net/sched/sch_cbq.c

   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 #include <net/pkt_cls.h>
  23
  24
  25 /*      Class-Based Queueing (CBQ) algorithm.
  26         =======================================
  27
  28         Sources: [1] Sally Floyd and Van Jacobson, "Link-sharing and Resource
  29                  Management Models for Packet Networks",
  30                  IEEE/ACM Transactions on Networking, Vol.3, No.4, 1995
  31
  32                  [2] Sally Floyd, "Notes on CBQ and Guaranteed Service", 1995
  33
  34                  [3] Sally Floyd, "Notes on Class-Based Queueing: Setting
  35                  Parameters", 1996
  36
  37                  [4] Sally Floyd and Michael Speer, "Experimental Results
  38                  for Class-Based Queueing", 1998, not published.
  39
  40         -----------------------------------------------------------------------
  41
  42         Algorithm skeleton was taken from NS simulator cbq.cc.
  43         If someone wants to check this code against the LBL version,
  44         he should take into account that ONLY the skeleton was borrowed,
  45         the implementation is different. Particularly:
  46
  47         --- The WRR algorithm is different. Our version looks more
  48         reasonable (I hope) and works when quanta are allowed to be
  49         less than MTU, which is always the case when real time classes
  50         have small rates. Note, that the statement of [3] is
  51         incomplete, delay may actually be estimated even if class
  52         per-round allotment is less than MTU. Namely, if per-round
  53         allotment is W*r_i, and r_1+...+r_k = r < 1
  54
  55         delay_i <= ([MTU/(W*r_i)]*W*r + W*r + k*MTU)/B
  56
  57         In the worst case we have IntServ estimate with D = W*r+k*MTU
  58         and C = MTU*r. The proof (if correct at all) is trivial.
  59
  60
  61         --- It seems that cbq-2.0 is not very accurate. At least, I cannot
  62         interpret some places, which look like wrong translations
  63         from NS. Anyone is advised to find these differences
  64         and explain to me, why I am wrong 8).
  65
  66         --- Linux has no EOI event, so that we cannot estimate true class
  67         idle time. Workaround is to consider the next dequeue event
  68         as sign that previous packet is finished. This is wrong because of
  69         internal device queueing, but on a permanently loaded link it is true.
  70         Moreover, combined with clock integrator, this scheme looks
  71         very close to an ideal solution.  */
  72
  73 struct cbq_sched_data;
  74
  75
  76 struct cbq_class {
  77         struct Qdisc_class_common common;
  78         struct cbq_class        *next_alive;    /* next class with backlog in this priority band */
  79
  80 /* Parameters */
  81         unsigned char           priority;       /* class priority */
  82         unsigned char           priority2;      /* priority to be used after overlimit */
  83         unsigned char           ewma_log;       /* time constant for idle time calculation */
  84
  85         u32                     defmap;
  86
  87         /* Link-sharing scheduler parameters */
  88         long                    maxidle;        /* Class parameters: see below. */
  89         long                    offtime;
  90         long                    minidle;
  91         u32                     avpkt;
  92         struct qdisc_rate_table *R_tab;
  93
  94         /* General scheduler (WRR) parameters */
  95         long                    allot;
  96         long                    quantum;        /* Allotment per WRR round */
  97         long                    weight;         /* Relative allotment: see below */
  98
  99         struct Qdisc            *qdisc;         /* Ptr to CBQ discipline */
 100         struct cbq_class        *split;         /* Ptr to split node */
 101         struct cbq_class        *share;         /* Ptr to LS parent in the class tree */
 102         struct cbq_class        *tparent;       /* Ptr to tree parent in the class tree */
 103         struct cbq_class        *borrow;        /* NULL if class is bandwidth limited;
 104                                                    parent otherwise */
 105         struct cbq_class        *sibling;       /* Sibling chain */
 106         struct cbq_class        *children;      /* Pointer to children chain */
 107
 108         struct Qdisc            *q;             /* Elementary queueing discipline */
 109
 110
 111 /* Variables */
 112         unsigned char           cpriority;      /* Effective priority */
 113         unsigned char           delayed;
 114         unsigned char           level;          /* level of the class in hierarchy:
 115                                                    0 for leaf classes, and maximal
 116                                                    level of children + 1 for nodes.
 117                                                  */
 118
 119         psched_time_t           last;           /* Last end of service */
 120         psched_time_t           undertime;
 121         long                    avgidle;
 122         long                    deficit;        /* Saved deficit for WRR */
 123         psched_time_t           penalized;
 124         struct gnet_stats_basic_packed bstats;
 125         struct gnet_stats_queue qstats;
 126         struct net_rate_estimator __rcu *rate_est;
 127         struct tc_cbq_xstats    xstats;
 128
 129         struct tcf_proto __rcu  *filter_list;
 130         struct tcf_block        *block;
 131
 132         int                     filters;
 133
 134         struct cbq_class        *defaults[TC_PRIO_MAX + 1];
 135 };
 136
 137 struct cbq_sched_data {
 138         struct Qdisc_class_hash clhash;                 /* Hash table of all classes */
 139         int                     nclasses[TC_CBQ_MAXPRIO + 1];
 140         unsigned int            quanta[TC_CBQ_MAXPRIO + 1];
 141
 142         struct cbq_class        link;
 143
 144         unsigned int            activemask;
 145         struct cbq_class        *active[TC_CBQ_MAXPRIO + 1];    /* List of all classes
 146                                                                    with backlog */
 147
 148 #ifdef CONFIG_NET_CLS_ACT
 149         struct cbq_class        *rx_class;
 150 #endif
 151         struct cbq_class        *tx_class;
 152         struct cbq_class        *tx_borrowed;
 153         int                     tx_len;
 154         psched_time_t           now;            /* Cached timestamp */
 155         unsigned int            pmask;
 156
 157         struct hrtimer          delay_timer;
 158         struct qdisc_watchdog   watchdog;       /* Watchdog timer,
 159                                                    started when CBQ has
 160                                                    backlog, but cannot
 161                                                    transmit just now */
 162         psched_tdiff_t          wd_expires;
 163         int                     toplevel;
 164         u32                     hgenerator;
 165 };
 166
 167
 168 #define L2T(cl, len)    qdisc_l2t((cl)->R_tab, len)
 169
 170 static inline struct cbq_class *
 171 cbq_class_lookup(struct cbq_sched_data *q, u32 classid)
 172 {
 173         struct Qdisc_class_common *clc;
 174
 175         clc = qdisc_class_find(&q->clhash, classid);
 176         if (clc == NULL)
 177                 return NULL;
 178         return container_of(clc, struct cbq_class, common);
 179 }
 180
 181 #ifdef CONFIG_NET_CLS_ACT
 182
 183 static struct cbq_class *
 184 cbq_reclassify(struct sk_buff *skb, struct cbq_class *this)
 185 {
 186         struct cbq_class *cl;
 187
 188         for (cl = this->tparent; cl; cl = cl->tparent) {
 189                 struct cbq_class *new = cl->defaults[TC_PRIO_BESTEFFORT];
 190
 191                 if (new != NULL && new != this)
 192                         return new;
 193         }
 194         return NULL;
 195 }
 196
 197 #endif
 198
 199 /* Classify packet. The procedure is pretty complicated, but
 200  * it allows us to combine link sharing and priority scheduling
 201  * transparently.
 202  *
 203  * Namely, you can put link sharing rules (f.e. route based) at root of CBQ,
 204  * so that it resolves to split nodes. Then packets are classified
 205  * by logical priority, or a more specific classifier may be attached
 206  * to the split node.
 207  */
 208
 209 static struct cbq_class *
 210 cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 211 {
 212         struct cbq_sched_data *q = qdisc_priv(sch);
 213         struct cbq_class *head = &q->link;
 214         struct cbq_class **defmap;
 215         struct cbq_class *cl = NULL;
 216         u32 prio = skb->priority;
 217         struct tcf_proto *fl;
 218         struct tcf_result res;
 219
 220         /*
 221          *  Step 1. If skb->priority points to one of our classes, use it.
 222          */
 223         if (TC_H_MAJ(prio ^ sch->handle) == 0 &&
 224             (cl = cbq_class_lookup(q, prio)) != NULL)
 225                 return cl;
 226
 227         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 228         for (;;) {
 229                 int result = 0;
 230                 defmap = head->defaults;
 231
 232                 fl = rcu_dereference_bh(head->filter_list);
 233                 /*
 234                  * Step 2+n. Apply classifier.
 235                  */
 236                 result = tcf_classify(skb, fl, &res, true);
 237                 if (!fl || result < 0)
 238                         goto fallback;
 239
 240                 cl = (void *)res.class;
 241                 if (!cl) {
 242                         if (TC_H_MAJ(res.classid))
 243                                 cl = cbq_class_lookup(q, res.classid);
 244                         else if ((cl = defmap[res.classid & TC_PRIO_MAX]) == NULL)
 245                                 cl = defmap[TC_PRIO_BESTEFFORT];
 246
 247                         if (cl == NULL)
 248                                 goto fallback;
 249                 }
 250                 if (cl->level >= head->level)
 251                         goto fallback;
 252 #ifdef CONFIG_NET_CLS_ACT
 253                 switch (result) {
 254                 case TC_ACT_QUEUED:
 255                 case TC_ACT_STOLEN:
 256                 case TC_ACT_TRAP:
 257                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 258                         /* fall through */
 259                 case TC_ACT_SHOT:
 260                         return NULL;
 261                 case TC_ACT_RECLASSIFY:
 262                         return cbq_reclassify(skb, cl);
 263                 }
 264 #endif
 265                 if (cl->level == 0)
 266                         return cl;
 267
 268                 /*
 269                  * Step 3+n. If classifier selected a link sharing class,
 270                  *         apply agency specific classifier.
 271                  *         Repeat this procdure until we hit a leaf node.
 272                  */
 273                 head = cl;
 274         }
 275
 276 fallback:
 277         cl = head;
 278
 279         /*
 280          * Step 4. No success...
 281          */
 282         if (TC_H_MAJ(prio) == 0 &&
 283             !(cl = head->defaults[prio & TC_PRIO_MAX]) &&
 284             !(cl = head->defaults[TC_PRIO_BESTEFFORT]))
 285                 return head;
 286
 287         return cl;
 288 }
 289
 290 /*
 291  * A packet has just been enqueued on the empty class.
 292  * cbq_activate_class adds it to the tail of active class list
 293  * of its priority band.
 294  */
 295
 296 static inline void cbq_activate_class(struct cbq_class *cl)
 297 {
 298         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 299         int prio = cl->cpriority;
 300         struct cbq_class *cl_tail;
 301
 302         cl_tail = q->active[prio];
 303         q->active[prio] = cl;
 304
 305         if (cl_tail != NULL) {
 306                 cl->next_alive = cl_tail->next_alive;
 307                 cl_tail->next_alive = cl;
 308         } else {
 309                 cl->next_alive = cl;
 310                 q->activemask |= (1<<prio);
 311         }
 312 }
 313
 314 /*
 315  * Unlink class from active chain.
 316  * Note that this same procedure is done directly in cbq_dequeue*
 317  * during round-robin procedure.
 318  */
 319
 320 static void cbq_deactivate_class(struct cbq_class *this)
 321 {
 322         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
 323         int prio = this->cpriority;
 324         struct cbq_class *cl;
 325         struct cbq_class *cl_prev = q->active[prio];
 326
 327         do {
 328                 cl = cl_prev->next_alive;
 329                 if (cl == this) {
 330                         cl_prev->next_alive = cl->next_alive;
 331                         cl->next_alive = NULL;
 332
 333                         if (cl == q->active[prio]) {
 334                                 q->active[prio] = cl_prev;
 335                                 if (cl == q->active[prio]) {
 336                                         q->active[prio] = NULL;
 337                                         q->activemask &= ~(1<<prio);
 338                                         return;
 339                                 }
 340                         }
 341                         return;
 342                 }
 343         } while ((cl_prev = cl) != q->active[prio]);
 344 }
 345
 346 static void
 347 cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl)
 348 {
 349         int toplevel = q->toplevel;
 350
 351         if (toplevel > cl->level) {
 352                 psched_time_t now = psched_get_time();
 353
 354                 do {
 355                         if (cl->undertime < now) {
 356                                 q->toplevel = cl->level;
 357                                 return;
 358                         }
 359                 } while ((cl = cl->borrow) != NULL && toplevel > cl->level);
 360         }
 361 }
 362
 363 static int
 364 cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 365             struct sk_buff **to_free)
 366 {
 367         struct cbq_sched_data *q = qdisc_priv(sch);
 368         int uninitialized_var(ret);
 369         struct cbq_class *cl = cbq_classify(skb, sch, &ret);
 370
 371 #ifdef CONFIG_NET_CLS_ACT
 372         q->rx_class = cl;
 373 #endif
 374         if (cl == NULL) {
 375                 if (ret & __NET_XMIT_BYPASS)
 376                         qdisc_qstats_drop(sch);
 377                 __qdisc_drop(skb, to_free);
 378                 return ret;
 379         }
 380
 381         ret = qdisc_enqueue(skb, cl->q, to_free);
 382         if (ret == NET_XMIT_SUCCESS) {
 383                 sch->q.qlen++;
 384                 cbq_mark_toplevel(q, cl);
 385                 if (!cl->next_alive)
 386                         cbq_activate_class(cl);
 387                 return ret;
 388         }
 389
 390         if (net_xmit_drop_count(ret)) {
 391                 qdisc_qstats_drop(sch);
 392                 cbq_mark_toplevel(q, cl);
 393                 cl->qstats.drops++;
 394         }
 395         return ret;
 396 }
 397
 398 /* Overlimit action: penalize leaf class by adding offtime */
 399 static void cbq_overlimit(struct cbq_class *cl)
 400 {
 401         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 402         psched_tdiff_t delay = cl->undertime - q->now;
 403
 404         if (!cl->delayed) {
 405                 delay += cl->offtime;
 406
 407                 /*
 408                  * Class goes to sleep, so that it will have no
 409                  * chance to work avgidle. Let's forgive it 8)
 410                  *
 411                  * BTW cbq-2.0 has a crap in this
 412                  * place, apparently they forgot to shift it by cl->ewma_log.
 413                  */
 414                 if (cl->avgidle < 0)
 415                         delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
 416                 if (cl->avgidle < cl->minidle)
 417                         cl->avgidle = cl->minidle;
 418                 if (delay <= 0)
 419                         delay = 1;
 420                 cl->undertime = q->now + delay;
 421
 422                 cl->xstats.overactions++;
 423                 cl->delayed = 1;
 424         }
 425         if (q->wd_expires == 0 || q->wd_expires > delay)
 426                 q->wd_expires = delay;
 427
 428         /* Dirty work! We must schedule wakeups based on
 429          * real available rate, rather than leaf rate,
 430          * which may be tiny (even zero).
 431          */
 432         if (q->toplevel == TC_CBQ_MAXLEVEL) {
 433                 struct cbq_class *b;
 434                 psched_tdiff_t base_delay = q->wd_expires;
 435
 436                 for (b = cl->borrow; b; b = b->borrow) {
 437                         delay = b->undertime - q->now;
 438                         if (delay < base_delay) {
 439                                 if (delay <= 0)
 440                                         delay = 1;
 441                                 base_delay = delay;
 442                         }
 443                 }
 444
 445                 q->wd_expires = base_delay;
 446         }
 447 }
 448
 449 static psched_tdiff_t cbq_undelay_prio(struct cbq_sched_data *q, int prio,
 450                                        psched_time_t now)
 451 {
 452         struct cbq_class *cl;
 453         struct cbq_class *cl_prev = q->active[prio];
 454         psched_time_t sched = now;
 455
 456         if (cl_prev == NULL)
 457                 return 0;
 458
 459         do {
 460                 cl = cl_prev->next_alive;
 461                 if (now - cl->penalized > 0) {
 462                         cl_prev->next_alive = cl->next_alive;
 463                         cl->next_alive = NULL;
 464                         cl->cpriority = cl->priority;
 465                         cl->delayed = 0;
 466                         cbq_activate_class(cl);
 467
 468                         if (cl == q->active[prio]) {
 469                                 q->active[prio] = cl_prev;
 470                                 if (cl == q->active[prio]) {
 471                                         q->active[prio] = NULL;
 472                                         return 0;
 473                                 }
 474                         }
 475
 476                         cl = cl_prev->next_alive;
 477                 } else if (sched - cl->penalized > 0)
 478                         sched = cl->penalized;
 479         } while ((cl_prev = cl) != q->active[prio]);
 480
 481         return sched - now;
 482 }
 483
 484 static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
 485 {
 486         struct cbq_sched_data *q = container_of(timer, struct cbq_sched_data,
 487                                                 delay_timer);
 488         struct Qdisc *sch = q->watchdog.qdisc;
 489         psched_time_t now;
 490         psched_tdiff_t delay = 0;
 491         unsigned int pmask;
 492
 493         now = psched_get_time();
 494
 495         pmask = q->pmask;
 496         q->pmask = 0;
 497
 498         while (pmask) {
 499                 int prio = ffz(~pmask);
 500                 psched_tdiff_t tmp;
 501
 502                 pmask &= ~(1<<prio);
 503
 504                 tmp = cbq_undelay_prio(q, prio, now);
 505                 if (tmp > 0) {
 506                         q->pmask |= 1<<prio;
 507                         if (tmp < delay || delay == 0)
 508                                 delay = tmp;
 509                 }
 510         }
 511
 512         if (delay) {
 513                 ktime_t time;
 514
 515                 time = 0;
 516                 time = ktime_add_ns(time, PSCHED_TICKS2NS(now + delay));
 517                 hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS_PINNED);
 518         }
 519
 520         __netif_schedule(qdisc_root(sch));
 521         return HRTIMER_NORESTART;
 522 }
 523
 524 /*
 525  * It is mission critical procedure.
 526  *
 527  * We "regenerate" toplevel cutoff, if transmitting class
 528  * has backlog and it is not regulated. It is not part of
 529  * original CBQ description, but looks more reasonable.
 530  * Probably, it is wrong. This question needs further investigation.
 531  */
 532
 533 static inline void
 534 cbq_update_toplevel(struct cbq_sched_data *q, struct cbq_class *cl,
 535                     struct cbq_class *borrowed)
 536 {
 537         if (cl && q->toplevel >= borrowed->level) {
 538                 if (cl->q->q.qlen > 1) {
 539                         do {
 540                                 if (borrowed->undertime == PSCHED_PASTPERFECT) {
 541                                         q->toplevel = borrowed->level;
 542                                         return;
 543                                 }
 544                         } while ((borrowed = borrowed->borrow) != NULL);
 545                 }
 546 #if 0
 547         /* It is not necessary now. Uncommenting it
 548            will save CPU cycles, but decrease fairness.
 549          */
 550                 q->toplevel = TC_CBQ_MAXLEVEL;
 551 #endif
 552         }
 553 }
 554
 555 static void
 556 cbq_update(struct cbq_sched_data *q)
 557 {
 558         struct cbq_class *this = q->tx_class;
 559         struct cbq_class *cl = this;
 560         int len = q->tx_len;
 561         psched_time_t now;
 562
 563         q->tx_class = NULL;
 564         /* Time integrator. We calculate EOS time
 565          * by adding expected packet transmission time.
 566          */
 567         now = q->now + L2T(&q->link, len);
 568
 569         for ( ; cl; cl = cl->share) {
 570                 long avgidle = cl->avgidle;
 571                 long idle;
 572
 573                 cl->bstats.packets++;
 574                 cl->bstats.bytes += len;
 575
 576                 /*
 577                  * (now - last) is total time between packet right edges.
 578                  * (last_pktlen/rate) is "virtual" busy time, so that
 579                  *
 580                  *      idle = (now - last) - last_pktlen/rate
 581                  */
 582
 583                 idle = now - cl->last;
 584                 if ((unsigned long)idle > 128*1024*1024) {
 585                         avgidle = cl->maxidle;
 586                 } else {
 587                         idle -= L2T(cl, len);
 588
 589                 /* true_avgidle := (1-W)*true_avgidle + W*idle,
 590                  * where W=2^{-ewma_log}. But cl->avgidle is scaled:
 591                  * cl->avgidle == true_avgidle/W,
 592                  * hence:
 593                  */
 594                         avgidle += idle - (avgidle>>cl->ewma_log);
 595                 }
 596
 597                 if (avgidle <= 0) {
 598                         /* Overlimit or at-limit */
 599
 600                         if (avgidle < cl->minidle)
 601                                 avgidle = cl->minidle;
 602
 603                         cl->avgidle = avgidle;
 604
 605                         /* Calculate expected time, when this class
 606                          * will be allowed to send.
 607                          * It will occur, when:
 608                          * (1-W)*true_avgidle + W*delay = 0, i.e.
 609                          * idle = (1/W - 1)*(-true_avgidle)
 610                          * or
 611                          * idle = (1 - W)*(-cl->avgidle);
 612                          */
 613                         idle = (-avgidle) - ((-avgidle) >> cl->ewma_log);
 614
 615                         /*
 616                          * That is not all.
 617                          * To maintain the rate allocated to the class,
 618                          * we add to undertime virtual clock,
 619                          * necessary to complete transmitted packet.
 620                          * (len/phys_bandwidth has been already passed
 621                          * to the moment of cbq_update)
 622                          */
 623
 624                         idle -= L2T(&q->link, len);
 625                         idle += L2T(cl, len);
 626
 627                         cl->undertime = now + idle;
 628                 } else {
 629                         /* Underlimit */
 630
 631                         cl->undertime = PSCHED_PASTPERFECT;
 632                         if (avgidle > cl->maxidle)
 633                                 cl->avgidle = cl->maxidle;
 634                         else
 635                                 cl->avgidle = avgidle;
 636                 }
 637                 if ((s64)(now - cl->last) > 0)
 638                         cl->last = now;
 639         }
 640
 641         cbq_update_toplevel(q, this, q->tx_borrowed);
 642 }
 643
 644 static inline struct cbq_class *
 645 cbq_under_limit(struct cbq_class *cl)
 646 {
 647         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 648         struct cbq_class *this_cl = cl;
 649
 650         if (cl->tparent == NULL)
 651                 return cl;
 652
 653         if (cl->undertime == PSCHED_PASTPERFECT || q->now >= cl->undertime) {
 654                 cl->delayed = 0;
 655                 return cl;
 656         }
 657
 658         do {
 659                 /* It is very suspicious place. Now overlimit
 660                  * action is generated for not bounded classes
 661                  * only if link is completely congested.
 662                  * Though it is in agree with ancestor-only paradigm,
 663                  * it looks very stupid. Particularly,
 664                  * it means that this chunk of code will either
 665                  * never be called or result in strong amplification
 666                  * of burstiness. Dangerous, silly, and, however,
 667                  * no another solution exists.
 668                  */
 669                 cl = cl->borrow;
 670                 if (!cl) {
 671                         this_cl->qstats.overlimits++;
 672                         cbq_overlimit(this_cl);
 673                         return NULL;
 674                 }
 675                 if (cl->level > q->toplevel)
 676                         return NULL;
 677         } while (cl->undertime != PSCHED_PASTPERFECT && q->now < cl->undertime);
 678
 679         cl->delayed = 0;
 680         return cl;
 681 }
 682
 683 static inline struct sk_buff *
 684 cbq_dequeue_prio(struct Qdisc *sch, int prio)
 685 {
 686         struct cbq_sched_data *q = qdisc_priv(sch);
 687         struct cbq_class *cl_tail, *cl_prev, *cl;
 688         struct sk_buff *skb;
 689         int deficit;
 690
 691         cl_tail = cl_prev = q->active[prio];
 692         cl = cl_prev->next_alive;
 693
 694         do {
 695                 deficit = 0;
 696
 697                 /* Start round */
 698                 do {
 699                         struct cbq_class *borrow = cl;
 700
 701                         if (cl->q->q.qlen &&
 702                             (borrow = cbq_under_limit(cl)) == NULL)
 703                                 goto skip_class;
 704
 705                         if (cl->deficit <= 0) {
 706                                 /* Class exhausted its allotment per
 707                                  * this round. Switch to the next one.
 708                                  */
 709                                 deficit = 1;
 710                                 cl->deficit += cl->quantum;
 711                                 goto next_class;
 712                         }
 713
 714                         skb = cl->q->dequeue(cl->q);
 715
 716                         /* Class did not give us any skb :-(
 717                          * It could occur even if cl->q->q.qlen != 0
 718                          * f.e. if cl->q == "tbf"
 719                          */
 720                         if (skb == NULL)
 721                                 goto skip_class;
 722
 723                         cl->deficit -= qdisc_pkt_len(skb);
 724                         q->tx_class = cl;
 725                         q->tx_borrowed = borrow;
 726                         if (borrow != cl) {
 727 #ifndef CBQ_XSTATS_BORROWS_BYTES
 728                                 borrow->xstats.borrows++;
 729                                 cl->xstats.borrows++;
 730 #else
 731                                 borrow->xstats.borrows += qdisc_pkt_len(skb);
 732                                 cl->xstats.borrows += qdisc_pkt_len(skb);
 733 #endif
 734                         }
 735                         q->tx_len = qdisc_pkt_len(skb);
 736
 737                         if (cl->deficit <= 0) {
 738                                 q->active[prio] = cl;
 739                                 cl = cl->next_alive;
 740                                 cl->deficit += cl->quantum;
 741                         }
 742                         return skb;
 743
 744 skip_class:
 745                         if (cl->q->q.qlen == 0 || prio != cl->cpriority) {
 746                                 /* Class is empty or penalized.
 747                                  * Unlink it from active chain.
 748                                  */
 749                                 cl_prev->next_alive = cl->next_alive;
 750                                 cl->next_alive = NULL;
 751
 752                                 /* Did cl_tail point to it? */
 753                                 if (cl == cl_tail) {
 754                                         /* Repair it! */
 755                                         cl_tail = cl_prev;
 756
 757                                         /* Was it the last class in this band? */
 758                                         if (cl == cl_tail) {
 759                                                 /* Kill the band! */
 760                                                 q->active[prio] = NULL;
 761                                                 q->activemask &= ~(1<<prio);
 762                                                 if (cl->q->q.qlen)
 763                                                         cbq_activate_class(cl);
 764                                                 return NULL;
 765                                         }
 766
 767                                         q->active[prio] = cl_tail;
 768                                 }
 769                                 if (cl->q->q.qlen)
 770                                         cbq_activate_class(cl);
 771
 772                                 cl = cl_prev;
 773                         }
 774
 775 next_class:
 776                         cl_prev = cl;
 777                         cl = cl->next_alive;
 778                 } while (cl_prev != cl_tail);
 779         } while (deficit);
 780
 781         q->active[prio] = cl_prev;
 782
 783         return NULL;
 784 }
 785
 786 static inline struct sk_buff *
 787 cbq_dequeue_1(struct Qdisc *sch)
 788 {
 789         struct cbq_sched_data *q = qdisc_priv(sch);
 790         struct sk_buff *skb;
 791         unsigned int activemask;
 792
 793         activemask = q->activemask & 0xFF;
 794         while (activemask) {
 795                 int prio = ffz(~activemask);
 796                 activemask &= ~(1<<prio);
 797                 skb = cbq_dequeue_prio(sch, prio);
 798                 if (skb)
 799                         return skb;
 800         }
 801         return NULL;
 802 }
 803
 804 static struct sk_buff *
 805 cbq_dequeue(struct Qdisc *sch)
 806 {
 807         struct sk_buff *skb;
 808         struct cbq_sched_data *q = qdisc_priv(sch);
 809         psched_time_t now;
 810
 811         now = psched_get_time();
 812
 813         if (q->tx_class)
 814                 cbq_update(q);
 815
 816         q->now = now;
 817
 818         for (;;) {
 819                 q->wd_expires = 0;
 820
 821                 skb = cbq_dequeue_1(sch);
 822                 if (skb) {
 823                         qdisc_bstats_update(sch, skb);
 824                         sch->q.qlen--;
 825                         return skb;
 826                 }
 827
 828                 /* All the classes are overlimit.
 829                  *
 830                  * It is possible, if:
 831                  *
 832                  * 1. Scheduler is empty.
 833                  * 2. Toplevel cutoff inhibited borrowing.
 834                  * 3. Root class is overlimit.
 835                  *
 836                  * Reset 2d and 3d conditions and retry.
 837                  *
 838                  * Note, that NS and cbq-2.0 are buggy, peeking
 839                  * an arbitrary class is appropriate for ancestor-only
 840                  * sharing, but not for toplevel algorithm.
 841                  *
 842                  * Our version is better, but slower, because it requires
 843                  * two passes, but it is unavoidable with top-level sharing.
 844                  */
 845
 846                 if (q->toplevel == TC_CBQ_MAXLEVEL &&
 847                     q->link.undertime == PSCHED_PASTPERFECT)
 848                         break;
 849
 850                 q->toplevel = TC_CBQ_MAXLEVEL;
 851                 q->link.undertime = PSCHED_PASTPERFECT;
 852         }
 853
 854         /* No packets in scheduler or nobody wants to give them to us :-(
 855          * Sigh... start watchdog timer in the last case.
 856          */
 857
 858         if (sch->q.qlen) {
 859                 qdisc_qstats_overlimit(sch);
 860                 if (q->wd_expires)
 861                         qdisc_watchdog_schedule(&q->watchdog,
 862                                                 now + q->wd_expires);
 863         }
 864         return NULL;
 865 }
 866
 867 /* CBQ class maintanance routines */
 868
 869 static void cbq_adjust_levels(struct cbq_class *this)
 870 {
 871         if (this == NULL)
 872                 return;
 873
 874         do {
 875                 int level = 0;
 876                 struct cbq_class *cl;
 877
 878                 cl = this->children;
 879                 if (cl) {
 880                         do {
 881                                 if (cl->level > level)
 882                                         level = cl->level;
 883                         } while ((cl = cl->sibling) != this->children);
 884                 }
 885                 this->level = level + 1;
 886         } while ((this = this->tparent) != NULL);
 887 }
 888
 889 static void cbq_normalize_quanta(struct cbq_sched_data *q, int prio)
 890 {
 891         struct cbq_class *cl;
 892         unsigned int h;
 893
 894         if (q->quanta[prio] == 0)
 895                 return;
 896
 897         for (h = 0; h < q->clhash.hashsize; h++) {
 898                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
 899                         /* BUGGGG... Beware! This expression suffer of
 900                          * arithmetic overflows!
 901                          */
 902                         if (cl->priority == prio) {
 903                                 cl->quantum = (cl->weight*cl->allot*q->nclasses[prio])/
 904                                         q->quanta[prio];
 905                         }
 906                         if (cl->quantum <= 0 ||
 907                             cl->quantum > 32*qdisc_dev(cl->qdisc)->mtu) {
 908                                 pr_warn("CBQ: class %08x has bad quantum==%ld, repaired.\n",
 909                                         cl->common.classid, cl->quantum);
 910                                 cl->quantum = qdisc_dev(cl->qdisc)->mtu/2 + 1;
 911                         }
 912                 }
 913         }
 914 }
 915
 916 static void cbq_sync_defmap(struct cbq_class *cl)
 917 {
 918         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 919         struct cbq_class *split = cl->split;
 920         unsigned int h;
 921         int i;
 922
 923         if (split == NULL)
 924                 return;
 925
 926         for (i = 0; i <= TC_PRIO_MAX; i++) {
 927                 if (split->defaults[i] == cl && !(cl->defmap & (1<<i)))
 928                         split->defaults[i] = NULL;
 929         }
 930
 931         for (i = 0; i <= TC_PRIO_MAX; i++) {
 932                 int level = split->level;
 933
 934                 if (split->defaults[i])
 935                         continue;
 936
 937                 for (h = 0; h < q->clhash.hashsize; h++) {
 938                         struct cbq_class *c;
 939
 940                         hlist_for_each_entry(c, &q->clhash.hash[h],
 941                                              common.hnode) {
 942                                 if (c->split == split && c->level < level &&
 943                                     c->defmap & (1<<i)) {
 944                                         split->defaults[i] = c;
 945                                         level = c->level;
 946                                 }
 947                         }
 948                 }
 949         }
 950 }
 951
 952 static void cbq_change_defmap(struct cbq_class *cl, u32 splitid, u32 def, u32 mask)
 953 {
 954         struct cbq_class *split = NULL;
 955
 956         if (splitid == 0) {
 957                 split = cl->split;
 958                 if (!split)
 959                         return;
 960                 splitid = split->common.classid;
 961         }
 962
 963         if (split == NULL || split->common.classid != splitid) {
 964                 for (split = cl->tparent; split; split = split->tparent)
 965                         if (split->common.classid == splitid)
 966                                 break;
 967         }
 968
 969         if (split == NULL)
 970                 return;
 971
 972         if (cl->split != split) {
 973                 cl->defmap = 0;
 974                 cbq_sync_defmap(cl);
 975                 cl->split = split;
 976                 cl->defmap = def & mask;
 977         } else
 978                 cl->defmap = (cl->defmap & ~mask) | (def & mask);
 979
 980         cbq_sync_defmap(cl);
 981 }
 982
 983 static void cbq_unlink_class(struct cbq_class *this)
 984 {
 985         struct cbq_class *cl, **clp;
 986         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
 987
 988         qdisc_class_hash_remove(&q->clhash, &this->common);
 989
 990         if (this->tparent) {
 991                 clp = &this->sibling;
 992                 cl = *clp;
 993                 do {
 994                         if (cl == this) {
 995                                 *clp = cl->sibling;
 996                                 break;
 997                         }
 998                         clp = &cl->sibling;
 999                 } while ((cl = *clp) != this->sibling);
1000
1001                 if (this->tparent->children == this) {
1002                         this->tparent->children = this->sibling;
1003                         if (this->sibling == this)
1004                                 this->tparent->children = NULL;
1005                 }
1006         } else {
1007                 WARN_ON(this->sibling != this);
1008         }
1009 }
1010
1011 static void cbq_link_class(struct cbq_class *this)
1012 {
1013         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
1014         struct cbq_class *parent = this->tparent;
1015
1016         this->sibling = this;
1017         qdisc_class_hash_insert(&q->clhash, &this->common);
1018
1019         if (parent == NULL)
1020                 return;
1021
1022         if (parent->children == NULL) {
1023                 parent->children = this;
1024         } else {
1025                 this->sibling = parent->children->sibling;
1026                 parent->children->sibling = this;
1027         }
1028 }
1029
1030 static void
1031 cbq_reset(struct Qdisc *sch)
1032 {
1033         struct cbq_sched_data *q = qdisc_priv(sch);
1034         struct cbq_class *cl;
1035         int prio;
1036         unsigned int h;
1037
1038         q->activemask = 0;
1039         q->pmask = 0;
1040         q->tx_class = NULL;
1041         q->tx_borrowed = NULL;
1042         qdisc_watchdog_cancel(&q->watchdog);
1043         hrtimer_cancel(&q->delay_timer);
1044         q->toplevel = TC_CBQ_MAXLEVEL;
1045         q->now = psched_get_time();
1046
1047         for (prio = 0; prio <= TC_CBQ_MAXPRIO; prio++)
1048                 q->active[prio] = NULL;
1049
1050         for (h = 0; h < q->clhash.hashsize; h++) {
1051                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1052                         qdisc_reset(cl->q);
1053
1054                         cl->next_alive = NULL;
1055                         cl->undertime = PSCHED_PASTPERFECT;
1056                         cl->avgidle = cl->maxidle;
1057                         cl->deficit = cl->quantum;
1058                         cl->cpriority = cl->priority;
1059                 }
1060         }
1061         sch->q.qlen = 0;
1062 }
1063
1064
1065 static int cbq_set_lss(struct cbq_class *cl, struct tc_cbq_lssopt *lss)
1066 {
1067         if (lss->change & TCF_CBQ_LSS_FLAGS) {
1068                 cl->share = (lss->flags & TCF_CBQ_LSS_ISOLATED) ? NULL : cl->tparent;
1069                 cl->borrow = (lss->flags & TCF_CBQ_LSS_BOUNDED) ? NULL : cl->tparent;
1070         }
1071         if (lss->change & TCF_CBQ_LSS_EWMA)
1072                 cl->ewma_log = lss->ewma_log;
1073         if (lss->change & TCF_CBQ_LSS_AVPKT)
1074                 cl->avpkt = lss->avpkt;
1075         if (lss->change & TCF_CBQ_LSS_MINIDLE)
1076                 cl->minidle = -(long)lss->minidle;
1077         if (lss->change & TCF_CBQ_LSS_MAXIDLE) {
1078                 cl->maxidle = lss->maxidle;
1079                 cl->avgidle = lss->maxidle;
1080         }
1081         if (lss->change & TCF_CBQ_LSS_OFFTIME)
1082                 cl->offtime = lss->offtime;
1083         return 0;
1084 }
1085
1086 static void cbq_rmprio(struct cbq_sched_data *q, struct cbq_class *cl)
1087 {
1088         q->nclasses[cl->priority]--;
1089         q->quanta[cl->priority] -= cl->weight;
1090         cbq_normalize_quanta(q, cl->priority);
1091 }
1092
1093 static void cbq_addprio(struct cbq_sched_data *q, struct cbq_class *cl)
1094 {
1095         q->nclasses[cl->priority]++;
1096         q->quanta[cl->priority] += cl->weight;
1097         cbq_normalize_quanta(q, cl->priority);
1098 }
1099
1100 static int cbq_set_wrr(struct cbq_class *cl, struct tc_cbq_wrropt *wrr)
1101 {
1102         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
1103
1104         if (wrr->allot)
1105                 cl->allot = wrr->allot;
1106         if (wrr->weight)
1107                 cl->weight = wrr->weight;
1108         if (wrr->priority) {
1109                 cl->priority = wrr->priority - 1;
1110                 cl->cpriority = cl->priority;
1111                 if (cl->priority >= cl->priority2)
1112                         cl->priority2 = TC_CBQ_MAXPRIO - 1;
1113         }
1114
1115         cbq_addprio(q, cl);
1116         return 0;
1117 }
1118
1119 static int cbq_set_fopt(struct cbq_class *cl, struct tc_cbq_fopt *fopt)
1120 {
1121         cbq_change_defmap(cl, fopt->split, fopt->defmap, fopt->defchange);
1122         return 0;
1123 }
1124
1125 static const struct nla_policy cbq_policy[TCA_CBQ_MAX + 1] = {
1126         [TCA_CBQ_LSSOPT]        = { .len = sizeof(struct tc_cbq_lssopt) },
1127         [TCA_CBQ_WRROPT]        = { .len = sizeof(struct tc_cbq_wrropt) },
1128         [TCA_CBQ_FOPT]          = { .len = sizeof(struct tc_cbq_fopt) },
1129         [TCA_CBQ_OVL_STRATEGY]  = { .len = sizeof(struct tc_cbq_ovl) },
1130         [TCA_CBQ_RATE]          = { .len = sizeof(struct tc_ratespec) },
1131         [TCA_CBQ_RTAB]          = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
1132         [TCA_CBQ_POLICE]        = { .len = sizeof(struct tc_cbq_police) },
1133 };
1134
1135 static int cbq_init(struct Qdisc *sch, struct nlattr *opt,
1136                     struct netlink_ext_ack *extack)
1137 {
1138         struct cbq_sched_data *q = qdisc_priv(sch);
1139         struct nlattr *tb[TCA_CBQ_MAX + 1];
1140         struct tc_ratespec *r;
1141         int err;
1142
1143         qdisc_watchdog_init(&q->watchdog, sch);
1144         hrtimer_init(&q->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1145         q->delay_timer.function = cbq_undelay;
1146
1147         if (!opt) {
1148                 NL_SET_ERR_MSG(extack, "CBQ options are required for this operation");
1149                 return -EINVAL;
1150         }
1151
1152         err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy, extack);
1153         if (err < 0)
1154                 return err;
1155
1156         if (!tb[TCA_CBQ_RTAB] || !tb[TCA_CBQ_RATE]) {
1157                 NL_SET_ERR_MSG(extack, "Rate specification missing or incomplete");
1158                 return -EINVAL;
1159         }
1160
1161         r = nla_data(tb[TCA_CBQ_RATE]);
1162
1163         q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB], extack);
1164         if (!q->link.R_tab)
1165                 return -EINVAL;
1166
1167         err = tcf_block_get(&q->link.block, &q->link.filter_list, sch, extack);
1168         if (err)
1169                 goto put_rtab;
1170
1171         err = qdisc_class_hash_init(&q->clhash);
1172         if (err < 0)
1173                 goto put_block;
1174
1175         q->link.sibling = &q->link;
1176         q->link.common.classid = sch->handle;
1177         q->link.qdisc = sch;
1178         q->link.q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1179                                       sch->handle, NULL);
1180         if (!q->link.q)
1181                 q->link.q = &noop_qdisc;
1182         else
1183                 qdisc_hash_add(q->link.q, true);
1184
1185         q->link.priority = TC_CBQ_MAXPRIO - 1;
1186         q->link.priority2 = TC_CBQ_MAXPRIO - 1;
1187         q->link.cpriority = TC_CBQ_MAXPRIO - 1;
1188         q->link.allot = psched_mtu(qdisc_dev(sch));
1189         q->link.quantum = q->link.allot;
1190         q->link.weight = q->link.R_tab->rate.rate;
1191
1192         q->link.ewma_log = TC_CBQ_DEF_EWMA;
1193         q->link.avpkt = q->link.allot/2;
1194         q->link.minidle = -0x7FFFFFFF;
1195
1196         q->toplevel = TC_CBQ_MAXLEVEL;
1197         q->now = psched_get_time();
1198
1199         cbq_link_class(&q->link);
1200
1201         if (tb[TCA_CBQ_LSSOPT])
1202                 cbq_set_lss(&q->link, nla_data(tb[TCA_CBQ_LSSOPT]));
1203
1204         cbq_addprio(q, &q->link);
1205         return 0;
1206
1207 put_block:
1208         tcf_block_put(q->link.block);
1209
1210 put_rtab:
1211         qdisc_put_rtab(q->link.R_tab);
1212         return err;
1213 }
1214
1215 static int cbq_dump_rate(struct sk_buff *skb, struct cbq_class *cl)
1216 {
1217         unsigned char *b = skb_tail_pointer(skb);
1218
1219         if (nla_put(skb, TCA_CBQ_RATE, sizeof(cl->R_tab->rate), &cl->R_tab->rate))
1220                 goto nla_put_failure;
1221         return skb->len;
1222
1223 nla_put_failure:
1224         nlmsg_trim(skb, b);
1225         return -1;
1226 }
1227
1228 static int cbq_dump_lss(struct sk_buff *skb, struct cbq_class *cl)
1229 {
1230         unsigned char *b = skb_tail_pointer(skb);
1231         struct tc_cbq_lssopt opt;
1232
1233         opt.flags = 0;
1234         if (cl->borrow == NULL)
1235                 opt.flags |= TCF_CBQ_LSS_BOUNDED;
1236         if (cl->share == NULL)
1237                 opt.flags |= TCF_CBQ_LSS_ISOLATED;
1238         opt.ewma_log = cl->ewma_log;
1239         opt.level = cl->level;
1240         opt.avpkt = cl->avpkt;
1241         opt.maxidle = cl->maxidle;
1242         opt.minidle = (u32)(-cl->minidle);
1243         opt.offtime = cl->offtime;
1244         opt.change = ~0;
1245         if (nla_put(skb, TCA_CBQ_LSSOPT, sizeof(opt), &opt))
1246                 goto nla_put_failure;
1247         return skb->len;
1248
1249 nla_put_failure:
1250         nlmsg_trim(skb, b);
1251         return -1;
1252 }
1253
1254 static int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
1255 {
1256         unsigned char *b = skb_tail_pointer(skb);
1257         struct tc_cbq_wrropt opt;
1258
1259         memset(&opt, 0, sizeof(opt));
1260         opt.flags = 0;
1261         opt.allot = cl->allot;
1262         opt.priority = cl->priority + 1;
1263         opt.cpriority = cl->cpriority + 1;
1264         opt.weight = cl->weight;
1265         if (nla_put(skb, TCA_CBQ_WRROPT, sizeof(opt), &opt))
1266                 goto nla_put_failure;
1267         return skb->len;
1268
1269 nla_put_failure:
1270         nlmsg_trim(skb, b);
1271         return -1;
1272 }
1273
1274 static int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
1275 {
1276         unsigned char *b = skb_tail_pointer(skb);
1277         struct tc_cbq_fopt opt;
1278
1279         if (cl->split || cl->defmap) {
1280                 opt.split = cl->split ? cl->split->common.classid : 0;
1281                 opt.defmap = cl->defmap;
1282                 opt.defchange = ~0;
1283                 if (nla_put(skb, TCA_CBQ_FOPT, sizeof(opt), &opt))
1284                         goto nla_put_failure;
1285         }
1286         return skb->len;
1287
1288 nla_put_failure:
1289         nlmsg_trim(skb, b);
1290         return -1;
1291 }
1292
1293 static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
1294 {
1295         if (cbq_dump_lss(skb, cl) < 0 ||
1296             cbq_dump_rate(skb, cl) < 0 ||
1297             cbq_dump_wrr(skb, cl) < 0 ||
1298             cbq_dump_fopt(skb, cl) < 0)
1299                 return -1;
1300         return 0;
1301 }
1302
1303 static int cbq_dump(struct Qdisc *sch, struct sk_buff *skb)
1304 {
1305         struct cbq_sched_data *q = qdisc_priv(sch);
1306         struct nlattr *nest;
1307
1308         nest = nla_nest_start(skb, TCA_OPTIONS);
1309         if (nest == NULL)
1310                 goto nla_put_failure;
1311         if (cbq_dump_attr(skb, &q->link) < 0)
1312                 goto nla_put_failure;
1313         return nla_nest_end(skb, nest);
1314
1315 nla_put_failure:
1316         nla_nest_cancel(skb, nest);
1317         return -1;
1318 }
1319
1320 static int
1321 cbq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
1322 {
1323         struct cbq_sched_data *q = qdisc_priv(sch);
1324
1325         q->link.xstats.avgidle = q->link.avgidle;
1326         return gnet_stats_copy_app(d, &q->link.xstats, sizeof(q->link.xstats));
1327 }
1328
1329 static int
1330 cbq_dump_class(struct Qdisc *sch, unsigned long arg,
1331                struct sk_buff *skb, struct tcmsg *tcm)
1332 {
1333         struct cbq_class *cl = (struct cbq_class *)arg;
1334         struct nlattr *nest;
1335
1336         if (cl->tparent)
1337                 tcm->tcm_parent = cl->tparent->common.classid;
1338         else
1339                 tcm->tcm_parent = TC_H_ROOT;
1340         tcm->tcm_handle = cl->common.classid;
1341         tcm->tcm_info = cl->q->handle;
1342
1343         nest = nla_nest_start(skb, TCA_OPTIONS);
1344         if (nest == NULL)
1345                 goto nla_put_failure;
1346         if (cbq_dump_attr(skb, cl) < 0)
1347                 goto nla_put_failure;
1348         return nla_nest_end(skb, nest);
1349
1350 nla_put_failure:
1351         nla_nest_cancel(skb, nest);
1352         return -1;
1353 }
1354
1355 static int
1356 cbq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
1357         struct gnet_dump *d)
1358 {
1359         struct cbq_sched_data *q = qdisc_priv(sch);
1360         struct cbq_class *cl = (struct cbq_class *)arg;
1361         __u32 qlen;
1362
1363         cl->xstats.avgidle = cl->avgidle;
1364         cl->xstats.undertime = 0;
1365         qdisc_qstats_qlen_backlog(cl->q, &qlen, &cl->qstats.backlog);
1366
1367         if (cl->undertime != PSCHED_PASTPERFECT)
1368                 cl->xstats.undertime = cl->undertime - q->now;
1369
1370         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
1371                                   d, NULL, &cl->bstats) < 0 ||
1372             gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1373             gnet_stats_copy_queue(d, NULL, &cl->qstats, qlen) < 0)
1374                 return -1;
1375
1376         return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1377 }
1378
1379 static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1380                      struct Qdisc **old, struct netlink_ext_ack *extack)
1381 {
1382         struct cbq_class *cl = (struct cbq_class *)arg;
1383
1384         if (new == NULL) {
1385                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1386                                         cl->common.classid, extack);
1387                 if (new == NULL)
1388                         return -ENOBUFS;
1389         }
1390
1391         *old = qdisc_replace(sch, new, &cl->q);
1392         return 0;
1393 }
1394
1395 static struct Qdisc *cbq_leaf(struct Qdisc *sch, unsigned long arg)
1396 {
1397         struct cbq_class *cl = (struct cbq_class *)arg;
1398
1399         return cl->q;
1400 }
1401
1402 static void cbq_qlen_notify(struct Qdisc *sch, unsigned long arg)
1403 {
1404         struct cbq_class *cl = (struct cbq_class *)arg;
1405
1406         cbq_deactivate_class(cl);
1407 }
1408
1409 static unsigned long cbq_find(struct Qdisc *sch, u32 classid)
1410 {
1411         struct cbq_sched_data *q = qdisc_priv(sch);
1412
1413         return (unsigned long)cbq_class_lookup(q, classid);
1414 }
1415
1416 static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
1417 {
1418         struct cbq_sched_data *q = qdisc_priv(sch);
1419
1420         WARN_ON(cl->filters);
1421
1422         tcf_block_put(cl->block);
1423         qdisc_put(cl->q);
1424         qdisc_put_rtab(cl->R_tab);
1425         gen_kill_estimator(&cl->rate_est);
1426         if (cl != &q->link)
1427                 kfree(cl);
1428 }
1429
1430 static void cbq_destroy(struct Qdisc *sch)
1431 {
1432         struct cbq_sched_data *q = qdisc_priv(sch);
1433         struct hlist_node *next;
1434         struct cbq_class *cl;
1435         unsigned int h;
1436
1437 #ifdef CONFIG_NET_CLS_ACT
1438         q->rx_class = NULL;
1439 #endif
1440         /*
1441          * Filters must be destroyed first because we don't destroy the
1442          * classes from root to leafs which means that filters can still
1443          * be bound to classes which have been destroyed already. --TGR '04
1444          */
1445         for (h = 0; h < q->clhash.hashsize; h++) {
1446                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1447                         tcf_block_put(cl->block);
1448                         cl->block = NULL;
1449                 }
1450         }
1451         for (h = 0; h < q->clhash.hashsize; h++) {
1452                 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[h],
1453                                           common.hnode)
1454                         cbq_destroy_class(sch, cl);
1455         }
1456         qdisc_class_hash_destroy(&q->clhash);
1457 }
1458
1459 static int
1460 cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca,
1461                  unsigned long *arg, struct netlink_ext_ack *extack)
1462 {
1463         int err;
1464         struct cbq_sched_data *q = qdisc_priv(sch);
1465         struct cbq_class *cl = (struct cbq_class *)*arg;
1466         struct nlattr *opt = tca[TCA_OPTIONS];
1467         struct nlattr *tb[TCA_CBQ_MAX + 1];
1468         struct cbq_class *parent;
1469         struct qdisc_rate_table *rtab = NULL;
1470
1471         if (!opt) {
1472                 NL_SET_ERR_MSG(extack, "Mandatory qdisc options missing");
1473                 return -EINVAL;
1474         }
1475
1476         err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy, extack);
1477         if (err < 0)
1478                 return err;
1479
1480         if (tb[TCA_CBQ_OVL_STRATEGY] || tb[TCA_CBQ_POLICE]) {
1481                 NL_SET_ERR_MSG(extack, "Neither overlimit strategy nor policing attributes can be used for changing class params");
1482                 return -EOPNOTSUPP;
1483         }
1484
1485         if (cl) {
1486                 /* Check parent */
1487                 if (parentid) {
1488                         if (cl->tparent &&
1489                             cl->tparent->common.classid != parentid) {
1490                                 NL_SET_ERR_MSG(extack, "Invalid parent id");
1491                                 return -EINVAL;
1492                         }
1493                         if (!cl->tparent && parentid != TC_H_ROOT) {
1494                                 NL_SET_ERR_MSG(extack, "Parent must be root");
1495                                 return -EINVAL;
1496                         }
1497                 }
1498
1499                 if (tb[TCA_CBQ_RATE]) {
1500                         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
1501                                               tb[TCA_CBQ_RTAB], extack);
1502                         if (rtab == NULL)
1503                                 return -EINVAL;
1504                 }
1505
1506                 if (tca[TCA_RATE]) {
1507                         err = gen_replace_estimator(&cl->bstats, NULL,
1508                                                     &cl->rate_est,
1509                                                     NULL,
1510                                                     qdisc_root_sleeping_running(sch),
1511                                                     tca[TCA_RATE]);
1512                         if (err) {
1513                                 NL_SET_ERR_MSG(extack, "Failed to replace specified rate estimator");
1514                                 qdisc_put_rtab(rtab);
1515                                 return err;
1516                         }
1517                 }
1518
1519                 /* Change class parameters */
1520                 sch_tree_lock(sch);
1521
1522                 if (cl->next_alive != NULL)
1523                         cbq_deactivate_class(cl);
1524
1525                 if (rtab) {
1526                         qdisc_put_rtab(cl->R_tab);
1527                         cl->R_tab = rtab;
1528                 }
1529
1530                 if (tb[TCA_CBQ_LSSOPT])
1531                         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1532
1533                 if (tb[TCA_CBQ_WRROPT]) {
1534                         cbq_rmprio(q, cl);
1535                         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1536                 }
1537
1538                 if (tb[TCA_CBQ_FOPT])
1539                         cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1540
1541                 if (cl->q->q.qlen)
1542                         cbq_activate_class(cl);
1543
1544                 sch_tree_unlock(sch);
1545
1546                 return 0;
1547         }
1548
1549         if (parentid == TC_H_ROOT)
1550                 return -EINVAL;
1551
1552         if (!tb[TCA_CBQ_WRROPT] || !tb[TCA_CBQ_RATE] || !tb[TCA_CBQ_LSSOPT]) {
1553                 NL_SET_ERR_MSG(extack, "One of the following attributes MUST be specified: WRR, rate or link sharing");
1554                 return -EINVAL;
1555         }
1556
1557         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB],
1558                               extack);
1559         if (rtab == NULL)
1560                 return -EINVAL;
1561
1562         if (classid) {
1563                 err = -EINVAL;
1564                 if (TC_H_MAJ(classid ^ sch->handle) ||
1565                     cbq_class_lookup(q, classid)) {
1566                         NL_SET_ERR_MSG(extack, "Specified class not found");
1567                         goto failure;
1568                 }
1569         } else {
1570                 int i;
1571                 classid = TC_H_MAKE(sch->handle, 0x8000);
1572
1573                 for (i = 0; i < 0x8000; i++) {
1574                         if (++q->hgenerator >= 0x8000)
1575                                 q->hgenerator = 1;
1576                         if (cbq_class_lookup(q, classid|q->hgenerator) == NULL)
1577                                 break;
1578                 }
1579                 err = -ENOSR;
1580                 if (i >= 0x8000) {
1581                         NL_SET_ERR_MSG(extack, "Unable to generate classid");
1582                         goto failure;
1583                 }
1584                 classid = classid|q->hgenerator;
1585         }
1586
1587         parent = &q->link;
1588         if (parentid) {
1589                 parent = cbq_class_lookup(q, parentid);
1590                 err = -EINVAL;
1591                 if (!parent) {
1592                         NL_SET_ERR_MSG(extack, "Failed to find parentid");
1593                         goto failure;
1594                 }
1595         }
1596
1597         err = -ENOBUFS;
1598         cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1599         if (cl == NULL)
1600                 goto failure;
1601
1602         err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
1603         if (err) {
1604                 kfree(cl);
1605                 return err;
1606         }
1607
1608         if (tca[TCA_RATE]) {
1609                 err = gen_new_estimator(&cl->bstats, NULL, &cl->rate_est,
1610                                         NULL,
1611                                         qdisc_root_sleeping_running(sch),
1612                                         tca[TCA_RATE]);
1613                 if (err) {
1614                         NL_SET_ERR_MSG(extack, "Couldn't create new estimator");
1615                         tcf_block_put(cl->block);
1616                         kfree(cl);
1617                         goto failure;
1618                 }
1619         }
1620
1621         cl->R_tab = rtab;
1622         rtab = NULL;
1623         cl->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid,
1624                                   NULL);
1625         if (!cl->q)
1626                 cl->q = &noop_qdisc;
1627         else
1628                 qdisc_hash_add(cl->q, true);
1629
1630         cl->common.classid = classid;
1631         cl->tparent = parent;
1632         cl->qdisc = sch;
1633         cl->allot = parent->allot;
1634         cl->quantum = cl->allot;
1635         cl->weight = cl->R_tab->rate.rate;
1636
1637         sch_tree_lock(sch);
1638         cbq_link_class(cl);
1639         cl->borrow = cl->tparent;
1640         if (cl->tparent != &q->link)
1641                 cl->share = cl->tparent;
1642         cbq_adjust_levels(parent);
1643         cl->minidle = -0x7FFFFFFF;
1644         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1645         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1646         if (cl->ewma_log == 0)
1647                 cl->ewma_log = q->link.ewma_log;
1648         if (cl->maxidle == 0)
1649                 cl->maxidle = q->link.maxidle;
1650         if (cl->avpkt == 0)
1651                 cl->avpkt = q->link.avpkt;
1652         if (tb[TCA_CBQ_FOPT])
1653                 cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1654         sch_tree_unlock(sch);
1655
1656         qdisc_class_hash_grow(sch, &q->clhash);
1657
1658         *arg = (unsigned long)cl;
1659         return 0;
1660
1661 failure:
1662         qdisc_put_rtab(rtab);
1663         return err;
1664 }
1665
1666 static int cbq_delete(struct Qdisc *sch, unsigned long arg)
1667 {
1668         struct cbq_sched_data *q = qdisc_priv(sch);
1669         struct cbq_class *cl = (struct cbq_class *)arg;
1670
1671         if (cl->filters || cl->children || cl == &q->link)
1672                 return -EBUSY;
1673
1674         sch_tree_lock(sch);
1675
1676         qdisc_purge_queue(cl->q);
1677
1678         if (cl->next_alive)
1679                 cbq_deactivate_class(cl);
1680
1681         if (q->tx_borrowed == cl)
1682                 q->tx_borrowed = q->tx_class;
1683         if (q->tx_class == cl) {
1684                 q->tx_class = NULL;
1685                 q->tx_borrowed = NULL;
1686         }
1687 #ifdef CONFIG_NET_CLS_ACT
1688         if (q->rx_class == cl)
1689                 q->rx_class = NULL;
1690 #endif
1691
1692         cbq_unlink_class(cl);
1693         cbq_adjust_levels(cl->tparent);
1694         cl->defmap = 0;
1695         cbq_sync_defmap(cl);
1696
1697         cbq_rmprio(q, cl);
1698         sch_tree_unlock(sch);
1699
1700         cbq_destroy_class(sch, cl);
1701         return 0;
1702 }
1703
1704 static struct tcf_block *cbq_tcf_block(struct Qdisc *sch, unsigned long arg,
1705                                        struct netlink_ext_ack *extack)
1706 {
1707         struct cbq_sched_data *q = qdisc_priv(sch);
1708         struct cbq_class *cl = (struct cbq_class *)arg;
1709
1710         if (cl == NULL)
1711                 cl = &q->link;
1712
1713         return cl->block;
1714 }
1715
1716 static unsigned long cbq_bind_filter(struct Qdisc *sch, unsigned long parent,
1717                                      u32 classid)
1718 {
1719         struct cbq_sched_data *q = qdisc_priv(sch);
1720         struct cbq_class *p = (struct cbq_class *)parent;
1721         struct cbq_class *cl = cbq_class_lookup(q, classid);
1722
1723         if (cl) {
1724                 if (p && p->level <= cl->level)
1725                         return 0;
1726                 cl->filters++;
1727                 return (unsigned long)cl;
1728         }
1729         return 0;
1730 }
1731
1732 static void cbq_unbind_filter(struct Qdisc *sch, unsigned long arg)
1733 {
1734         struct cbq_class *cl = (struct cbq_class *)arg;
1735
1736         cl->filters--;
1737 }
1738
1739 static void cbq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1740 {
1741         struct cbq_sched_data *q = qdisc_priv(sch);
1742         struct cbq_class *cl;
1743         unsigned int h;
1744
1745         if (arg->stop)
1746                 return;
1747
1748         for (h = 0; h < q->clhash.hashsize; h++) {
1749                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1750                         if (arg->count < arg->skip) {
1751                                 arg->count++;
1752                                 continue;
1753                         }
1754                         if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1755                                 arg->stop = 1;
1756                                 return;
1757                         }
1758                         arg->count++;
1759                 }
1760         }
1761 }
1762
1763 static const struct Qdisc_class_ops cbq_class_ops = {
1764         .graft          =       cbq_graft,
1765         .leaf           =       cbq_leaf,
1766         .qlen_notify    =       cbq_qlen_notify,
1767         .find           =       cbq_find,
1768         .change         =       cbq_change_class,
1769         .delete         =       cbq_delete,
1770         .walk           =       cbq_walk,
1771         .tcf_block      =       cbq_tcf_block,
1772         .bind_tcf       =       cbq_bind_filter,
1773         .unbind_tcf     =       cbq_unbind_filter,
1774         .dump           =       cbq_dump_class,
1775         .dump_stats     =       cbq_dump_class_stats,
1776 };
1777
1778 static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
1779         .next           =       NULL,
1780         .cl_ops         =       &cbq_class_ops,
1781         .id             =       "cbq",
1782         .priv_size      =       sizeof(struct cbq_sched_data),
1783         .enqueue        =       cbq_enqueue,
1784         .dequeue        =       cbq_dequeue,
1785         .peek           =       qdisc_peek_dequeued,
1786         .init           =       cbq_init,
1787         .reset          =       cbq_reset,
1788         .destroy        =       cbq_destroy,
1789         .change         =       NULL,
1790         .dump           =       cbq_dump,
1791         .dump_stats     =       cbq_dump_stats,
1792         .owner          =       THIS_MODULE,
1793 };
1794
1795 static int __init cbq_module_init(void)
1796 {
1797         return register_qdisc(&cbq_qdisc_ops);
1798 }
1799 static void __exit cbq_module_exit(void)
1800 {
1801         unregister_qdisc(&cbq_qdisc_ops);
1802 }
1803 module_init(cbq_module_init)
1804 module_exit(cbq_module_exit)
1805 MODULE_LICENSE("GPL");