since initial revision of cbq in 2004 iproute2 never implemented
support for TCA_CBQ_OVL_STRATEGY, which is what needs to be set to
activate the class->drop() call (TC_CBQ_OVL_DROP strategy must be
set by userspace).
So lets remove this. We can even do this in a backwards compatible
way by switching ovl_drop to perform a dequeue+drop on the leaf.
A followup commit can then remove all .drop qdisc methods since this
was the only caller.
Signed-off-by: Florian Westphal <f...@strlen.de>
---
On a related note, iproute2 doesn't support the TCA_CBQ_POLICE
attribute either. If we'd remove that too we could then get rid
of __parent and reshape_fail in struct Qdisc.
However, in TCA_CBQ_POLICE case there is no way to replace
the functionality, i.e. we'd have to -EOPNOTSUPP or ignore
TCA_CBQ_POLICE if some other non-iproute2 tool presents it to us.
AFAICS TCA_CBQ_POLICE doesn't work all that well even if userspace
would set it, one needs to:
add a class
attach a qdisc to the class (default pfifo doesn't work as
q->handle is 0 and cbq_set_police() is a no-op in this case)
re-'add' the same class (tc class change ...) again
user must also specifiy a defmap (e.g. 'split 1:0 defmap 3f'), since
this 'police' feature relies on its presence
the added qdisc (or the leaves) must be one of bfifo, pfifo, tbf or
netem as only these implement qdisc_reshape_fail() call.
If all of these conditions are met, then instead of drop the leaf
qdiscs mentioned above would attempt to re-enqueue the skb in the
cbq TC_PRIO_BESTEFFORT class if their limit is reached.
I think it would be safe to just ignore TCA_CBQ_POLICE and change the
qdiscs to drop right away.
Does anyone have a reason to leave this in the tree? Thanks!
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index baafddf..df79791 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -542,9 +542,14 @@ static void cbq_ovl_lowprio(struct cbq_class *cl)
static void cbq_ovl_drop(struct cbq_class *cl)
{
- if (cl->q->ops->drop)
- if (cl->q->ops->drop(cl->q))
- cl->qdisc->q.qlen--;
+ struct sk_buff *skb = cl->q->ops->dequeue(cl->q);
+
+ if (skb) {
+ cl->deficit -= qdisc_pkt_len(skb);
+ cl->qdisc->q.qlen--;
+ qdisc_drop(skb, cl->qdisc);
+ }
+
cl->xstats.overactions++;
cbq_ovl_classic(cl);
}
--
2.7.3
