[RFC Patch net-next 3/4] net_sched: use RCU for tc actions traverse

[Cong Wang <xiyou.wangcong@gmail.com>]

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/sched/act_api.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index f63e146..e3c655e 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -351,7 +351,7 @@ int tcf_action_exec(struct sk_buff *skb, const struct list_head *actions,
 		ret = TC_ACT_OK;
 		goto exec_done;
 	}
-	list_for_each_entry(a, actions, list) {
+	list_for_each_entry_rcu(a, actions, list) {
 repeat:
 		ret = a->ops->act(skb, a, res);
 		if (TC_MUNGED & skb->tc_verd) {
@@ -372,11 +372,13 @@ EXPORT_SYMBOL(tcf_action_exec);
 void tcf_action_destroy(struct list_head *actions, int bind)
 {
 	struct tc_action *a, *tmp;
+	LIST_HEAD(list);
+	list_splice_init_rcu(actions, &list, synchronize_rcu);
 
-	list_for_each_entry_safe(a, tmp, actions, list) {
+	list_for_each_entry_safe(a, tmp, &list, list) {
 		if (a->ops->cleanup(a, bind) == ACT_P_DELETED)
 			module_put(a->ops->owner);
-		list_del(&a->list);
+		list_del_rcu(&a->list);
 		kfree(a);
 	}
 }
@@ -420,7 +422,7 @@ tcf_action_dump(struct sk_buff *skb, struct list_head *actions, int bind, int re
 	int err = -EINVAL;
 	struct nlattr *nest;
 
-	list_for_each_entry(a, actions, list) {
+	list_for_each_entry_rcu(a, actions, list) {
 		nest = nla_nest_start(skb, a->order);
 		if (nest == NULL)
 			goto nla_put_failure;
@@ -542,7 +544,7 @@ int tcf_action_init(struct net *net, struct nlattr *nla,
 			goto err;
 		}
 		act->order = i;
-		list_add_tail(&act->list, actions);
+		list_add_tail_rcu(&act->list, actions);
 	}
 	return 0;
 
-- 
1.8.3.1