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>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 61fdc77a48d2..435076cf620e 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -192,7 +192,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
                 toks -= L2T(q, len);
 
                 if ((toks|ptoks) >= 0) {
-                        skb = q->qdisc->dequeue(q->qdisc);
+                        skb = qdisc_dequeue_peeked(q->qdisc);
                         if (unlikely(!skb))
                                 return NULL;
 
@@ -467,6 +467,7 @@ static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
         .priv_size      =       sizeof(struct tbf_sched_data),
         .enqueue        =       tbf_enqueue,
         .dequeue        =       tbf_dequeue,
+        .peek           =       qdisc_peek_dequeued,
         .requeue        =       tbf_requeue,
         .drop           =       tbf_drop,
         .init           =       tbf_init,