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Linux 3.8-rc7
[cris-mirror.git] / net / sched / sch_gred.c
blobd42234c0f13bf4d4829930e0f6bcb30681ad4782
1 /*
2 * net/sched/sch_gred.c Generic Random Early Detection queue.
3 *
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * Authors: J Hadi Salim (hadi@cyberus.ca) 1998-2002
11 *
12 * 991129: - Bug fix with grio mode
13 * - a better sing. AvgQ mode with Grio(WRED)
14 * - A finer grained VQ dequeue based on sugestion
15 * from Ren Liu
16 * - More error checks
17 *
18 * For all the glorious comments look at include/net/red.h
19 */
20
21 #include <linux/slab.h>
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/skbuff.h>
26 #include <net/pkt_sched.h>
27 #include <net/red.h>
28
29 #define GRED_DEF_PRIO (MAX_DPs / 2)
30 #define GRED_VQ_MASK (MAX_DPs - 1)
31
32 struct gred_sched_data;
33 struct gred_sched;
34
35 struct gred_sched_data {
36 u32 limit; /* HARD maximal queue length */
37 u32 DP; /* the drop parameters */
38 u32 bytesin; /* bytes seen on virtualQ so far*/
39 u32 packetsin; /* packets seen on virtualQ so far*/
40 u32 backlog; /* bytes on the virtualQ */
41 u8 prio; /* the prio of this vq */
42
43 struct red_parms parms;
44 struct red_vars vars;
45 struct red_stats stats;
46 };
47
48 enum {
49 GRED_WRED_MODE = 1,
50 GRED_RIO_MODE,
51 };
52
53 struct gred_sched {
54 struct gred_sched_data *tab[MAX_DPs];
55 unsigned long flags;
56 u32 red_flags;
57 u32 DPs;
58 u32 def;
59 struct red_vars wred_set;
60 };
61
62 static inline int gred_wred_mode(struct gred_sched *table)
63 {
64 return test_bit(GRED_WRED_MODE, &table->flags);
65 }
66
67 static inline void gred_enable_wred_mode(struct gred_sched *table)
68 {
69 __set_bit(GRED_WRED_MODE, &table->flags);
70 }
71
72 static inline void gred_disable_wred_mode(struct gred_sched *table)
73 {
74 __clear_bit(GRED_WRED_MODE, &table->flags);
75 }
76
77 static inline int gred_rio_mode(struct gred_sched *table)
78 {
79 return test_bit(GRED_RIO_MODE, &table->flags);
80 }
81
82 static inline void gred_enable_rio_mode(struct gred_sched *table)
83 {
84 __set_bit(GRED_RIO_MODE, &table->flags);
85 }
86
87 static inline void gred_disable_rio_mode(struct gred_sched *table)
88 {
89 __clear_bit(GRED_RIO_MODE, &table->flags);
90 }
91
92 static inline int gred_wred_mode_check(struct Qdisc *sch)
93 {
94 struct gred_sched *table = qdisc_priv(sch);
95 int i;
96
97 /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
98 for (i = 0; i < table->DPs; i++) {
99 struct gred_sched_data *q = table->tab[i];
100 int n;
101
102 if (q == NULL)
103 continue;
104
105 for (n = i + 1; n < table->DPs; n++)
106 if (table->tab[n] && table->tab[n]->prio == q->prio)
107 return 1;
108 }
109
110 return 0;
111 }
112
113 static inline unsigned int gred_backlog(struct gred_sched *table,
114 struct gred_sched_data *q,
115 struct Qdisc *sch)
116 {
117 if (gred_wred_mode(table))
118 return sch->qstats.backlog;
119 else
120 return q->backlog;
121 }
122
123 static inline u16 tc_index_to_dp(struct sk_buff *skb)
124 {
125 return skb->tc_index & GRED_VQ_MASK;
126 }
127
128 static inline void gred_load_wred_set(const struct gred_sched *table,
129 struct gred_sched_data *q)
130 {
131 q->vars.qavg = table->wred_set.qavg;
132 q->vars.qidlestart = table->wred_set.qidlestart;
133 }
134
135 static inline void gred_store_wred_set(struct gred_sched *table,
136 struct gred_sched_data *q)
137 {
138 table->wred_set.qavg = q->vars.qavg;
139 table->wred_set.qidlestart = q->vars.qidlestart;
140 }
141
142 static inline int gred_use_ecn(struct gred_sched *t)
143 {
144 return t->red_flags & TC_RED_ECN;
145 }
146
147 static inline int gred_use_harddrop(struct gred_sched *t)
148 {
149 return t->red_flags & TC_RED_HARDDROP;
150 }
151
152 static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
153 {
154 struct gred_sched_data *q = NULL;
155 struct gred_sched *t = qdisc_priv(sch);
156 unsigned long qavg = 0;
157 u16 dp = tc_index_to_dp(skb);
158
159 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
160 dp = t->def;
161
162 q = t->tab[dp];
163 if (!q) {
164 /* Pass through packets not assigned to a DP
165 * if no default DP has been configured. This
166 * allows for DP flows to be left untouched.
167 */
168 if (skb_queue_len(&sch->q) < qdisc_dev(sch)->tx_queue_len)
169 return qdisc_enqueue_tail(skb, sch);
170 else
171 goto drop;
172 }
173
174 /* fix tc_index? --could be controversial but needed for
175 requeueing */
176 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
177 }
178
179 /* sum up all the qaves of prios < ours to get the new qave */
180 if (!gred_wred_mode(t) && gred_rio_mode(t)) {
181 int i;
182
183 for (i = 0; i < t->DPs; i++) {
184 if (t->tab[i] && t->tab[i]->prio < q->prio &&
185 !red_is_idling(&t->tab[i]->vars))
186 qavg += t->tab[i]->vars.qavg;
187 }
188
189 }
190
191 q->packetsin++;
192 q->bytesin += qdisc_pkt_len(skb);
193
194 if (gred_wred_mode(t))
195 gred_load_wred_set(t, q);
196
197 q->vars.qavg = red_calc_qavg(&q->parms,
198 &q->vars,
199 gred_backlog(t, q, sch));
200
201 if (red_is_idling(&q->vars))
202 red_end_of_idle_period(&q->vars);
203
204 if (gred_wred_mode(t))
205 gred_store_wred_set(t, q);
206
207 switch (red_action(&q->parms, &q->vars, q->vars.qavg + qavg)) {
208 case RED_DONT_MARK:
209 break;
210
211 case RED_PROB_MARK:
212 sch->qstats.overlimits++;
213 if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
214 q->stats.prob_drop++;
215 goto congestion_drop;
216 }
217
218 q->stats.prob_mark++;
219 break;
220
221 case RED_HARD_MARK:
222 sch->qstats.overlimits++;
223 if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
224 !INET_ECN_set_ce(skb)) {
225 q->stats.forced_drop++;
226 goto congestion_drop;
227 }
228 q->stats.forced_mark++;
229 break;
230 }
231
232 if (q->backlog + qdisc_pkt_len(skb) <= q->limit) {
233 q->backlog += qdisc_pkt_len(skb);
234 return qdisc_enqueue_tail(skb, sch);
235 }
236
237 q->stats.pdrop++;
238 drop:
239 return qdisc_drop(skb, sch);
240
241 congestion_drop:
242 qdisc_drop(skb, sch);
243 return NET_XMIT_CN;
244 }
245
246 static struct sk_buff *gred_dequeue(struct Qdisc *sch)
247 {
248 struct sk_buff *skb;
249 struct gred_sched *t = qdisc_priv(sch);
250
251 skb = qdisc_dequeue_head(sch);
252
253 if (skb) {
254 struct gred_sched_data *q;
255 u16 dp = tc_index_to_dp(skb);
256
257 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
258 net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x after dequeue, screwing up backlog\n",
259 tc_index_to_dp(skb));
260 } else {
261 q->backlog -= qdisc_pkt_len(skb);
262
263 if (gred_wred_mode(t)) {
264 if (!sch->qstats.backlog)
265 red_start_of_idle_period(&t->wred_set);
266 } else {
267 if (!q->backlog)
268 red_start_of_idle_period(&q->vars);
269 }
270 }
271
272 return skb;
273 }
274
275 return NULL;
276 }
277
278 static unsigned int gred_drop(struct Qdisc *sch)
279 {
280 struct sk_buff *skb;
281 struct gred_sched *t = qdisc_priv(sch);
282
283 skb = qdisc_dequeue_tail(sch);
284 if (skb) {
285 unsigned int len = qdisc_pkt_len(skb);
286 struct gred_sched_data *q;
287 u16 dp = tc_index_to_dp(skb);
288
289 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
290 net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x while dropping, screwing up backlog\n",
291 tc_index_to_dp(skb));
292 } else {
293 q->backlog -= len;
294 q->stats.other++;
295
296 if (gred_wred_mode(t)) {
297 if (!sch->qstats.backlog)
298 red_start_of_idle_period(&t->wred_set);
299 } else {
300 if (!q->backlog)
301 red_start_of_idle_period(&q->vars);
302 }
303 }
304
305 qdisc_drop(skb, sch);
306 return len;
307 }
308
309 return 0;
310 }
311
312 static void gred_reset(struct Qdisc *sch)
313 {
314 int i;
315 struct gred_sched *t = qdisc_priv(sch);
316
317 qdisc_reset_queue(sch);
318
319 for (i = 0; i < t->DPs; i++) {
320 struct gred_sched_data *q = t->tab[i];
321
322 if (!q)
323 continue;
324
325 red_restart(&q->vars);
326 q->backlog = 0;
327 }
328 }
329
330 static inline void gred_destroy_vq(struct gred_sched_data *q)
331 {
332 kfree(q);
333 }
334
335 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
336 {
337 struct gred_sched *table = qdisc_priv(sch);
338 struct tc_gred_sopt *sopt;
339 int i;
340
341 if (dps == NULL)
342 return -EINVAL;
343
344 sopt = nla_data(dps);
345
346 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
347 return -EINVAL;
348
349 sch_tree_lock(sch);
350 table->DPs = sopt->DPs;
351 table->def = sopt->def_DP;
352 table->red_flags = sopt->flags;
353
354 /*
355 * Every entry point to GRED is synchronized with the above code
356 * and the DP is checked against DPs, i.e. shadowed VQs can no
357 * longer be found so we can unlock right here.
358 */
359 sch_tree_unlock(sch);
360
361 if (sopt->grio) {
362 gred_enable_rio_mode(table);
363 gred_disable_wred_mode(table);
364 if (gred_wred_mode_check(sch))
365 gred_enable_wred_mode(table);
366 } else {
367 gred_disable_rio_mode(table);
368 gred_disable_wred_mode(table);
369 }
370
371 for (i = table->DPs; i < MAX_DPs; i++) {
372 if (table->tab[i]) {
373 pr_warning("GRED: Warning: Destroying "
374 "shadowed VQ 0x%x\n", i);
375 gred_destroy_vq(table->tab[i]);
376 table->tab[i] = NULL;
377 }
378 }
379
380 return 0;
381 }
382
383 static inline int gred_change_vq(struct Qdisc *sch, int dp,
384 struct tc_gred_qopt *ctl, int prio,
385 u8 *stab, u32 max_P,
386 struct gred_sched_data **prealloc)
387 {
388 struct gred_sched *table = qdisc_priv(sch);
389 struct gred_sched_data *q = table->tab[dp];
390
391 if (!q) {
392 table->tab[dp] = q = *prealloc;
393 *prealloc = NULL;
394 if (!q)
395 return -ENOMEM;
396 }
397
398 q->DP = dp;
399 q->prio = prio;
400 q->limit = ctl->limit;
401
402 if (q->backlog == 0)
403 red_end_of_idle_period(&q->vars);
404
405 red_set_parms(&q->parms,
406 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
407 ctl->Scell_log, stab, max_P);
408 red_set_vars(&q->vars);
409 return 0;
410 }
411
412 static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
413 [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
414 [TCA_GRED_STAB] = { .len = 256 },
415 [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
416 [TCA_GRED_MAX_P] = { .type = NLA_U32 },
417 };
418
419 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
420 {
421 struct gred_sched *table = qdisc_priv(sch);
422 struct tc_gred_qopt *ctl;
423 struct nlattr *tb[TCA_GRED_MAX + 1];
424 int err, prio = GRED_DEF_PRIO;
425 u8 *stab;
426 u32 max_P;
427 struct gred_sched_data *prealloc;
428
429 if (opt == NULL)
430 return -EINVAL;
431
432 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
433 if (err < 0)
434 return err;
435
436 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
437 return gred_change_table_def(sch, opt);
438
439 if (tb[TCA_GRED_PARMS] == NULL ||
440 tb[TCA_GRED_STAB] == NULL)
441 return -EINVAL;
442
443 max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
444
445 err = -EINVAL;
446 ctl = nla_data(tb[TCA_GRED_PARMS]);
447 stab = nla_data(tb[TCA_GRED_STAB]);
448
449 if (ctl->DP >= table->DPs)
450 goto errout;
451
452 if (gred_rio_mode(table)) {
453 if (ctl->prio == 0) {
454 int def_prio = GRED_DEF_PRIO;
455
456 if (table->tab[table->def])
457 def_prio = table->tab[table->def]->prio;
458
459 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
460 "setting default to %d\n", ctl->DP, def_prio);
461
462 prio = def_prio;
463 } else
464 prio = ctl->prio;
465 }
466
467 prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
468 sch_tree_lock(sch);
469
470 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
471 if (err < 0)
472 goto errout_locked;
473
474 if (gred_rio_mode(table)) {
475 gred_disable_wred_mode(table);
476 if (gred_wred_mode_check(sch))
477 gred_enable_wred_mode(table);
478 }
479
480 err = 0;
481
482 errout_locked:
483 sch_tree_unlock(sch);
484 kfree(prealloc);
485 errout:
486 return err;
487 }
488
489 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
490 {
491 struct nlattr *tb[TCA_GRED_MAX + 1];
492 int err;
493
494 if (opt == NULL)
495 return -EINVAL;
496
497 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
498 if (err < 0)
499 return err;
500
501 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
502 return -EINVAL;
503
504 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
505 }
506
507 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
508 {
509 struct gred_sched *table = qdisc_priv(sch);
510 struct nlattr *parms, *opts = NULL;
511 int i;
512 u32 max_p[MAX_DPs];
513 struct tc_gred_sopt sopt = {
514 .DPs = table->DPs,
515 .def_DP = table->def,
516 .grio = gred_rio_mode(table),
517 .flags = table->red_flags,
518 };
519
520 opts = nla_nest_start(skb, TCA_OPTIONS);
521 if (opts == NULL)
522 goto nla_put_failure;
523 if (nla_put(skb, TCA_GRED_DPS, sizeof(sopt), &sopt))
524 goto nla_put_failure;
525
526 for (i = 0; i < MAX_DPs; i++) {
527 struct gred_sched_data *q = table->tab[i];
528
529 max_p[i] = q ? q->parms.max_P : 0;
530 }
531 if (nla_put(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p))
532 goto nla_put_failure;
533
534 parms = nla_nest_start(skb, TCA_GRED_PARMS);
535 if (parms == NULL)
536 goto nla_put_failure;
537
538 for (i = 0; i < MAX_DPs; i++) {
539 struct gred_sched_data *q = table->tab[i];
540 struct tc_gred_qopt opt;
541 unsigned long qavg;
542
543 memset(&opt, 0, sizeof(opt));
544
545 if (!q) {
546 /* hack -- fix at some point with proper message
547 This is how we indicate to tc that there is no VQ
548 at this DP */
549
550 opt.DP = MAX_DPs + i;
551 goto append_opt;
552 }
553
554 opt.limit = q->limit;
555 opt.DP = q->DP;
556 opt.backlog = q->backlog;
557 opt.prio = q->prio;
558 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
559 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
560 opt.Wlog = q->parms.Wlog;
561 opt.Plog = q->parms.Plog;
562 opt.Scell_log = q->parms.Scell_log;
563 opt.other = q->stats.other;
564 opt.early = q->stats.prob_drop;
565 opt.forced = q->stats.forced_drop;
566 opt.pdrop = q->stats.pdrop;
567 opt.packets = q->packetsin;
568 opt.bytesin = q->bytesin;
569
570 if (gred_wred_mode(table))
571 gred_load_wred_set(table, q);
572
573 qavg = red_calc_qavg(&q->parms, &q->vars,
574 q->vars.qavg >> q->parms.Wlog);
575 opt.qave = qavg >> q->parms.Wlog;
576
577 append_opt:
578 if (nla_append(skb, sizeof(opt), &opt) < 0)
579 goto nla_put_failure;
580 }
581
582 nla_nest_end(skb, parms);
583
584 return nla_nest_end(skb, opts);
585
586 nla_put_failure:
587 nla_nest_cancel(skb, opts);
588 return -EMSGSIZE;
589 }
590
591 static void gred_destroy(struct Qdisc *sch)
592 {
593 struct gred_sched *table = qdisc_priv(sch);
594 int i;
595
596 for (i = 0; i < table->DPs; i++) {
597 if (table->tab[i])
598 gred_destroy_vq(table->tab[i]);
599 }
600 }
601
602 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
603 .id = "gred",
604 .priv_size = sizeof(struct gred_sched),
605 .enqueue = gred_enqueue,
606 .dequeue = gred_dequeue,
607 .peek = qdisc_peek_head,
608 .drop = gred_drop,
609 .init = gred_init,
610 .reset = gred_reset,
611 .destroy = gred_destroy,
612 .change = gred_change,
613 .dump = gred_dump,
614 .owner = THIS_MODULE,
615 };
616
617 static int __init gred_module_init(void)
618 {
619 return register_qdisc(&gred_qdisc_ops);
620 }
621
622 static void __exit gred_module_exit(void)
623 {
624 unregister_qdisc(&gred_qdisc_ops);
625 }
626
627 module_init(gred_module_init)
628 module_exit(gred_module_exit)
629
630 MODULE_LICENSE("GPL");
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