pkt_sched: Add ->peek() methods for fifo, prio and SFQ qdiscs.
From: Patrick McHardy <kaber@trash.net>
Just as a demonstration how easy adding a peek operation to the
work-conserving qdiscs actually is. It doesn't need to keep or change
any internal state in many cases thanks to the guarantee that the
packet will either be dequeued or, if another packet arrives, the
upper qdisc will immediately ->peek again to reevaluate the state.
(This is only slightly modified Patrick's patch.)
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index fe1508e..198b83d 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -391,8 +391,19 @@
return NET_XMIT_CN;
}
+static struct sk_buff *
+sfq_peek(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ sfq_index a;
+ /* No active slots */
+ if (q->tail == SFQ_DEPTH)
+ return NULL;
+ a = q->next[q->tail];
+ return skb_peek(&q->qs[a]);
+}
static struct sk_buff *
sfq_dequeue(struct Qdisc *sch)
@@ -624,6 +635,7 @@
.priv_size = sizeof(struct sfq_sched_data),
.enqueue = sfq_enqueue,
.dequeue = sfq_dequeue,
+ .peek = sfq_peek,
.requeue = sfq_requeue,
.drop = sfq_drop,
.init = sfq_init,