net/sched: introduce flow_offload action cookie

Currently a hardware action is uniquely identified by the <id, hw_index>
tuple. However, the id is set by the flow_act_setup callback and tc core
cannot enforce this, and it is possible that a future change could break
this. In addition, <id, hw_index> are not unique across network namespaces.

Uniquely identify the action by setting an action cookie by the tc core.
Use the unique action cookie to query the action's hardware stats.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/net/flow_offload.h

@@ -228,6 +228,7 @@ void flow_action_cookie_destroy(struct flow_action_cookie *cookie);
 struct flow_action_entry {
 	enum flow_action_id		id;
 	u32				hw_index;
+	unsigned long			act_cookie;
 	enum flow_action_hw_stats	hw_stats;
 	action_destr			destructor;
 	void				*destructor_priv;
@@ -610,6 +611,7 @@ struct flow_offload_action {
 	enum offload_act_command  command;
 	enum flow_action_id id;
 	u32 index;
+	unsigned long cookie;
 	struct flow_stats stats;
 	struct flow_action action;
 };

net/sched/act_api.c

@@ -192,6 +192,7 @@ static int offload_action_init(struct flow_offload_action *fl_action,
 	fl_action->extack = extack;
 	fl_action->command = cmd;
 	fl_action->index = act->tcfa_index;
+	fl_action->cookie = (unsigned long)act;
 
 	if (act->ops->offload_act_setup) {
 		spin_lock_bh(&act->tcfa_lock);

net/sched/cls_api.c

@@ -3577,6 +3577,7 @@ int tc_setup_action(struct flow_action *flow_action,
 		for (k = 0; k < index ; k++) {
 			entry[k].hw_stats = tc_act_hw_stats(act->hw_stats);
 			entry[k].hw_index = act->tcfa_index;
+			entry[k].act_cookie = (unsigned long)act;
 		}
 
 		j += index;