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 | ||
cc7ec456 | 22 | static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 | 23 | { |
d276055c | 24 | if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit)) |
aaae3013 | 25 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 26 | |
aaae3013 | 27 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
28 | } |
29 | ||
cc7ec456 | 30 | static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 | 31 | { |
d276055c | 32 | if (likely(skb_queue_len(&sch->q) < sch->limit)) |
aaae3013 | 33 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 34 | |
aaae3013 | 35 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
36 | } |
37 | ||
cc7ec456 | 38 | static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
57dbb2d8 | 39 | { |
6c0d54f1 ED |
40 | unsigned int prev_backlog; |
41 | ||
d276055c | 42 | if (likely(skb_queue_len(&sch->q) < sch->limit)) |
57dbb2d8 HPP |
43 | return qdisc_enqueue_tail(skb, sch); |
44 | ||
6c0d54f1 | 45 | prev_backlog = sch->qstats.backlog; |
57dbb2d8 | 46 | /* queue full, remove one skb to fulfill the limit */ |
9190b3b3 | 47 | __qdisc_queue_drop_head(sch, &sch->q); |
25331d6c | 48 | qdisc_qstats_drop(sch); |
57dbb2d8 HPP |
49 | qdisc_enqueue_tail(skb, sch); |
50 | ||
6c0d54f1 | 51 | qdisc_tree_reduce_backlog(sch, 0, prev_backlog - sch->qstats.backlog); |
57dbb2d8 HPP |
52 | return NET_XMIT_CN; |
53 | } | |
54 | ||
1e90474c | 55 | static int fifo_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 | 56 | { |
23624935 ED |
57 | bool bypass; |
58 | bool is_bfifo = sch->ops == &bfifo_qdisc_ops; | |
1da177e4 LT |
59 | |
60 | if (opt == NULL) { | |
348e3435 | 61 | u32 limit = qdisc_dev(sch)->tx_queue_len; |
1da177e4 | 62 | |
23624935 | 63 | if (is_bfifo) |
6473990c | 64 | limit *= psched_mtu(qdisc_dev(sch)); |
6fc8e84f | 65 | |
d276055c | 66 | sch->limit = limit; |
1da177e4 | 67 | } else { |
1e90474c | 68 | struct tc_fifo_qopt *ctl = nla_data(opt); |
6fc8e84f | 69 | |
1e90474c | 70 | if (nla_len(opt) < sizeof(*ctl)) |
1da177e4 | 71 | return -EINVAL; |
6fc8e84f | 72 | |
d276055c | 73 | sch->limit = ctl->limit; |
1da177e4 | 74 | } |
6fc8e84f | 75 | |
23624935 | 76 | if (is_bfifo) |
d276055c | 77 | bypass = sch->limit >= psched_mtu(qdisc_dev(sch)); |
23624935 | 78 | else |
d276055c | 79 | bypass = sch->limit >= 1; |
23624935 ED |
80 | |
81 | if (bypass) | |
82 | sch->flags |= TCQ_F_CAN_BYPASS; | |
83 | else | |
84 | sch->flags &= ~TCQ_F_CAN_BYPASS; | |
1da177e4 LT |
85 | return 0; |
86 | } | |
87 | ||
88 | static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) | |
89 | { | |
d276055c | 90 | struct tc_fifo_qopt opt = { .limit = sch->limit }; |
1da177e4 | 91 | |
1b34ec43 DM |
92 | if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) |
93 | goto nla_put_failure; | |
1da177e4 LT |
94 | return skb->len; |
95 | ||
1e90474c | 96 | nla_put_failure: |
1da177e4 LT |
97 | return -1; |
98 | } | |
99 | ||
20fea08b | 100 | struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { |
1da177e4 | 101 | .id = "pfifo", |
d276055c | 102 | .priv_size = 0, |
1da177e4 | 103 | .enqueue = pfifo_enqueue, |
aaae3013 | 104 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 105 | .peek = qdisc_peek_head, |
aaae3013 | 106 | .drop = qdisc_queue_drop, |
1da177e4 | 107 | .init = fifo_init, |
aaae3013 | 108 | .reset = qdisc_reset_queue, |
1da177e4 LT |
109 | .change = fifo_init, |
110 | .dump = fifo_dump, | |
111 | .owner = THIS_MODULE, | |
112 | }; | |
62e3ba1b | 113 | EXPORT_SYMBOL(pfifo_qdisc_ops); |
1da177e4 | 114 | |
20fea08b | 115 | struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { |
1da177e4 | 116 | .id = "bfifo", |
d276055c | 117 | .priv_size = 0, |
1da177e4 | 118 | .enqueue = bfifo_enqueue, |
aaae3013 | 119 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 120 | .peek = qdisc_peek_head, |
aaae3013 | 121 | .drop = qdisc_queue_drop, |
1da177e4 | 122 | .init = fifo_init, |
aaae3013 | 123 | .reset = qdisc_reset_queue, |
1da177e4 LT |
124 | .change = fifo_init, |
125 | .dump = fifo_dump, | |
126 | .owner = THIS_MODULE, | |
127 | }; | |
1da177e4 | 128 | EXPORT_SYMBOL(bfifo_qdisc_ops); |
fb0305ce | 129 | |
57dbb2d8 HPP |
130 | struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { |
131 | .id = "pfifo_head_drop", | |
d276055c | 132 | .priv_size = 0, |
57dbb2d8 HPP |
133 | .enqueue = pfifo_tail_enqueue, |
134 | .dequeue = qdisc_dequeue_head, | |
135 | .peek = qdisc_peek_head, | |
136 | .drop = qdisc_queue_drop_head, | |
137 | .init = fifo_init, | |
138 | .reset = qdisc_reset_queue, | |
139 | .change = fifo_init, | |
140 | .dump = fifo_dump, | |
141 | .owner = THIS_MODULE, | |
142 | }; | |
143 | ||
fb0305ce PM |
144 | /* Pass size change message down to embedded FIFO */ |
145 | int 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 | } | |
165 | EXPORT_SYMBOL(fifo_set_limit); | |
166 | ||
167 | struct 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 | ||
3511c913 | 173 | q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1)); |
fb0305ce PM |
174 | 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 | } | |
184 | EXPORT_SYMBOL(fifo_create_dflt); |