Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | ||
1da177e4 | 12 | #include <linux/module.h> |
5a0e3ad6 | 13 | #include <linux/slab.h> |
1da177e4 LT |
14 | #include <linux/types.h> |
15 | #include <linux/kernel.h> | |
1da177e4 | 16 | #include <linux/errno.h> |
1da177e4 | 17 | #include <linux/skbuff.h> |
1da177e4 LT |
18 | #include <net/pkt_sched.h> |
19 | ||
20 | /* 1 band FIFO pseudo-"scheduler" */ | |
21 | ||
520ac30f ED |
22 | static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
23 | struct sk_buff **to_free) | |
1da177e4 | 24 | { |
d276055c | 25 | if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit)) |
aaae3013 | 26 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 27 | |
520ac30f | 28 | return qdisc_drop(skb, sch, to_free); |
1da177e4 LT |
29 | } |
30 | ||
520ac30f ED |
31 | static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
32 | struct sk_buff **to_free) | |
1da177e4 | 33 | { |
97d0678f | 34 | if (likely(sch->q.qlen < sch->limit)) |
aaae3013 | 35 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 36 | |
520ac30f | 37 | return qdisc_drop(skb, sch, to_free); |
1da177e4 LT |
38 | } |
39 | ||
520ac30f ED |
40 | static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
41 | struct sk_buff **to_free) | |
57dbb2d8 | 42 | { |
6c0d54f1 ED |
43 | unsigned int prev_backlog; |
44 | ||
97d0678f | 45 | if (likely(sch->q.qlen < sch->limit)) |
57dbb2d8 HPP |
46 | return qdisc_enqueue_tail(skb, sch); |
47 | ||
6c0d54f1 | 48 | prev_backlog = sch->qstats.backlog; |
57dbb2d8 | 49 | /* queue full, remove one skb to fulfill the limit */ |
520ac30f | 50 | __qdisc_queue_drop_head(sch, &sch->q, to_free); |
25331d6c | 51 | qdisc_qstats_drop(sch); |
57dbb2d8 HPP |
52 | qdisc_enqueue_tail(skb, sch); |
53 | ||
6c0d54f1 | 54 | qdisc_tree_reduce_backlog(sch, 0, prev_backlog - sch->qstats.backlog); |
57dbb2d8 HPP |
55 | return NET_XMIT_CN; |
56 | } | |
57 | ||
e63d7dfd AA |
58 | static int fifo_init(struct Qdisc *sch, struct nlattr *opt, |
59 | struct netlink_ext_ack *extack) | |
1da177e4 | 60 | { |
23624935 ED |
61 | bool bypass; |
62 | bool is_bfifo = sch->ops == &bfifo_qdisc_ops; | |
1da177e4 LT |
63 | |
64 | if (opt == NULL) { | |
348e3435 | 65 | u32 limit = qdisc_dev(sch)->tx_queue_len; |
1da177e4 | 66 | |
23624935 | 67 | if (is_bfifo) |
6473990c | 68 | limit *= psched_mtu(qdisc_dev(sch)); |
6fc8e84f | 69 | |
d276055c | 70 | sch->limit = limit; |
1da177e4 | 71 | } else { |
1e90474c | 72 | struct tc_fifo_qopt *ctl = nla_data(opt); |
6fc8e84f | 73 | |
1e90474c | 74 | if (nla_len(opt) < sizeof(*ctl)) |
1da177e4 | 75 | return -EINVAL; |
6fc8e84f | 76 | |
d276055c | 77 | sch->limit = ctl->limit; |
1da177e4 | 78 | } |
6fc8e84f | 79 | |
23624935 | 80 | if (is_bfifo) |
d276055c | 81 | bypass = sch->limit >= psched_mtu(qdisc_dev(sch)); |
23624935 | 82 | else |
d276055c | 83 | bypass = sch->limit >= 1; |
23624935 ED |
84 | |
85 | if (bypass) | |
86 | sch->flags |= TCQ_F_CAN_BYPASS; | |
87 | else | |
88 | sch->flags &= ~TCQ_F_CAN_BYPASS; | |
1da177e4 LT |
89 | return 0; |
90 | } | |
91 | ||
92 | static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) | |
93 | { | |
d276055c | 94 | struct tc_fifo_qopt opt = { .limit = sch->limit }; |
1da177e4 | 95 | |
1b34ec43 DM |
96 | if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) |
97 | goto nla_put_failure; | |
1da177e4 LT |
98 | return skb->len; |
99 | ||
1e90474c | 100 | nla_put_failure: |
1da177e4 LT |
101 | return -1; |
102 | } | |
103 | ||
20fea08b | 104 | struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { |
1da177e4 | 105 | .id = "pfifo", |
d276055c | 106 | .priv_size = 0, |
1da177e4 | 107 | .enqueue = pfifo_enqueue, |
aaae3013 | 108 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 109 | .peek = qdisc_peek_head, |
1da177e4 | 110 | .init = fifo_init, |
aaae3013 | 111 | .reset = qdisc_reset_queue, |
2030721c | 112 | .change = fifo_init, |
1da177e4 LT |
113 | .dump = fifo_dump, |
114 | .owner = THIS_MODULE, | |
115 | }; | |
62e3ba1b | 116 | EXPORT_SYMBOL(pfifo_qdisc_ops); |
1da177e4 | 117 | |
20fea08b | 118 | struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { |
1da177e4 | 119 | .id = "bfifo", |
d276055c | 120 | .priv_size = 0, |
1da177e4 | 121 | .enqueue = bfifo_enqueue, |
aaae3013 | 122 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 123 | .peek = qdisc_peek_head, |
1da177e4 | 124 | .init = fifo_init, |
aaae3013 | 125 | .reset = qdisc_reset_queue, |
2030721c | 126 | .change = fifo_init, |
1da177e4 LT |
127 | .dump = fifo_dump, |
128 | .owner = THIS_MODULE, | |
129 | }; | |
1da177e4 | 130 | EXPORT_SYMBOL(bfifo_qdisc_ops); |
fb0305ce | 131 | |
57dbb2d8 HPP |
132 | struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { |
133 | .id = "pfifo_head_drop", | |
d276055c | 134 | .priv_size = 0, |
57dbb2d8 HPP |
135 | .enqueue = pfifo_tail_enqueue, |
136 | .dequeue = qdisc_dequeue_head, | |
137 | .peek = qdisc_peek_head, | |
57dbb2d8 HPP |
138 | .init = fifo_init, |
139 | .reset = qdisc_reset_queue, | |
2030721c | 140 | .change = fifo_init, |
57dbb2d8 HPP |
141 | .dump = fifo_dump, |
142 | .owner = THIS_MODULE, | |
143 | }; | |
144 | ||
fb0305ce PM |
145 | /* Pass size change message down to embedded FIFO */ |
146 | int fifo_set_limit(struct Qdisc *q, unsigned int limit) | |
147 | { | |
148 | struct nlattr *nla; | |
149 | int ret = -ENOMEM; | |
150 | ||
151 | /* Hack to avoid sending change message to non-FIFO */ | |
152 | if (strncmp(q->ops->id + 1, "fifo", 4) != 0) | |
153 | return 0; | |
154 | ||
155 | nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); | |
156 | if (nla) { | |
157 | nla->nla_type = RTM_NEWQDISC; | |
158 | nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt)); | |
159 | ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit; | |
160 | ||
2030721c | 161 | ret = q->ops->change(q, nla, NULL); |
fb0305ce PM |
162 | kfree(nla); |
163 | } | |
164 | return ret; | |
165 | } | |
166 | EXPORT_SYMBOL(fifo_set_limit); | |
167 | ||
168 | struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops, | |
169 | unsigned int limit) | |
170 | { | |
171 | struct Qdisc *q; | |
172 | int err = -ENOMEM; | |
173 | ||
3511c913 | 174 | q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1)); |
fb0305ce PM |
175 | if (q) { |
176 | err = fifo_set_limit(q, limit); | |
177 | if (err < 0) { | |
178 | qdisc_destroy(q); | |
179 | q = NULL; | |
180 | } | |
181 | } | |
182 | ||
183 | return q ? : ERR_PTR(err); | |
184 | } | |
185 | EXPORT_SYMBOL(fifo_create_dflt); |