1 /*
2 * net/sched/sch_prio.c Simple 3-band priority "scheduler".
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 * Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>:
11 * Init -- EINVAL when opt undefined
12 */
13
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/string.h>
19 #include <linux/errno.h>
20 #include <linux/skbuff.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23 #include <net/pkt_cls.h>
24
25 struct prio_sched_data {
26 int bands;
27 struct tcf_proto __rcu *filter_list;
28 struct tcf_block *block;
29 u8 prio2band[TC_PRIO_MAX+1];
30 struct Qdisc *queues[TCQ_PRIO_BANDS];
31 };
32
33
34 static struct Qdisc *
prio_classify(struct sk_buff * skb,struct Qdisc * sch,int * qerr)35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
36 {
37 struct prio_sched_data *q = qdisc_priv(sch);
38 u32 band = skb->priority;
39 struct tcf_result res;
40 struct tcf_proto *fl;
41 int err;
42
43 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
44 if (TC_H_MAJ(skb->priority) != sch->handle) {
45 fl = rcu_dereference_bh(q->filter_list);
46 err = tcf_classify(skb, fl, &res, false);
47 #ifdef CONFIG_NET_CLS_ACT
48 switch (err) {
49 case TC_ACT_STOLEN:
50 case TC_ACT_QUEUED:
51 case TC_ACT_TRAP:
52 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
53 case TC_ACT_SHOT:
54 return NULL;
55 }
56 #endif
57 if (!fl || err < 0) {
58 if (TC_H_MAJ(band))
59 band = 0;
60 return q->queues[q->prio2band[band & TC_PRIO_MAX]];
61 }
62 band = res.classid;
63 }
64 band = TC_H_MIN(band) - 1;
65 if (band >= q->bands)
66 return q->queues[q->prio2band[0]];
67
68 return q->queues[band];
69 }
70
71 static int
prio_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)72 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
73 {
74 struct Qdisc *qdisc;
75 int ret;
76
77 qdisc = prio_classify(skb, sch, &ret);
78 #ifdef CONFIG_NET_CLS_ACT
79 if (qdisc == NULL) {
80
81 if (ret & __NET_XMIT_BYPASS)
82 qdisc_qstats_drop(sch);
83 __qdisc_drop(skb, to_free);
84 return ret;
85 }
86 #endif
87
88 ret = qdisc_enqueue(skb, qdisc, to_free);
89 if (ret == NET_XMIT_SUCCESS) {
90 qdisc_qstats_backlog_inc(sch, skb);
91 sch->q.qlen++;
92 return NET_XMIT_SUCCESS;
93 }
94 if (net_xmit_drop_count(ret))
95 qdisc_qstats_drop(sch);
96 return ret;
97 }
98
prio_peek(struct Qdisc * sch)99 static struct sk_buff *prio_peek(struct Qdisc *sch)
100 {
101 struct prio_sched_data *q = qdisc_priv(sch);
102 int prio;
103
104 for (prio = 0; prio < q->bands; prio++) {
105 struct Qdisc *qdisc = q->queues[prio];
106 struct sk_buff *skb = qdisc->ops->peek(qdisc);
107 if (skb)
108 return skb;
109 }
110 return NULL;
111 }
112
prio_dequeue(struct Qdisc * sch)113 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
114 {
115 struct prio_sched_data *q = qdisc_priv(sch);
116 int prio;
117
118 for (prio = 0; prio < q->bands; prio++) {
119 struct Qdisc *qdisc = q->queues[prio];
120 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
121 if (skb) {
122 qdisc_bstats_update(sch, skb);
123 qdisc_qstats_backlog_dec(sch, skb);
124 sch->q.qlen--;
125 return skb;
126 }
127 }
128 return NULL;
129
130 }
131
132 static void
prio_reset(struct Qdisc * sch)133 prio_reset(struct Qdisc *sch)
134 {
135 int prio;
136 struct prio_sched_data *q = qdisc_priv(sch);
137
138 for (prio = 0; prio < q->bands; prio++)
139 qdisc_reset(q->queues[prio]);
140 sch->qstats.backlog = 0;
141 sch->q.qlen = 0;
142 }
143
144 static void
prio_destroy(struct Qdisc * sch)145 prio_destroy(struct Qdisc *sch)
146 {
147 int prio;
148 struct prio_sched_data *q = qdisc_priv(sch);
149
150 tcf_block_put(q->block);
151 for (prio = 0; prio < q->bands; prio++)
152 qdisc_destroy(q->queues[prio]);
153 }
154
prio_tune(struct Qdisc * sch,struct nlattr * opt)155 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
156 {
157 struct prio_sched_data *q = qdisc_priv(sch);
158 struct Qdisc *queues[TCQ_PRIO_BANDS];
159 int oldbands = q->bands, i;
160 struct tc_prio_qopt *qopt;
161
162 if (nla_len(opt) < sizeof(*qopt))
163 return -EINVAL;
164 qopt = nla_data(opt);
165
166 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
167 return -EINVAL;
168
169 for (i = 0; i <= TC_PRIO_MAX; i++) {
170 if (qopt->priomap[i] >= qopt->bands)
171 return -EINVAL;
172 }
173
174 /* Before commit, make sure we can allocate all new qdiscs */
175 for (i = oldbands; i < qopt->bands; i++) {
176 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
177 TC_H_MAKE(sch->handle, i + 1));
178 if (!queues[i]) {
179 while (i > oldbands)
180 qdisc_destroy(queues[--i]);
181 return -ENOMEM;
182 }
183 }
184
185 sch_tree_lock(sch);
186 q->bands = qopt->bands;
187 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
188
189 for (i = q->bands; i < oldbands; i++) {
190 struct Qdisc *child = q->queues[i];
191
192 qdisc_tree_reduce_backlog(child, child->q.qlen,
193 child->qstats.backlog);
194 qdisc_destroy(child);
195 }
196
197 for (i = oldbands; i < q->bands; i++) {
198 q->queues[i] = queues[i];
199 if (q->queues[i] != &noop_qdisc)
200 qdisc_hash_add(q->queues[i], true);
201 }
202
203 sch_tree_unlock(sch);
204 return 0;
205 }
206
prio_init(struct Qdisc * sch,struct nlattr * opt)207 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
208 {
209 struct prio_sched_data *q = qdisc_priv(sch);
210 int err;
211
212 if (!opt)
213 return -EINVAL;
214
215 err = tcf_block_get(&q->block, &q->filter_list);
216 if (err)
217 return err;
218
219 return prio_tune(sch, opt);
220 }
221
prio_dump(struct Qdisc * sch,struct sk_buff * skb)222 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
223 {
224 struct prio_sched_data *q = qdisc_priv(sch);
225 unsigned char *b = skb_tail_pointer(skb);
226 struct tc_prio_qopt opt;
227
228 opt.bands = q->bands;
229 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
230
231 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
232 goto nla_put_failure;
233
234 return skb->len;
235
236 nla_put_failure:
237 nlmsg_trim(skb, b);
238 return -1;
239 }
240
prio_graft(struct Qdisc * sch,unsigned long arg,struct Qdisc * new,struct Qdisc ** old)241 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
242 struct Qdisc **old)
243 {
244 struct prio_sched_data *q = qdisc_priv(sch);
245 unsigned long band = arg - 1;
246
247 if (!new) {
248 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
249 TC_H_MAKE(sch->handle, arg));
250 if (!new)
251 new = &noop_qdisc;
252 else
253 qdisc_hash_add(new, true);
254 }
255
256 *old = qdisc_replace(sch, new, &q->queues[band]);
257 return 0;
258 }
259
260 static struct Qdisc *
prio_leaf(struct Qdisc * sch,unsigned long arg)261 prio_leaf(struct Qdisc *sch, unsigned long arg)
262 {
263 struct prio_sched_data *q = qdisc_priv(sch);
264 unsigned long band = arg - 1;
265
266 return q->queues[band];
267 }
268
prio_find(struct Qdisc * sch,u32 classid)269 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
270 {
271 struct prio_sched_data *q = qdisc_priv(sch);
272 unsigned long band = TC_H_MIN(classid);
273
274 if (band - 1 >= q->bands)
275 return 0;
276 return band;
277 }
278
prio_bind(struct Qdisc * sch,unsigned long parent,u32 classid)279 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
280 {
281 return prio_find(sch, classid);
282 }
283
284
prio_unbind(struct Qdisc * q,unsigned long cl)285 static void prio_unbind(struct Qdisc *q, unsigned long cl)
286 {
287 }
288
prio_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)289 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
290 struct tcmsg *tcm)
291 {
292 struct prio_sched_data *q = qdisc_priv(sch);
293
294 tcm->tcm_handle |= TC_H_MIN(cl);
295 tcm->tcm_info = q->queues[cl-1]->handle;
296 return 0;
297 }
298
prio_dump_class_stats(struct Qdisc * sch,unsigned long cl,struct gnet_dump * d)299 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
300 struct gnet_dump *d)
301 {
302 struct prio_sched_data *q = qdisc_priv(sch);
303 struct Qdisc *cl_q;
304
305 cl_q = q->queues[cl - 1];
306 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
307 d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
308 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
309 return -1;
310
311 return 0;
312 }
313
prio_walk(struct Qdisc * sch,struct qdisc_walker * arg)314 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
315 {
316 struct prio_sched_data *q = qdisc_priv(sch);
317 int prio;
318
319 if (arg->stop)
320 return;
321
322 for (prio = 0; prio < q->bands; prio++) {
323 if (arg->count < arg->skip) {
324 arg->count++;
325 continue;
326 }
327 if (arg->fn(sch, prio + 1, arg) < 0) {
328 arg->stop = 1;
329 break;
330 }
331 arg->count++;
332 }
333 }
334
prio_tcf_block(struct Qdisc * sch,unsigned long cl)335 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl)
336 {
337 struct prio_sched_data *q = qdisc_priv(sch);
338
339 if (cl)
340 return NULL;
341 return q->block;
342 }
343
344 static const struct Qdisc_class_ops prio_class_ops = {
345 .graft = prio_graft,
346 .leaf = prio_leaf,
347 .find = prio_find,
348 .walk = prio_walk,
349 .tcf_block = prio_tcf_block,
350 .bind_tcf = prio_bind,
351 .unbind_tcf = prio_unbind,
352 .dump = prio_dump_class,
353 .dump_stats = prio_dump_class_stats,
354 };
355
356 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
357 .next = NULL,
358 .cl_ops = &prio_class_ops,
359 .id = "prio",
360 .priv_size = sizeof(struct prio_sched_data),
361 .enqueue = prio_enqueue,
362 .dequeue = prio_dequeue,
363 .peek = prio_peek,
364 .init = prio_init,
365 .reset = prio_reset,
366 .destroy = prio_destroy,
367 .change = prio_tune,
368 .dump = prio_dump,
369 .owner = THIS_MODULE,
370 };
371
prio_module_init(void)372 static int __init prio_module_init(void)
373 {
374 return register_qdisc(&prio_qdisc_ops);
375 }
376
prio_module_exit(void)377 static void __exit prio_module_exit(void)
378 {
379 unregister_qdisc(&prio_qdisc_ops);
380 }
381
382 module_init(prio_module_init)
383 module_exit(prio_module_exit)
384
385 MODULE_LICENSE("GPL");
386