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 | ||
22 | struct fifo_sched_data | |
23 | { | |
6fc8e84f | 24 | u32 limit; |
1da177e4 LT |
25 | }; |
26 | ||
6fc8e84f | 27 | static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
1da177e4 LT |
28 | { |
29 | struct fifo_sched_data *q = qdisc_priv(sch); | |
30 | ||
0abf77e5 | 31 | if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit)) |
aaae3013 | 32 | return qdisc_enqueue_tail(skb, sch); |
1da177e4 | 33 | |
aaae3013 | 34 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
35 | } |
36 | ||
6fc8e84f | 37 | static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
1da177e4 LT |
38 | { |
39 | struct fifo_sched_data *q = qdisc_priv(sch); | |
40 | ||
aaae3013 TG |
41 | if (likely(skb_queue_len(&sch->q) < q->limit)) |
42 | return qdisc_enqueue_tail(skb, sch); | |
1da177e4 | 43 | |
aaae3013 | 44 | return qdisc_reshape_fail(skb, sch); |
1da177e4 LT |
45 | } |
46 | ||
57dbb2d8 HPP |
47 | static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
48 | { | |
57dbb2d8 HPP |
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 */ | |
9190b3b3 | 55 | __qdisc_queue_drop_head(sch, &sch->q); |
57dbb2d8 | 56 | sch->qstats.drops++; |
57dbb2d8 HPP |
57 | qdisc_enqueue_tail(skb, sch); |
58 | ||
59 | return NET_XMIT_CN; | |
60 | } | |
61 | ||
1e90474c | 62 | static int fifo_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
63 | { |
64 | struct fifo_sched_data *q = qdisc_priv(sch); | |
65 | ||
66 | if (opt == NULL) { | |
5ce2d488 | 67 | u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1; |
1da177e4 LT |
68 | |
69 | if (sch->ops == &bfifo_qdisc_ops) | |
6473990c | 70 | limit *= psched_mtu(qdisc_dev(sch)); |
6fc8e84f TG |
71 | |
72 | q->limit = limit; | |
1da177e4 | 73 | } else { |
1e90474c | 74 | struct tc_fifo_qopt *ctl = nla_data(opt); |
6fc8e84f | 75 | |
1e90474c | 76 | if (nla_len(opt) < sizeof(*ctl)) |
1da177e4 | 77 | return -EINVAL; |
6fc8e84f | 78 | |
1da177e4 LT |
79 | q->limit = ctl->limit; |
80 | } | |
6fc8e84f | 81 | |
1da177e4 LT |
82 | return 0; |
83 | } | |
84 | ||
85 | static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) | |
86 | { | |
87 | struct fifo_sched_data *q = qdisc_priv(sch); | |
6fc8e84f | 88 | struct tc_fifo_qopt opt = { .limit = q->limit }; |
1da177e4 | 89 | |
1e90474c | 90 | NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); |
1da177e4 LT |
91 | return skb->len; |
92 | ||
1e90474c | 93 | nla_put_failure: |
1da177e4 LT |
94 | return -1; |
95 | } | |
96 | ||
20fea08b | 97 | struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
98 | .id = "pfifo", |
99 | .priv_size = sizeof(struct fifo_sched_data), | |
100 | .enqueue = pfifo_enqueue, | |
aaae3013 | 101 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 102 | .peek = qdisc_peek_head, |
aaae3013 | 103 | .drop = qdisc_queue_drop, |
1da177e4 | 104 | .init = fifo_init, |
aaae3013 | 105 | .reset = qdisc_reset_queue, |
1da177e4 LT |
106 | .change = fifo_init, |
107 | .dump = fifo_dump, | |
108 | .owner = THIS_MODULE, | |
109 | }; | |
62e3ba1b | 110 | EXPORT_SYMBOL(pfifo_qdisc_ops); |
1da177e4 | 111 | |
20fea08b | 112 | struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
113 | .id = "bfifo", |
114 | .priv_size = sizeof(struct fifo_sched_data), | |
115 | .enqueue = bfifo_enqueue, | |
aaae3013 | 116 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 117 | .peek = qdisc_peek_head, |
aaae3013 | 118 | .drop = qdisc_queue_drop, |
1da177e4 | 119 | .init = fifo_init, |
aaae3013 | 120 | .reset = qdisc_reset_queue, |
1da177e4 LT |
121 | .change = fifo_init, |
122 | .dump = fifo_dump, | |
123 | .owner = THIS_MODULE, | |
124 | }; | |
1da177e4 | 125 | EXPORT_SYMBOL(bfifo_qdisc_ops); |
fb0305ce | 126 | |
57dbb2d8 HPP |
127 | struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { |
128 | .id = "pfifo_head_drop", | |
129 | .priv_size = sizeof(struct fifo_sched_data), | |
130 | .enqueue = pfifo_tail_enqueue, | |
131 | .dequeue = qdisc_dequeue_head, | |
132 | .peek = qdisc_peek_head, | |
133 | .drop = qdisc_queue_drop_head, | |
134 | .init = fifo_init, | |
135 | .reset = qdisc_reset_queue, | |
136 | .change = fifo_init, | |
137 | .dump = fifo_dump, | |
138 | .owner = THIS_MODULE, | |
139 | }; | |
140 | ||
fb0305ce PM |
141 | /* Pass size change message down to embedded FIFO */ |
142 | int fifo_set_limit(struct Qdisc *q, unsigned int limit) | |
143 | { | |
144 | struct nlattr *nla; | |
145 | int ret = -ENOMEM; | |
146 | ||
147 | /* Hack to avoid sending change message to non-FIFO */ | |
148 | if (strncmp(q->ops->id + 1, "fifo", 4) != 0) | |
149 | return 0; | |
150 | ||
151 | nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); | |
152 | if (nla) { | |
153 | nla->nla_type = RTM_NEWQDISC; | |
154 | nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt)); | |
155 | ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit; | |
156 | ||
157 | ret = q->ops->change(q, nla); | |
158 | kfree(nla); | |
159 | } | |
160 | return ret; | |
161 | } | |
162 | EXPORT_SYMBOL(fifo_set_limit); | |
163 | ||
164 | struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops, | |
165 | unsigned int limit) | |
166 | { | |
167 | struct Qdisc *q; | |
168 | int err = -ENOMEM; | |
169 | ||
3511c913 | 170 | q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1)); |
fb0305ce PM |
171 | if (q) { |
172 | err = fifo_set_limit(q, limit); | |
173 | if (err < 0) { | |
174 | qdisc_destroy(q); | |
175 | q = NULL; | |
176 | } | |
177 | } | |
178 | ||
179 | return q ? : ERR_PTR(err); | |
180 | } | |
181 | EXPORT_SYMBOL(fifo_create_dflt); |