pkt_sched: Use qdisc->ops->peek() instead of ->dequeue() & ->requeue()

Use qdisc->ops->peek() instead of ->dequeue() & ->requeue() pair.
After this patch the only remaining user of qdisc->ops->requeue() is
netem_enqueue(). Based on ideas of Herbert Xu, Patrick McHardy and
David S. Miller.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 7 deletions

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 94c61598b86a..61fdc77a48d2 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -169,7 +169,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
         struct tbf_sched_data *q = qdisc_priv(sch);
         struct sk_buff *skb;
 
-        skb = q->qdisc->dequeue(q->qdisc);
+        skb = q->qdisc->ops->peek(q->qdisc);
 
         if (skb) {
                 psched_time_t now;
@@ -192,6 +192,10 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
                 toks -= L2T(q, len);
 
                 if ((toks|ptoks) >= 0) {
+                        skb = q->qdisc->dequeue(q->qdisc);
+                        if (unlikely(!skb))
+                                return NULL;
+
                         q->t_c = now;
                         q->tokens = toks;
                         q->ptokens = ptoks;
@@ -214,12 +218,6 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
                    (cf. CSZ, HPFQ, HFSC)
                  */
 
-                if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
-                        /* When requeue fails skb is dropped */
-                        qdisc_tree_decrease_qlen(q->qdisc, 1);
-                        sch->qstats.drops++;
-                }
-
                 sch->qstats.overlimits++;
         }
         return NULL;