Commit 77be155c authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller

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: default avatarJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 03c05f0d
......@@ -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)
{
......
......@@ -484,7 +484,7 @@ static void sch_atm_dequeue(unsigned long data)
if (!atm_may_send(flow->vcc, skb->truesize))
break;
skb = flow->q->dequeue(flow->q);
skb = qdisc_dequeue_peeked(flow->q);
if (unlikely(!skb))
break;
......@@ -519,7 +519,7 @@ static struct sk_buff *atm_tc_dequeue(struct Qdisc *sch)
pr_debug("atm_tc_dequeue(sch %p,[qdisc %p])\n", sch, p);
tasklet_schedule(&p->task);
skb = p->link.q->dequeue(p->link.q);
skb = qdisc_dequeue_peeked(p->link.q);
if (skb)
sch->q.qlen--;
return skb;
......
......@@ -2066,6 +2066,7 @@ static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct cbq_sched_data),
.enqueue = cbq_enqueue,
.dequeue = cbq_dequeue,
.peek = qdisc_peek_dequeued,
.requeue = cbq_requeue,
.drop = cbq_drop,
.init = cbq_init,
......
......@@ -1634,7 +1634,7 @@ hfsc_dequeue(struct Qdisc *sch)
}
}
skb = cl->qdisc->dequeue(cl->qdisc);
skb = qdisc_dequeue_peeked(cl->qdisc);
if (skb == NULL) {
if (net_ratelimit())
printk("HFSC: Non-work-conserving qdisc ?\n");
......@@ -1727,6 +1727,7 @@ static struct Qdisc_ops hfsc_qdisc_ops __read_mostly = {
.dump = hfsc_dump_qdisc,
.enqueue = hfsc_enqueue,
.dequeue = hfsc_dequeue,
.peek = qdisc_peek_dequeued,
.requeue = hfsc_requeue,
.drop = hfsc_drop,
.cl_ops = &hfsc_class_ops,
......
......@@ -1565,6 +1565,7 @@ static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct htb_sched),
.enqueue = htb_enqueue,
.dequeue = htb_dequeue,
.peek = qdisc_peek_dequeued,
.requeue = htb_requeue,
.drop = htb_drop,
.init = htb_init,
......
......@@ -290,8 +290,8 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
/* if more time remaining? */
if (cb->time_to_send <= now) {
skb = q->qdisc->dequeue(q->qdisc);
if (!skb)
skb = qdisc_dequeue_peeked(q->qdisc);
if (unlikely(!skb))
return NULL;
pr_debug("netem_dequeue: return skb=%p\n", skb);
......@@ -714,6 +714,7 @@ static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct netem_sched_data),
.enqueue = netem_enqueue,
.dequeue = netem_dequeue,
.peek = qdisc_peek_dequeued,
.requeue = netem_requeue,
.drop = netem_drop,
.init = netem_init,
......
......@@ -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,
......
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