net/mlx5e: Use flag to properly monitor a flow rule offloading state

Instead of relaying on the 'flow->rule' pointer value which can be
valid or invalid (in case the FW returns an error while trying to offload
the rule), monitor the rule state using a flag.

In downstream patch which adds support to IP tunneling neigh update
flow, a TC rule could be cached in the driver and not offloaded into the
HW. In this case, the flow handle pointer stays NULL.

Check the offloaded flag to properly deal with rules which are currently
not offloaded when querying rule statistics.

This patch doesn't add any new functionality.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -59,6 +59,7 @@ struct mlx5_nic_flow_attr {
 enum {
 	MLX5E_TC_FLOW_ESWITCH	= BIT(0),
 	MLX5E_TC_FLOW_NIC	= BIT(1),
+	MLX5E_TC_FLOW_OFFLOADED	= BIT(2),
 };
 
 struct mlx5e_tc_flow {
@@ -245,6 +246,7 @@ static void mlx5e_tc_del_fdb_flow(struct mlx5e_priv *priv,
 	struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
 	struct mlx5_esw_flow_attr *attr = flow->esw_attr;
 
+	if (flow->flags & MLX5E_TC_FLOW_OFFLOADED)
 		mlx5_eswitch_del_offloaded_rule(esw, flow->rule, flow->esw_attr);
 
 	mlx5_eswitch_del_vlan_action(esw, flow->esw_attr);
@@ -1591,6 +1593,7 @@ int mlx5e_configure_flower(struct mlx5e_priv *priv, __be16 protocol,
 		goto err_free;
 	}
 
+	flow->flags |= MLX5E_TC_FLOW_OFFLOADED;
 	err = rhashtable_insert_fast(&tc->ht, &flow->node,
 				     tc->ht_params);
 	if (err)
@@ -1646,6 +1649,9 @@ int mlx5e_stats_flower(struct mlx5e_priv *priv,
 	if (!flow)
 		return -EINVAL;
 
+	if (!(flow->flags & MLX5E_TC_FLOW_OFFLOADED))
+		return 0;
+
 	counter = mlx5_flow_rule_counter(flow->rule);
 	if (!counter)
 		return 0;