Commit | Line | Data |
---|---|---|
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> |
1da177e4 LT |
13 | #include <linux/types.h> |
14 | #include <linux/kernel.h> | |
1da177e4 | 15 | #include <linux/errno.h> |
1da177e4 | 16 | #include <linux/skbuff.h> |
1da177e4 LT |
17 | #include <net/pkt_sched.h> |
18 | ||
19 | /* 1 band FIFO pseudo-"scheduler" */ | |
20 | ||
21 | struct fifo_sched_data | |
22 | { | |
6fc8e84f | 23 | u32 limit; |
1da177e4 LT |
24 | }; |
25 | ||
6fc8e84f | 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 | ||
6fc8e84f | 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 | ||
57dbb2d8 HPP |
46 | static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
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); | |
56 | sch->bstats.bytes -= qdisc_pkt_len(skb_head); | |
57 | sch->bstats.packets--; | |
58 | sch->qstats.drops++; | |
59 | kfree_skb(skb_head); | |
60 | ||
61 | qdisc_enqueue_tail(skb, sch); | |
62 | ||
63 | return NET_XMIT_CN; | |
64 | } | |
65 | ||
1e90474c | 66 | static int fifo_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
67 | { |
68 | struct fifo_sched_data *q = qdisc_priv(sch); | |
69 | ||
70 | if (opt == NULL) { | |
5ce2d488 | 71 | u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1; |
1da177e4 LT |
72 | |
73 | if (sch->ops == &bfifo_qdisc_ops) | |
6473990c | 74 | limit *= psched_mtu(qdisc_dev(sch)); |
6fc8e84f TG |
75 | |
76 | q->limit = limit; | |
1da177e4 | 77 | } else { |
1e90474c | 78 | struct tc_fifo_qopt *ctl = nla_data(opt); |
6fc8e84f | 79 | |
1e90474c | 80 | if (nla_len(opt) < sizeof(*ctl)) |
1da177e4 | 81 | return -EINVAL; |
6fc8e84f | 82 | |
1da177e4 LT |
83 | q->limit = ctl->limit; |
84 | } | |
6fc8e84f | 85 | |
1da177e4 LT |
86 | return 0; |
87 | } | |
88 | ||
89 | static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) | |
90 | { | |
91 | struct fifo_sched_data *q = qdisc_priv(sch); | |
6fc8e84f | 92 | struct tc_fifo_qopt opt = { .limit = q->limit }; |
1da177e4 | 93 | |
1e90474c | 94 | NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); |
1da177e4 LT |
95 | return skb->len; |
96 | ||
1e90474c | 97 | nla_put_failure: |
1da177e4 LT |
98 | return -1; |
99 | } | |
100 | ||
20fea08b | 101 | struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
102 | .id = "pfifo", |
103 | .priv_size = sizeof(struct fifo_sched_data), | |
104 | .enqueue = pfifo_enqueue, | |
aaae3013 | 105 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 106 | .peek = qdisc_peek_head, |
aaae3013 | 107 | .drop = qdisc_queue_drop, |
1da177e4 | 108 | .init = fifo_init, |
aaae3013 | 109 | .reset = qdisc_reset_queue, |
1da177e4 LT |
110 | .change = fifo_init, |
111 | .dump = fifo_dump, | |
112 | .owner = THIS_MODULE, | |
113 | }; | |
62e3ba1b | 114 | EXPORT_SYMBOL(pfifo_qdisc_ops); |
1da177e4 | 115 | |
20fea08b | 116 | struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { |
1da177e4 LT |
117 | .id = "bfifo", |
118 | .priv_size = sizeof(struct fifo_sched_data), | |
119 | .enqueue = bfifo_enqueue, | |
aaae3013 | 120 | .dequeue = qdisc_dequeue_head, |
48a8f519 | 121 | .peek = qdisc_peek_head, |
aaae3013 | 122 | .drop = qdisc_queue_drop, |
1da177e4 | 123 | .init = fifo_init, |
aaae3013 | 124 | .reset = qdisc_reset_queue, |
1da177e4 LT |
125 | .change = fifo_init, |
126 | .dump = fifo_dump, | |
127 | .owner = THIS_MODULE, | |
128 | }; | |
1da177e4 | 129 | EXPORT_SYMBOL(bfifo_qdisc_ops); |
fb0305ce | 130 | |
57dbb2d8 HPP |
131 | struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { |
132 | .id = "pfifo_head_drop", | |
133 | .priv_size = sizeof(struct fifo_sched_data), | |
134 | .enqueue = pfifo_tail_enqueue, | |
135 | .dequeue = qdisc_dequeue_head, | |
136 | .peek = qdisc_peek_head, | |
137 | .drop = qdisc_queue_drop_head, | |
138 | .init = fifo_init, | |
139 | .reset = qdisc_reset_queue, | |
140 | .change = fifo_init, | |
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 | ||
161 | ret = q->ops->change(q, nla); | |
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 | ||
5ce2d488 | 174 | q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue, |
bb949fbd | 175 | ops, TC_H_MAKE(sch->handle, 1)); |
fb0305ce PM |
176 | if (q) { |
177 | err = fifo_set_limit(q, limit); | |
178 | if (err < 0) { | |
179 | qdisc_destroy(q); | |
180 | q = NULL; | |
181 | } | |
182 | } | |
183 | ||
184 | return q ? : ERR_PTR(err); | |
185 | } | |
186 | EXPORT_SYMBOL(fifo_create_dflt); |