2 * net/sched/sch_fifo.c The simplest FIFO queue.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
12 #include <linux/config.h>
13 #include <linux/module.h>
14 #include <asm/uaccess.h>
15 #include <asm/system.h>
16 #include <linux/bitops.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/string.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
25 #include <linux/errno.h>
26 #include <linux/interrupt.h>
27 #include <linux/if_ether.h>
28 #include <linux/inet.h>
29 #include <linux/netdevice.h>
30 #include <linux/etherdevice.h>
31 #include <linux/notifier.h>
33 #include <net/route.h>
34 #include <linux/skbuff.h>
36 #include <net/pkt_sched.h>
38 /* 1 band FIFO pseudo-"scheduler" */
40 struct fifo_sched_data
46 bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
48 struct fifo_sched_data *q = qdisc_priv(sch);
50 if (likely(sch->qstats.backlog + skb->len <= q->limit))
51 return qdisc_enqueue_tail(skb, sch);
53 return qdisc_reshape_fail(skb, sch);
57 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
59 struct fifo_sched_data *q = qdisc_priv(sch);
61 if (likely(skb_queue_len(&sch->q) < q->limit))
62 return qdisc_enqueue_tail(skb, sch);
64 return qdisc_reshape_fail(skb, sch);
67 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
69 struct fifo_sched_data *q = qdisc_priv(sch);
72 unsigned int limit = sch->dev->tx_queue_len ? : 1;
74 if (sch->ops == &bfifo_qdisc_ops)
75 q->limit = limit*sch->dev->mtu;
79 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
80 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
82 q->limit = ctl->limit;
87 static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
89 struct fifo_sched_data *q = qdisc_priv(sch);
90 unsigned char *b = skb->tail;
91 struct tc_fifo_qopt opt;
94 RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
99 skb_trim(skb, b - skb->data);
103 struct Qdisc_ops pfifo_qdisc_ops = {
107 .priv_size = sizeof(struct fifo_sched_data),
108 .enqueue = pfifo_enqueue,
109 .dequeue = qdisc_dequeue_head,
110 .requeue = qdisc_requeue,
111 .drop = qdisc_queue_drop,
113 .reset = qdisc_reset_queue,
117 .owner = THIS_MODULE,
120 struct Qdisc_ops bfifo_qdisc_ops = {
124 .priv_size = sizeof(struct fifo_sched_data),
125 .enqueue = bfifo_enqueue,
126 .dequeue = qdisc_dequeue_head,
127 .requeue = qdisc_requeue,
128 .drop = qdisc_queue_drop,
130 .reset = qdisc_reset_queue,
134 .owner = THIS_MODULE,
137 EXPORT_SYMBOL(bfifo_qdisc_ops);
138 EXPORT_SYMBOL(pfifo_qdisc_ops);