pkt_sched: sch_generic: Add generic qdisc->ops->peek() implementation.

With feedback from Patrick McHardy.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 93cd30ce6501..318c9f656e8e 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -320,6 +320,7 @@ struct Qdisc_ops noop_qdisc_ops __read_mostly = {
         .priv_size      =       0,
         .enqueue        =       noop_enqueue,
         .dequeue        =       noop_dequeue,
+        .peek           =       noop_dequeue,
         .requeue        =       noop_requeue,
         .owner          =       THIS_MODULE,
 };
@@ -346,6 +347,7 @@ static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
         .priv_size      =       0,
         .enqueue        =       noop_enqueue,
         .dequeue        =       noop_dequeue,
+        .peek           =       noop_dequeue,
         .requeue        =       noop_requeue,
         .owner          =       THIS_MODULE,
 };
@@ -411,6 +413,19 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
         return NULL;
 }
 
+static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc)
+{
+        int prio;
+        struct sk_buff_head *list = qdisc_priv(qdisc);
+
+        for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+                if (!skb_queue_empty(list + prio))
+                        return skb_peek(list + prio);
+        }
+
+        return NULL;
+}
+
 static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
 {
         qdisc->q.qlen++;
@@ -457,6 +472,7 @@ static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
         .priv_size      =       PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
         .enqueue        =       pfifo_fast_enqueue,
         .dequeue        =       pfifo_fast_dequeue,
+        .peek           =       pfifo_fast_peek,
         .requeue        =       pfifo_fast_requeue,
         .init           =       pfifo_fast_init,
         .reset          =       pfifo_fast_reset,