net_sched: make cls_ops->change and cls_ops->delete optional

Some schedulers don't support creating, changing or deleting classes.
Make the respective callbacks optionally and consistently return
-EOPNOTSUPP for unsupported operations, instead of currently either
-EOPNOTSUPP, -ENOSYS or no error.

In case of sch_prio and sch_multiq, the removed operations additionally
checked for an invalid class. This is not necessary since the class
argument can only orginate from ->get() or in case of ->change is 0
for creation of new classes, in which case ->change() incorrectly
returned -ENOENT.

As a side-effect, this patch fixes a possible (root-only) NULL pointer
function call in sch_ingress, which didn't implement a so far mandatory
->delete() operation.

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

1 files changed, 0 insertions, 7 deletions

diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index ace7902b5097..a9e646bdb605 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -42,12 +42,6 @@ static void ingress_put(struct Qdisc *sch, unsigned long cl)
 {
 }
 
-static int ingress_change(struct Qdisc *sch, u32 classid, u32 parent,
-                          struct nlattr **tca, unsigned long *arg)
-{
-        return 0;
-}
-
 static void ingress_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 {
         return;
@@ -120,7 +114,6 @@ static const struct Qdisc_class_ops ingress_class_ops = {
         .leaf           =       ingress_leaf,
         .get            =       ingress_get,
         .put            =       ingress_put,
-        .change         =       ingress_change,
         .walk           =       ingress_walk,
         .tcf_chain      =       ingress_find_tcf,
         .bind_tcf       =       ingress_bind_filter,