sched: add helper for updating statistics on all actions

Forgetting to disable preemption around tcf_action_stats_update()
seems to be a common mistake.  Add a helper function for updating
stats on all actions of a filter.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1863,9 +1863,7 @@ int mlx5e_stats_flower(struct mlx5e_priv *priv,
 {
 	struct mlx5e_tc_table *tc = &priv->fs.tc;
 	struct mlx5e_tc_flow *flow;
-	struct tc_action *a;
 	struct mlx5_fc *counter;
-	LIST_HEAD(actions);
 	u64 bytes;
 	u64 packets;
 	u64 lastuse;
@@ -1884,13 +1882,7 @@ int mlx5e_stats_flower(struct mlx5e_priv *priv,
 
 	mlx5_fc_query_cached(counter, &bytes, &packets, &lastuse);
 
-	preempt_disable();
-
-	tcf_exts_to_list(f->exts, &actions);
-	list_for_each_entry(a, &actions, list)
-		tcf_action_stats_update(a, bytes, packets, lastuse);
-
-	preempt_enable();
+	tcf_exts_stats_update(f->exts, bytes, packets, lastuse);
 
 	return 0;
 }

drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c

@@ -397,8 +397,6 @@ int mlxsw_sp_flower_stats(struct mlxsw_sp_port *mlxsw_sp_port, bool ingress,
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	struct mlxsw_sp_acl_ruleset *ruleset;
 	struct mlxsw_sp_acl_rule *rule;
-	struct tc_action *a;
-	LIST_HEAD(actions);
 	u64 packets;
 	u64 lastuse;
 	u64 bytes;
@@ -419,13 +417,7 @@ int mlxsw_sp_flower_stats(struct mlxsw_sp_port *mlxsw_sp_port, bool ingress,
 	if (err)
 		goto err_rule_get_stats;
 
-	preempt_disable();
-
-	tcf_exts_to_list(f->exts, &actions);
-	list_for_each_entry(a, &actions, list)
-		tcf_action_stats_update(a, bytes, packets, lastuse);
-
-	preempt_enable();
+	tcf_exts_stats_update(f->exts, bytes, packets, lastuse);
 
 	mlxsw_sp_acl_ruleset_put(mlxsw_sp, ruleset);
 	return 0;

drivers/net/ethernet/netronome/nfp/nfp_net_offload.c

@@ -84,8 +84,6 @@ static void nfp_net_bpf_stats_reset(struct nfp_net *nn)
 static int
 nfp_net_bpf_stats_update(struct nfp_net *nn, struct tc_cls_bpf_offload *cls_bpf)
 {
-	struct tc_action *a;
-	LIST_HEAD(actions);
 	u64 bytes, pkts;
 
 	pkts = nn->rx_filter.pkts - nn->rx_filter_prev.pkts;
@@ -94,13 +92,8 @@ nfp_net_bpf_stats_update(struct nfp_net *nn, struct tc_cls_bpf_offload *cls_bpf)
 
 	nn->rx_filter_prev = nn->rx_filter;
 
-	preempt_disable();
-
-	tcf_exts_to_list(cls_bpf->exts, &actions);
-	list_for_each_entry(a, &actions, list)
-		tcf_action_stats_update(a, bytes, pkts, nn->rx_filter_change);
-
-	preempt_enable();
+	tcf_exts_stats_update(cls_bpf->exts,
+			      bytes, pkts, nn->rx_filter_change);
 
 	return 0;
 }

include/net/pkt_cls.h

@@ -157,6 +157,25 @@ static inline void tcf_exts_to_list(const struct tcf_exts *exts,
 #endif
 }
 
+static inline void
+tcf_exts_stats_update(const struct tcf_exts *exts,
+		      u64 bytes, u64 packets, u64 lastuse)
+{
+#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, lastuse);
+	}
+
+	preempt_enable();
+#endif
+}
+
 /**
  * tcf_exts_exec - execute tc filter extensions
  * @skb: socket buffer