net_sched: fix class grafting errno codes

If the parent qdisc doesn't support classes, use EOPNOTSUPP.
If the parent class doesn't exist, use ENOENT. Currently EINVAL
is returned in both cases.

Additionally check whether grafting is supported and remove a now
unnecessary graft function from sch_ingress.

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

1 files changed, 4 insertions, 4 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 24d17ce9c294..bef2d645a366 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -728,14 +728,14 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
         } else {
                 const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
 
-                err = -EINVAL;
-
-                if (cops) {
+                err = -EOPNOTSUPP;
+                if (cops && cops->graft) {
                         unsigned long cl = cops->get(parent, classid);
                         if (cl) {
                                 err = cops->graft(parent, cl, new, &old);
                                 cops->put(parent, cl);
-                        }
+                        } else
+                                err = -ENOENT;
                 }
                 if (!err)
                         notify_and_destroy(skb, n, classid, old, new);