Subject: [PATCH] net: ethernet: mtk_eth_soc: improve keeping track of offloaded flows
From: Felix Fietkau <[email-masked]>
Date: Thu, 23 Mar 2023 10:24:11 +0100

Unify tracking of L2 and L3 flows. Use the generic list field in struct
mtk_foe_entry for tracking L2 subflows. Preparation for improving
flow accounting support.

Signed-off-by: Felix Fietkau <[email-masked]>
---
 drivers/net/ethernet/mediatek/mtk_ppe.c | 162 ++++++++++++------------
 drivers/net/ethernet/mediatek/mtk_ppe.h |  15 +--
 2 files changed, 86 insertions(+), 91 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -482,42 +482,43 @@ int mtk_foe_entry_set_queue(struct mtk_e
 	return 0;
 }
 
+static int
+mtk_flow_entry_match_len(struct mtk_eth *eth, struct mtk_foe_entry *entry)
+{
+	int type = mtk_get_ib1_pkt_type(eth, entry->ib1);
+
+	if (type > MTK_PPE_PKT_TYPE_IPV4_DSLITE)
+		return offsetof(struct mtk_foe_entry, ipv6._rsv);
+	else
+		return offsetof(struct mtk_foe_entry, ipv4.ib2);
+}
+
 static bool
 mtk_flow_entry_match(struct mtk_eth *eth, struct mtk_flow_entry *entry,
-		     struct mtk_foe_entry *data)
+		     struct mtk_foe_entry *data, int len)
 {
-	int type, len;
-
 	if ((data->ib1 ^ entry->data.ib1) & MTK_FOE_IB1_UDP)
 		return false;
 
-	type = mtk_get_ib1_pkt_type(eth, entry->data.ib1);
-	if (type > MTK_PPE_PKT_TYPE_IPV4_DSLITE)
-		len = offsetof(struct mtk_foe_entry, ipv6._rsv);
-	else
-		len = offsetof(struct mtk_foe_entry, ipv4.ib2);
-
 	return !memcmp(&entry->data.data, &data->data, len - 4);
 }
 
 static void
-__mtk_foe_entry_clear(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
+__mtk_foe_entry_clear(struct mtk_ppe *ppe, struct mtk_flow_entry *entry,
+		      bool set_state)
 {
-	struct hlist_head *head;
 	struct hlist_node *tmp;
 
 	if (entry->type == MTK_FLOW_TYPE_L2) {
 		rhashtable_remove_fast(&ppe->l2_flows, &entry->l2_node,
 				       mtk_flow_l2_ht_params);
 
-		head = &entry->l2_flows;
-		hlist_for_each_entry_safe(entry, tmp, head, l2_data.list)
-			__mtk_foe_entry_clear(ppe, entry);
+		hlist_for_each_entry_safe(entry, tmp, &entry->l2_flows, l2_list)
+			__mtk_foe_entry_clear(ppe, entry, set_state);
 		return;
 	}
 
-	hlist_del_init(&entry->list);
-	if (entry->hash != 0xffff) {
+	if (entry->hash != 0xffff && set_state) {
 		struct mtk_foe_entry *hwe = mtk_foe_get_entry(ppe, entry->hash);
 
 		hwe->ib1 &= ~MTK_FOE_IB1_STATE;
@@ -537,7 +538,8 @@ __mtk_foe_entry_clear(struct mtk_ppe *pp
 	if (entry->type != MTK_FLOW_TYPE_L2_SUBFLOW)
 		return;
 
-	hlist_del_init(&entry->l2_data.list);
+	hlist_del_init(&entry->l2_list);
+	hlist_del_init(&entry->list);
 	kfree(entry);
 }
 
@@ -553,66 +555,55 @@ static int __mtk_foe_entry_idle_time(str
 		return now - timestamp;
 }
 
+static bool
+mtk_flow_entry_update(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
+{
+	struct mtk_foe_entry foe = {};
+	struct mtk_foe_entry *hwe;
+	u16 hash = entry->hash;
+	int len;
+
+	if (hash == 0xffff)
+		return false;
+
+	hwe = mtk_foe_get_entry(ppe, hash);
+	len = mtk_flow_entry_match_len(ppe->eth, &entry->data);
+	memcpy(&foe, hwe, len);
+
+	if (!mtk_flow_entry_match(ppe->eth, entry, &foe, len) ||
+	    FIELD_GET(MTK_FOE_IB1_STATE, foe.ib1) != MTK_FOE_STATE_BIND)
+		return false;
+
+	entry->data.ib1 = foe.ib1;
+
+	return true;
+}
+
 static void
 mtk_flow_entry_update_l2(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
 {
 	u32 ib1_ts_mask = mtk_get_ib1_ts_mask(ppe->eth);
 	struct mtk_flow_entry *cur;
-	struct mtk_foe_entry *hwe;
 	struct hlist_node *tmp;
 	int idle;
 
 	idle = __mtk_foe_entry_idle_time(ppe, entry->data.ib1);
-	hlist_for_each_entry_safe(cur, tmp, &entry->l2_flows, l2_data.list) {
+	hlist_for_each_entry_safe(cur, tmp, &entry->l2_flows, l2_list) {
 		int cur_idle;
-		u32 ib1;
-
-		hwe = mtk_foe_get_entry(ppe, cur->hash);
-		ib1 = READ_ONCE(hwe->ib1);
 
-		if (FIELD_GET(MTK_FOE_IB1_STATE, ib1) != MTK_FOE_STATE_BIND) {
-			cur->hash = 0xffff;
-			__mtk_foe_entry_clear(ppe, cur);
+		if (!mtk_flow_entry_update(ppe, cur)) {
+			__mtk_foe_entry_clear(ppe, entry, false);
 			continue;
 		}
 
-		cur_idle = __mtk_foe_entry_idle_time(ppe, ib1);
+		cur_idle = __mtk_foe_entry_idle_time(ppe, cur->data.ib1);
 		if (cur_idle >= idle)
 			continue;
 
 		idle = cur_idle;
 		entry->data.ib1 &= ~ib1_ts_mask;
-		entry->data.ib1 |= hwe->ib1 & ib1_ts_mask;
-	}
-}
-
-static void
-mtk_flow_entry_update(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
-{
-	struct mtk_foe_entry foe = {};
-	struct mtk_foe_entry *hwe;
-
-	spin_lock_bh(&ppe_lock);
-
-	if (entry->type == MTK_FLOW_TYPE_L2) {
-		mtk_flow_entry_update_l2(ppe, entry);
-		goto out;
+		entry->data.ib1 |= cur->data.ib1 & ib1_ts_mask;
 	}
-
-	if (entry->hash == 0xffff)
-		goto out;
-
-	hwe = mtk_foe_get_entry(ppe, entry->hash);
-	memcpy(&foe, hwe, ppe->eth->soc->foe_entry_size);
-	if (!mtk_flow_entry_match(ppe->eth, entry, &foe)) {
-		entry->hash = 0xffff;
-		goto out;
-	}
-
-	entry->data.ib1 = foe.ib1;
-
-out:
-	spin_unlock_bh(&ppe_lock);
 }
 
 static void
@@ -655,7 +646,8 @@ __mtk_foe_entry_commit(struct mtk_ppe *p
 void mtk_foe_entry_clear(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
 {
 	spin_lock_bh(&ppe_lock);
-	__mtk_foe_entry_clear(ppe, entry);
+	__mtk_foe_entry_clear(ppe, entry, true);
+	hlist_del_init(&entry->list);
 	spin_unlock_bh(&ppe_lock);
 }
 
@@ -702,8 +694,8 @@ mtk_foe_entry_commit_subflow(struct mtk_
 {
 	const struct mtk_soc_data *soc = ppe->eth->soc;
 	struct mtk_flow_entry *flow_info;
-	struct mtk_foe_entry foe = {}, *hwe;
 	struct mtk_foe_mac_info *l2;
+	struct mtk_foe_entry *hwe;
 	u32 ib1_mask = mtk_get_ib1_pkt_type_mask(ppe->eth) | MTK_FOE_IB1_UDP;
 	int type;
 
@@ -711,30 +703,30 @@ mtk_foe_entry_commit_subflow(struct mtk_
 	if (!flow_info)
 		return;
 
-	flow_info->l2_data.base_flow = entry;
 	flow_info->type = MTK_FLOW_TYPE_L2_SUBFLOW;
 	flow_info->hash = hash;
 	hlist_add_head(&flow_info->list,
 		       &ppe->foe_flow[hash / soc->hash_offset]);
-	hlist_add_head(&flow_info->l2_data.list, &entry->l2_flows);
+	hlist_add_head(&flow_info->l2_list, &entry->l2_flows);
 
 	hwe = mtk_foe_get_entry(ppe, hash);
-	memcpy(&foe, hwe, soc->foe_entry_size);
-	foe.ib1 &= ib1_mask;
-	foe.ib1 |= entry->data.ib1 & ~ib1_mask;
+	memcpy(&flow_info->data, hwe, soc->foe_entry_size);
+	flow_info->data.ib1 &= ib1_mask;
+	flow_info->data.ib1 |= entry->data.ib1 & ~ib1_mask;
 
-	l2 = mtk_foe_entry_l2(ppe->eth, &foe);
+	l2 = mtk_foe_entry_l2(ppe->eth, &flow_info->data);
 	memcpy(l2, &entry->data.bridge.l2, sizeof(*l2));
 
-	type = mtk_get_ib1_pkt_type(ppe->eth, foe.ib1);
+	type = mtk_get_ib1_pkt_type(ppe->eth, flow_info->data.ib1);
 	if (type == MTK_PPE_PKT_TYPE_IPV4_HNAPT)
-		memcpy(&foe.ipv4.new, &foe.ipv4.orig, sizeof(foe.ipv4.new));
+		memcpy(&flow_info->data.ipv4.new, &flow_info->data.ipv4.orig,
+		       sizeof(flow_info->data.ipv4.new));
 	else if (type >= MTK_PPE_PKT_TYPE_IPV6_ROUTE_3T && l2->etype == ETH_P_IP)
 		l2->etype = ETH_P_IPV6;
 
-	*mtk_foe_entry_ib2(ppe->eth, &foe) = entry->data.bridge.ib2;
+	*mtk_foe_entry_ib2(ppe->eth, &flow_info->data) = entry->data.bridge.ib2;
 
-	__mtk_foe_entry_commit(ppe, &foe, hash);
+	__mtk_foe_entry_commit(ppe, &flow_info->data, hash);
 }
 
 void __mtk_ppe_check_skb(struct mtk_ppe *ppe, struct sk_buff *skb, u16 hash)
@@ -744,9 +736,11 @@ void __mtk_ppe_check_skb(struct mtk_ppe
 	struct mtk_foe_entry *hwe = mtk_foe_get_entry(ppe, hash);
 	struct mtk_flow_entry *entry;
 	struct mtk_foe_bridge key = {};
+	struct mtk_foe_entry foe = {};
 	struct hlist_node *n;
 	struct ethhdr *eh;
 	bool found = false;
+	int entry_len;
 	u8 *tag;
 
 	spin_lock_bh(&ppe_lock);
@@ -754,20 +748,14 @@ void __mtk_ppe_check_skb(struct mtk_ppe
 	if (FIELD_GET(MTK_FOE_IB1_STATE, hwe->ib1) == MTK_FOE_STATE_BIND)
 		goto out;
 
-	hlist_for_each_entry_safe(entry, n, head, list) {
-		if (entry->type == MTK_FLOW_TYPE_L2_SUBFLOW) {
-			if (unlikely(FIELD_GET(MTK_FOE_IB1_STATE, hwe->ib1) ==
-				     MTK_FOE_STATE_BIND))
-				continue;
-
-			entry->hash = 0xffff;
-			__mtk_foe_entry_clear(ppe, entry);
-			continue;
-		}
+	entry_len = mtk_flow_entry_match_len(ppe->eth, hwe);
+	memcpy(&foe, hwe, entry_len);
 
-		if (found || !mtk_flow_entry_match(ppe->eth, entry, hwe)) {
+	hlist_for_each_entry_safe(entry, n, head, list) {
+		if (found ||
+		    !mtk_flow_entry_match(ppe->eth, entry, &foe, entry_len)) {
 			if (entry->hash != 0xffff)
-				entry->hash = 0xffff;
+				__mtk_foe_entry_clear(ppe, entry, false);
 			continue;
 		}
 
@@ -816,9 +804,17 @@ out:
 
 int mtk_foe_entry_idle_time(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
 {
-	mtk_flow_entry_update(ppe, entry);
+	int idle;
+
+	spin_lock_bh(&ppe_lock);
+	if (entry->type == MTK_FLOW_TYPE_L2)
+		mtk_flow_entry_update_l2(ppe, entry);
+	else
+		mtk_flow_entry_update(ppe, entry);
+	idle = __mtk_foe_entry_idle_time(ppe, entry->data.ib1);
+	spin_unlock_bh(&ppe_lock);
 
-	return __mtk_foe_entry_idle_time(ppe, entry->data.ib1);
+	return idle;
 }
 
 int mtk_ppe_prepare_reset(struct mtk_ppe *ppe)
--- a/drivers/net/ethernet/mediatek/mtk_ppe.h
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.h
@@ -286,7 +286,12 @@ enum {
 
 struct mtk_flow_entry {
 	union {
-		struct hlist_node list;
+		/* regular flows + L2 subflows */
+		struct {
+			struct hlist_node list;
+			struct hlist_node l2_list;
+		};
+		/* L2 flows */
 		struct {
 			struct rhash_head l2_node;
 			struct hlist_head l2_flows;
@@ -296,13 +301,7 @@ struct mtk_flow_entry {
 	s8 wed_index;
 	u8 ppe_index;
 	u16 hash;
-	union {
-		struct mtk_foe_entry data;
-		struct {
-			struct mtk_flow_entry *base_flow;
-			struct hlist_node list;
-		} l2_data;
-	};
+	struct mtk_foe_entry data;
 	struct rhash_head node;
 	unsigned long cookie;
 };