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mm: always lock the root (oldest) anon_vma
[linux-2.6/libata-dev.git] / net / sched / sch_gred.c
blob51dcc2aa5c926b735fa683135bddaf3c66114355
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 {
37 u32 limit; /* HARD maximal queue length */
38 u32 DP; /* the drop pramaters */
39 u32 bytesin; /* bytes seen on virtualQ so far*/
40 u32 packetsin; /* packets seen on virtualQ so far*/
41 u32 backlog; /* bytes on the virtualQ */
42 u8 prio; /* the prio of this vq */
43
44 struct red_parms parms;
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 {
55 struct gred_sched_data *tab[MAX_DPs];
56 unsigned long flags;
57 u32 red_flags;
58 u32 DPs;
59 u32 def;
60 struct red_parms wred_set;
61 };
62
63 static inline int gred_wred_mode(struct gred_sched *table)
64 {
65 return test_bit(GRED_WRED_MODE, &table->flags);
66 }
67
68 static inline void gred_enable_wred_mode(struct gred_sched *table)
69 {
70 __set_bit(GRED_WRED_MODE, &table->flags);
71 }
72
73 static inline void gred_disable_wred_mode(struct gred_sched *table)
74 {
75 __clear_bit(GRED_WRED_MODE, &table->flags);
76 }
77
78 static inline int gred_rio_mode(struct gred_sched *table)
79 {
80 return test_bit(GRED_RIO_MODE, &table->flags);
81 }
82
83 static inline void gred_enable_rio_mode(struct gred_sched *table)
84 {
85 __set_bit(GRED_RIO_MODE, &table->flags);
86 }
87
88 static inline void gred_disable_rio_mode(struct gred_sched *table)
89 {
90 __clear_bit(GRED_RIO_MODE, &table->flags);
91 }
92
93 static inline int gred_wred_mode_check(struct Qdisc *sch)
94 {
95 struct gred_sched *table = qdisc_priv(sch);
96 int i;
97
98 /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
99 for (i = 0; i < table->DPs; i++) {
100 struct gred_sched_data *q = table->tab[i];
101 int n;
102
103 if (q == NULL)
104 continue;
105
106 for (n = 0; n < table->DPs; n++)
107 if (table->tab[n] && table->tab[n] != q &&
108 table->tab[n]->prio == q->prio)
109 return 1;
110 }
111
112 return 0;
113 }
114
115 static inline unsigned int gred_backlog(struct gred_sched *table,
116 struct gred_sched_data *q,
117 struct Qdisc *sch)
118 {
119 if (gred_wred_mode(table))
120 return sch->qstats.backlog;
121 else
122 return q->backlog;
123 }
124
125 static inline u16 tc_index_to_dp(struct sk_buff *skb)
126 {
127 return skb->tc_index & GRED_VQ_MASK;
128 }
129
130 static inline void gred_load_wred_set(struct gred_sched *table,
131 struct gred_sched_data *q)
132 {
133 q->parms.qavg = table->wred_set.qavg;
134 q->parms.qidlestart = table->wred_set.qidlestart;
135 }
136
137 static inline void gred_store_wred_set(struct gred_sched *table,
138 struct gred_sched_data *q)
139 {
140 table->wred_set.qavg = q->parms.qavg;
141 }
142
143 static inline int gred_use_ecn(struct gred_sched *t)
144 {
145 return t->red_flags & TC_RED_ECN;
146 }
147
148 static inline int gred_use_harddrop(struct gred_sched *t)
149 {
150 return t->red_flags & TC_RED_HARDDROP;
151 }
152
153 static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
154 {
155 struct gred_sched_data *q=NULL;
156 struct gred_sched *t= qdisc_priv(sch);
157 unsigned long qavg = 0;
158 u16 dp = tc_index_to_dp(skb);
159
160 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
161 dp = t->def;
162
163 if ((q = t->tab[dp]) == NULL) {
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 controvesial 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]->parms))
186 qavg +=t->tab[i]->parms.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->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
198
199 if (red_is_idling(&q->parms))
200 red_end_of_idle_period(&q->parms);
201
202 if (gred_wred_mode(t))
203 gred_store_wred_set(t, q);
204
205 switch (red_action(&q->parms, q->parms.qavg + qavg)) {
206 case RED_DONT_MARK:
207 break;
208
209 case RED_PROB_MARK:
210 sch->qstats.overlimits++;
211 if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
212 q->stats.prob_drop++;
213 goto congestion_drop;
214 }
215
216 q->stats.prob_mark++;
217 break;
218
219 case RED_HARD_MARK:
220 sch->qstats.overlimits++;
221 if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
222 !INET_ECN_set_ce(skb)) {
223 q->stats.forced_drop++;
224 goto congestion_drop;
225 }
226 q->stats.forced_mark++;
227 break;
228 }
229
230 if (q->backlog + qdisc_pkt_len(skb) <= q->limit) {
231 q->backlog += qdisc_pkt_len(skb);
232 return qdisc_enqueue_tail(skb, sch);
233 }
234
235 q->stats.pdrop++;
236 drop:
237 return qdisc_drop(skb, sch);
238
239 congestion_drop:
240 qdisc_drop(skb, sch);
241 return NET_XMIT_CN;
242 }
243
244 static struct sk_buff *gred_dequeue(struct Qdisc* sch)
245 {
246 struct sk_buff *skb;
247 struct gred_sched *t = qdisc_priv(sch);
248
249 skb = qdisc_dequeue_head(sch);
250
251 if (skb) {
252 struct gred_sched_data *q;
253 u16 dp = tc_index_to_dp(skb);
254
255 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
256 if (net_ratelimit())
257 printk(KERN_WARNING "GRED: Unable to relocate "
258 "VQ 0x%x after dequeue, screwing up "
259 "backlog.\n", 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->parms);
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 if (net_ratelimit())
289 printk(KERN_WARNING "GRED: Unable to relocate "
290 "VQ 0x%x while dropping, screwing up "
291 "backlog.\n", tc_index_to_dp(skb));
292 } else {
293 q->backlog -= len;
294 q->stats.other++;
295
296 if (!q->backlog && !gred_wred_mode(t))
297 red_start_of_idle_period(&q->parms);
298 }
299
300 qdisc_drop(skb, sch);
301 return len;
302 }
303
304 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
305 red_start_of_idle_period(&t->wred_set);
306
307 return 0;
308
309 }
310
311 static void gred_reset(struct Qdisc* sch)
312 {
313 int i;
314 struct gred_sched *t = qdisc_priv(sch);
315
316 qdisc_reset_queue(sch);
317
318 for (i = 0; i < t->DPs; i++) {
319 struct gred_sched_data *q = t->tab[i];
320
321 if (!q)
322 continue;
323
324 red_restart(&q->parms);
325 q->backlog = 0;
326 }
327 }
328
329 static inline void gred_destroy_vq(struct gred_sched_data *q)
330 {
331 kfree(q);
332 }
333
334 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
335 {
336 struct gred_sched *table = qdisc_priv(sch);
337 struct tc_gred_sopt *sopt;
338 int i;
339
340 if (dps == NULL)
341 return -EINVAL;
342
343 sopt = nla_data(dps);
344
345 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
346 return -EINVAL;
347
348 sch_tree_lock(sch);
349 table->DPs = sopt->DPs;
350 table->def = sopt->def_DP;
351 table->red_flags = sopt->flags;
352
353 /*
354 * Every entry point to GRED is synchronized with the above code
355 * and the DP is checked against DPs, i.e. shadowed VQs can no
356 * longer be found so we can unlock right here.
357 */
358 sch_tree_unlock(sch);
359
360 if (sopt->grio) {
361 gred_enable_rio_mode(table);
362 gred_disable_wred_mode(table);
363 if (gred_wred_mode_check(sch))
364 gred_enable_wred_mode(table);
365 } else {
366 gred_disable_rio_mode(table);
367 gred_disable_wred_mode(table);
368 }
369
370 for (i = table->DPs; i < MAX_DPs; i++) {
371 if (table->tab[i]) {
372 printk(KERN_WARNING "GRED: Warning: Destroying "
373 "shadowed VQ 0x%x\n", i);
374 gred_destroy_vq(table->tab[i]);
375 table->tab[i] = NULL;
376 }
377 }
378
379 return 0;
380 }
381
382 static inline int gred_change_vq(struct Qdisc *sch, int dp,
383 struct tc_gred_qopt *ctl, int prio, u8 *stab)
384 {
385 struct gred_sched *table = qdisc_priv(sch);
386 struct gred_sched_data *q;
387
388 if (table->tab[dp] == NULL) {
389 table->tab[dp] = kzalloc(sizeof(*q), GFP_KERNEL);
390 if (table->tab[dp] == NULL)
391 return -ENOMEM;
392 }
393
394 q = table->tab[dp];
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->parms);
401
402 red_set_parms(&q->parms,
403 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
404 ctl->Scell_log, stab);
405
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 };
414
415 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
416 {
417 struct gred_sched *table = qdisc_priv(sch);
418 struct tc_gred_qopt *ctl;
419 struct nlattr *tb[TCA_GRED_MAX + 1];
420 int err, prio = GRED_DEF_PRIO;
421 u8 *stab;
422
423 if (opt == NULL)
424 return -EINVAL;
425
426 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
427 if (err < 0)
428 return err;
429
430 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
431 return gred_change_table_def(sch, opt);
432
433 if (tb[TCA_GRED_PARMS] == NULL ||
434 tb[TCA_GRED_STAB] == NULL)
435 return -EINVAL;
436
437 err = -EINVAL;
438 ctl = nla_data(tb[TCA_GRED_PARMS]);
439 stab = nla_data(tb[TCA_GRED_STAB]);
440
441 if (ctl->DP >= table->DPs)
442 goto errout;
443
444 if (gred_rio_mode(table)) {
445 if (ctl->prio == 0) {
446 int def_prio = GRED_DEF_PRIO;
447
448 if (table->tab[table->def])
449 def_prio = table->tab[table->def]->prio;
450
451 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
452 "setting default to %d\n", ctl->DP, def_prio);
453
454 prio = def_prio;
455 } else
456 prio = ctl->prio;
457 }
458
459 sch_tree_lock(sch);
460
461 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
462 if (err < 0)
463 goto errout_locked;
464
465 if (gred_rio_mode(table)) {
466 gred_disable_wred_mode(table);
467 if (gred_wred_mode_check(sch))
468 gred_enable_wred_mode(table);
469 }
470
471 err = 0;
472
473 errout_locked:
474 sch_tree_unlock(sch);
475 errout:
476 return err;
477 }
478
479 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
480 {
481 struct nlattr *tb[TCA_GRED_MAX + 1];
482 int err;
483
484 if (opt == NULL)
485 return -EINVAL;
486
487 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
488 if (err < 0)
489 return err;
490
491 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
492 return -EINVAL;
493
494 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
495 }
496
497 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
498 {
499 struct gred_sched *table = qdisc_priv(sch);
500 struct nlattr *parms, *opts = NULL;
501 int i;
502 struct tc_gred_sopt sopt = {
503 .DPs = table->DPs,
504 .def_DP = table->def,
505 .grio = gred_rio_mode(table),
506 .flags = table->red_flags,
507 };
508
509 opts = nla_nest_start(skb, TCA_OPTIONS);
510 if (opts == NULL)
511 goto nla_put_failure;
512 NLA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
513 parms = nla_nest_start(skb, TCA_GRED_PARMS);
514 if (parms == NULL)
515 goto nla_put_failure;
516
517 for (i = 0; i < MAX_DPs; i++) {
518 struct gred_sched_data *q = table->tab[i];
519 struct tc_gred_qopt opt;
520
521 memset(&opt, 0, sizeof(opt));
522
523 if (!q) {
524 /* hack -- fix at some point with proper message
525 This is how we indicate to tc that there is no VQ
526 at this DP */
527
528 opt.DP = MAX_DPs + i;
529 goto append_opt;
530 }
531
532 opt.limit = q->limit;
533 opt.DP = q->DP;
534 opt.backlog = q->backlog;
535 opt.prio = q->prio;
536 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
537 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
538 opt.Wlog = q->parms.Wlog;
539 opt.Plog = q->parms.Plog;
540 opt.Scell_log = q->parms.Scell_log;
541 opt.other = q->stats.other;
542 opt.early = q->stats.prob_drop;
543 opt.forced = q->stats.forced_drop;
544 opt.pdrop = q->stats.pdrop;
545 opt.packets = q->packetsin;
546 opt.bytesin = q->bytesin;
547
548 if (gred_wred_mode(table)) {
549 q->parms.qidlestart =
550 table->tab[table->def]->parms.qidlestart;
551 q->parms.qavg = table->tab[table->def]->parms.qavg;
552 }
553
554 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
555
556 append_opt:
557 if (nla_append(skb, sizeof(opt), &opt) < 0)
558 goto nla_put_failure;
559 }
560
561 nla_nest_end(skb, parms);
562
563 return nla_nest_end(skb, opts);
564
565 nla_put_failure:
566 nla_nest_cancel(skb, opts);
567 return -EMSGSIZE;
568 }
569
570 static void gred_destroy(struct Qdisc *sch)
571 {
572 struct gred_sched *table = qdisc_priv(sch);
573 int i;
574
575 for (i = 0; i < table->DPs; i++) {
576 if (table->tab[i])
577 gred_destroy_vq(table->tab[i]);
578 }
579 }
580
581 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
582 .id = "gred",
583 .priv_size = sizeof(struct gred_sched),
584 .enqueue = gred_enqueue,
585 .dequeue = gred_dequeue,
586 .peek = qdisc_peek_head,
587 .drop = gred_drop,
588 .init = gred_init,
589 .reset = gred_reset,
590 .destroy = gred_destroy,
591 .change = gred_change,
592 .dump = gred_dump,
593 .owner = THIS_MODULE,
594 };
595
596 static int __init gred_module_init(void)
597 {
598 return register_qdisc(&gred_qdisc_ops);
599 }
600
601 static void __exit gred_module_exit(void)
602 {
603 unregister_qdisc(&gred_qdisc_ops);
604 }
605
606 module_init(gred_module_init)
607 module_exit(gred_module_exit)
608
609 MODULE_LICENSE("GPL");
Linux 2.6 libata-dev (mirror)