net sched: simple action fix late binding

The process below was broken and is fixed with this patch.

//add a simple action and give it an instance id of 1
sudo tc actions add action simple sdata "foobar" index 1
//create a filter which binds to simple action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action simple index 1

Message before fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel

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

1 files changed, 12 insertions, 6 deletions

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 75b2be13fbcc..3a33fb648a6d 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -87,7 +87,7 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
         struct tc_defact *parm;
         struct tcf_defact *d;
         char *defdata;
-        int ret = 0, err;
+        int ret = 0, err, exists = 0;
 
         if (nla == NULL)
                 return -EINVAL;
@@ -99,13 +99,21 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
         if (tb[TCA_DEF_PARMS] == NULL)
                 return -EINVAL;
 
-        if (tb[TCA_DEF_DATA] == NULL)
-                return -EINVAL;
 
         parm = nla_data(tb[TCA_DEF_PARMS]);
+        exists = tcf_hash_check(tn, parm->index, a, bind);
+        if (exists && bind)
+                return 0;
+
+        if (tb[TCA_DEF_DATA] == NULL) {
+                if (exists)
+                        tcf_hash_release(a, bind);
+                return -EINVAL;
+        }
+
         defdata = nla_data(tb[TCA_DEF_DATA]);
 
-        if (!tcf_hash_check(tn, parm->index, a, bind)) {
+        if (!exists) {
                 ret = tcf_hash_create(tn, parm->index, est, a,
                                       sizeof(*d), bind, false);
                 if (ret)
@@ -122,8 +130,6 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
         } else {
                 d = to_defact(a);
 
-                if (bind)
-                        return 0;
                 tcf_hash_release(a, bind);
                 if (!ovr)
                         return -EEXIST;