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 | struct fifo_sched_data { |
6fc8e84f | 23 | u32 limit; |
1da177e4 LT |
24 | }; |
25 | ||
cc7ec456 | 26 | static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 LT |
27 | { |
28 | struct fifo_sched_data *q = qdisc_priv(sch); | |
29 | ||
0abf77e5 | 30 | if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit)) |
aaae3013 | 31 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 32 | |
aaae3013 | 33 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
34 | } |
35 | ||
cc7ec456 | 36 | static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 LT |
37 | { |
38 | struct fifo_sched_data *q = qdisc_priv(sch); | |
39 | ||
aaae3013 TG |
40 | if (likely(skb_queue_len(&sch->q) < q->limit)) |
41 | return qdisc_enqueue_tail(skb, sch); | |
1da177e4 | 42 | |
aaae3013 | 43 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
44 | } |
45 | ||
cc7ec456 | 46 | static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
57dbb2d8 HPP |
47 | { |
48 | struct sk_buff *skb_head; | |
49 | struct fifo_sched_data *q = qdisc_priv(sch); | |
50 | ||
51 | if (likely(skb_queue_len(&sch->q) < q->limit)) | |
52 | return qdisc_enqueue_tail(skb, sch); | |
53 | ||
54 | /* queue full, remove one skb to fulfill the limit */ | |
55 | skb_head = qdisc_dequeue_head(sch); | |
57dbb2d8 HPP |
56 | sch->qstats.drops++; |
57 | kfree_skb(skb_head); | |
58 | ||
59 | qdisc_enqueue_tail(skb, sch); | |
60 | ||
61 | return NET_XMIT_CN; | |
62 | } | |
63 | ||
1e90474c | 64 | static int fifo_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
65 | { |
66 | struct fifo_sched_data *q = qdisc_priv(sch); | |
67 | ||
68 | if (opt == NULL) { | |
5ce2d488 | 69 | u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1; |
1da177e4 LT |
70 | |
71 | if (sch->ops == &bfifo_qdisc_ops) | |
6473990c | 72 | limit *= psched_mtu(qdisc_dev(sch)); |
6fc8e84f TG |
73 | |
74 | q->limit = limit; | |
1da177e4 | 75 | } else { |
1e90474c | 76 | struct tc_fifo_qopt *ctl = nla_data(opt); |
6fc8e84f | 77 | |
1e90474c | 78 | if (nla_len(opt) < sizeof(*ctl)) |
1da177e4 | 79 | return -EINVAL; |
6fc8e84f | 80 | |
1da177e4 LT |
81 | q->limit = ctl->limit; |
82 | } | |
6fc8e84f | 83 | |
1da177e4 LT |
84 | return 0; |
85 | } | |
86 | ||
87 | static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) | |
88 | { | |
89 | struct fifo_sched_data *q = qdisc_priv(sch); | |
6fc8e84f | 90 | struct tc_fifo_qopt opt = { .limit = q->limit }; |
1da177e4 | 91 | |
1e90474c | 92 | NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); |
1da177e4 LT |
93 | return skb->len; |
94 | ||
1e90474c | 95 | nla_put_failure: |
1da177e4 LT |
96 | return -1; |
97 | } | |
98 | ||
20fea08b | 99 | struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
100 | .id = "pfifo", |
101 | .priv_size = sizeof(struct fifo_sched_data), | |
102 | .enqueue = pfifo_enqueue, | |
aaae3013 | 103 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 104 | .peek = qdisc_peek_head, |
aaae3013 | 105 | .drop = qdisc_queue_drop, |
1da177e4 | 106 | .init = fifo_init, |
aaae3013 | 107 | .reset = qdisc_reset_queue, |
1da177e4 LT |
108 | .change = fifo_init, |
109 | .dump = fifo_dump, | |
110 | .owner = THIS_MODULE, | |
111 | }; | |
62e3ba1b | 112 | EXPORT_SYMBOL(pfifo_qdisc_ops); |
1da177e4 | 113 | |
20fea08b | 114 | struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
115 | .id = "bfifo", |
116 | .priv_size = sizeof(struct fifo_sched_data), | |
117 | .enqueue = bfifo_enqueue, | |
aaae3013 | 118 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 119 | .peek = qdisc_peek_head, |
aaae3013 | 120 | .drop = qdisc_queue_drop, |
1da177e4 | 121 | .init = fifo_init, |
aaae3013 | 122 | .reset = qdisc_reset_queue, |
1da177e4 LT |
123 | .change = fifo_init, |
124 | .dump = fifo_dump, | |
125 | .owner = THIS_MODULE, | |
126 | }; | |
1da177e4 | 127 | EXPORT_SYMBOL(bfifo_qdisc_ops); |
fb0305ce | 128 | |
57dbb2d8 HPP |
129 | struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { |
130 | .id = "pfifo_head_drop", | |
131 | .priv_size = sizeof(struct fifo_sched_data), | |
132 | .enqueue = pfifo_tail_enqueue, | |
133 | .dequeue = qdisc_dequeue_head, | |
134 | .peek = qdisc_peek_head, | |
135 | .drop = qdisc_queue_drop_head, | |
136 | .init = fifo_init, | |
137 | .reset = qdisc_reset_queue, | |
138 | .change = fifo_init, | |
139 | .dump = fifo_dump, | |
140 | .owner = THIS_MODULE, | |
141 | }; | |
142 | ||
fb0305ce PM |
143 | /* Pass size change message down to embedded FIFO */ |
144 | int fifo_set_limit(struct Qdisc *q, unsigned int limit) | |
145 | { | |
146 | struct nlattr *nla; | |
147 | int ret = -ENOMEM; | |
148 | ||
149 | /* Hack to avoid sending change message to non-FIFO */ | |
150 | if (strncmp(q->ops->id + 1, "fifo", 4) != 0) | |
151 | return 0; | |
152 | ||
153 | nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); | |
154 | if (nla) { | |
155 | nla->nla_type = RTM_NEWQDISC; | |
156 | nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt)); | |
157 | ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit; | |
158 | ||
159 | ret = q->ops->change(q, nla); | |
160 | kfree(nla); | |
161 | } | |
162 | return ret; | |
163 | } | |
164 | EXPORT_SYMBOL(fifo_set_limit); | |
165 | ||
166 | struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops, | |
167 | unsigned int limit) | |
168 | { | |
169 | struct Qdisc *q; | |
170 | int err = -ENOMEM; | |
171 | ||
3511c913 | 172 | q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1)); |
fb0305ce PM |
173 | if (q) { |
174 | err = fifo_set_limit(q, limit); | |
175 | if (err < 0) { | |
176 | qdisc_destroy(q); | |
177 | q = NULL; | |
178 | } | |
179 | } | |
180 | ||
181 | return q ? : ERR_PTR(err); | |
182 | } | |
183 | EXPORT_SYMBOL(fifo_create_dflt); |