	/* class characteristics */
 	cake_set_rate(&q->tins[0], rate, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	cake_set_rate(&q->tins[1], rate >> 4, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	cake_set_rate(&q->tins[2], rate >> 1, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	cake_set_rate(&q->tins[3], rate >> 2, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 
 	/* bandwidth-sharing weights */
 	q->tins[0].tin_quantum = quantum;
···
  */
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 mtu = psched_mtu(qdisc_dev(sch));
-	u64 rate = q->rate_bps;
+	u64 rate = q->config->rate_bps;
 	u32 quantum = 1024;
 
 	q->tin_cnt = 3;
···
 
 	/* class characteristics */
 	cake_set_rate(&q->tins[0], rate, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	cake_set_rate(&q->tins[1], rate >> 4, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 	cake_set_rate(&q->tins[2], rate >> 2, mtu,
-		      us_to_ns(q->target), us_to_ns(q->interval));
+		      us_to_ns(q->config->target), us_to_ns(q->config->interval));
 
 	/* bandwidth-sharing weights */
 	q->tins[0].tin_quantum = quantum;
···
 
 static void cake_reconfigure(struct Qdisc *sch)
 {
-	struct cake_sched_data *q = qdisc_priv(sch);
+	struct cake_sched_data *qd = qdisc_priv(sch);
+	struct cake_sched_config *q = qd->config;
 	int c, ft;
 
 	switch (q->tin_mode) {
···
 		break;
 	}
 
-	for (c = q->tin_cnt; c < CAKE_MAX_TINS; c++) {
+	for (c = qd->tin_cnt; c < CAKE_MAX_TINS; c++) {
 		cake_clear_tin(sch, c);
-		q->tins[c].cparams.mtu_time = q->tins[ft].cparams.mtu_time;
+		qd->tins[c].cparams.mtu_time = qd->tins[ft].cparams.mtu_time;
 	}
 
-	q->rate_ns   = q->tins[ft].tin_rate_ns;
-	q->rate_shft = q->tins[ft].tin_rate_shft;
+	qd->rate_ns   = qd->tins[ft].tin_rate_ns;
+	qd->rate_shft = qd->tins[ft].tin_rate_shft;
 
 	if (q->buffer_config_limit) {
-		q->buffer_limit = q->buffer_config_limit;
+		qd->buffer_limit = q->buffer_config_limit;
 	} else if (q->rate_bps) {
 		u64 t = q->rate_bps * q->interval;
 
 		do_div(t, USEC_PER_SEC / 4);
-		q->buffer_limit = max_t(u32, t, 4U << 20);
+		qd->buffer_limit = max_t(u32, t, 4U << 20);
 	} else {
-		q->buffer_limit = ~0;
+		qd->buffer_limit = ~0;
 	}
 
 	sch->flags &= ~TCQ_F_CAN_BYPASS;
 
-	q->buffer_limit = min(q->buffer_limit,
-			      max(sch->limit * psched_mtu(qdisc_dev(sch)),
-				  q->buffer_config_limit));
+	qd->buffer_limit = min(qd->buffer_limit,
+			       max(sch->limit * psched_mtu(qdisc_dev(sch)),
+				   q->buffer_config_limit));
 }
 
 static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 		       struct netlink_ext_ack *extack)
 {
-	struct cake_sched_data *q = qdisc_priv(sch);
+	struct cake_sched_data *qd = qdisc_priv(sch);
+	struct cake_sched_config *q = qd->config;
 	struct nlattr *tb[TCA_CAKE_MAX + 1];
 	u16 rate_flags;
 	u8 flow_mode;
···
 			   nla_get_s32(tb[TCA_CAKE_OVERHEAD]));
 		rate_flags |= CAKE_FLAG_OVERHEAD;
 
-		q->max_netlen = 0;
-		q->max_adjlen = 0;
-		q->min_netlen = ~0;
-		q->min_adjlen = ~0;
+		qd->max_netlen = 0;
+		qd->max_adjlen = 0;
+		qd->min_netlen = ~0;
+		qd->min_adjlen = ~0;
 	}
 
 	if (tb[TCA_CAKE_RAW]) {
 		rate_flags &= ~CAKE_FLAG_OVERHEAD;
 
-		q->max_netlen = 0;
-		q->max_adjlen = 0;
-		q->min_netlen = ~0;
-		q->min_adjlen = ~0;
+		qd->max_netlen = 0;
+		qd->max_adjlen = 0;
+		qd->min_netlen = ~0;
+		qd->min_adjlen = ~0;
 	}
 
 	if (tb[TCA_CAKE_MPU])
···
 
 	WRITE_ONCE(q->rate_flags, rate_flags);
 	WRITE_ONCE(q->flow_mode, flow_mode);
-	if (q->tins) {
+	if (qd->tins) {
 		sch_tree_lock(sch);
 		cake_reconfigure(sch);
 		sch_tree_unlock(sch);
···
 	qdisc_watchdog_cancel(&q->watchdog);
 	tcf_block_put(q->block);
 	kvfree(q->tins);
+	kvfree(q->config);
 }
 
 static int cake_init(struct Qdisc *sch, struct nlattr *opt,
 		     struct netlink_ext_ack *extack)
 {
-	struct cake_sched_data *q = qdisc_priv(sch);
+	struct cake_sched_data *qd = qdisc_priv(sch);
+	struct cake_sched_config *q;
 	int i, j, err;
+
+	q = kzalloc(sizeof(*q), GFP_KERNEL);
+	if (!q)
+		return -ENOMEM;
 
 	sch->limit = 10240;
 	sch->flags |= TCQ_F_DEQUEUE_DROPS;
···
 			       * for 5 to 10% of interval
 			       */
 	q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
-	q->cur_tin = 0;
-	q->cur_flow  = 0;
+	qd->cur_tin = 0;
+	qd->cur_flow  = 0;
+	qd->config = q;
 
-	qdisc_watchdog_init(&q->watchdog, sch);
+	qdisc_watchdog_init(&qd->watchdog, sch);
 
 	if (opt) {
 		err = cake_change(sch, opt, extack);
 
 		if (err)
-			return err;
+			goto err;
 	}
 
-	err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
+	err = tcf_block_get(&qd->block, &qd->filter_list, sch, extack);
 	if (err)
-		return err;
+		goto err;
 
 	quantum_div[0] = ~0;
 	for (i = 1; i <= CAKE_QUEUES; i++)
 		quantum_div[i] = 65535 / i;
 
-	q->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
-			   GFP_KERNEL);
-	if (!q->tins)
-		return -ENOMEM;
+	qd->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
+			    GFP_KERNEL);
+	if (!qd->tins) {
+		err = -ENOMEM;
+		goto err;
+	}
 
 	for (i = 0; i < CAKE_MAX_TINS; i++) {
-		struct cake_tin_data *b = q->tins + i;
+		struct cake_tin_data *b = qd->tins + i;
 
 		INIT_LIST_HEAD(&b->new_flows);
 		INIT_LIST_HEAD(&b->old_flows);
···
 			INIT_LIST_HEAD(&flow->flowchain);
 			cobalt_vars_init(&flow->cvars);
 
-			q->overflow_heap[k].t = i;
-			q->overflow_heap[k].b = j;
+			qd->overflow_heap[k].t = i;
+			qd->overflow_heap[k].b = j;
 			b->overflow_idx[j] = k;
 		}
 	}
 
 	cake_reconfigure(sch);
-	q->avg_peak_bandwidth = q->rate_bps;
-	q->min_netlen = ~0;
-	q->min_adjlen = ~0;
+	qd->avg_peak_bandwidth = q->rate_bps;
+	qd->min_netlen = ~0;
+	qd->min_adjlen = ~0;
 	return 0;
+err:
+	kvfree(qd->config);
+	qd->config = NULL;
+	return err;
 }
 
 static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
-	struct cake_sched_data *q = qdisc_priv(sch);
+	struct cake_sched_data *qd = qdisc_priv(sch);
+	struct cake_sched_config *q = qd->config;
 	struct nlattr *opts;
 	u16 rate_flags;
 	u8 flow_mode;