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, 21 deletions

diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 94cecef70145..209a4ca4b98d 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -311,25 +311,6 @@ static void prio_put(struct Qdisc *q, unsigned long cl)
         return;
 }
 
-static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg)
-{
-        unsigned long cl = *arg;
-        struct prio_sched_data *q = qdisc_priv(sch);
-
-        if (cl - 1 > q->bands)
-                return -ENOENT;
-        return 0;
-}
-
-static int prio_delete(struct Qdisc *sch, unsigned long cl)
-{
-        struct prio_sched_data *q = qdisc_priv(sch);
-        if (cl - 1 > q->bands)
-                return -ENOENT;
-        return 0;
-}
-
-
 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
                            struct tcmsg *tcm)
 {
@@ -392,8 +373,6 @@ static const struct Qdisc_class_ops prio_class_ops = {
         .leaf           =       prio_leaf,
         .get            =       prio_get,
         .put            =       prio_put,
-        .change         =       prio_change,
-        .delete         =       prio_delete,
         .walk           =       prio_walk,
         .tcf_chain      =       prio_find_tcf,
         .bind_tcf       =       prio_bind,