net/mlx5e: CT: Use the same counter for both directions

A connection is represented by two 5-tuple entries, one for each direction.
Currently, each direction allocates its own hw counter, which is
inefficient as ct aging is managed per connection.

Share the counter that was allocated for the original direction with the
reverse direction.

Signed-off-by: Oz Shlomo <ozsh@mellanox.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c

@@ -51,6 +51,7 @@ struct mlx5_tc_ct_priv {
 	struct mlx5_flow_table *ct_nat;
 	struct mlx5_flow_table *post_ct;
 	struct mutex control_lock; /* guards parallel adds/dels */
+	struct mutex shared_counter_lock;
 	struct mapping_ctx *zone_mapping;
 	struct mapping_ctx *labels_mapping;
 	enum mlx5_flow_namespace_type ns_type;
@@ -117,11 +118,16 @@ struct mlx5_ct_tuple {
 	u16 zone;
 };
 
+struct mlx5_ct_shared_counter {
+	struct mlx5_fc *counter;
+	refcount_t refcount;
+};
+
 struct mlx5_ct_entry {
 	struct rhash_head node;
 	struct rhash_head tuple_node;
 	struct rhash_head tuple_nat_node;
-	struct mlx5_fc *counter;
+	struct mlx5_ct_shared_counter *shared_counter;
 	unsigned long cookie;
 	unsigned long restore_cookie;
 	struct mlx5_ct_tuple tuple;
@@ -385,6 +391,16 @@ mlx5_tc_ct_set_tuple_match(struct mlx5e_priv *priv, struct mlx5_flow_spec *spec,
 	return 0;
 }
 
+static void
+mlx5_tc_ct_shared_counter_put(struct mlx5_tc_ct_priv *ct_priv, struct mlx5_ct_entry *entry)
+{
+	if (!refcount_dec_and_test(&entry->shared_counter->refcount))
+		return;
+
+	mlx5_fc_destroy(ct_priv->esw->dev, entry->shared_counter->counter);
+	kfree(entry->shared_counter);
+}
+
 static void
 mlx5_tc_ct_entry_del_rule(struct mlx5_tc_ct_priv *ct_priv,
 			  struct mlx5_ct_entry *entry,
@@ -409,7 +425,6 @@ mlx5_tc_ct_entry_del_rules(struct mlx5_tc_ct_priv *ct_priv,
 	mlx5_tc_ct_entry_del_rule(ct_priv, entry, true);
 	mlx5_tc_ct_entry_del_rule(ct_priv, entry, false);
 
-	mlx5_fc_destroy(ct_priv->esw->dev, entry->counter);
 }
 
 static struct flow_action_entry *
@@ -683,7 +698,7 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 	attr->dest_ft = ct_priv->post_ct;
 	attr->ft = nat ? ct_priv->ct_nat : ct_priv->ct;
 	attr->outer_match_level = MLX5_MATCH_L4;
-	attr->counter = entry->counter;
+	attr->counter = entry->shared_counter->counter;
 	attr->flags |= MLX5_ESW_ATTR_FLAG_NO_IN_PORT;
 
 	mlx5_tc_ct_set_tuple_match(netdev_priv(ct_priv->netdev), spec, flow_rule);
@@ -716,18 +731,73 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 	return err;
 }
 
+static struct mlx5_ct_shared_counter *
+mlx5_tc_ct_shared_counter_get(struct mlx5_tc_ct_priv *ct_priv,
+			      struct mlx5_ct_entry *entry)
+{
+	struct mlx5_ct_tuple rev_tuple = entry->tuple;
+	struct mlx5_ct_shared_counter *shared_counter;
+	struct mlx5_eswitch *esw = ct_priv->esw;
+	struct mlx5_ct_entry *rev_entry;
+	__be16 tmp_port;
+
+	/* get the reversed tuple */
+	tmp_port = rev_tuple.port.src;
+	rev_tuple.port.src = rev_tuple.port.dst;
+	rev_tuple.port.dst = tmp_port;
+
+	if (rev_tuple.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
+		__be32 tmp_addr = rev_tuple.ip.src_v4;
+
+		rev_tuple.ip.src_v4 = rev_tuple.ip.dst_v4;
+		rev_tuple.ip.dst_v4 = tmp_addr;
+	} else if (rev_tuple.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
+		struct in6_addr tmp_addr = rev_tuple.ip.src_v6;
+
+		rev_tuple.ip.src_v6 = rev_tuple.ip.dst_v6;
+		rev_tuple.ip.dst_v6 = tmp_addr;
+	} else {
+		return ERR_PTR(-EOPNOTSUPP);
+	}
+
+	/* Use the same counter as the reverse direction */
+	mutex_lock(&ct_priv->shared_counter_lock);
+	rev_entry = rhashtable_lookup_fast(&ct_priv->ct_tuples_ht, &rev_tuple,
+					   tuples_ht_params);
+	if (rev_entry) {
+		if (refcount_inc_not_zero(&rev_entry->shared_counter->refcount)) {
+			mutex_unlock(&ct_priv->shared_counter_lock);
+			return rev_entry->shared_counter;
+		}
+	}
+	mutex_unlock(&ct_priv->shared_counter_lock);
+
+	shared_counter = kzalloc(sizeof(*shared_counter), GFP_KERNEL);
+	if (!shared_counter)
+		return ERR_PTR(-ENOMEM);
+
+	shared_counter->counter = mlx5_fc_create(esw->dev, true);
+	if (IS_ERR(shared_counter->counter)) {
+		ct_dbg("Failed to create counter for ct entry");
+		kfree(shared_counter);
+		return ERR_PTR(PTR_ERR(shared_counter->counter));
+	}
+
+	refcount_set(&shared_counter->refcount, 1);
+	return shared_counter;
+}
+
 static int
 mlx5_tc_ct_entry_add_rules(struct mlx5_tc_ct_priv *ct_priv,
 			   struct flow_rule *flow_rule,
 			   struct mlx5_ct_entry *entry,
 			   u8 zone_restore_id)
 {
-	struct mlx5_eswitch *esw = ct_priv->esw;
 	int err;
 
-	entry->counter = mlx5_fc_create(esw->dev, true);
-	if (IS_ERR(entry->counter)) {
-		err = PTR_ERR(entry->counter);
+	entry->shared_counter = mlx5_tc_ct_shared_counter_get(ct_priv, entry);
+	if (IS_ERR(entry->shared_counter)) {
+		err = PTR_ERR(entry->shared_counter);
 		ct_dbg("Failed to create counter for ct entry");
 		return err;
 	}
@@ -747,7 +817,7 @@ mlx5_tc_ct_entry_add_rules(struct mlx5_tc_ct_priv *ct_priv,
 err_nat:
 	mlx5_tc_ct_entry_del_rule(ct_priv, entry, false);
 err_orig:
-	mlx5_fc_destroy(esw->dev, entry->counter);
+	mlx5_tc_ct_shared_counter_put(ct_priv, entry);
 	return err;
 }
 
@@ -837,12 +907,16 @@ mlx5_tc_ct_del_ft_entry(struct mlx5_tc_ct_priv *ct_priv,
 			struct mlx5_ct_entry *entry)
 {
 	mlx5_tc_ct_entry_del_rules(ct_priv, entry);
+	mutex_lock(&ct_priv->shared_counter_lock);
 	if (entry->tuple_node.next)
 		rhashtable_remove_fast(&ct_priv->ct_tuples_nat_ht,
 				       &entry->tuple_nat_node,
 				       tuples_nat_ht_params);
 	rhashtable_remove_fast(&ct_priv->ct_tuples_ht, &entry->tuple_node,
 			       tuples_ht_params);
+	mutex_unlock(&ct_priv->shared_counter_lock);
+	mlx5_tc_ct_shared_counter_put(ct_priv, entry);
+
 }
 
 static int
@@ -879,7 +953,7 @@ mlx5_tc_ct_block_flow_offload_stats(struct mlx5_ct_ft *ft,
 	if (!entry)
 		return -ENOENT;
 
-	mlx5_fc_query_cached(entry->counter, &bytes, &packets, &lastuse);
+	mlx5_fc_query_cached(entry->shared_counter->counter, &bytes, &packets, &lastuse);
 	flow_stats_update(&f->stats, bytes, packets, 0, lastuse,
 			  FLOW_ACTION_HW_STATS_DELAYED);
 
@@ -1892,6 +1966,7 @@ mlx5_tc_ct_init(struct mlx5e_priv *priv, struct mlx5_fs_chains *chains,
 
 	idr_init(&ct_priv->fte_ids);
 	mutex_init(&ct_priv->control_lock);
+	mutex_init(&ct_priv->shared_counter_lock);
 	rhashtable_init(&ct_priv->zone_ht, &zone_params);
 	rhashtable_init(&ct_priv->ct_tuples_ht, &tuples_ht_params);
 	rhashtable_init(&ct_priv->ct_tuples_nat_ht, &tuples_nat_ht_params);
@@ -1934,6 +2009,7 @@ mlx5_tc_ct_clean(struct mlx5_tc_ct_priv *ct_priv)
 	rhashtable_destroy(&ct_priv->ct_tuples_nat_ht);
 	rhashtable_destroy(&ct_priv->zone_ht);
 	mutex_destroy(&ct_priv->control_lock);
+	mutex_destroy(&ct_priv->shared_counter_lock);
 	idr_destroy(&ct_priv->fte_ids);
 	kfree(ct_priv);
 }