pkt_sched: Add peek emulation for non-work-conserving qdiscs.
This patch adds qdisc_peek_dequeued() wrapper to emulate peek method
with qdisc->dequeue() and storing "peeked" skb in qdisc->gso_skb until
dequeuing. This is mainly for compatibility reasons not to break some
strange configs because peeking is expected for non-work-conserving
parent qdiscs to query work-conserving child qdiscs.
This implementation requires using qdisc_dequeue_peeked() wrapper
instead of directly calling qdisc->dequeue() for all qdiscs ever
querried with qdisc->ops->peek() or qdisc_peek_dequeued().
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index da6839a..9dcb5bf 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -438,6 +438,29 @@
return skb_peek(&sch->q);
}
+/* generic pseudo peek method for non-work-conserving qdisc */
+static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
+{
+ /* we can reuse ->gso_skb because peek isn't called for root qdiscs */
+ if (!sch->gso_skb)
+ sch->gso_skb = sch->dequeue(sch);
+
+ return sch->gso_skb;
+}
+
+/* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
+static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
+{
+ struct sk_buff *skb = sch->gso_skb;
+
+ if (skb)
+ sch->gso_skb = NULL;
+ else
+ skb = sch->dequeue(sch);
+
+ return skb;
+}
+
static inline int __qdisc_requeue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff_head *list)
{