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>
This commit is contained in:
Jarek Poplawski
2008-10-31 00:47:01 -07:00
committed by David S. Miller
parent 03c05f0d4b
commit 77be155cba
7 changed files with 34 additions and 6 deletions

View File

@@ -438,6 +438,29 @@ static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
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)
{