[net-next PATCH 4/6] tc simple action fix late binding

[Jamal Hadi Salim]

From: Jamal Hadi Salim <j...@mojatatu.com>

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 <j...@mojatatu.com>
---
 net/sched/act_simple.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 2057fd56..d9f44be 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, aexists = 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]);
+       aexists = tcf_hash_check(tn, parm->index, a, bind);
+       if (aexists && bind)
+               return 0;
+
+       if (tb[TCA_DEF_DATA] == NULL) {
+               if (aexists)
+                       tcf_hash_release(a, bind);
+               return -EINVAL;
+       }
+
        defdata = nla_data(tb[TCA_DEF_DATA]);
 
-       if (!tcf_hash_check(tn, parm->index, a, bind)) {
+       if (!aexists) {
                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;
-- 
1.9.1