+ return 0;
+}
+
+/*
+ * Special case version of FIFO queue for use by netem.
+ * It queues in order based on timestamps in skb's
+ */
+struct fifo_sched_data {
+ u32 limit;
+};
+
+static int tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
+{
+ struct fifo_sched_data *q = qdisc_priv(sch);
+ struct sk_buff_head *list = &sch->q;
+ const struct netem_skb_cb *ncb
+ = (const struct netem_skb_cb *)nskb->cb;
+ struct sk_buff *skb;
+
+ if (likely(skb_queue_len(list) < q->limit)) {
+ skb_queue_reverse_walk(list, skb) {
+ const struct netem_skb_cb *cb
+ = (const struct netem_skb_cb *)skb->cb;
+
+ if (!PSCHED_TLESS(ncb->time_to_send, cb->time_to_send))
+ break;
+ }
+
+ __skb_queue_after(list, skb, nskb);
+
+ sch->qstats.backlog += nskb->len;
+ sch->bstats.bytes += nskb->len;
+ sch->bstats.packets++;
+
+ return NET_XMIT_SUCCESS;
+ }
+
+ return qdisc_drop(nskb, sch);
+}
+
+static int tfifo_init(struct Qdisc *sch, struct rtattr *opt)
+{
+ struct fifo_sched_data *q = qdisc_priv(sch);
+
+ if (opt) {
+ struct tc_fifo_qopt *ctl = RTA_DATA(opt);
+ if (RTA_PAYLOAD(opt) < sizeof(*ctl))
+ return -EINVAL;
+
+ q->limit = ctl->limit;
+ } else
+ q->limit = max_t(u32, sch->dev->tx_queue_len, 1);