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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * net/sched/sch_fifo.c The simplest FIFO queue.
3 *
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.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/types.h>
14#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/skbuff.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <net/pkt_sched.h>
18
19/* 1 band FIFO pseudo-"scheduler" */
20
21struct fifo_sched_data
22{
Thomas Graf6fc8e842005-06-18 22:58:00 -070023 u32 limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -070024};
25
Thomas Graf6fc8e842005-06-18 22:58:00 -070026static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
28 struct fifo_sched_data *q = qdisc_priv(sch);
29
Jussi Kivilinna0abf77e2008-07-20 00:08:27 -070030 if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit))
Thomas Grafaaae3012005-06-18 22:57:42 -070031 return qdisc_enqueue_tail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Thomas Grafaaae3012005-06-18 22:57:42 -070033 return qdisc_reshape_fail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034}
35
Thomas Graf6fc8e842005-06-18 22:58:00 -070036static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
Linus Torvalds1da177e2005-04-16 15:20:36 -070037{
38 struct fifo_sched_data *q = qdisc_priv(sch);
39
Thomas Grafaaae3012005-06-18 22:57:42 -070040 if (likely(skb_queue_len(&sch->q) < q->limit))
41 return qdisc_enqueue_tail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Thomas Grafaaae3012005-06-18 22:57:42 -070043 return qdisc_reshape_fail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044}
45
Patrick McHardy1e904742008-01-22 22:11:17 -080046static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
48 struct fifo_sched_data *q = qdisc_priv(sch);
49
50 if (opt == NULL) {
David S. Miller5ce2d482008-07-08 17:06:30 -070051 u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53 if (sch->ops == &bfifo_qdisc_ops)
Patrick McHardy64739902009-05-06 16:45:07 -070054 limit *= psched_mtu(qdisc_dev(sch));
Thomas Graf6fc8e842005-06-18 22:58:00 -070055
56 q->limit = limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 } else {
Patrick McHardy1e904742008-01-22 22:11:17 -080058 struct tc_fifo_qopt *ctl = nla_data(opt);
Thomas Graf6fc8e842005-06-18 22:58:00 -070059
Patrick McHardy1e904742008-01-22 22:11:17 -080060 if (nla_len(opt) < sizeof(*ctl))
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 return -EINVAL;
Thomas Graf6fc8e842005-06-18 22:58:00 -070062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 q->limit = ctl->limit;
64 }
Thomas Graf6fc8e842005-06-18 22:58:00 -070065
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 return 0;
67}
68
69static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
70{
71 struct fifo_sched_data *q = qdisc_priv(sch);
Thomas Graf6fc8e842005-06-18 22:58:00 -070072 struct tc_fifo_qopt opt = { .limit = q->limit };
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Patrick McHardy1e904742008-01-22 22:11:17 -080074 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 return skb->len;
76
Patrick McHardy1e904742008-01-22 22:11:17 -080077nla_put_failure:
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 return -1;
79}
80
Eric Dumazet20fea082007-11-14 01:44:41 -080081struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 .id = "pfifo",
83 .priv_size = sizeof(struct fifo_sched_data),
84 .enqueue = pfifo_enqueue,
Thomas Grafaaae3012005-06-18 22:57:42 -070085 .dequeue = qdisc_dequeue_head,
Patrick McHardy48a8f512008-10-31 00:44:18 -070086 .peek = qdisc_peek_head,
Thomas Grafaaae3012005-06-18 22:57:42 -070087 .drop = qdisc_queue_drop,
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 .init = fifo_init,
Thomas Grafaaae3012005-06-18 22:57:42 -070089 .reset = qdisc_reset_queue,
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 .change = fifo_init,
91 .dump = fifo_dump,
92 .owner = THIS_MODULE,
93};
Patrick McHardy62e3ba12008-01-22 22:10:23 -080094EXPORT_SYMBOL(pfifo_qdisc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
Eric Dumazet20fea082007-11-14 01:44:41 -080096struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 .id = "bfifo",
98 .priv_size = sizeof(struct fifo_sched_data),
99 .enqueue = bfifo_enqueue,
Thomas Grafaaae3012005-06-18 22:57:42 -0700100 .dequeue = qdisc_dequeue_head,
Patrick McHardy48a8f512008-10-31 00:44:18 -0700101 .peek = qdisc_peek_head,
Thomas Grafaaae3012005-06-18 22:57:42 -0700102 .drop = qdisc_queue_drop,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 .init = fifo_init,
Thomas Grafaaae3012005-06-18 22:57:42 -0700104 .reset = qdisc_reset_queue,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 .change = fifo_init,
106 .dump = fifo_dump,
107 .owner = THIS_MODULE,
108};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109EXPORT_SYMBOL(bfifo_qdisc_ops);
Patrick McHardyfb0305c2008-07-05 23:40:21 -0700110
111/* Pass size change message down to embedded FIFO */
112int fifo_set_limit(struct Qdisc *q, unsigned int limit)
113{
114 struct nlattr *nla;
115 int ret = -ENOMEM;
116
117 /* Hack to avoid sending change message to non-FIFO */
118 if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
119 return 0;
120
121 nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
122 if (nla) {
123 nla->nla_type = RTM_NEWQDISC;
124 nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
125 ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
126
127 ret = q->ops->change(q, nla);
128 kfree(nla);
129 }
130 return ret;
131}
132EXPORT_SYMBOL(fifo_set_limit);
133
134struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
135 unsigned int limit)
136{
137 struct Qdisc *q;
138 int err = -ENOMEM;
139
David S. Miller5ce2d482008-07-08 17:06:30 -0700140 q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
David S. Millerbb949fb2008-07-08 16:55:56 -0700141 ops, TC_H_MAKE(sch->handle, 1));
Patrick McHardyfb0305c2008-07-05 23:40:21 -0700142 if (q) {
143 err = fifo_set_limit(q, limit);
144 if (err < 0) {
145 qdisc_destroy(q);
146 q = NULL;
147 }
148 }
149
150 return q ? : ERR_PTR(err);
151}
152EXPORT_SYMBOL(fifo_create_dflt);