?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Xilinx: ARM: Update Zynq defconfig to enable USB errata.
[linux-2.6-xlnx.git] / net / sched / sch_gred.c
blobe901583e4ea533581f13e0fb39599f72e57b3e4c
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 = 0; n < table->DPs; n++)
106 if (table->tab[n] && table->tab[n] != q &&
107 table->tab[n]->prio == q->prio)
108 return 1;
109 }
110
111 return 0;
112 }
113
114 static inline unsigned int gred_backlog(struct gred_sched *table,
115 struct gred_sched_data *q,
116 struct Qdisc *sch)
117 {
118 if (gred_wred_mode(table))
119 return sch->qstats.backlog;
120 else
121 return q->backlog;
122 }
123
124 static inline u16 tc_index_to_dp(struct sk_buff *skb)
125 {
126 return skb->tc_index & GRED_VQ_MASK;
127 }
128
129 static inline void gred_load_wred_set(const struct gred_sched *table,
130 struct gred_sched_data *q)
131 {
132 q->vars.qavg = table->wred_set.qavg;
133 q->vars.qidlestart = table->wred_set.qidlestart;
134 }
135
136 static inline void gred_store_wred_set(struct gred_sched *table,
137 struct gred_sched_data *q)
138 {
139 table->wred_set.qavg = q->vars.qavg;
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 <= to 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 (!q->backlog && !gred_wred_mode(t))
264 red_start_of_idle_period(&q->vars);
265 }
266
267 return skb;
268 }
269
270 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
271 red_start_of_idle_period(&t->wred_set);
272
273 return NULL;
274 }
275
276 static unsigned int gred_drop(struct Qdisc *sch)
277 {
278 struct sk_buff *skb;
279 struct gred_sched *t = qdisc_priv(sch);
280
281 skb = qdisc_dequeue_tail(sch);
282 if (skb) {
283 unsigned int len = qdisc_pkt_len(skb);
284 struct gred_sched_data *q;
285 u16 dp = tc_index_to_dp(skb);
286
287 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
288 net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x while dropping, screwing up backlog\n",
289 tc_index_to_dp(skb));
290 } else {
291 q->backlog -= len;
292 q->stats.other++;
293
294 if (!q->backlog && !gred_wred_mode(t))
295 red_start_of_idle_period(&q->vars);
296 }
297
298 qdisc_drop(skb, sch);
299 return len;
300 }
301
302 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
303 red_start_of_idle_period(&t->wred_set);
304
305 return 0;
306
307 }
308
309 static void gred_reset(struct Qdisc *sch)
310 {
311 int i;
312 struct gred_sched *t = qdisc_priv(sch);
313
314 qdisc_reset_queue(sch);
315
316 for (i = 0; i < t->DPs; i++) {
317 struct gred_sched_data *q = t->tab[i];
318
319 if (!q)
320 continue;
321
322 red_restart(&q->vars);
323 q->backlog = 0;
324 }
325 }
326
327 static inline void gred_destroy_vq(struct gred_sched_data *q)
328 {
329 kfree(q);
330 }
331
332 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
333 {
334 struct gred_sched *table = qdisc_priv(sch);
335 struct tc_gred_sopt *sopt;
336 int i;
337
338 if (dps == NULL)
339 return -EINVAL;
340
341 sopt = nla_data(dps);
342
343 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
344 return -EINVAL;
345
346 sch_tree_lock(sch);
347 table->DPs = sopt->DPs;
348 table->def = sopt->def_DP;
349 table->red_flags = sopt->flags;
350
351 /*
352 * Every entry point to GRED is synchronized with the above code
353 * and the DP is checked against DPs, i.e. shadowed VQs can no
354 * longer be found so we can unlock right here.
355 */
356 sch_tree_unlock(sch);
357
358 if (sopt->grio) {
359 gred_enable_rio_mode(table);
360 gred_disable_wred_mode(table);
361 if (gred_wred_mode_check(sch))
362 gred_enable_wred_mode(table);
363 } else {
364 gred_disable_rio_mode(table);
365 gred_disable_wred_mode(table);
366 }
367
368 for (i = table->DPs; i < MAX_DPs; i++) {
369 if (table->tab[i]) {
370 pr_warning("GRED: Warning: Destroying "
371 "shadowed VQ 0x%x\n", i);
372 gred_destroy_vq(table->tab[i]);
373 table->tab[i] = NULL;
374 }
375 }
376
377 return 0;
378 }
379
380 static inline int gred_change_vq(struct Qdisc *sch, int dp,
381 struct tc_gred_qopt *ctl, int prio,
382 u8 *stab, u32 max_P,
383 struct gred_sched_data **prealloc)
384 {
385 struct gred_sched *table = qdisc_priv(sch);
386 struct gred_sched_data *q = table->tab[dp];
387
388 if (!q) {
389 table->tab[dp] = q = *prealloc;
390 *prealloc = NULL;
391 if (!q)
392 return -ENOMEM;
393 }
394
395 q->DP = dp;
396 q->prio = prio;
397 q->limit = ctl->limit;
398
399 if (q->backlog == 0)
400 red_end_of_idle_period(&q->vars);
401
402 red_set_parms(&q->parms,
403 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
404 ctl->Scell_log, stab, max_P);
405 red_set_vars(&q->vars);
406 return 0;
407 }
408
409 static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
410 [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
411 [TCA_GRED_STAB] = { .len = 256 },
412 [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
413 [TCA_GRED_MAX_P] = { .type = NLA_U32 },
414 };
415
416 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
417 {
418 struct gred_sched *table = qdisc_priv(sch);
419 struct tc_gred_qopt *ctl;
420 struct nlattr *tb[TCA_GRED_MAX + 1];
421 int err, prio = GRED_DEF_PRIO;
422 u8 *stab;
423 u32 max_P;
424 struct gred_sched_data *prealloc;
425
426 if (opt == NULL)
427 return -EINVAL;
428
429 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
430 if (err < 0)
431 return err;
432
433 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
434 return gred_change_table_def(sch, opt);
435
436 if (tb[TCA_GRED_PARMS] == NULL ||
437 tb[TCA_GRED_STAB] == NULL)
438 return -EINVAL;
439
440 max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
441
442 err = -EINVAL;
443 ctl = nla_data(tb[TCA_GRED_PARMS]);
444 stab = nla_data(tb[TCA_GRED_STAB]);
445
446 if (ctl->DP >= table->DPs)
447 goto errout;
448
449 if (gred_rio_mode(table)) {
450 if (ctl->prio == 0) {
451 int def_prio = GRED_DEF_PRIO;
452
453 if (table->tab[table->def])
454 def_prio = table->tab[table->def]->prio;
455
456 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
457 "setting default to %d\n", ctl->DP, def_prio);
458
459 prio = def_prio;
460 } else
461 prio = ctl->prio;
462 }
463
464 prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
465 sch_tree_lock(sch);
466
467 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
468 if (err < 0)
469 goto errout_locked;
470
471 if (gred_rio_mode(table)) {
472 gred_disable_wred_mode(table);
473 if (gred_wred_mode_check(sch))
474 gred_enable_wred_mode(table);
475 }
476
477 err = 0;
478
479 errout_locked:
480 sch_tree_unlock(sch);
481 kfree(prealloc);
482 errout:
483 return err;
484 }
485
486 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
487 {
488 struct nlattr *tb[TCA_GRED_MAX + 1];
489 int err;
490
491 if (opt == NULL)
492 return -EINVAL;
493
494 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
495 if (err < 0)
496 return err;
497
498 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
499 return -EINVAL;
500
501 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
502 }
503
504 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
505 {
506 struct gred_sched *table = qdisc_priv(sch);
507 struct nlattr *parms, *opts = NULL;
508 int i;
509 u32 max_p[MAX_DPs];
510 struct tc_gred_sopt sopt = {
511 .DPs = table->DPs,
512 .def_DP = table->def,
513 .grio = gred_rio_mode(table),
514 .flags = table->red_flags,
515 };
516
517 opts = nla_nest_start(skb, TCA_OPTIONS);
518 if (opts == NULL)
519 goto nla_put_failure;
520 if (nla_put(skb, TCA_GRED_DPS, sizeof(sopt), &sopt))
521 goto nla_put_failure;
522
523 for (i = 0; i < MAX_DPs; i++) {
524 struct gred_sched_data *q = table->tab[i];
525
526 max_p[i] = q ? q->parms.max_P : 0;
527 }
528 if (nla_put(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p))
529 goto nla_put_failure;
530
531 parms = nla_nest_start(skb, TCA_GRED_PARMS);
532 if (parms == NULL)
533 goto nla_put_failure;
534
535 for (i = 0; i < MAX_DPs; i++) {
536 struct gred_sched_data *q = table->tab[i];
537 struct tc_gred_qopt opt;
538
539 memset(&opt, 0, sizeof(opt));
540
541 if (!q) {
542 /* hack -- fix at some point with proper message
543 This is how we indicate to tc that there is no VQ
544 at this DP */
545
546 opt.DP = MAX_DPs + i;
547 goto append_opt;
548 }
549
550 opt.limit = q->limit;
551 opt.DP = q->DP;
552 opt.backlog = q->backlog;
553 opt.prio = q->prio;
554 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
555 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
556 opt.Wlog = q->parms.Wlog;
557 opt.Plog = q->parms.Plog;
558 opt.Scell_log = q->parms.Scell_log;
559 opt.other = q->stats.other;
560 opt.early = q->stats.prob_drop;
561 opt.forced = q->stats.forced_drop;
562 opt.pdrop = q->stats.pdrop;
563 opt.packets = q->packetsin;
564 opt.bytesin = q->bytesin;
565
566 if (gred_wred_mode(table))
567 gred_load_wred_set(table, q);
568
569 opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);
570
571 append_opt:
572 if (nla_append(skb, sizeof(opt), &opt) < 0)
573 goto nla_put_failure;
574 }
575
576 nla_nest_end(skb, parms);
577
578 return nla_nest_end(skb, opts);
579
580 nla_put_failure:
581 nla_nest_cancel(skb, opts);
582 return -EMSGSIZE;
583 }
584
585 static void gred_destroy(struct Qdisc *sch)
586 {
587 struct gred_sched *table = qdisc_priv(sch);
588 int i;
589
590 for (i = 0; i < table->DPs; i++) {
591 if (table->tab[i])
592 gred_destroy_vq(table->tab[i]);
593 }
594 }
595
596 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
597 .id = "gred",
598 .priv_size = sizeof(struct gred_sched),
599 .enqueue = gred_enqueue,
600 .dequeue = gred_dequeue,
601 .peek = qdisc_peek_head,
602 .drop = gred_drop,
603 .init = gred_init,
604 .reset = gred_reset,
605 .destroy = gred_destroy,
606 .change = gred_change,
607 .dump = gred_dump,
608 .owner = THIS_MODULE,
609 };
610
611 static int __init gred_module_init(void)
612 {
613 return register_qdisc(&gred_qdisc_ops);
614 }
615
616 static void __exit gred_module_exit(void)
617 {
618 unregister_qdisc(&gred_qdisc_ops);
619 }
620
621 module_init(gred_module_init)
622 module_exit(gred_module_exit)
623
624 MODULE_LICENSE("GPL");