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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index bef2d64..166fcca 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1417,7 +1417,9 @@
goto out;
break;
case RTM_DELTCLASS:
- err = cops->delete(q, cl);
+ err = -EOPNOTSUPP;
+ if (cops->delete)
+ err = cops->delete(q, cl);
if (err == 0)
tclass_notify(skb, n, q, cl, RTM_DELTCLASS);
goto out;
@@ -1431,7 +1433,9 @@
}
new_cl = cl;
- err = cops->change(q, clid, pid, tca, &new_cl);
+ err = -EOPNOTSUPP;
+ if (cops->change)
+ err = cops->change(q, clid, pid, tca, &new_cl);
if (err == 0)
tclass_notify(skb, n, q, new_cl, RTM_NEWTCLASS);
