net/sched: act_tunnel_key: Remove rcu_read_lock protection

Remove rcu_read_lock protection from tunnel_key_dump and use
rtnl_dereference, dump operation is protected by  rtnl lock.

Also, remove rcu_read_lock from tunnel_key_release and use
rcu_dereference_protected.

Both operations are running exclusively and a writer couldn't modify
t->params while those functions are executed.

Fixes: 54d94fd89d90 ('net/sched: Introduce act_tunnel_key')
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index dceff74..af47bdf 100644 (file)
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -194,15 +194,12 @@ static void tunnel_key_release(struct tc_action *a, int bind)
        struct tcf_tunnel_key *t = to_tunnel_key(a);
        struct tcf_tunnel_key_params *params;
 
-       rcu_read_lock();
-       params = rcu_dereference(t->params);
+       params = rcu_dereference_protected(t->params, 1);
 
        if (params->tcft_action == TCA_TUNNEL_KEY_ACT_SET)
                dst_release(&params->tcft_enc_metadata->dst);
 
        kfree_rcu(params, rcu);
-
-       rcu_read_unlock();
 }
 
 static int tunnel_key_dump_addresses(struct sk_buff *skb,
@@ -245,10 +242,8 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
                .bindcnt  = t->tcf_bindcnt - bind,
        };
        struct tcf_t tm;
-       int ret = -1;
 
-       rcu_read_lock();
-       params = rcu_dereference(t->params);
+       params = rtnl_dereference(t->params);
 
        opt.t_action = params->tcft_action;
        opt.action = params->action;
@@ -272,15 +267,11 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
                          &tm, TCA_TUNNEL_KEY_PAD))
                goto nla_put_failure;
 
-       ret = skb->len;
-       goto out;
+       return skb->len;
 
 nla_put_failure:
        nlmsg_trim(skb, b);
-out:
-       rcu_read_unlock();
-
-       return ret;
+       return -1;
 }
 
 static int tunnel_key_walker(struct net *net, struct sk_buff *skb,