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cbq: incorrect processing of high limits
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1 /*
2 * net/sched/sch_cbq.c Class-Based Queueing discipline.
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 */
12
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <net/netlink.h>
21 #include <net/pkt_sched.h>
22
23
24 /* Class-Based Queueing (CBQ) algorithm.
25 =======================================
26
27 Sources: [1] Sally Floyd and Van Jacobson, "Link-sharing and Resource
28 Management Models for Packet Networks",
29 IEEE/ACM Transactions on Networking, Vol.3, No.4, 1995
30
31 [2] Sally Floyd, "Notes on CBQ and Guaranteed Service", 1995
32
33 [3] Sally Floyd, "Notes on Class-Based Queueing: Setting
34 Parameters", 1996
35
36 [4] Sally Floyd and Michael Speer, "Experimental Results
37 for Class-Based Queueing", 1998, not published.
38
39 -----------------------------------------------------------------------
40
41 Algorithm skeleton was taken from NS simulator cbq.cc.
42 If someone wants to check this code against the LBL version,
43 he should take into account that ONLY the skeleton was borrowed,
44 the implementation is different. Particularly:
45
46 --- The WRR algorithm is different. Our version looks more
47 reasonable (I hope) and works when quanta are allowed to be
48 less than MTU, which is always the case when real time classes
49 have small rates. Note, that the statement of [3] is
50 incomplete, delay may actually be estimated even if class
51 per-round allotment is less than MTU. Namely, if per-round
52 allotment is W*r_i, and r_1+...+r_k = r < 1
53
54 delay_i <= ([MTU/(W*r_i)]*W*r + W*r + k*MTU)/B
55
56 In the worst case we have IntServ estimate with D = W*r+k*MTU
57 and C = MTU*r. The proof (if correct at all) is trivial.
58
59
60 --- It seems that cbq-2.0 is not very accurate. At least, I cannot
61 interpret some places, which look like wrong translations
62 from NS. Anyone is advised to find these differences
63 and explain to me, why I am wrong 8).
64
65 --- Linux has no EOI event, so that we cannot estimate true class
66 idle time. Workaround is to consider the next dequeue event
67 as sign that previous packet is finished. This is wrong because of
68 internal device queueing, but on a permanently loaded link it is true.
69 Moreover, combined with clock integrator, this scheme looks
70 very close to an ideal solution. */
71
72 struct cbq_sched_data;
73
74
75 struct cbq_class {
76 struct Qdisc_class_common common;
77 struct cbq_class *next_alive; /* next class with backlog in this priority band */
78
79 /* Parameters */
80 unsigned char priority; /* class priority */
81 unsigned char priority2; /* priority to be used after overlimit */
82 unsigned char ewma_log; /* time constant for idle time calculation */
83 unsigned char ovl_strategy;
84 #ifdef CONFIG_NET_CLS_ACT
85 unsigned char police;
86 #endif
87
88 u32 defmap;
89
90 /* Link-sharing scheduler parameters */
91 long maxidle; /* Class parameters: see below. */
92 long offtime;
93 long minidle;
94 u32 avpkt;
95 struct qdisc_rate_table *R_tab;
96
97 /* Overlimit strategy parameters */
98 void (*overlimit)(struct cbq_class *cl);
99 psched_tdiff_t penalty;
100
101 /* General scheduler (WRR) parameters */
102 long allot;
103 long quantum; /* Allotment per WRR round */
104 long weight; /* Relative allotment: see below */
105
106 struct Qdisc *qdisc; /* Ptr to CBQ discipline */
107 struct cbq_class *split; /* Ptr to split node */
108 struct cbq_class *share; /* Ptr to LS parent in the class tree */
109 struct cbq_class *tparent; /* Ptr to tree parent in the class tree */
110 struct cbq_class *borrow; /* NULL if class is bandwidth limited;
111 parent otherwise */
112 struct cbq_class *sibling; /* Sibling chain */
113 struct cbq_class *children; /* Pointer to children chain */
114
115 struct Qdisc *q; /* Elementary queueing discipline */
116
117
118 /* Variables */
119 unsigned char cpriority; /* Effective priority */
120 unsigned char delayed;
121 unsigned char level; /* level of the class in hierarchy:
122 0 for leaf classes, and maximal
123 level of children + 1 for nodes.
124 */
125
126 psched_time_t last; /* Last end of service */
127 psched_time_t undertime;
128 long avgidle;
129 long deficit; /* Saved deficit for WRR */
130 psched_time_t penalized;
131 struct gnet_stats_basic_packed bstats;
132 struct gnet_stats_queue qstats;
133 struct gnet_stats_rate_est rate_est;
134 struct tc_cbq_xstats xstats;
135
136 struct tcf_proto *filter_list;
137
138 int refcnt;
139 int filters;
140
141 struct cbq_class *defaults[TC_PRIO_MAX + 1];
142 };
143
144 struct cbq_sched_data {
145 struct Qdisc_class_hash clhash; /* Hash table of all classes */
146 int nclasses[TC_CBQ_MAXPRIO + 1];
147 unsigned int quanta[TC_CBQ_MAXPRIO + 1];
148
149 struct cbq_class link;
150
151 unsigned int activemask;
152 struct cbq_class *active[TC_CBQ_MAXPRIO + 1]; /* List of all classes
153 with backlog */
154
155 #ifdef CONFIG_NET_CLS_ACT
156 struct cbq_class *rx_class;
157 #endif
158 struct cbq_class *tx_class;
159 struct cbq_class *tx_borrowed;
160 int tx_len;
161 psched_time_t now; /* Cached timestamp */
162 psched_time_t now_rt; /* Cached real time */
163 unsigned int pmask;
164
165 struct hrtimer delay_timer;
166 struct qdisc_watchdog watchdog; /* Watchdog timer,
167 started when CBQ has
168 backlog, but cannot
169 transmit just now */
170 psched_tdiff_t wd_expires;
171 int toplevel;
172 u32 hgenerator;
173 };
174
175
176 #define L2T(cl, len) qdisc_l2t((cl)->R_tab, len)
177
178 static inline struct cbq_class *
179 cbq_class_lookup(struct cbq_sched_data *q, u32 classid)
180 {
181 struct Qdisc_class_common *clc;
182
183 clc = qdisc_class_find(&q->clhash, classid);
184 if (clc == NULL)
185 return NULL;
186 return container_of(clc, struct cbq_class, common);
187 }
188
189 #ifdef CONFIG_NET_CLS_ACT
190
191 static struct cbq_class *
192 cbq_reclassify(struct sk_buff *skb, struct cbq_class *this)
193 {
194 struct cbq_class *cl;
195
196 for (cl = this->tparent; cl; cl = cl->tparent) {
197 struct cbq_class *new = cl->defaults[TC_PRIO_BESTEFFORT];
198
199 if (new != NULL && new != this)
200 return new;
201 }
202 return NULL;
203 }
204
205 #endif
206
207 /* Classify packet. The procedure is pretty complicated, but
208 * it allows us to combine link sharing and priority scheduling
209 * transparently.
210 *
211 * Namely, you can put link sharing rules (f.e. route based) at root of CBQ,
212 * so that it resolves to split nodes. Then packets are classified
213 * by logical priority, or a more specific classifier may be attached
214 * to the split node.
215 */
216
217 static struct cbq_class *
218 cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
219 {
220 struct cbq_sched_data *q = qdisc_priv(sch);
221 struct cbq_class *head = &q->link;
222 struct cbq_class **defmap;
223 struct cbq_class *cl = NULL;
224 u32 prio = skb->priority;
225 struct tcf_result res;
226
227 /*
228 * Step 1. If skb->priority points to one of our classes, use it.
229 */
230 if (TC_H_MAJ(prio ^ sch->handle) == 0 &&
231 (cl = cbq_class_lookup(q, prio)) != NULL)
232 return cl;
233
234 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
235 for (;;) {
236 int result = 0;
237 defmap = head->defaults;
238
239 /*
240 * Step 2+n. Apply classifier.
241 */
242 if (!head->filter_list ||
243 (result = tc_classify_compat(skb, head->filter_list, &res)) < 0)
244 goto fallback;
245
246 cl = (void *)res.class;
247 if (!cl) {
248 if (TC_H_MAJ(res.classid))
249 cl = cbq_class_lookup(q, res.classid);
250 else if ((cl = defmap[res.classid & TC_PRIO_MAX]) == NULL)
251 cl = defmap[TC_PRIO_BESTEFFORT];
252
253 if (cl == NULL)
254 goto fallback;
255 }
256 if (cl->level >= head->level)
257 goto fallback;
258 #ifdef CONFIG_NET_CLS_ACT
259 switch (result) {
260 case TC_ACT_QUEUED:
261 case TC_ACT_STOLEN:
262 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
263 case TC_ACT_SHOT:
264 return NULL;
265 case TC_ACT_RECLASSIFY:
266 return cbq_reclassify(skb, cl);
267 }
268 #endif
269 if (cl->level == 0)
270 return cl;
271
272 /*
273 * Step 3+n. If classifier selected a link sharing class,
274 * apply agency specific classifier.
275 * Repeat this procdure until we hit a leaf node.
276 */
277 head = cl;
278 }
279
280 fallback:
281 cl = head;
282
283 /*
284 * Step 4. No success...
285 */
286 if (TC_H_MAJ(prio) == 0 &&
287 !(cl = head->defaults[prio & TC_PRIO_MAX]) &&
288 !(cl = head->defaults[TC_PRIO_BESTEFFORT]))
289 return head;
290
291 return cl;
292 }
293
294 /*
295 * A packet has just been enqueued on the empty class.
296 * cbq_activate_class adds it to the tail of active class list
297 * of its priority band.
298 */
299
300 static inline void cbq_activate_class(struct cbq_class *cl)
301 {
302 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
303 int prio = cl->cpriority;
304 struct cbq_class *cl_tail;
305
306 cl_tail = q->active[prio];
307 q->active[prio] = cl;
308
309 if (cl_tail != NULL) {
310 cl->next_alive = cl_tail->next_alive;
311 cl_tail->next_alive = cl;
312 } else {
313 cl->next_alive = cl;
314 q->activemask |= (1<<prio);
315 }
316 }
317
318 /*
319 * Unlink class from active chain.
320 * Note that this same procedure is done directly in cbq_dequeue*
321 * during round-robin procedure.
322 */
323
324 static void cbq_deactivate_class(struct cbq_class *this)
325 {
326 struct cbq_sched_data *q = qdisc_priv(this->qdisc);
327 int prio = this->cpriority;
328 struct cbq_class *cl;
329 struct cbq_class *cl_prev = q->active[prio];
330
331 do {
332 cl = cl_prev->next_alive;
333 if (cl == this) {
334 cl_prev->next_alive = cl->next_alive;
335 cl->next_alive = NULL;
336
337 if (cl == q->active[prio]) {
338 q->active[prio] = cl_prev;
339 if (cl == q->active[prio]) {
340 q->active[prio] = NULL;
341 q->activemask &= ~(1<<prio);
342 return;
343 }
344 }
345 return;
346 }
347 } while ((cl_prev = cl) != q->active[prio]);
348 }
349
350 static void
351 cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl)
352 {
353 int toplevel = q->toplevel;
354
355 if (toplevel > cl->level && !(qdisc_is_throttled(cl->q))) {
356 psched_time_t now;
357 psched_tdiff_t incr;
358
359 now = psched_get_time();
360 incr = now - q->now_rt;
361 now = q->now + incr;
362
363 do {
364 if (cl->undertime < now) {
365 q->toplevel = cl->level;
366 return;
367 }
368 } while ((cl = cl->borrow) != NULL && toplevel > cl->level);
369 }
370 }
371
372 static int
373 cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
374 {
375 struct cbq_sched_data *q = qdisc_priv(sch);
376 int uninitialized_var(ret);
377 struct cbq_class *cl = cbq_classify(skb, sch, &ret);
378
379 #ifdef CONFIG_NET_CLS_ACT
380 q->rx_class = cl;
381 #endif
382 if (cl == NULL) {
383 if (ret & __NET_XMIT_BYPASS)
384 sch->qstats.drops++;
385 kfree_skb(skb);
386 return ret;
387 }
388
389 #ifdef CONFIG_NET_CLS_ACT
390 cl->q->__parent = sch;
391 #endif
392 ret = qdisc_enqueue(skb, cl->q);
393 if (ret == NET_XMIT_SUCCESS) {
394 sch->q.qlen++;
395 cbq_mark_toplevel(q, cl);
396 if (!cl->next_alive)
397 cbq_activate_class(cl);
398 return ret;
399 }
400
401 if (net_xmit_drop_count(ret)) {
402 sch->qstats.drops++;
403 cbq_mark_toplevel(q, cl);
404 cl->qstats.drops++;
405 }
406 return ret;
407 }
408
409 /* Overlimit actions */
410
411 /* TC_CBQ_OVL_CLASSIC: (default) penalize leaf class by adding offtime */
412
413 static void cbq_ovl_classic(struct cbq_class *cl)
414 {
415 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
416 psched_tdiff_t delay = cl->undertime - q->now;
417
418 if (!cl->delayed) {
419 delay += cl->offtime;
420
421 /*
422 * Class goes to sleep, so that it will have no
423 * chance to work avgidle. Let's forgive it 8)
424 *
425 * BTW cbq-2.0 has a crap in this
426 * place, apparently they forgot to shift it by cl->ewma_log.
427 */
428 if (cl->avgidle < 0)
429 delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
430 if (cl->avgidle < cl->minidle)
431 cl->avgidle = cl->minidle;
432 if (delay <= 0)
433 delay = 1;
434 cl->undertime = q->now + delay;
435
436 cl->xstats.overactions++;
437 cl->delayed = 1;
438 }
439 if (q->wd_expires == 0 || q->wd_expires > delay)
440 q->wd_expires = delay;
441
442 /* Dirty work! We must schedule wakeups based on
443 * real available rate, rather than leaf rate,
444 * which may be tiny (even zero).
445 */
446 if (q->toplevel == TC_CBQ_MAXLEVEL) {
447 struct cbq_class *b;
448 psched_tdiff_t base_delay = q->wd_expires;
449
450 for (b = cl->borrow; b; b = b->borrow) {
451 delay = b->undertime - q->now;
452 if (delay < base_delay) {
453 if (delay <= 0)
454 delay = 1;
455 base_delay = delay;
456 }
457 }
458
459 q->wd_expires = base_delay;
460 }
461 }
462
463 /* TC_CBQ_OVL_RCLASSIC: penalize by offtime classes in hierarchy, when
464 * they go overlimit
465 */
466
467 static void cbq_ovl_rclassic(struct cbq_class *cl)
468 {
469 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
470 struct cbq_class *this = cl;
471
472 do {
473 if (cl->level > q->toplevel) {
474 cl = NULL;
475 break;
476 }
477 } while ((cl = cl->borrow) != NULL);
478
479 if (cl == NULL)
480 cl = this;
481 cbq_ovl_classic(cl);
482 }
483
484 /* TC_CBQ_OVL_DELAY: delay until it will go to underlimit */
485
486 static void cbq_ovl_delay(struct cbq_class *cl)
487 {
488 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
489 psched_tdiff_t delay = cl->undertime - q->now;
490
491 if (test_bit(__QDISC_STATE_DEACTIVATED,
492 &qdisc_root_sleeping(cl->qdisc)->state))
493 return;
494
495 if (!cl->delayed) {
496 psched_time_t sched = q->now;
497 ktime_t expires;
498
499 delay += cl->offtime;
500 if (cl->avgidle < 0)
501 delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
502 if (cl->avgidle < cl->minidle)
503 cl->avgidle = cl->minidle;
504 cl->undertime = q->now + delay;
505
506 if (delay > 0) {
507 sched += delay + cl->penalty;
508 cl->penalized = sched;
509 cl->cpriority = TC_CBQ_MAXPRIO;
510 q->pmask |= (1<<TC_CBQ_MAXPRIO);
511
512 expires = ns_to_ktime(PSCHED_TICKS2NS(sched));
513 if (hrtimer_try_to_cancel(&q->delay_timer) &&
514 ktime_to_ns(ktime_sub(
515 hrtimer_get_expires(&q->delay_timer),
516 expires)) > 0)
517 hrtimer_set_expires(&q->delay_timer, expires);
518 hrtimer_restart(&q->delay_timer);
519 cl->delayed = 1;
520 cl->xstats.overactions++;
521 return;
522 }
523 delay = 1;
524 }
525 if (q->wd_expires == 0 || q->wd_expires > delay)
526 q->wd_expires = delay;
527 }
528
529 /* TC_CBQ_OVL_LOWPRIO: penalize class by lowering its priority band */
530
531 static void cbq_ovl_lowprio(struct cbq_class *cl)
532 {
533 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
534
535 cl->penalized = q->now + cl->penalty;
536
537 if (cl->cpriority != cl->priority2) {
538 cl->cpriority = cl->priority2;
539 q->pmask |= (1<<cl->cpriority);
540 cl->xstats.overactions++;
541 }
542 cbq_ovl_classic(cl);
543 }
544
545 /* TC_CBQ_OVL_DROP: penalize class by dropping */
546
547 static void cbq_ovl_drop(struct cbq_class *cl)
548 {
549 if (cl->q->ops->drop)
550 if (cl->q->ops->drop(cl->q))
551 cl->qdisc->q.qlen--;
552 cl->xstats.overactions++;
553 cbq_ovl_classic(cl);
554 }
555
556 static psched_tdiff_t cbq_undelay_prio(struct cbq_sched_data *q, int prio,
557 psched_time_t now)
558 {
559 struct cbq_class *cl;
560 struct cbq_class *cl_prev = q->active[prio];
561 psched_time_t sched = now;
562
563 if (cl_prev == NULL)
564 return 0;
565
566 do {
567 cl = cl_prev->next_alive;
568 if (now - cl->penalized > 0) {
569 cl_prev->next_alive = cl->next_alive;
570 cl->next_alive = NULL;
571 cl->cpriority = cl->priority;
572 cl->delayed = 0;
573 cbq_activate_class(cl);
574
575 if (cl == q->active[prio]) {
576 q->active[prio] = cl_prev;
577 if (cl == q->active[prio]) {
578 q->active[prio] = NULL;
579 return 0;
580 }
581 }
582
583 cl = cl_prev->next_alive;
584 } else if (sched - cl->penalized > 0)
585 sched = cl->penalized;
586 } while ((cl_prev = cl) != q->active[prio]);
587
588 return sched - now;
589 }
590
591 static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
592 {
593 struct cbq_sched_data *q = container_of(timer, struct cbq_sched_data,
594 delay_timer);
595 struct Qdisc *sch = q->watchdog.qdisc;
596 psched_time_t now;
597 psched_tdiff_t delay = 0;
598 unsigned int pmask;
599
600 now = psched_get_time();
601
602 pmask = q->pmask;
603 q->pmask = 0;
604
605 while (pmask) {
606 int prio = ffz(~pmask);
607 psched_tdiff_t tmp;
608
609 pmask &= ~(1<<prio);
610
611 tmp = cbq_undelay_prio(q, prio, now);
612 if (tmp > 0) {
613 q->pmask |= 1<<prio;
614 if (tmp < delay || delay == 0)
615 delay = tmp;
616 }
617 }
618
619 if (delay) {
620 ktime_t time;
621
622 time = ktime_set(0, 0);
623 time = ktime_add_ns(time, PSCHED_TICKS2NS(now + delay));
624 hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS);
625 }
626
627 qdisc_unthrottled(sch);
628 __netif_schedule(qdisc_root(sch));
629 return HRTIMER_NORESTART;
630 }
631
632 #ifdef CONFIG_NET_CLS_ACT
633 static int cbq_reshape_fail(struct sk_buff *skb, struct Qdisc *child)
634 {
635 struct Qdisc *sch = child->__parent;
636 struct cbq_sched_data *q = qdisc_priv(sch);
637 struct cbq_class *cl = q->rx_class;
638
639 q->rx_class = NULL;
640
641 if (cl && (cl = cbq_reclassify(skb, cl)) != NULL) {
642 int ret;
643
644 cbq_mark_toplevel(q, cl);
645
646 q->rx_class = cl;
647 cl->q->__parent = sch;
648
649 ret = qdisc_enqueue(skb, cl->q);
650 if (ret == NET_XMIT_SUCCESS) {
651 sch->q.qlen++;
652 if (!cl->next_alive)
653 cbq_activate_class(cl);
654 return 0;
655 }
656 if (net_xmit_drop_count(ret))
657 sch->qstats.drops++;
658 return 0;
659 }
660
661 sch->qstats.drops++;
662 return -1;
663 }
664 #endif
665
666 /*
667 * It is mission critical procedure.
668 *
669 * We "regenerate" toplevel cutoff, if transmitting class
670 * has backlog and it is not regulated. It is not part of
671 * original CBQ description, but looks more reasonable.
672 * Probably, it is wrong. This question needs further investigation.
673 */
674
675 static inline void
676 cbq_update_toplevel(struct cbq_sched_data *q, struct cbq_class *cl,
677 struct cbq_class *borrowed)
678 {
679 if (cl && q->toplevel >= borrowed->level) {
680 if (cl->q->q.qlen > 1) {
681 do {
682 if (borrowed->undertime == PSCHED_PASTPERFECT) {
683 q->toplevel = borrowed->level;
684 return;
685 }
686 } while ((borrowed = borrowed->borrow) != NULL);
687 }
688 #if 0
689 /* It is not necessary now. Uncommenting it
690 will save CPU cycles, but decrease fairness.
691 */
692 q->toplevel = TC_CBQ_MAXLEVEL;
693 #endif
694 }
695 }
696
697 static void
698 cbq_update(struct cbq_sched_data *q)
699 {
700 struct cbq_class *this = q->tx_class;
701 struct cbq_class *cl = this;
702 int len = q->tx_len;
703
704 q->tx_class = NULL;
705
706 for ( ; cl; cl = cl->share) {
707 long avgidle = cl->avgidle;
708 long idle;
709
710 cl->bstats.packets++;
711 cl->bstats.bytes += len;
712
713 /*
714 * (now - last) is total time between packet right edges.
715 * (last_pktlen/rate) is "virtual" busy time, so that
716 *
717 * idle = (now - last) - last_pktlen/rate
718 */
719
720 idle = q->now - cl->last;
721 if ((unsigned long)idle > 128*1024*1024) {
722 avgidle = cl->maxidle;
723 } else {
724 idle -= L2T(cl, len);
725
726 /* true_avgidle := (1-W)*true_avgidle + W*idle,
727 * where W=2^{-ewma_log}. But cl->avgidle is scaled:
728 * cl->avgidle == true_avgidle/W,
729 * hence:
730 */
731 avgidle += idle - (avgidle>>cl->ewma_log);
732 }
733
734 if (avgidle <= 0) {
735 /* Overlimit or at-limit */
736
737 if (avgidle < cl->minidle)
738 avgidle = cl->minidle;
739
740 cl->avgidle = avgidle;
741
742 /* Calculate expected time, when this class
743 * will be allowed to send.
744 * It will occur, when:
745 * (1-W)*true_avgidle + W*delay = 0, i.e.
746 * idle = (1/W - 1)*(-true_avgidle)
747 * or
748 * idle = (1 - W)*(-cl->avgidle);
749 */
750 idle = (-avgidle) - ((-avgidle) >> cl->ewma_log);
751
752 /*
753 * That is not all.
754 * To maintain the rate allocated to the class,
755 * we add to undertime virtual clock,
756 * necessary to complete transmitted packet.
757 * (len/phys_bandwidth has been already passed
758 * to the moment of cbq_update)
759 */
760
761 idle -= L2T(&q->link, len);
762 idle += L2T(cl, len);
763
764 cl->undertime = q->now + idle;
765 } else {
766 /* Underlimit */
767
768 cl->undertime = PSCHED_PASTPERFECT;
769 if (avgidle > cl->maxidle)
770 cl->avgidle = cl->maxidle;
771 else
772 cl->avgidle = avgidle;
773 }
774 cl->last = q->now;
775 }
776
777 cbq_update_toplevel(q, this, q->tx_borrowed);
778 }
779
780 static inline struct cbq_class *
781 cbq_under_limit(struct cbq_class *cl)
782 {
783 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
784 struct cbq_class *this_cl = cl;
785
786 if (cl->tparent == NULL)
787 return cl;
788
789 if (cl->undertime == PSCHED_PASTPERFECT || q->now >= cl->undertime) {
790 cl->delayed = 0;
791 return cl;
792 }
793
794 do {
795 /* It is very suspicious place. Now overlimit
796 * action is generated for not bounded classes
797 * only if link is completely congested.
798 * Though it is in agree with ancestor-only paradigm,
799 * it looks very stupid. Particularly,
800 * it means that this chunk of code will either
801 * never be called or result in strong amplification
802 * of burstiness. Dangerous, silly, and, however,
803 * no another solution exists.
804 */
805 cl = cl->borrow;
806 if (!cl) {
807 this_cl->qstats.overlimits++;
808 this_cl->overlimit(this_cl);
809 return NULL;
810 }
811 if (cl->level > q->toplevel)
812 return NULL;
813 } while (cl->undertime != PSCHED_PASTPERFECT && q->now < cl->undertime);
814
815 cl->delayed = 0;
816 return cl;
817 }
818
819 static inline struct sk_buff *
820 cbq_dequeue_prio(struct Qdisc *sch, int prio)
821 {
822 struct cbq_sched_data *q = qdisc_priv(sch);
823 struct cbq_class *cl_tail, *cl_prev, *cl;
824 struct sk_buff *skb;
825 int deficit;
826
827 cl_tail = cl_prev = q->active[prio];
828 cl = cl_prev->next_alive;
829
830 do {
831 deficit = 0;
832
833 /* Start round */
834 do {
835 struct cbq_class *borrow = cl;
836
837 if (cl->q->q.qlen &&
838 (borrow = cbq_under_limit(cl)) == NULL)
839 goto skip_class;
840
841 if (cl->deficit <= 0) {
842 /* Class exhausted its allotment per
843 * this round. Switch to the next one.
844 */
845 deficit = 1;
846 cl->deficit += cl->quantum;
847 goto next_class;
848 }
849
850 skb = cl->q->dequeue(cl->q);
851
852 /* Class did not give us any skb :-(
853 * It could occur even if cl->q->q.qlen != 0
854 * f.e. if cl->q == "tbf"
855 */
856 if (skb == NULL)
857 goto skip_class;
858
859 cl->deficit -= qdisc_pkt_len(skb);
860 q->tx_class = cl;
861 q->tx_borrowed = borrow;
862 if (borrow != cl) {
863 #ifndef CBQ_XSTATS_BORROWS_BYTES
864 borrow->xstats.borrows++;
865 cl->xstats.borrows++;
866 #else
867 borrow->xstats.borrows += qdisc_pkt_len(skb);
868 cl->xstats.borrows += qdisc_pkt_len(skb);
869 #endif
870 }
871 q->tx_len = qdisc_pkt_len(skb);
872
873 if (cl->deficit <= 0) {
874 q->active[prio] = cl;
875 cl = cl->next_alive;
876 cl->deficit += cl->quantum;
877 }
878 return skb;
879
880 skip_class:
881 if (cl->q->q.qlen == 0 || prio != cl->cpriority) {
882 /* Class is empty or penalized.
883 * Unlink it from active chain.
884 */
885 cl_prev->next_alive = cl->next_alive;
886 cl->next_alive = NULL;
887
888 /* Did cl_tail point to it? */
889 if (cl == cl_tail) {
890 /* Repair it! */
891 cl_tail = cl_prev;
892
893 /* Was it the last class in this band? */
894 if (cl == cl_tail) {
895 /* Kill the band! */
896 q->active[prio] = NULL;
897 q->activemask &= ~(1<<prio);
898 if (cl->q->q.qlen)
899 cbq_activate_class(cl);
900 return NULL;
901 }
902
903 q->active[prio] = cl_tail;
904 }
905 if (cl->q->q.qlen)
906 cbq_activate_class(cl);
907
908 cl = cl_prev;
909 }
910
911 next_class:
912 cl_prev = cl;
913 cl = cl->next_alive;
914 } while (cl_prev != cl_tail);
915 } while (deficit);
916
917 q->active[prio] = cl_prev;
918
919 return NULL;
920 }
921
922 static inline struct sk_buff *
923 cbq_dequeue_1(struct Qdisc *sch)
924 {
925 struct cbq_sched_data *q = qdisc_priv(sch);
926 struct sk_buff *skb;
927 unsigned int activemask;
928
929 activemask = q->activemask & 0xFF;
930 while (activemask) {
931 int prio = ffz(~activemask);
932 activemask &= ~(1<<prio);
933 skb = cbq_dequeue_prio(sch, prio);
934 if (skb)
935 return skb;
936 }
937 return NULL;
938 }
939
940 static struct sk_buff *
941 cbq_dequeue(struct Qdisc *sch)
942 {
943 struct sk_buff *skb;
944 struct cbq_sched_data *q = qdisc_priv(sch);
945 psched_time_t now;
946 psched_tdiff_t incr;
947
948 now = psched_get_time();
949 incr = now - q->now_rt;
950
951 if (q->tx_class) {
952 psched_tdiff_t incr2;
953 /* Time integrator. We calculate EOS time
954 * by adding expected packet transmission time.
955 * If real time is greater, we warp artificial clock,
956 * so that:
957 *
958 * cbq_time = max(real_time, work);
959 */
960 incr2 = L2T(&q->link, q->tx_len);
961 q->now += incr2;
962 cbq_update(q);
963 if ((incr -= incr2) < 0)
964 incr = 0;
965 q->now += incr;
966 } else {
967 if (now > q->now)
968 q->now = now;
969 }
970 q->now_rt = now;
971
972 for (;;) {
973 q->wd_expires = 0;
974
975 skb = cbq_dequeue_1(sch);
976 if (skb) {
977 qdisc_bstats_update(sch, skb);
978 sch->q.qlen--;
979 qdisc_unthrottled(sch);
980 return skb;
981 }
982
983 /* All the classes are overlimit.
984 *
985 * It is possible, if:
986 *
987 * 1. Scheduler is empty.
988 * 2. Toplevel cutoff inhibited borrowing.
989 * 3. Root class is overlimit.
990 *
991 * Reset 2d and 3d conditions and retry.
992 *
993 * Note, that NS and cbq-2.0 are buggy, peeking
994 * an arbitrary class is appropriate for ancestor-only
995 * sharing, but not for toplevel algorithm.
996 *
997 * Our version is better, but slower, because it requires
998 * two passes, but it is unavoidable with top-level sharing.
999 */
1000
1001 if (q->toplevel == TC_CBQ_MAXLEVEL &&
1002 q->link.undertime == PSCHED_PASTPERFECT)
1003 break;
1004
1005 q->toplevel = TC_CBQ_MAXLEVEL;
1006 q->link.undertime = PSCHED_PASTPERFECT;
1007 }
1008
1009 /* No packets in scheduler or nobody wants to give them to us :-(
1010 * Sigh... start watchdog timer in the last case.
1011 */
1012
1013 if (sch->q.qlen) {
1014 sch->qstats.overlimits++;
1015 if (q->wd_expires)
1016 qdisc_watchdog_schedule(&q->watchdog,
1017 now + q->wd_expires);
1018 }
1019 return NULL;
1020 }
1021
1022 /* CBQ class maintanance routines */
1023
1024 static void cbq_adjust_levels(struct cbq_class *this)
1025 {
1026 if (this == NULL)
1027 return;
1028
1029 do {
1030 int level = 0;
1031 struct cbq_class *cl;
1032
1033 cl = this->children;
1034 if (cl) {
1035 do {
1036 if (cl->level > level)
1037 level = cl->level;
1038 } while ((cl = cl->sibling) != this->children);
1039 }
1040 this->level = level + 1;
1041 } while ((this = this->tparent) != NULL);
1042 }
1043
1044 static void cbq_normalize_quanta(struct cbq_sched_data *q, int prio)
1045 {
1046 struct cbq_class *cl;
1047 unsigned int h;
1048
1049 if (q->quanta[prio] == 0)
1050 return;
1051
1052 for (h = 0; h < q->clhash.hashsize; h++) {
1053 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1054 /* BUGGGG... Beware! This expression suffer of
1055 * arithmetic overflows!
1056 */
1057 if (cl->priority == prio) {
1058 cl->quantum = (cl->weight*cl->allot*q->nclasses[prio])/
1059 q->quanta[prio];
1060 }
1061 if (cl->quantum <= 0 || cl->quantum>32*qdisc_dev(cl->qdisc)->mtu) {
1062 pr_warning("CBQ: class %08x has bad quantum==%ld, repaired.\n",
1063 cl->common.classid, cl->quantum);
1064 cl->quantum = qdisc_dev(cl->qdisc)->mtu/2 + 1;
1065 }
1066 }
1067 }
1068 }
1069
1070 static void cbq_sync_defmap(struct cbq_class *cl)
1071 {
1072 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
1073 struct cbq_class *split = cl->split;
1074 unsigned int h;
1075 int i;
1076
1077 if (split == NULL)
1078 return;
1079
1080 for (i = 0; i <= TC_PRIO_MAX; i++) {
1081 if (split->defaults[i] == cl && !(cl->defmap & (1<<i)))
1082 split->defaults[i] = NULL;
1083 }
1084
1085 for (i = 0; i <= TC_PRIO_MAX; i++) {
1086 int level = split->level;
1087
1088 if (split->defaults[i])
1089 continue;
1090
1091 for (h = 0; h < q->clhash.hashsize; h++) {
1092 struct cbq_class *c;
1093
1094 hlist_for_each_entry(c, &q->clhash.hash[h],
1095 common.hnode) {
1096 if (c->split == split && c->level < level &&
1097 c->defmap & (1<<i)) {
1098 split->defaults[i] = c;
1099 level = c->level;
1100 }
1101 }
1102 }
1103 }
1104 }
1105
1106 static void cbq_change_defmap(struct cbq_class *cl, u32 splitid, u32 def, u32 mask)
1107 {
1108 struct cbq_class *split = NULL;
1109
1110 if (splitid == 0) {
1111 split = cl->split;
1112 if (!split)
1113 return;
1114 splitid = split->common.classid;
1115 }
1116
1117 if (split == NULL || split->common.classid != splitid) {
1118 for (split = cl->tparent; split; split = split->tparent)
1119 if (split->common.classid == splitid)
1120 break;
1121 }
1122
1123 if (split == NULL)
1124 return;
1125
1126 if (cl->split != split) {
1127 cl->defmap = 0;
1128 cbq_sync_defmap(cl);
1129 cl->split = split;
1130 cl->defmap = def & mask;
1131 } else
1132 cl->defmap = (cl->defmap & ~mask) | (def & mask);
1133
1134 cbq_sync_defmap(cl);
1135 }
1136
1137 static void cbq_unlink_class(struct cbq_class *this)
1138 {
1139 struct cbq_class *cl, **clp;
1140 struct cbq_sched_data *q = qdisc_priv(this->qdisc);
1141
1142 qdisc_class_hash_remove(&q->clhash, &this->common);
1143
1144 if (this->tparent) {
1145 clp = &this->sibling;
1146 cl = *clp;
1147 do {
1148 if (cl == this) {
1149 *clp = cl->sibling;
1150 break;
1151 }
1152 clp = &cl->sibling;
1153 } while ((cl = *clp) != this->sibling);
1154
1155 if (this->tparent->children == this) {
1156 this->tparent->children = this->sibling;
1157 if (this->sibling == this)
1158 this->tparent->children = NULL;
1159 }
1160 } else {
1161 WARN_ON(this->sibling != this);
1162 }
1163 }
1164
1165 static void cbq_link_class(struct cbq_class *this)
1166 {
1167 struct cbq_sched_data *q = qdisc_priv(this->qdisc);
1168 struct cbq_class *parent = this->tparent;
1169
1170 this->sibling = this;
1171 qdisc_class_hash_insert(&q->clhash, &this->common);
1172
1173 if (parent == NULL)
1174 return;
1175
1176 if (parent->children == NULL) {
1177 parent->children = this;
1178 } else {
1179 this->sibling = parent->children->sibling;
1180 parent->children->sibling = this;
1181 }
1182 }
1183
1184 static unsigned int cbq_drop(struct Qdisc *sch)
1185 {
1186 struct cbq_sched_data *q = qdisc_priv(sch);
1187 struct cbq_class *cl, *cl_head;
1188 int prio;
1189 unsigned int len;
1190
1191 for (prio = TC_CBQ_MAXPRIO; prio >= 0; prio--) {
1192 cl_head = q->active[prio];
1193 if (!cl_head)
1194 continue;
1195
1196 cl = cl_head;
1197 do {
1198 if (cl->q->ops->drop && (len = cl->q->ops->drop(cl->q))) {
1199 sch->q.qlen--;
1200 if (!cl->q->q.qlen)
1201 cbq_deactivate_class(cl);
1202 return len;
1203 }
1204 } while ((cl = cl->next_alive) != cl_head);
1205 }
1206 return 0;
1207 }
1208
1209 static void
1210 cbq_reset(struct Qdisc *sch)
1211 {
1212 struct cbq_sched_data *q = qdisc_priv(sch);
1213 struct cbq_class *cl;
1214 int prio;
1215 unsigned int h;
1216
1217 q->activemask = 0;
1218 q->pmask = 0;
1219 q->tx_class = NULL;
1220 q->tx_borrowed = NULL;
1221 qdisc_watchdog_cancel(&q->watchdog);
1222 hrtimer_cancel(&q->delay_timer);
1223 q->toplevel = TC_CBQ_MAXLEVEL;
1224 q->now = psched_get_time();
1225 q->now_rt = q->now;
1226
1227 for (prio = 0; prio <= TC_CBQ_MAXPRIO; prio++)
1228 q->active[prio] = NULL;
1229
1230 for (h = 0; h < q->clhash.hashsize; h++) {
1231 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1232 qdisc_reset(cl->q);
1233
1234 cl->next_alive = NULL;
1235 cl->undertime = PSCHED_PASTPERFECT;
1236 cl->avgidle = cl->maxidle;
1237 cl->deficit = cl->quantum;
1238 cl->cpriority = cl->priority;
1239 }
1240 }
1241 sch->q.qlen = 0;
1242 }
1243
1244
1245 static int cbq_set_lss(struct cbq_class *cl, struct tc_cbq_lssopt *lss)
1246 {
1247 if (lss->change & TCF_CBQ_LSS_FLAGS) {
1248 cl->share = (lss->flags & TCF_CBQ_LSS_ISOLATED) ? NULL : cl->tparent;
1249 cl->borrow = (lss->flags & TCF_CBQ_LSS_BOUNDED) ? NULL : cl->tparent;
1250 }
1251 if (lss->change & TCF_CBQ_LSS_EWMA)
1252 cl->ewma_log = lss->ewma_log;
1253 if (lss->change & TCF_CBQ_LSS_AVPKT)
1254 cl->avpkt = lss->avpkt;
1255 if (lss->change & TCF_CBQ_LSS_MINIDLE)
1256 cl->minidle = -(long)lss->minidle;
1257 if (lss->change & TCF_CBQ_LSS_MAXIDLE) {
1258 cl->maxidle = lss->maxidle;
1259 cl->avgidle = lss->maxidle;
1260 }
1261 if (lss->change & TCF_CBQ_LSS_OFFTIME)
1262 cl->offtime = lss->offtime;
1263 return 0;
1264 }
1265
1266 static void cbq_rmprio(struct cbq_sched_data *q, struct cbq_class *cl)
1267 {
1268 q->nclasses[cl->priority]--;
1269 q->quanta[cl->priority] -= cl->weight;
1270 cbq_normalize_quanta(q, cl->priority);
1271 }
1272
1273 static void cbq_addprio(struct cbq_sched_data *q, struct cbq_class *cl)
1274 {
1275 q->nclasses[cl->priority]++;
1276 q->quanta[cl->priority] += cl->weight;
1277 cbq_normalize_quanta(q, cl->priority);
1278 }
1279
1280 static int cbq_set_wrr(struct cbq_class *cl, struct tc_cbq_wrropt *wrr)
1281 {
1282 struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
1283
1284 if (wrr->allot)
1285 cl->allot = wrr->allot;
1286 if (wrr->weight)
1287 cl->weight = wrr->weight;
1288 if (wrr->priority) {
1289 cl->priority = wrr->priority - 1;
1290 cl->cpriority = cl->priority;
1291 if (cl->priority >= cl->priority2)
1292 cl->priority2 = TC_CBQ_MAXPRIO - 1;
1293 }
1294
1295 cbq_addprio(q, cl);
1296 return 0;
1297 }
1298
1299 static int cbq_set_overlimit(struct cbq_class *cl, struct tc_cbq_ovl *ovl)
1300 {
1301 switch (ovl->strategy) {
1302 case TC_CBQ_OVL_CLASSIC:
1303 cl->overlimit = cbq_ovl_classic;
1304 break;
1305 case TC_CBQ_OVL_DELAY:
1306 cl->overlimit = cbq_ovl_delay;
1307 break;
1308 case TC_CBQ_OVL_LOWPRIO:
1309 if (ovl->priority2 - 1 >= TC_CBQ_MAXPRIO ||
1310 ovl->priority2 - 1 <= cl->priority)
1311 return -EINVAL;
1312 cl->priority2 = ovl->priority2 - 1;
1313 cl->overlimit = cbq_ovl_lowprio;
1314 break;
1315 case TC_CBQ_OVL_DROP:
1316 cl->overlimit = cbq_ovl_drop;
1317 break;
1318 case TC_CBQ_OVL_RCLASSIC:
1319 cl->overlimit = cbq_ovl_rclassic;
1320 break;
1321 default:
1322 return -EINVAL;
1323 }
1324 cl->penalty = ovl->penalty;
1325 return 0;
1326 }
1327
1328 #ifdef CONFIG_NET_CLS_ACT
1329 static int cbq_set_police(struct cbq_class *cl, struct tc_cbq_police *p)
1330 {
1331 cl->police = p->police;
1332
1333 if (cl->q->handle) {
1334 if (p->police == TC_POLICE_RECLASSIFY)
1335 cl->q->reshape_fail = cbq_reshape_fail;
1336 else
1337 cl->q->reshape_fail = NULL;
1338 }
1339 return 0;
1340 }
1341 #endif
1342
1343 static int cbq_set_fopt(struct cbq_class *cl, struct tc_cbq_fopt *fopt)
1344 {
1345 cbq_change_defmap(cl, fopt->split, fopt->defmap, fopt->defchange);
1346 return 0;
1347 }
1348
1349 static const struct nla_policy cbq_policy[TCA_CBQ_MAX + 1] = {
1350 [TCA_CBQ_LSSOPT] = { .len = sizeof(struct tc_cbq_lssopt) },
1351 [TCA_CBQ_WRROPT] = { .len = sizeof(struct tc_cbq_wrropt) },
1352 [TCA_CBQ_FOPT] = { .len = sizeof(struct tc_cbq_fopt) },
1353 [TCA_CBQ_OVL_STRATEGY] = { .len = sizeof(struct tc_cbq_ovl) },
1354 [TCA_CBQ_RATE] = { .len = sizeof(struct tc_ratespec) },
1355 [TCA_CBQ_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
1356 [TCA_CBQ_POLICE] = { .len = sizeof(struct tc_cbq_police) },
1357 };
1358
1359 static int cbq_init(struct Qdisc *sch, struct nlattr *opt)
1360 {
1361 struct cbq_sched_data *q = qdisc_priv(sch);
1362 struct nlattr *tb[TCA_CBQ_MAX + 1];
1363 struct tc_ratespec *r;
1364 int err;
1365
1366 err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy);
1367 if (err < 0)
1368 return err;
1369
1370 if (tb[TCA_CBQ_RTAB] == NULL || tb[TCA_CBQ_RATE] == NULL)
1371 return -EINVAL;
1372
1373 r = nla_data(tb[TCA_CBQ_RATE]);
1374
1375 if ((q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB])) == NULL)
1376 return -EINVAL;
1377
1378 err = qdisc_class_hash_init(&q->clhash);
1379 if (err < 0)
1380 goto put_rtab;
1381
1382 q->link.refcnt = 1;
1383 q->link.sibling = &q->link;
1384 q->link.common.classid = sch->handle;
1385 q->link.qdisc = sch;
1386 q->link.q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1387 sch->handle);
1388 if (!q->link.q)
1389 q->link.q = &noop_qdisc;
1390
1391 q->link.priority = TC_CBQ_MAXPRIO - 1;
1392 q->link.priority2 = TC_CBQ_MAXPRIO - 1;
1393 q->link.cpriority = TC_CBQ_MAXPRIO - 1;
1394 q->link.ovl_strategy = TC_CBQ_OVL_CLASSIC;
1395 q->link.overlimit = cbq_ovl_classic;
1396 q->link.allot = psched_mtu(qdisc_dev(sch));
1397 q->link.quantum = q->link.allot;
1398 q->link.weight = q->link.R_tab->rate.rate;
1399
1400 q->link.ewma_log = TC_CBQ_DEF_EWMA;
1401 q->link.avpkt = q->link.allot/2;
1402 q->link.minidle = -0x7FFFFFFF;
1403
1404 qdisc_watchdog_init(&q->watchdog, sch);
1405 hrtimer_init(&q->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1406 q->delay_timer.function = cbq_undelay;
1407 q->toplevel = TC_CBQ_MAXLEVEL;
1408 q->now = psched_get_time();
1409 q->now_rt = q->now;
1410
1411 cbq_link_class(&q->link);
1412
1413 if (tb[TCA_CBQ_LSSOPT])
1414 cbq_set_lss(&q->link, nla_data(tb[TCA_CBQ_LSSOPT]));
1415
1416 cbq_addprio(q, &q->link);
1417 return 0;
1418
1419 put_rtab:
1420 qdisc_put_rtab(q->link.R_tab);
1421 return err;
1422 }
1423
1424 static int cbq_dump_rate(struct sk_buff *skb, struct cbq_class *cl)
1425 {
1426 unsigned char *b = skb_tail_pointer(skb);
1427
1428 if (nla_put(skb, TCA_CBQ_RATE, sizeof(cl->R_tab->rate), &cl->R_tab->rate))
1429 goto nla_put_failure;
1430 return skb->len;
1431
1432 nla_put_failure:
1433 nlmsg_trim(skb, b);
1434 return -1;
1435 }
1436
1437 static int cbq_dump_lss(struct sk_buff *skb, struct cbq_class *cl)
1438 {
1439 unsigned char *b = skb_tail_pointer(skb);
1440 struct tc_cbq_lssopt opt;
1441
1442 opt.flags = 0;
1443 if (cl->borrow == NULL)
1444 opt.flags |= TCF_CBQ_LSS_BOUNDED;
1445 if (cl->share == NULL)
1446 opt.flags |= TCF_CBQ_LSS_ISOLATED;
1447 opt.ewma_log = cl->ewma_log;
1448 opt.level = cl->level;
1449 opt.avpkt = cl->avpkt;
1450 opt.maxidle = cl->maxidle;
1451 opt.minidle = (u32)(-cl->minidle);
1452 opt.offtime = cl->offtime;
1453 opt.change = ~0;
1454 if (nla_put(skb, TCA_CBQ_LSSOPT, sizeof(opt), &opt))
1455 goto nla_put_failure;
1456 return skb->len;
1457
1458 nla_put_failure:
1459 nlmsg_trim(skb, b);
1460 return -1;
1461 }
1462
1463 static int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
1464 {
1465 unsigned char *b = skb_tail_pointer(skb);
1466 struct tc_cbq_wrropt opt;
1467
1468 opt.flags = 0;
1469 opt.allot = cl->allot;
1470 opt.priority = cl->priority + 1;
1471 opt.cpriority = cl->cpriority + 1;
1472 opt.weight = cl->weight;
1473 if (nla_put(skb, TCA_CBQ_WRROPT, sizeof(opt), &opt))
1474 goto nla_put_failure;
1475 return skb->len;
1476
1477 nla_put_failure:
1478 nlmsg_trim(skb, b);
1479 return -1;
1480 }
1481
1482 static int cbq_dump_ovl(struct sk_buff *skb, struct cbq_class *cl)
1483 {
1484 unsigned char *b = skb_tail_pointer(skb);
1485 struct tc_cbq_ovl opt;
1486
1487 opt.strategy = cl->ovl_strategy;
1488 opt.priority2 = cl->priority2 + 1;
1489 opt.pad = 0;
1490 opt.penalty = cl->penalty;
1491 if (nla_put(skb, TCA_CBQ_OVL_STRATEGY, sizeof(opt), &opt))
1492 goto nla_put_failure;
1493 return skb->len;
1494
1495 nla_put_failure:
1496 nlmsg_trim(skb, b);
1497 return -1;
1498 }
1499
1500 static int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
1501 {
1502 unsigned char *b = skb_tail_pointer(skb);
1503 struct tc_cbq_fopt opt;
1504
1505 if (cl->split || cl->defmap) {
1506 opt.split = cl->split ? cl->split->common.classid : 0;
1507 opt.defmap = cl->defmap;
1508 opt.defchange = ~0;
1509 if (nla_put(skb, TCA_CBQ_FOPT, sizeof(opt), &opt))
1510 goto nla_put_failure;
1511 }
1512 return skb->len;
1513
1514 nla_put_failure:
1515 nlmsg_trim(skb, b);
1516 return -1;
1517 }
1518
1519 #ifdef CONFIG_NET_CLS_ACT
1520 static int cbq_dump_police(struct sk_buff *skb, struct cbq_class *cl)
1521 {
1522 unsigned char *b = skb_tail_pointer(skb);
1523 struct tc_cbq_police opt;
1524
1525 if (cl->police) {
1526 opt.police = cl->police;
1527 opt.__res1 = 0;
1528 opt.__res2 = 0;
1529 if (nla_put(skb, TCA_CBQ_POLICE, sizeof(opt), &opt))
1530 goto nla_put_failure;
1531 }
1532 return skb->len;
1533
1534 nla_put_failure:
1535 nlmsg_trim(skb, b);
1536 return -1;
1537 }
1538 #endif
1539
1540 static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
1541 {
1542 if (cbq_dump_lss(skb, cl) < 0 ||
1543 cbq_dump_rate(skb, cl) < 0 ||
1544 cbq_dump_wrr(skb, cl) < 0 ||
1545 cbq_dump_ovl(skb, cl) < 0 ||
1546 #ifdef CONFIG_NET_CLS_ACT
1547 cbq_dump_police(skb, cl) < 0 ||
1548 #endif
1549 cbq_dump_fopt(skb, cl) < 0)
1550 return -1;
1551 return 0;
1552 }
1553
1554 static int cbq_dump(struct Qdisc *sch, struct sk_buff *skb)
1555 {
1556 struct cbq_sched_data *q = qdisc_priv(sch);
1557 struct nlattr *nest;
1558
1559 nest = nla_nest_start(skb, TCA_OPTIONS);
1560 if (nest == NULL)
1561 goto nla_put_failure;
1562 if (cbq_dump_attr(skb, &q->link) < 0)
1563 goto nla_put_failure;
1564 nla_nest_end(skb, nest);
1565 return skb->len;
1566
1567 nla_put_failure:
1568 nla_nest_cancel(skb, nest);
1569 return -1;
1570 }
1571
1572 static int
1573 cbq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
1574 {
1575 struct cbq_sched_data *q = qdisc_priv(sch);
1576
1577 q->link.xstats.avgidle = q->link.avgidle;
1578 return gnet_stats_copy_app(d, &q->link.xstats, sizeof(q->link.xstats));
1579 }
1580
1581 static int
1582 cbq_dump_class(struct Qdisc *sch, unsigned long arg,
1583 struct sk_buff *skb, struct tcmsg *tcm)
1584 {
1585 struct cbq_class *cl = (struct cbq_class *)arg;
1586 struct nlattr *nest;
1587
1588 if (cl->tparent)
1589 tcm->tcm_parent = cl->tparent->common.classid;
1590 else
1591 tcm->tcm_parent = TC_H_ROOT;
1592 tcm->tcm_handle = cl->common.classid;
1593 tcm->tcm_info = cl->q->handle;
1594
1595 nest = nla_nest_start(skb, TCA_OPTIONS);
1596 if (nest == NULL)
1597 goto nla_put_failure;
1598 if (cbq_dump_attr(skb, cl) < 0)
1599 goto nla_put_failure;
1600 nla_nest_end(skb, nest);
1601 return skb->len;
1602
1603 nla_put_failure:
1604 nla_nest_cancel(skb, nest);
1605 return -1;
1606 }
1607
1608 static int
1609 cbq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
1610 struct gnet_dump *d)
1611 {
1612 struct cbq_sched_data *q = qdisc_priv(sch);
1613 struct cbq_class *cl = (struct cbq_class *)arg;
1614
1615 cl->qstats.qlen = cl->q->q.qlen;
1616 cl->xstats.avgidle = cl->avgidle;
1617 cl->xstats.undertime = 0;
1618
1619 if (cl->undertime != PSCHED_PASTPERFECT)
1620 cl->xstats.undertime = cl->undertime - q->now;
1621
1622 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1623 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
1624 gnet_stats_copy_queue(d, &cl->qstats) < 0)
1625 return -1;
1626
1627 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1628 }
1629
1630 static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1631 struct Qdisc **old)
1632 {
1633 struct cbq_class *cl = (struct cbq_class *)arg;
1634
1635 if (new == NULL) {
1636 new = qdisc_create_dflt(sch->dev_queue,
1637 &pfifo_qdisc_ops, cl->common.classid);
1638 if (new == NULL)
1639 return -ENOBUFS;
1640 } else {
1641 #ifdef CONFIG_NET_CLS_ACT
1642 if (cl->police == TC_POLICE_RECLASSIFY)
1643 new->reshape_fail = cbq_reshape_fail;
1644 #endif
1645 }
1646 sch_tree_lock(sch);
1647 *old = cl->q;
1648 cl->q = new;
1649 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1650 qdisc_reset(*old);
1651 sch_tree_unlock(sch);
1652
1653 return 0;
1654 }
1655
1656 static struct Qdisc *cbq_leaf(struct Qdisc *sch, unsigned long arg)
1657 {
1658 struct cbq_class *cl = (struct cbq_class *)arg;
1659
1660 return cl->q;
1661 }
1662
1663 static void cbq_qlen_notify(struct Qdisc *sch, unsigned long arg)
1664 {
1665 struct cbq_class *cl = (struct cbq_class *)arg;
1666
1667 if (cl->q->q.qlen == 0)
1668 cbq_deactivate_class(cl);
1669 }
1670
1671 static unsigned long cbq_get(struct Qdisc *sch, u32 classid)
1672 {
1673 struct cbq_sched_data *q = qdisc_priv(sch);
1674 struct cbq_class *cl = cbq_class_lookup(q, classid);
1675
1676 if (cl) {
1677 cl->refcnt++;
1678 return (unsigned long)cl;
1679 }
1680 return 0;
1681 }
1682
1683 static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
1684 {
1685 struct cbq_sched_data *q = qdisc_priv(sch);
1686
1687 WARN_ON(cl->filters);
1688
1689 tcf_destroy_chain(&cl->filter_list);
1690 qdisc_destroy(cl->q);
1691 qdisc_put_rtab(cl->R_tab);
1692 gen_kill_estimator(&cl->bstats, &cl->rate_est);
1693 if (cl != &q->link)
1694 kfree(cl);
1695 }
1696
1697 static void cbq_destroy(struct Qdisc *sch)
1698 {
1699 struct cbq_sched_data *q = qdisc_priv(sch);
1700 struct hlist_node *next;
1701 struct cbq_class *cl;
1702 unsigned int h;
1703
1704 #ifdef CONFIG_NET_CLS_ACT
1705 q->rx_class = NULL;
1706 #endif
1707 /*
1708 * Filters must be destroyed first because we don't destroy the
1709 * classes from root to leafs which means that filters can still
1710 * be bound to classes which have been destroyed already. --TGR '04
1711 */
1712 for (h = 0; h < q->clhash.hashsize; h++) {
1713 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode)
1714 tcf_destroy_chain(&cl->filter_list);
1715 }
1716 for (h = 0; h < q->clhash.hashsize; h++) {
1717 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[h],
1718 common.hnode)
1719 cbq_destroy_class(sch, cl);
1720 }
1721 qdisc_class_hash_destroy(&q->clhash);
1722 }
1723
1724 static void cbq_put(struct Qdisc *sch, unsigned long arg)
1725 {
1726 struct cbq_class *cl = (struct cbq_class *)arg;
1727
1728 if (--cl->refcnt == 0) {
1729 #ifdef CONFIG_NET_CLS_ACT
1730 spinlock_t *root_lock = qdisc_root_sleeping_lock(sch);
1731 struct cbq_sched_data *q = qdisc_priv(sch);
1732
1733 spin_lock_bh(root_lock);
1734 if (q->rx_class == cl)
1735 q->rx_class = NULL;
1736 spin_unlock_bh(root_lock);
1737 #endif
1738
1739 cbq_destroy_class(sch, cl);
1740 }
1741 }
1742
1743 static int
1744 cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca,
1745 unsigned long *arg)
1746 {
1747 int err;
1748 struct cbq_sched_data *q = qdisc_priv(sch);
1749 struct cbq_class *cl = (struct cbq_class *)*arg;
1750 struct nlattr *opt = tca[TCA_OPTIONS];
1751 struct nlattr *tb[TCA_CBQ_MAX + 1];
1752 struct cbq_class *parent;
1753 struct qdisc_rate_table *rtab = NULL;
1754
1755 if (opt == NULL)
1756 return -EINVAL;
1757
1758 err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy);
1759 if (err < 0)
1760 return err;
1761
1762 if (cl) {
1763 /* Check parent */
1764 if (parentid) {
1765 if (cl->tparent &&
1766 cl->tparent->common.classid != parentid)
1767 return -EINVAL;
1768 if (!cl->tparent && parentid != TC_H_ROOT)
1769 return -EINVAL;
1770 }
1771
1772 if (tb[TCA_CBQ_RATE]) {
1773 rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
1774 tb[TCA_CBQ_RTAB]);
1775 if (rtab == NULL)
1776 return -EINVAL;
1777 }
1778
1779 if (tca[TCA_RATE]) {
1780 err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
1781 qdisc_root_sleeping_lock(sch),
1782 tca[TCA_RATE]);
1783 if (err) {
1784 if (rtab)
1785 qdisc_put_rtab(rtab);
1786 return err;
1787 }
1788 }
1789
1790 /* Change class parameters */
1791 sch_tree_lock(sch);
1792
1793 if (cl->next_alive != NULL)
1794 cbq_deactivate_class(cl);
1795
1796 if (rtab) {
1797 qdisc_put_rtab(cl->R_tab);
1798 cl->R_tab = rtab;
1799 }
1800
1801 if (tb[TCA_CBQ_LSSOPT])
1802 cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1803
1804 if (tb[TCA_CBQ_WRROPT]) {
1805 cbq_rmprio(q, cl);
1806 cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1807 }
1808
1809 if (tb[TCA_CBQ_OVL_STRATEGY])
1810 cbq_set_overlimit(cl, nla_data(tb[TCA_CBQ_OVL_STRATEGY]));
1811
1812 #ifdef CONFIG_NET_CLS_ACT
1813 if (tb[TCA_CBQ_POLICE])
1814 cbq_set_police(cl, nla_data(tb[TCA_CBQ_POLICE]));
1815 #endif
1816
1817 if (tb[TCA_CBQ_FOPT])
1818 cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1819
1820 if (cl->q->q.qlen)
1821 cbq_activate_class(cl);
1822
1823 sch_tree_unlock(sch);
1824
1825 return 0;
1826 }
1827
1828 if (parentid == TC_H_ROOT)
1829 return -EINVAL;
1830
1831 if (tb[TCA_CBQ_WRROPT] == NULL || tb[TCA_CBQ_RATE] == NULL ||
1832 tb[TCA_CBQ_LSSOPT] == NULL)
1833 return -EINVAL;
1834
1835 rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB]);
1836 if (rtab == NULL)
1837 return -EINVAL;
1838
1839 if (classid) {
1840 err = -EINVAL;
1841 if (TC_H_MAJ(classid ^ sch->handle) ||
1842 cbq_class_lookup(q, classid))
1843 goto failure;
1844 } else {
1845 int i;
1846 classid = TC_H_MAKE(sch->handle, 0x8000);
1847
1848 for (i = 0; i < 0x8000; i++) {
1849 if (++q->hgenerator >= 0x8000)
1850 q->hgenerator = 1;
1851 if (cbq_class_lookup(q, classid|q->hgenerator) == NULL)
1852 break;
1853 }
1854 err = -ENOSR;
1855 if (i >= 0x8000)
1856 goto failure;
1857 classid = classid|q->hgenerator;
1858 }
1859
1860 parent = &q->link;
1861 if (parentid) {
1862 parent = cbq_class_lookup(q, parentid);
1863 err = -EINVAL;
1864 if (parent == NULL)
1865 goto failure;
1866 }
1867
1868 err = -ENOBUFS;
1869 cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1870 if (cl == NULL)
1871 goto failure;
1872
1873 if (tca[TCA_RATE]) {
1874 err = gen_new_estimator(&cl->bstats, &cl->rate_est,
1875 qdisc_root_sleeping_lock(sch),
1876 tca[TCA_RATE]);
1877 if (err) {
1878 kfree(cl);
1879 goto failure;
1880 }
1881 }
1882
1883 cl->R_tab = rtab;
1884 rtab = NULL;
1885 cl->refcnt = 1;
1886 cl->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid);
1887 if (!cl->q)
1888 cl->q = &noop_qdisc;
1889 cl->common.classid = classid;
1890 cl->tparent = parent;
1891 cl->qdisc = sch;
1892 cl->allot = parent->allot;
1893 cl->quantum = cl->allot;
1894 cl->weight = cl->R_tab->rate.rate;
1895
1896 sch_tree_lock(sch);
1897 cbq_link_class(cl);
1898 cl->borrow = cl->tparent;
1899 if (cl->tparent != &q->link)
1900 cl->share = cl->tparent;
1901 cbq_adjust_levels(parent);
1902 cl->minidle = -0x7FFFFFFF;
1903 cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1904 cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1905 if (cl->ewma_log == 0)
1906 cl->ewma_log = q->link.ewma_log;
1907 if (cl->maxidle == 0)
1908 cl->maxidle = q->link.maxidle;
1909 if (cl->avpkt == 0)
1910 cl->avpkt = q->link.avpkt;
1911 cl->overlimit = cbq_ovl_classic;
1912 if (tb[TCA_CBQ_OVL_STRATEGY])
1913 cbq_set_overlimit(cl, nla_data(tb[TCA_CBQ_OVL_STRATEGY]));
1914 #ifdef CONFIG_NET_CLS_ACT
1915 if (tb[TCA_CBQ_POLICE])
1916 cbq_set_police(cl, nla_data(tb[TCA_CBQ_POLICE]));
1917 #endif
1918 if (tb[TCA_CBQ_FOPT])
1919 cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1920 sch_tree_unlock(sch);
1921
1922 qdisc_class_hash_grow(sch, &q->clhash);
1923
1924 *arg = (unsigned long)cl;
1925 return 0;
1926
1927 failure:
1928 qdisc_put_rtab(rtab);
1929 return err;
1930 }
1931
1932 static int cbq_delete(struct Qdisc *sch, unsigned long arg)
1933 {
1934 struct cbq_sched_data *q = qdisc_priv(sch);
1935 struct cbq_class *cl = (struct cbq_class *)arg;
1936 unsigned int qlen;
1937
1938 if (cl->filters || cl->children || cl == &q->link)
1939 return -EBUSY;
1940
1941 sch_tree_lock(sch);
1942
1943 qlen = cl->q->q.qlen;
1944 qdisc_reset(cl->q);
1945 qdisc_tree_decrease_qlen(cl->q, qlen);
1946
1947 if (cl->next_alive)
1948 cbq_deactivate_class(cl);
1949
1950 if (q->tx_borrowed == cl)
1951 q->tx_borrowed = q->tx_class;
1952 if (q->tx_class == cl) {
1953 q->tx_class = NULL;
1954 q->tx_borrowed = NULL;
1955 }
1956 #ifdef CONFIG_NET_CLS_ACT
1957 if (q->rx_class == cl)
1958 q->rx_class = NULL;
1959 #endif
1960
1961 cbq_unlink_class(cl);
1962 cbq_adjust_levels(cl->tparent);
1963 cl->defmap = 0;
1964 cbq_sync_defmap(cl);
1965
1966 cbq_rmprio(q, cl);
1967 sch_tree_unlock(sch);
1968
1969 BUG_ON(--cl->refcnt == 0);
1970 /*
1971 * This shouldn't happen: we "hold" one cops->get() when called
1972 * from tc_ctl_tclass; the destroy method is done from cops->put().
1973 */
1974
1975 return 0;
1976 }
1977
1978 static struct tcf_proto **cbq_find_tcf(struct Qdisc *sch, unsigned long arg)
1979 {
1980 struct cbq_sched_data *q = qdisc_priv(sch);
1981 struct cbq_class *cl = (struct cbq_class *)arg;
1982
1983 if (cl == NULL)
1984 cl = &q->link;
1985
1986 return &cl->filter_list;
1987 }
1988
1989 static unsigned long cbq_bind_filter(struct Qdisc *sch, unsigned long parent,
1990 u32 classid)
1991 {
1992 struct cbq_sched_data *q = qdisc_priv(sch);
1993 struct cbq_class *p = (struct cbq_class *)parent;
1994 struct cbq_class *cl = cbq_class_lookup(q, classid);
1995
1996 if (cl) {
1997 if (p && p->level <= cl->level)
1998 return 0;
1999 cl->filters++;
2000 return (unsigned long)cl;
2001 }
2002 return 0;
2003 }
2004
2005 static void cbq_unbind_filter(struct Qdisc *sch, unsigned long arg)
2006 {
2007 struct cbq_class *cl = (struct cbq_class *)arg;
2008
2009 cl->filters--;
2010 }
2011
2012 static void cbq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
2013 {
2014 struct cbq_sched_data *q = qdisc_priv(sch);
2015 struct cbq_class *cl;
2016 unsigned int h;
2017
2018 if (arg->stop)
2019 return;
2020
2021 for (h = 0; h < q->clhash.hashsize; h++) {
2022 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
2023 if (arg->count < arg->skip) {
2024 arg->count++;
2025 continue;
2026 }
2027 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
2028 arg->stop = 1;
2029 return;
2030 }
2031 arg->count++;
2032 }
2033 }
2034 }
2035
2036 static const struct Qdisc_class_ops cbq_class_ops = {
2037 .graft = cbq_graft,
2038 .leaf = cbq_leaf,
2039 .qlen_notify = cbq_qlen_notify,
2040 .get = cbq_get,
2041 .put = cbq_put,
2042 .change = cbq_change_class,
2043 .delete = cbq_delete,
2044 .walk = cbq_walk,
2045 .tcf_chain = cbq_find_tcf,
2046 .bind_tcf = cbq_bind_filter,
2047 .unbind_tcf = cbq_unbind_filter,
2048 .dump = cbq_dump_class,
2049 .dump_stats = cbq_dump_class_stats,
2050 };
2051
2052 static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
2053 .next = NULL,
2054 .cl_ops = &cbq_class_ops,
2055 .id = "cbq",
2056 .priv_size = sizeof(struct cbq_sched_data),
2057 .enqueue = cbq_enqueue,
2058 .dequeue = cbq_dequeue,
2059 .peek = qdisc_peek_dequeued,
2060 .drop = cbq_drop,
2061 .init = cbq_init,
2062 .reset = cbq_reset,
2063 .destroy = cbq_destroy,
2064 .change = NULL,
2065 .dump = cbq_dump,
2066 .dump_stats = cbq_dump_stats,
2067 .owner = THIS_MODULE,
2068 };
2069
2070 static int __init cbq_module_init(void)
2071 {
2072 return register_qdisc(&cbq_qdisc_ops);
2073 }
2074 static void __exit cbq_module_exit(void)
2075 {
2076 unregister_qdisc(&cbq_qdisc_ops);
2077 }
2078 module_init(cbq_module_init)
2079 module_exit(cbq_module_exit)
2080 MODULE_LICENSE("GPL");
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