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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / net / sched / sch_red.c
blob16644b3d236271533b6e96a62705bc1903ab1d8a
1 /*
2 * net/sched/sch_red.c Random Early Detection 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 * Changes:
12 * J Hadi Salim 980914: computation fixes
13 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
14 * J Hadi Salim 980816: ECN support
15 */
16
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/skbuff.h>
21 #include <net/pkt_sched.h>
22 #include <net/pkt_cls.h>
23 #include <net/inet_ecn.h>
24 #include <net/red.h>
25
26
27 /* Parameters, settable by user:
28 -----------------------------
29
30 limit - bytes (must be > qth_max + burst)
31
32 Hard limit on queue length, should be chosen >qth_max
33 to allow packet bursts. This parameter does not
34 affect the algorithms behaviour and can be chosen
35 arbitrarily high (well, less than ram size)
36 Really, this limit will never be reached
37 if RED works correctly.
38 */
39
40 struct red_sched_data {
41 u32 limit; /* HARD maximal queue length */
42 unsigned char flags;
43 struct timer_list adapt_timer;
44 struct Qdisc *sch;
45 struct red_parms parms;
46 struct red_vars vars;
47 struct red_stats stats;
48 struct Qdisc *qdisc;
49 };
50
51 static inline int red_use_ecn(struct red_sched_data *q)
52 {
53 return q->flags & TC_RED_ECN;
54 }
55
56 static inline int red_use_harddrop(struct red_sched_data *q)
57 {
58 return q->flags & TC_RED_HARDDROP;
59 }
60
61 static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
62 struct sk_buff **to_free)
63 {
64 struct red_sched_data *q = qdisc_priv(sch);
65 struct Qdisc *child = q->qdisc;
66 int ret;
67
68 q->vars.qavg = red_calc_qavg(&q->parms,
69 &q->vars,
70 child->qstats.backlog);
71
72 if (red_is_idling(&q->vars))
73 red_end_of_idle_period(&q->vars);
74
75 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
76 case RED_DONT_MARK:
77 break;
78
79 case RED_PROB_MARK:
80 qdisc_qstats_overlimit(sch);
81 if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
82 q->stats.prob_drop++;
83 goto congestion_drop;
84 }
85
86 q->stats.prob_mark++;
87 break;
88
89 case RED_HARD_MARK:
90 qdisc_qstats_overlimit(sch);
91 if (red_use_harddrop(q) || !red_use_ecn(q) ||
92 !INET_ECN_set_ce(skb)) {
93 q->stats.forced_drop++;
94 goto congestion_drop;
95 }
96
97 q->stats.forced_mark++;
98 break;
99 }
100
101 ret = qdisc_enqueue(skb, child, to_free);
102 if (likely(ret == NET_XMIT_SUCCESS)) {
103 qdisc_qstats_backlog_inc(sch, skb);
104 sch->q.qlen++;
105 } else if (net_xmit_drop_count(ret)) {
106 q->stats.pdrop++;
107 qdisc_qstats_drop(sch);
108 }
109 return ret;
110
111 congestion_drop:
112 qdisc_drop(skb, sch, to_free);
113 return NET_XMIT_CN;
114 }
115
116 static struct sk_buff *red_dequeue(struct Qdisc *sch)
117 {
118 struct sk_buff *skb;
119 struct red_sched_data *q = qdisc_priv(sch);
120 struct Qdisc *child = q->qdisc;
121
122 skb = child->dequeue(child);
123 if (skb) {
124 qdisc_bstats_update(sch, skb);
125 qdisc_qstats_backlog_dec(sch, skb);
126 sch->q.qlen--;
127 } else {
128 if (!red_is_idling(&q->vars))
129 red_start_of_idle_period(&q->vars);
130 }
131 return skb;
132 }
133
134 static struct sk_buff *red_peek(struct Qdisc *sch)
135 {
136 struct red_sched_data *q = qdisc_priv(sch);
137 struct Qdisc *child = q->qdisc;
138
139 return child->ops->peek(child);
140 }
141
142 static void red_reset(struct Qdisc *sch)
143 {
144 struct red_sched_data *q = qdisc_priv(sch);
145
146 qdisc_reset(q->qdisc);
147 sch->qstats.backlog = 0;
148 sch->q.qlen = 0;
149 red_restart(&q->vars);
150 }
151
152 static int red_offload(struct Qdisc *sch, bool enable)
153 {
154 struct red_sched_data *q = qdisc_priv(sch);
155 struct net_device *dev = qdisc_dev(sch);
156 struct tc_red_qopt_offload opt = {
157 .handle = sch->handle,
158 .parent = sch->parent,
159 };
160
161 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
162 return -EOPNOTSUPP;
163
164 if (enable) {
165 opt.command = TC_RED_REPLACE;
166 opt.set.min = q->parms.qth_min >> q->parms.Wlog;
167 opt.set.max = q->parms.qth_max >> q->parms.Wlog;
168 opt.set.probability = q->parms.max_P;
169 opt.set.is_ecn = red_use_ecn(q);
170 opt.set.qstats = &sch->qstats;
171 } else {
172 opt.command = TC_RED_DESTROY;
173 }
174
175 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
176 }
177
178 static void red_destroy(struct Qdisc *sch)
179 {
180 struct red_sched_data *q = qdisc_priv(sch);
181
182 del_timer_sync(&q->adapt_timer);
183 red_offload(sch, false);
184 qdisc_destroy(q->qdisc);
185 }
186
187 static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
188 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
189 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
190 [TCA_RED_MAX_P] = { .type = NLA_U32 },
191 };
192
193 static int red_change(struct Qdisc *sch, struct nlattr *opt,
194 struct netlink_ext_ack *extack)
195 {
196 struct red_sched_data *q = qdisc_priv(sch);
197 struct nlattr *tb[TCA_RED_MAX + 1];
198 struct tc_red_qopt *ctl;
199 struct Qdisc *child = NULL;
200 int err;
201 u32 max_P;
202
203 if (opt == NULL)
204 return -EINVAL;
205
206 err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy, NULL);
207 if (err < 0)
208 return err;
209
210 if (tb[TCA_RED_PARMS] == NULL ||
211 tb[TCA_RED_STAB] == NULL)
212 return -EINVAL;
213
214 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
215
216 ctl = nla_data(tb[TCA_RED_PARMS]);
217 if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
218 return -EINVAL;
219
220 if (ctl->limit > 0) {
221 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
222 extack);
223 if (IS_ERR(child))
224 return PTR_ERR(child);
225 }
226
227 if (child != &noop_qdisc)
228 qdisc_hash_add(child, true);
229 sch_tree_lock(sch);
230 q->flags = ctl->flags;
231 q->limit = ctl->limit;
232 if (child) {
233 qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
234 q->qdisc->qstats.backlog);
235 qdisc_destroy(q->qdisc);
236 q->qdisc = child;
237 }
238
239 red_set_parms(&q->parms,
240 ctl->qth_min, ctl->qth_max, ctl->Wlog,
241 ctl->Plog, ctl->Scell_log,
242 nla_data(tb[TCA_RED_STAB]),
243 max_P);
244 red_set_vars(&q->vars);
245
246 del_timer(&q->adapt_timer);
247 if (ctl->flags & TC_RED_ADAPTATIVE)
248 mod_timer(&q->adapt_timer, jiffies + HZ/2);
249
250 if (!q->qdisc->q.qlen)
251 red_start_of_idle_period(&q->vars);
252
253 sch_tree_unlock(sch);
254 red_offload(sch, true);
255 return 0;
256 }
257
258 static inline void red_adaptative_timer(struct timer_list *t)
259 {
260 struct red_sched_data *q = from_timer(q, t, adapt_timer);
261 struct Qdisc *sch = q->sch;
262 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
263
264 spin_lock(root_lock);
265 red_adaptative_algo(&q->parms, &q->vars);
266 mod_timer(&q->adapt_timer, jiffies + HZ/2);
267 spin_unlock(root_lock);
268 }
269
270 static int red_init(struct Qdisc *sch, struct nlattr *opt,
271 struct netlink_ext_ack *extack)
272 {
273 struct red_sched_data *q = qdisc_priv(sch);
274
275 q->qdisc = &noop_qdisc;
276 q->sch = sch;
277 timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
278 return red_change(sch, opt, extack);
279 }
280
281 static int red_dump_offload_stats(struct Qdisc *sch, struct tc_red_qopt *opt)
282 {
283 struct net_device *dev = qdisc_dev(sch);
284 struct tc_red_qopt_offload hw_stats = {
285 .command = TC_RED_STATS,
286 .handle = sch->handle,
287 .parent = sch->parent,
288 {
289 .stats.bstats = &sch->bstats,
290 .stats.qstats = &sch->qstats,
291 },
292 };
293 int err;
294
295 sch->flags &= ~TCQ_F_OFFLOADED;
296
297 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
298 return 0;
299
300 err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
301 &hw_stats);
302 if (err == -EOPNOTSUPP)
303 return 0;
304
305 if (!err)
306 sch->flags |= TCQ_F_OFFLOADED;
307
308 return err;
309 }
310
311 static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
312 {
313 struct red_sched_data *q = qdisc_priv(sch);
314 struct nlattr *opts = NULL;
315 struct tc_red_qopt opt = {
316 .limit = q->limit,
317 .flags = q->flags,
318 .qth_min = q->parms.qth_min >> q->parms.Wlog,
319 .qth_max = q->parms.qth_max >> q->parms.Wlog,
320 .Wlog = q->parms.Wlog,
321 .Plog = q->parms.Plog,
322 .Scell_log = q->parms.Scell_log,
323 };
324 int err;
325
326 err = red_dump_offload_stats(sch, &opt);
327 if (err)
328 goto nla_put_failure;
329
330 opts = nla_nest_start(skb, TCA_OPTIONS);
331 if (opts == NULL)
332 goto nla_put_failure;
333 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
334 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
335 goto nla_put_failure;
336 return nla_nest_end(skb, opts);
337
338 nla_put_failure:
339 nla_nest_cancel(skb, opts);
340 return -EMSGSIZE;
341 }
342
343 static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
344 {
345 struct red_sched_data *q = qdisc_priv(sch);
346 struct net_device *dev = qdisc_dev(sch);
347 struct tc_red_xstats st = {0};
348
349 if (sch->flags & TCQ_F_OFFLOADED) {
350 struct tc_red_qopt_offload hw_stats_request = {
351 .command = TC_RED_XSTATS,
352 .handle = sch->handle,
353 .parent = sch->parent,
354 {
355 .xstats = &q->stats,
356 },
357 };
358 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
359 &hw_stats_request);
360 }
361 st.early = q->stats.prob_drop + q->stats.forced_drop;
362 st.pdrop = q->stats.pdrop;
363 st.other = q->stats.other;
364 st.marked = q->stats.prob_mark + q->stats.forced_mark;
365
366 return gnet_stats_copy_app(d, &st, sizeof(st));
367 }
368
369 static int red_dump_class(struct Qdisc *sch, unsigned long cl,
370 struct sk_buff *skb, struct tcmsg *tcm)
371 {
372 struct red_sched_data *q = qdisc_priv(sch);
373
374 tcm->tcm_handle |= TC_H_MIN(1);
375 tcm->tcm_info = q->qdisc->handle;
376 return 0;
377 }
378
379 static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
380 struct Qdisc **old, struct netlink_ext_ack *extack)
381 {
382 struct red_sched_data *q = qdisc_priv(sch);
383
384 if (new == NULL)
385 new = &noop_qdisc;
386
387 *old = qdisc_replace(sch, new, &q->qdisc);
388 return 0;
389 }
390
391 static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
392 {
393 struct red_sched_data *q = qdisc_priv(sch);
394 return q->qdisc;
395 }
396
397 static unsigned long red_find(struct Qdisc *sch, u32 classid)
398 {
399 return 1;
400 }
401
402 static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
403 {
404 if (!walker->stop) {
405 if (walker->count >= walker->skip)
406 if (walker->fn(sch, 1, walker) < 0) {
407 walker->stop = 1;
408 return;
409 }
410 walker->count++;
411 }
412 }
413
414 static const struct Qdisc_class_ops red_class_ops = {
415 .graft = red_graft,
416 .leaf = red_leaf,
417 .find = red_find,
418 .walk = red_walk,
419 .dump = red_dump_class,
420 };
421
422 static struct Qdisc_ops red_qdisc_ops __read_mostly = {
423 .id = "red",
424 .priv_size = sizeof(struct red_sched_data),
425 .cl_ops = &red_class_ops,
426 .enqueue = red_enqueue,
427 .dequeue = red_dequeue,
428 .peek = red_peek,
429 .init = red_init,
430 .reset = red_reset,
431 .destroy = red_destroy,
432 .change = red_change,
433 .dump = red_dump,
434 .dump_stats = red_dump_stats,
435 .owner = THIS_MODULE,
436 };
437
438 static int __init red_module_init(void)
439 {
440 return register_qdisc(&red_qdisc_ops);
441 }
442
443 static void __exit red_module_exit(void)
444 {
445 unregister_qdisc(&red_qdisc_ops);
446 }
447
448 module_init(red_module_init)
449 module_exit(red_module_exit)
450
451 MODULE_LICENSE("GPL");
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