net/sched: support per action hw stats

There are currently two mechanisms for populating hardware stats:
1. Using flow_offload api to query the flow's statistics.
   The api assumes that the same stats values apply to all
   the flow's actions.
   This assumption breaks when action drops or jumps over following
   actions.
2. Using hw_action api to query specific action stats via a driver
   callback method. This api assures the correct action stats for
   the offloaded action, however, it does not apply to the rest of the
   actions in the flow's actions array.

Extend the flow_offload stats callback to indicate that a per action
stats update is required.
Use the existing flow_offload_action api to query the action's hw stats.
In addition, currently the tc action stats utility only updates hw actions.
Reuse the existing action stats cb infrastructure to query any action
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

@@ -594,6 +594,7 @@ struct flow_cls_common_offload {
 struct flow_cls_offload {
 	struct flow_cls_common_offload common;
 	enum flow_cls_command command;
+	bool use_act_stats;
 	unsigned long cookie;
 	struct flow_rule *rule;
 	struct flow_stats stats;

include/net/pkt_cls.h

@@ -292,9 +292,15 @@ static inline void tcf_exts_put_net(struct tcf_exts *exts)
 #define tcf_act_for_each_action(i, a, actions) \
 	for (i = 0; i < TCA_ACT_MAX_PRIO && ((a) = actions[i]); i++)
 
+static inline bool tc_act_in_hw(struct tc_action *act)
+{
+	return !!act->in_hw_count;
+}
+
 static inline void
 tcf_exts_hw_stats_update(const struct tcf_exts *exts,
-			 struct flow_stats *stats)
+			 struct flow_stats *stats,
+			 bool use_act_stats)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	int i;
@@ -302,16 +308,18 @@ tcf_exts_hw_stats_update(const struct tcf_exts *exts,
 	for (i = 0; i < exts->nr_actions; i++) {
 		struct tc_action *a = exts->actions[i];
 
-		/* if stats from hw, just skip */
-		if (tcf_action_update_hw_stats(a)) {
-			preempt_disable();
-			tcf_action_stats_update(a, stats->bytes, stats->pkts, stats->drops,
-						stats->lastused, true);
-			preempt_enable();
-
-			a->used_hw_stats = stats->used_hw_stats;
-			a->used_hw_stats_valid = stats->used_hw_stats_valid;
+		if (use_act_stats || tc_act_in_hw(a)) {
+			if (!tcf_action_update_hw_stats(a))
+				continue;
 		}
+
+		preempt_disable();
+		tcf_action_stats_update(a, stats->bytes, stats->pkts, stats->drops,
+					stats->lastused, true);
+		preempt_enable();
+
+		a->used_hw_stats = stats->used_hw_stats;
+		a->used_hw_stats_valid = stats->used_hw_stats_valid;
 	}
 #endif
 }
@@ -769,6 +777,7 @@ struct tc_cls_matchall_offload {
 	enum tc_matchall_command command;
 	struct flow_rule *rule;
 	struct flow_stats stats;
+	bool use_act_stats;
 	unsigned long cookie;
 };
 

net/sched/act_api.c

@@ -169,11 +169,6 @@ static bool tc_act_skip_sw(u32 flags)
 	return (flags & TCA_ACT_FLAGS_SKIP_SW) ? true : false;
 }
 
-static bool tc_act_in_hw(struct tc_action *act)
-{
-	return !!act->in_hw_count;
-}
-
 /* SKIP_HW and SKIP_SW are mutually exclusive flags. */
 static bool tc_act_flags_valid(u32 flags)
 {
@@ -308,9 +303,6 @@ int tcf_action_update_hw_stats(struct tc_action *action)
 	struct flow_offload_action fl_act = {};
 	int err;
 
-	if (!tc_act_in_hw(action))
-		return -EOPNOTSUPP;
-
 	err = offload_action_init(&fl_act, action, FLOW_ACT_STATS, NULL);
 	if (err)
 		return err;

net/sched/cls_flower.c

@@ -502,7 +502,7 @@ static void fl_hw_update_stats(struct tcf_proto *tp, struct cls_fl_filter *f,
 	tc_setup_cb_call(block, TC_SETUP_CLSFLOWER, &cls_flower, false,
 			 rtnl_held);
 
-	tcf_exts_hw_stats_update(&f->exts, &cls_flower.stats);
+	tcf_exts_hw_stats_update(&f->exts, &cls_flower.stats, cls_flower.use_act_stats);
 }
 
 static void __fl_put(struct cls_fl_filter *f)

net/sched/cls_matchall.c

@@ -331,7 +331,7 @@ static void mall_stats_hw_filter(struct tcf_proto *tp,
 
 	tc_setup_cb_call(block, TC_SETUP_CLSMATCHALL, &cls_mall, false, true);
 
-	tcf_exts_hw_stats_update(&head->exts, &cls_mall.stats);
+	tcf_exts_hw_stats_update(&head->exts, &cls_mall.stats, cls_mall.use_act_stats);
 }
 
 static int mall_dump(struct net *net, struct tcf_proto *tp, void *fh,