net/mlx5e: CT: Update connection tracking steering entries

Previously, replacing a connection tracking steering entry was done by
adding a new rule (with the same tag but possibly different mod hdr
actions/labels) then removing the old rule.

This approach doesn't work in hardware steering because two steering
entries with the same tag cannot coexist in a hardware steering table.

This commit prepares for that by adding a new ct_rule_update operation on
the ct_fs_ops struct which is used instead of add+delete.
Implementations for both dmfs (firmware steering) and smfs (software
steering) are provided, which simply add the new rule and delete the old
one.
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20240808055927.2059700-12-tariqt@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlx5/core/en/tc/ct_fs.h

@@ -25,6 +25,8 @@ struct mlx5_ct_fs_ops {
 						struct mlx5_flow_attr *attr,
 						struct flow_rule *flow_rule);
 	void (*ct_rule_del)(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule);
+	int (*ct_rule_update)(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule,
+			      struct mlx5_flow_spec *spec, struct mlx5_flow_attr *attr);
 
 	size_t priv_size;
 };

drivers/net/ethernet/mellanox/mlx5/core/en/tc/ct_fs_dmfs.c

@@ -65,9 +65,30 @@ mlx5_ct_fs_dmfs_ct_rule_del(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_ru
 	kfree(dmfs_rule);
 }
 
+static int mlx5_ct_fs_dmfs_ct_rule_update(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule,
+					  struct mlx5_flow_spec *spec, struct mlx5_flow_attr *attr)
+{
+	struct mlx5_ct_fs_dmfs_rule *dmfs_rule = container_of(fs_rule,
+							      struct mlx5_ct_fs_dmfs_rule,
+							      fs_rule);
+	struct mlx5e_priv *priv = netdev_priv(fs->netdev);
+	struct mlx5_flow_handle *rule;
+
+	rule = mlx5_tc_rule_insert(priv, spec, attr);
+	if (IS_ERR(rule))
+		return PTR_ERR(rule);
+	mlx5_tc_rule_delete(priv, dmfs_rule->rule, dmfs_rule->attr);
+
+	dmfs_rule->rule = rule;
+	dmfs_rule->attr = attr;
+
+	return 0;
+}
+
 static struct mlx5_ct_fs_ops dmfs_ops = {
 	.ct_rule_add = mlx5_ct_fs_dmfs_ct_rule_add,
 	.ct_rule_del = mlx5_ct_fs_dmfs_ct_rule_del,
+	.ct_rule_update = mlx5_ct_fs_dmfs_ct_rule_update,
 
 	.init = mlx5_ct_fs_dmfs_init,
 	.destroy = mlx5_ct_fs_dmfs_destroy,

drivers/net/ethernet/mellanox/mlx5/core/en/tc/ct_fs_smfs.c

@@ -368,9 +368,35 @@ mlx5_ct_fs_smfs_ct_rule_del(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_ru
 	kfree(smfs_rule);
 }
 
+static int mlx5_ct_fs_smfs_ct_rule_update(struct mlx5_ct_fs *fs, struct mlx5_ct_fs_rule *fs_rule,
+					  struct mlx5_flow_spec *spec, struct mlx5_flow_attr *attr)
+{
+	struct mlx5_ct_fs_smfs_rule *smfs_rule = container_of(fs_rule,
+							      struct mlx5_ct_fs_smfs_rule,
+							      fs_rule);
+	struct mlx5_ct_fs_smfs *fs_smfs = mlx5_ct_fs_priv(fs);
+	struct mlx5dr_action *actions[3];  /* We only need to create 3 actions, see below. */
+	struct mlx5dr_rule *rule;
+
+	actions[0] = smfs_rule->count_action;
+	actions[1] = attr->modify_hdr->action.dr_action;
+	actions[2] = fs_smfs->fwd_action;
+
+	rule = mlx5_smfs_rule_create(smfs_rule->smfs_matcher->dr_matcher, spec,
+				     ARRAY_SIZE(actions), actions, spec->flow_context.flow_source);
+	if (!rule)
+		return -EINVAL;
+
+	mlx5_smfs_rule_destroy(smfs_rule->rule);
+	smfs_rule->rule = rule;
+
+	return 0;
+}
+
 static struct mlx5_ct_fs_ops fs_smfs_ops = {
 	.ct_rule_add = mlx5_ct_fs_smfs_ct_rule_add,
 	.ct_rule_del = mlx5_ct_fs_smfs_ct_rule_del,
+	.ct_rule_update = mlx5_ct_fs_smfs_ct_rule_update,
 
 	.init = mlx5_ct_fs_smfs_init,
 	.destroy = mlx5_ct_fs_smfs_destroy,

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

@@ -884,7 +884,6 @@ mlx5_tc_ct_entry_update_rule(struct mlx5_tc_ct_priv *ct_priv,
 	struct mlx5_ct_zone_rule *zone_rule = &entry->zone_rules[nat];
 	struct mlx5_flow_attr *attr = zone_rule->attr, *old_attr;
 	struct mlx5e_mod_hdr_handle *mh;
-	struct mlx5_ct_fs_rule *rule;
 	struct mlx5_flow_spec *spec;
 	int err;
 
@@ -902,22 +901,19 @@ mlx5_tc_ct_entry_update_rule(struct mlx5_tc_ct_priv *ct_priv,
 	err = mlx5_tc_ct_entry_create_mod_hdr(ct_priv, attr, flow_rule, &mh, zone_restore_id,
 					      nat, mlx5_tc_ct_entry_in_ct_nat_table(entry));
 	if (err) {
-		ct_dbg("Failed to create ct entry mod hdr");
+		ct_dbg("Failed to create ct entry mod hdr, err: %d", err);
 		goto err_mod_hdr;
 	}
 
 	mlx5_tc_ct_set_tuple_match(ct_priv, spec, flow_rule);
 	mlx5e_tc_match_to_reg_match(spec, ZONE_TO_REG, entry->tuple.zone, MLX5_CT_ZONE_MASK);
 
-	rule = ct_priv->fs_ops->ct_rule_add(ct_priv->fs, spec, attr, flow_rule);
-	if (IS_ERR(rule)) {
-		err = PTR_ERR(rule);
-		ct_dbg("Failed to add replacement ct entry rule, nat: %d", nat);
+	err = ct_priv->fs_ops->ct_rule_update(ct_priv->fs, zone_rule->rule, spec, attr);
+	if (err) {
+		ct_dbg("Failed to update ct entry rule, nat: %d, err: %d", nat, err);
 		goto err_rule;
 	}
 
-	ct_priv->fs_ops->ct_rule_del(ct_priv->fs, zone_rule->rule);
-	zone_rule->rule = rule;
 	mlx5_tc_ct_entry_destroy_mod_hdr(ct_priv, old_attr, zone_rule->mh);
 	zone_rule->mh = mh;
 	mlx5_put_label_mapping(ct_priv, old_attr->ct_attr.ct_labels_id);