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Merge tag 'md-3.4-fixes' of git://neil.brown.name/md
[deliverable/linux.git] / net / sched / sch_gred.c
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 if (net_ratelimit())
259 pr_warning("GRED: Unable to relocate VQ 0x%x "
260 "after dequeue, screwing up "
261 "backlog.\n", tc_index_to_dp(skb));
262 } else {
263 q->backlog -= qdisc_pkt_len(skb);
264
265 if (!q->backlog && !gred_wred_mode(t))
266 red_start_of_idle_period(&q->vars);
267 }
268
269 return skb;
270 }
271
272 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
273 red_start_of_idle_period(&t->wred_set);
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 if (net_ratelimit())
291 pr_warning("GRED: Unable to relocate VQ 0x%x "
292 "while dropping, screwing up "
293 "backlog.\n", tc_index_to_dp(skb));
294 } else {
295 q->backlog -= len;
296 q->stats.other++;
297
298 if (!q->backlog && !gred_wred_mode(t))
299 red_start_of_idle_period(&q->vars);
300 }
301
302 qdisc_drop(skb, sch);
303 return len;
304 }
305
306 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
307 red_start_of_idle_period(&t->wred_set);
308
309 return 0;
310
311 }
312
313 static void gred_reset(struct Qdisc *sch)
314 {
315 int i;
316 struct gred_sched *t = qdisc_priv(sch);
317
318 qdisc_reset_queue(sch);
319
320 for (i = 0; i < t->DPs; i++) {
321 struct gred_sched_data *q = t->tab[i];
322
323 if (!q)
324 continue;
325
326 red_restart(&q->vars);
327 q->backlog = 0;
328 }
329 }
330
331 static inline void gred_destroy_vq(struct gred_sched_data *q)
332 {
333 kfree(q);
334 }
335
336 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
337 {
338 struct gred_sched *table = qdisc_priv(sch);
339 struct tc_gred_sopt *sopt;
340 int i;
341
342 if (dps == NULL)
343 return -EINVAL;
344
345 sopt = nla_data(dps);
346
347 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
348 return -EINVAL;
349
350 sch_tree_lock(sch);
351 table->DPs = sopt->DPs;
352 table->def = sopt->def_DP;
353 table->red_flags = sopt->flags;
354
355 /*
356 * Every entry point to GRED is synchronized with the above code
357 * and the DP is checked against DPs, i.e. shadowed VQs can no
358 * longer be found so we can unlock right here.
359 */
360 sch_tree_unlock(sch);
361
362 if (sopt->grio) {
363 gred_enable_rio_mode(table);
364 gred_disable_wred_mode(table);
365 if (gred_wred_mode_check(sch))
366 gred_enable_wred_mode(table);
367 } else {
368 gred_disable_rio_mode(table);
369 gred_disable_wred_mode(table);
370 }
371
372 for (i = table->DPs; i < MAX_DPs; i++) {
373 if (table->tab[i]) {
374 pr_warning("GRED: Warning: Destroying "
375 "shadowed VQ 0x%x\n", i);
376 gred_destroy_vq(table->tab[i]);
377 table->tab[i] = NULL;
378 }
379 }
380
381 return 0;
382 }
383
384 static inline int gred_change_vq(struct Qdisc *sch, int dp,
385 struct tc_gred_qopt *ctl, int prio,
386 u8 *stab, u32 max_P,
387 struct gred_sched_data **prealloc)
388 {
389 struct gred_sched *table = qdisc_priv(sch);
390 struct gred_sched_data *q = table->tab[dp];
391
392 if (!q) {
393 table->tab[dp] = q = *prealloc;
394 *prealloc = NULL;
395 if (!q)
396 return -ENOMEM;
397 }
398
399 q->DP = dp;
400 q->prio = prio;
401 q->limit = ctl->limit;
402
403 if (q->backlog == 0)
404 red_end_of_idle_period(&q->vars);
405
406 red_set_parms(&q->parms,
407 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
408 ctl->Scell_log, stab, max_P);
409 red_set_vars(&q->vars);
410 return 0;
411 }
412
413 static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
414 [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
415 [TCA_GRED_STAB] = { .len = 256 },
416 [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
417 [TCA_GRED_MAX_P] = { .type = NLA_U32 },
418 };
419
420 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
421 {
422 struct gred_sched *table = qdisc_priv(sch);
423 struct tc_gred_qopt *ctl;
424 struct nlattr *tb[TCA_GRED_MAX + 1];
425 int err, prio = GRED_DEF_PRIO;
426 u8 *stab;
427 u32 max_P;
428 struct gred_sched_data *prealloc;
429
430 if (opt == NULL)
431 return -EINVAL;
432
433 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
434 if (err < 0)
435 return err;
436
437 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
438 return gred_change_table_def(sch, opt);
439
440 if (tb[TCA_GRED_PARMS] == NULL ||
441 tb[TCA_GRED_STAB] == NULL)
442 return -EINVAL;
443
444 max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
445
446 err = -EINVAL;
447 ctl = nla_data(tb[TCA_GRED_PARMS]);
448 stab = nla_data(tb[TCA_GRED_STAB]);
449
450 if (ctl->DP >= table->DPs)
451 goto errout;
452
453 if (gred_rio_mode(table)) {
454 if (ctl->prio == 0) {
455 int def_prio = GRED_DEF_PRIO;
456
457 if (table->tab[table->def])
458 def_prio = table->tab[table->def]->prio;
459
460 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
461 "setting default to %d\n", ctl->DP, def_prio);
462
463 prio = def_prio;
464 } else
465 prio = ctl->prio;
466 }
467
468 prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
469 sch_tree_lock(sch);
470
471 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
472 if (err < 0)
473 goto errout_locked;
474
475 if (gred_rio_mode(table)) {
476 gred_disable_wred_mode(table);
477 if (gred_wred_mode_check(sch))
478 gred_enable_wred_mode(table);
479 }
480
481 err = 0;
482
483 errout_locked:
484 sch_tree_unlock(sch);
485 kfree(prealloc);
486 errout:
487 return err;
488 }
489
490 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
491 {
492 struct nlattr *tb[TCA_GRED_MAX + 1];
493 int err;
494
495 if (opt == NULL)
496 return -EINVAL;
497
498 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
499 if (err < 0)
500 return err;
501
502 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
503 return -EINVAL;
504
505 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
506 }
507
508 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
509 {
510 struct gred_sched *table = qdisc_priv(sch);
511 struct nlattr *parms, *opts = NULL;
512 int i;
513 u32 max_p[MAX_DPs];
514 struct tc_gred_sopt sopt = {
515 .DPs = table->DPs,
516 .def_DP = table->def,
517 .grio = gred_rio_mode(table),
518 .flags = table->red_flags,
519 };
520
521 opts = nla_nest_start(skb, TCA_OPTIONS);
522 if (opts == NULL)
523 goto nla_put_failure;
524 NLA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
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 NLA_PUT(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p);
532
533 parms = nla_nest_start(skb, TCA_GRED_PARMS);
534 if (parms == NULL)
535 goto nla_put_failure;
536
537 for (i = 0; i < MAX_DPs; i++) {
538 struct gred_sched_data *q = table->tab[i];
539 struct tc_gred_qopt opt;
540
541 memset(&opt, 0, sizeof(opt));
542
543 if (!q) {
544 /* hack -- fix at some point with proper message
545 This is how we indicate to tc that there is no VQ
546 at this DP */
547
548 opt.DP = MAX_DPs + i;
549 goto append_opt;
550 }
551
552 opt.limit = q->limit;
553 opt.DP = q->DP;
554 opt.backlog = q->backlog;
555 opt.prio = q->prio;
556 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
557 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
558 opt.Wlog = q->parms.Wlog;
559 opt.Plog = q->parms.Plog;
560 opt.Scell_log = q->parms.Scell_log;
561 opt.other = q->stats.other;
562 opt.early = q->stats.prob_drop;
563 opt.forced = q->stats.forced_drop;
564 opt.pdrop = q->stats.pdrop;
565 opt.packets = q->packetsin;
566 opt.bytesin = q->bytesin;
567
568 if (gred_wred_mode(table))
569 gred_load_wred_set(table, q);
570
571 opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);
572
573 append_opt:
574 if (nla_append(skb, sizeof(opt), &opt) < 0)
575 goto nla_put_failure;
576 }
577
578 nla_nest_end(skb, parms);
579
580 return nla_nest_end(skb, opts);
581
582 nla_put_failure:
583 nla_nest_cancel(skb, opts);
584 return -EMSGSIZE;
585 }
586
587 static void gred_destroy(struct Qdisc *sch)
588 {
589 struct gred_sched *table = qdisc_priv(sch);
590 int i;
591
592 for (i = 0; i < table->DPs; i++) {
593 if (table->tab[i])
594 gred_destroy_vq(table->tab[i]);
595 }
596 }
597
598 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
599 .id = "gred",
600 .priv_size = sizeof(struct gred_sched),
601 .enqueue = gred_enqueue,
602 .dequeue = gred_dequeue,
603 .peek = qdisc_peek_head,
604 .drop = gred_drop,
605 .init = gred_init,
606 .reset = gred_reset,
607 .destroy = gred_destroy,
608 .change = gred_change,
609 .dump = gred_dump,
610 .owner = THIS_MODULE,
611 };
612
613 static int __init gred_module_init(void)
614 {
615 return register_qdisc(&gred_qdisc_ops);
616 }
617
618 static void __exit gred_module_exit(void)
619 {
620 unregister_qdisc(&gred_qdisc_ops);
621 }
622
623 module_init(gred_module_init)
624 module_exit(gred_module_exit)
625
626 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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