blob: 1e37247656f80e5c3368538c2f73b5f86c77ad50 [file] [log] [blame]
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090013#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/types.h>
15#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/skbuff.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <net/pkt_sched.h>
19
20/* 1 band FIFO pseudo-"scheduler" */
21
Eric Dumazet520ac302016-06-21 23:16:49 -070022static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch,
23 struct sk_buff **to_free)
Linus Torvalds1da177e2005-04-16 15:20:36 -070024{
Eric Dumazetd2760552011-03-03 11:10:02 -080025 if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit))
Thomas Grafaaae3012005-06-18 22:57:42 -070026 return qdisc_enqueue_tail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Eric Dumazet520ac302016-06-21 23:16:49 -070028 return qdisc_drop(skb, sch, to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029}
30
Eric Dumazet520ac302016-06-21 23:16:49 -070031static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch,
32 struct sk_buff **to_free)
Linus Torvalds1da177e2005-04-16 15:20:36 -070033{
Florian Westphal97d06782016-09-18 00:57:31 +020034 if (likely(sch->q.qlen < sch->limit))
Thomas Grafaaae3012005-06-18 22:57:42 -070035 return qdisc_enqueue_tail(skb, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Eric Dumazet520ac302016-06-21 23:16:49 -070037 return qdisc_drop(skb, sch, to_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038}
39
Eric Dumazet520ac302016-06-21 23:16:49 -070040static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch,
41 struct sk_buff **to_free)
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +000042{
Eric Dumazet6c0d54f2016-06-12 20:01:25 -070043 unsigned int prev_backlog;
44
Florian Westphal97d06782016-09-18 00:57:31 +020045 if (likely(sch->q.qlen < sch->limit))
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +000046 return qdisc_enqueue_tail(skb, sch);
47
Eric Dumazet6c0d54f2016-06-12 20:01:25 -070048 prev_backlog = sch->qstats.backlog;
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +000049 /* queue full, remove one skb to fulfill the limit */
Eric Dumazet520ac302016-06-21 23:16:49 -070050 __qdisc_queue_drop_head(sch, &sch->q, to_free);
John Fastabend25331d62014-09-28 11:53:29 -070051 qdisc_qstats_drop(sch);
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +000052 qdisc_enqueue_tail(skb, sch);
53
Eric Dumazet6c0d54f2016-06-12 20:01:25 -070054 qdisc_tree_reduce_backlog(sch, 0, prev_backlog - sch->qstats.backlog);
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +000055 return NET_XMIT_CN;
56}
57
Patrick McHardy1e904742008-01-22 22:11:17 -080058static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070059{
Eric Dumazet23624932011-01-21 16:26:09 -080060 bool bypass;
61 bool is_bfifo = sch->ops == &bfifo_qdisc_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 if (opt == NULL) {
Phil Sutter348e3432015-08-18 10:30:49 +020064 u32 limit = qdisc_dev(sch)->tx_queue_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Eric Dumazet23624932011-01-21 16:26:09 -080066 if (is_bfifo)
Patrick McHardy64739902009-05-06 16:45:07 -070067 limit *= psched_mtu(qdisc_dev(sch));
Thomas Graf6fc8e842005-06-18 22:58:00 -070068
Eric Dumazetd2760552011-03-03 11:10:02 -080069 sch->limit = limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 } else {
Patrick McHardy1e904742008-01-22 22:11:17 -080071 struct tc_fifo_qopt *ctl = nla_data(opt);
Thomas Graf6fc8e842005-06-18 22:58:00 -070072
Patrick McHardy1e904742008-01-22 22:11:17 -080073 if (nla_len(opt) < sizeof(*ctl))
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 return -EINVAL;
Thomas Graf6fc8e842005-06-18 22:58:00 -070075
Eric Dumazetd2760552011-03-03 11:10:02 -080076 sch->limit = ctl->limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 }
Thomas Graf6fc8e842005-06-18 22:58:00 -070078
Eric Dumazet23624932011-01-21 16:26:09 -080079 if (is_bfifo)
Eric Dumazetd2760552011-03-03 11:10:02 -080080 bypass = sch->limit >= psched_mtu(qdisc_dev(sch));
Eric Dumazet23624932011-01-21 16:26:09 -080081 else
Eric Dumazetd2760552011-03-03 11:10:02 -080082 bypass = sch->limit >= 1;
Eric Dumazet23624932011-01-21 16:26:09 -080083
84 if (bypass)
85 sch->flags |= TCQ_F_CAN_BYPASS;
86 else
87 sch->flags &= ~TCQ_F_CAN_BYPASS;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 return 0;
89}
90
91static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
92{
Eric Dumazetd2760552011-03-03 11:10:02 -080093 struct tc_fifo_qopt opt = { .limit = sch->limit };
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
David S. Miller1b34ec42012-03-29 05:11:39 -040095 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
96 goto nla_put_failure;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 return skb->len;
98
Patrick McHardy1e904742008-01-22 22:11:17 -080099nla_put_failure:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 return -1;
101}
102
Eric Dumazet20fea082007-11-14 01:44:41 -0800103struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 .id = "pfifo",
Eric Dumazetd2760552011-03-03 11:10:02 -0800105 .priv_size = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 .enqueue = pfifo_enqueue,
Thomas Grafaaae3012005-06-18 22:57:42 -0700107 .dequeue = qdisc_dequeue_head,
Patrick McHardy48a8f512008-10-31 00:44:18 -0700108 .peek = qdisc_peek_head,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 .init = fifo_init,
Thomas Grafaaae3012005-06-18 22:57:42 -0700110 .reset = qdisc_reset_queue,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 .change = fifo_init,
112 .dump = fifo_dump,
113 .owner = THIS_MODULE,
114};
Patrick McHardy62e3ba12008-01-22 22:10:23 -0800115EXPORT_SYMBOL(pfifo_qdisc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116
Eric Dumazet20fea082007-11-14 01:44:41 -0800117struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 .id = "bfifo",
Eric Dumazetd2760552011-03-03 11:10:02 -0800119 .priv_size = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 .enqueue = bfifo_enqueue,
Thomas Grafaaae3012005-06-18 22:57:42 -0700121 .dequeue = qdisc_dequeue_head,
Patrick McHardy48a8f512008-10-31 00:44:18 -0700122 .peek = qdisc_peek_head,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 .init = fifo_init,
Thomas Grafaaae3012005-06-18 22:57:42 -0700124 .reset = qdisc_reset_queue,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 .change = fifo_init,
126 .dump = fifo_dump,
127 .owner = THIS_MODULE,
128};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129EXPORT_SYMBOL(bfifo_qdisc_ops);
Patrick McHardyfb0305c2008-07-05 23:40:21 -0700130
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +0000131struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = {
132 .id = "pfifo_head_drop",
Eric Dumazetd2760552011-03-03 11:10:02 -0800133 .priv_size = 0,
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +0000134 .enqueue = pfifo_tail_enqueue,
135 .dequeue = qdisc_dequeue_head,
136 .peek = qdisc_peek_head,
Hagen Paul Pfeifer57dbb2d2010-01-24 12:30:59 +0000137 .init = fifo_init,
138 .reset = qdisc_reset_queue,
139 .change = fifo_init,
140 .dump = fifo_dump,
141 .owner = THIS_MODULE,
142};
143
Patrick McHardyfb0305c2008-07-05 23:40:21 -0700144/* Pass size change message down to embedded FIFO */
145int fifo_set_limit(struct Qdisc *q, unsigned int limit)
146{
147 struct nlattr *nla;
148 int ret = -ENOMEM;
149
150 /* Hack to avoid sending change message to non-FIFO */
151 if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
152 return 0;
153
154 nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
155 if (nla) {
156 nla->nla_type = RTM_NEWQDISC;
157 nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
158 ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
159
160 ret = q->ops->change(q, nla);
161 kfree(nla);
162 }
163 return ret;
164}
165EXPORT_SYMBOL(fifo_set_limit);
166
167struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
168 unsigned int limit)
169{
170 struct Qdisc *q;
171 int err = -ENOMEM;
172
Changli Gao3511c912010-10-16 13:04:08 +0000173 q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1));
Patrick McHardyfb0305c2008-07-05 23:40:21 -0700174 if (q) {
175 err = fifo_set_limit(q, limit);
176 if (err < 0) {
177 qdisc_destroy(q);
178 q = NULL;
179 }
180 }
181
182 return q ? : ERR_PTR(err);
183}
184EXPORT_SYMBOL(fifo_create_dflt);