net_sched: make cls_ops->tcf_chain() optional

Some qdiscs don't support attaching filters. Handle this centrally in
cls_api and return a proper errno code (EOPNOTSUPP) instead of EINVAL.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 5 insertions, 12 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 09cdcdfe7e91..bcfbdb4758c9 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -181,6 +181,9 @@ replay:
         if ((cops = q->ops->cl_ops) == NULL)
                 return -EINVAL;
 
+        if (cops->tcf_chain == NULL)
+                return -EOPNOTSUPP;
+
         /* Do we search for filter, attached to class? */
         if (TC_H_MIN(parent)) {
                 cl = cops->get(q, parent);
@@ -433,6 +436,8 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
                 goto out;
         if ((cops = q->ops->cl_ops) == NULL)
                 goto errout;
+        if (cops->tcf_chain == NULL)
+                goto errout;
         if (TC_H_MIN(tcm->tcm_parent)) {
                 cl = cops->get(q, tcm->tcm_parent);
                 if (cl == 0)
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 2bdf241f6315..c27b8023f079 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -331,11 +331,6 @@ static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
         }
 }
 
-static struct tcf_proto **red_find_tcf(struct Qdisc *sch, unsigned long cl)
-{
-        return NULL;
-}
-
 static const struct Qdisc_class_ops red_class_ops = {
         .graft          =       red_graft,
         .leaf           =       red_leaf,
@@ -344,7 +339,6 @@ static const struct Qdisc_class_ops red_class_ops = {
         .change         =       red_change_class,
         .delete         =       red_delete,
         .walk           =       red_walk,
-        .tcf_chain      =       red_find_tcf,
         .dump           =       red_dump_class,
 };
 
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index e22dfe85e43e..28909699d24d 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -433,11 +433,6 @@ static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
         }
 }
 
-static struct tcf_proto **tbf_find_tcf(struct Qdisc *sch, unsigned long cl)
-{
-        return NULL;
-}
-
 static const struct Qdisc_class_ops tbf_class_ops =
 {
         .graft          =       tbf_graft,
@@ -447,7 +442,6 @@ static const struct Qdisc_class_ops tbf_class_ops =
         .change         =       tbf_change_class,
         .delete         =       tbf_delete,
         .walk           =       tbf_walk,
-        .tcf_chain      =       tbf_find_tcf,
         .dump           =       tbf_dump_class,
 };