sched, cls: check if we could overwrite actions when changing a filter

When actions are attached to a filter, they are a part of the filter
itself, so when changing a filter we should allow to overwrite the actions
inside as well.

In my specific case, when I tried to _append_ a new action to an existing
filter which already has an action, I got EEXIST since kernel refused
to overwrite the existing one in kernel.

This patch checks if we are changing the filter checking NLM_F_CREATE flag
(Sigh, filters don't use NLM_F_REPLACE...) and then passes the boolean down
to actions. This fixes the problem above.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 257029c54332..35be16f7c192 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -349,7 +349,7 @@ static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
 static int flow_change(struct net *net, struct sk_buff *in_skb,
                        struct tcf_proto *tp, unsigned long base,
                        u32 handle, struct nlattr **tca,
-                       unsigned long *arg)
+                       unsigned long *arg, bool ovr)
 {
         struct flow_head *head = tp->root;
         struct flow_filter *f;
@@ -393,7 +393,7 @@ static int flow_change(struct net *net, struct sk_buff *in_skb,
         }
 
         tcf_exts_init(&e, TCA_FLOW_ACT, TCA_FLOW_POLICE);
-        err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e);
+        err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
         if (err < 0)
                 return err;