[PATCH v8 net-next 09/13] flow_offload: add process to update action stats from hardware

[Simon Horman <simon.horman@xxxxxxxxxxxx>]

From: Baowen Zheng <baowen.zheng@xxxxxxxxxxxx>

When collecting stats for actions update them using both
hardware and software counters.

Stats update process should not run in context of preempt_disable.

Signed-off-by: Baowen Zheng <baowen.zheng@xxxxxxxxxxxx>
Signed-off-by: Louis Peens <louis.peens@xxxxxxxxxxxx>
Signed-off-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
---
 include/net/act_api.h |  1 +
 include/net/pkt_cls.h | 18 ++++++++++--------
 net/sched/act_api.c   | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 15c6a881817d..20104dfdd57c 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -253,6 +253,7 @@ void tcf_action_update_stats(struct tc_action *a, u64 bytes, u64 packets,
 			     u64 drops, bool hw);
 int tcf_action_copy_stats(struct sk_buff *, struct tc_action *, int);
 
+int tcf_action_update_hw_stats(struct tc_action *action);
 int tcf_action_check_ctrlact(int action, struct tcf_proto *tp,
 			     struct tcf_chain **handle,
 			     struct netlink_ext_ack *newchain);
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index efdfab8eb00c..337a3ebb4666 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -273,18 +273,20 @@ tcf_exts_hw_stats_update(const struct tcf_exts *exts,
 #ifdef CONFIG_NET_CLS_ACT
 	int i;
 
-	preempt_disable();
-
 	for (i = 0; i < exts->nr_actions; i++) {
 		struct tc_action *a = exts->actions[i];
 
-		tcf_action_stats_update(a, bytes, packets, drops,
-					lastuse, true);
-		a->used_hw_stats = used_hw_stats;
-		a->used_hw_stats_valid = used_hw_stats_valid;
-	}
+		/* if stats from hw, just skip */
+		if (tcf_action_update_hw_stats(a)) {
+			preempt_disable();
+			tcf_action_stats_update(a, bytes, packets, drops,
+						lastuse, true);
+			preempt_enable();
 
-	preempt_enable();
+			a->used_hw_stats = used_hw_stats;
+			a->used_hw_stats_valid = used_hw_stats_valid;
+		}
+	}
 #endif
 }
 
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index d446e89ececc..f9186f283488 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -246,6 +246,37 @@ static int tcf_action_offload_add(struct tc_action *action,
 	return err;
 }
 
+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;
+
+	err = tcf_action_offload_cmd(&fl_act, NULL, NULL);
+	if (!err) {
+		preempt_disable();
+		tcf_action_stats_update(action, fl_act.stats.bytes,
+					fl_act.stats.pkts,
+					fl_act.stats.drops,
+					fl_act.stats.lastused,
+					true);
+		preempt_enable();
+		action->used_hw_stats = fl_act.stats.used_hw_stats;
+		action->used_hw_stats_valid = true;
+	} else {
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(tcf_action_update_hw_stats);
+
 static int tcf_action_offload_del(struct tc_action *action)
 {
 	struct flow_offload_action fl_act = {};
@@ -1318,6 +1349,9 @@ int tcf_action_copy_stats(struct sk_buff *skb, struct tc_action *p,
 	if (p == NULL)
 		goto errout;
 
+	/* update hw stats for this action */
+	tcf_action_update_hw_stats(p);
+
 	/* compat_mode being true specifies a call that is supposed
 	 * to add additional backward compatibility statistic TLVs.
 	 */
-- 
2.20.1