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
1362         cl->xstats.avgidle = cl->avgidle;
1363         cl->xstats.undertime = 0;
1364
1365         if (cl->undertime != PSCHED_PASTPERFECT)
1366                 cl->xstats.undertime = cl->undertime - q->now;
1367
1368         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
1369                                   d, NULL, &cl->bstats) < 0 ||
1370             gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1371             gnet_stats_copy_queue(d, NULL, &cl->qstats, cl->q->q.qlen) < 0)
1372                 return -1;
1373
1374         return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1375 }
1376
1377 static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1378                      struct Qdisc **old, struct netlink_ext_ack *extack)
1379 {
1380         struct cbq_class *cl = (struct cbq_class *)arg;
1381
1382         if (new == NULL) {
1383                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1384                                         cl->common.classid, extack);
1385                 if (new == NULL)
1386                         return -ENOBUFS;
1387         }
1388
1389         *old = qdisc_replace(sch, new, &cl->q);
1390         return 0;
1391 }
1392
1393 static struct Qdisc *cbq_leaf(struct Qdisc *sch, unsigned long arg)
1394 {
1395         struct cbq_class *cl = (struct cbq_class *)arg;
1396
1397         return cl->q;
1398 }
1399
1400 static void cbq_qlen_notify(struct Qdisc *sch, unsigned long arg)
1401 {
1402         struct cbq_class *cl = (struct cbq_class *)arg;
1403
1404         cbq_deactivate_class(cl);
1405 }
1406
1407 static unsigned long cbq_find(struct Qdisc *sch, u32 classid)
1408 {
1409         struct cbq_sched_data *q = qdisc_priv(sch);
1410
1411         return (unsigned long)cbq_class_lookup(q, classid);
1412 }
1413
1414 static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
1415 {
1416         struct cbq_sched_data *q = qdisc_priv(sch);
1417
1418         WARN_ON(cl->filters);
1419
1420         tcf_block_put(cl->block);
1421         qdisc_put(cl->q);
1422         qdisc_put_rtab(cl->R_tab);
1423         gen_kill_estimator(&cl->rate_est);
1424         if (cl != &q->link)
1425                 kfree(cl);
1426 }
1427
1428 static void cbq_destroy(struct Qdisc *sch)
1429 {
1430         struct cbq_sched_data *q = qdisc_priv(sch);
1431         struct hlist_node *next;
1432         struct cbq_class *cl;
1433         unsigned int h;
1434
1435 #ifdef CONFIG_NET_CLS_ACT
1436         q->rx_class = NULL;
1437 #endif
1438         /*
1439          * Filters must be destroyed first because we don't destroy the
1440          * classes from root to leafs which means that filters can still
1441          * be bound to classes which have been destroyed already. --TGR '04
1442          */
1443         for (h = 0; h < q->clhash.hashsize; h++) {
1444                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1445                         tcf_block_put(cl->block);
1446                         cl->block = NULL;
1447                 }
1448         }
1449         for (h = 0; h < q->clhash.hashsize; h++) {
1450                 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[h],
1451                                           common.hnode)
1452                         cbq_destroy_class(sch, cl);
1453         }
1454         qdisc_class_hash_destroy(&q->clhash);
1455 }
1456
1457 static int
1458 cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca,
1459                  unsigned long *arg, struct netlink_ext_ack *extack)
1460 {
1461         int err;
1462         struct cbq_sched_data *q = qdisc_priv(sch);
1463         struct cbq_class *cl = (struct cbq_class *)*arg;
1464         struct nlattr *opt = tca[TCA_OPTIONS];
1465         struct nlattr *tb[TCA_CBQ_MAX + 1];
1466         struct cbq_class *parent;
1467         struct qdisc_rate_table *rtab = NULL;
1468
1469         if (!opt) {
1470                 NL_SET_ERR_MSG(extack, "Mandatory qdisc options missing");
1471                 return -EINVAL;
1472         }
1473
1474         err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy, extack);
1475         if (err < 0)
1476                 return err;
1477
1478         if (tb[TCA_CBQ_OVL_STRATEGY] || tb[TCA_CBQ_POLICE]) {
1479                 NL_SET_ERR_MSG(extack, "Neither overlimit strategy nor policing attributes can be used for changing class params");
1480                 return -EOPNOTSUPP;
1481         }
1482
1483         if (cl) {
1484                 /* Check parent */
1485                 if (parentid) {
1486                         if (cl->tparent &&
1487                             cl->tparent->common.classid != parentid) {
1488                                 NL_SET_ERR_MSG(extack, "Invalid parent id");
1489                                 return -EINVAL;
1490                         }
1491                         if (!cl->tparent && parentid != TC_H_ROOT) {
1492                                 NL_SET_ERR_MSG(extack, "Parent must be root");
1493                                 return -EINVAL;
1494                         }
1495                 }
1496
1497                 if (tb[TCA_CBQ_RATE]) {
1498                         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
1499                                               tb[TCA_CBQ_RTAB], extack);
1500                         if (rtab == NULL)
1501                                 return -EINVAL;
1502                 }
1503
1504                 if (tca[TCA_RATE]) {
1505                         err = gen_replace_estimator(&cl->bstats, NULL,
1506                                                     &cl->rate_est,
1507                                                     NULL,
1508                                                     qdisc_root_sleeping_running(sch),
1509                                                     tca[TCA_RATE]);
1510                         if (err) {
1511                                 NL_SET_ERR_MSG(extack, "Failed to replace specified rate estimator");
1512                                 qdisc_put_rtab(rtab);
1513                                 return err;
1514                         }
1515                 }
1516
1517                 /* Change class parameters */
1518                 sch_tree_lock(sch);
1519
1520                 if (cl->next_alive != NULL)
1521                         cbq_deactivate_class(cl);
1522
1523                 if (rtab) {
1524                         qdisc_put_rtab(cl->R_tab);
1525                         cl->R_tab = rtab;
1526                 }
1527
1528                 if (tb[TCA_CBQ_LSSOPT])
1529                         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1530
1531                 if (tb[TCA_CBQ_WRROPT]) {
1532                         cbq_rmprio(q, cl);
1533                         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1534                 }
1535
1536                 if (tb[TCA_CBQ_FOPT])
1537                         cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1538
1539                 if (cl->q->q.qlen)
1540                         cbq_activate_class(cl);
1541
1542                 sch_tree_unlock(sch);
1543
1544                 return 0;
1545         }
1546
1547         if (parentid == TC_H_ROOT)
1548                 return -EINVAL;
1549
1550         if (!tb[TCA_CBQ_WRROPT] || !tb[TCA_CBQ_RATE] || !tb[TCA_CBQ_LSSOPT]) {
1551                 NL_SET_ERR_MSG(extack, "One of the following attributes MUST be specified: WRR, rate or link sharing");
1552                 return -EINVAL;
1553         }
1554
1555         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB],
1556                               extack);
1557         if (rtab == NULL)
1558                 return -EINVAL;
1559
1560         if (classid) {
1561                 err = -EINVAL;
1562                 if (TC_H_MAJ(classid ^ sch->handle) ||
1563                     cbq_class_lookup(q, classid)) {
1564                         NL_SET_ERR_MSG(extack, "Specified class not found");
1565                         goto failure;
1566                 }
1567         } else {
1568                 int i;
1569                 classid = TC_H_MAKE(sch->handle, 0x8000);
1570
1571                 for (i = 0; i < 0x8000; i++) {
1572                         if (++q->hgenerator >= 0x8000)
1573                                 q->hgenerator = 1;
1574                         if (cbq_class_lookup(q, classid|q->hgenerator) == NULL)
1575                                 break;
1576                 }
1577                 err = -ENOSR;
1578                 if (i >= 0x8000) {
1579                         NL_SET_ERR_MSG(extack, "Unable to generate classid");
1580                         goto failure;
1581                 }
1582                 classid = classid|q->hgenerator;
1583         }
1584
1585         parent = &q->link;
1586         if (parentid) {
1587                 parent = cbq_class_lookup(q, parentid);
1588                 err = -EINVAL;
1589                 if (!parent) {
1590                         NL_SET_ERR_MSG(extack, "Failed to find parentid");
1591                         goto failure;
1592                 }
1593         }
1594
1595         err = -ENOBUFS;
1596         cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1597         if (cl == NULL)
1598                 goto failure;
1599
1600         err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
1601         if (err) {
1602                 kfree(cl);
1603                 return err;
1604         }
1605
1606         if (tca[TCA_RATE]) {
1607                 err = gen_new_estimator(&cl->bstats, NULL, &cl->rate_est,
1608                                         NULL,
1609                                         qdisc_root_sleeping_running(sch),
1610                                         tca[TCA_RATE]);
1611                 if (err) {
1612                         NL_SET_ERR_MSG(extack, "Couldn't create new estimator");
1613                         tcf_block_put(cl->block);
1614                         kfree(cl);
1615                         goto failure;
1616                 }
1617         }
1618
1619         cl->R_tab = rtab;
1620         rtab = NULL;
1621         cl->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid,
1622                                   NULL);
1623         if (!cl->q)
1624                 cl->q = &noop_qdisc;
1625         else
1626                 qdisc_hash_add(cl->q, true);
1627
1628         cl->common.classid = classid;
1629         cl->tparent = parent;
1630         cl->qdisc = sch;
1631         cl->allot = parent->allot;
1632         cl->quantum = cl->allot;
1633         cl->weight = cl->R_tab->rate.rate;
1634
1635         sch_tree_lock(sch);
1636         cbq_link_class(cl);
1637         cl->borrow = cl->tparent;
1638         if (cl->tparent != &q->link)
1639                 cl->share = cl->tparent;
1640         cbq_adjust_levels(parent);
1641         cl->minidle = -0x7FFFFFFF;
1642         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1643         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1644         if (cl->ewma_log == 0)
1645                 cl->ewma_log = q->link.ewma_log;
1646         if (cl->maxidle == 0)
1647                 cl->maxidle = q->link.maxidle;
1648         if (cl->avpkt == 0)
1649                 cl->avpkt = q->link.avpkt;
1650         if (tb[TCA_CBQ_FOPT])
1651                 cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1652         sch_tree_unlock(sch);
1653
1654         qdisc_class_hash_grow(sch, &q->clhash);
1655
1656         *arg = (unsigned long)cl;
1657         return 0;
1658
1659 failure:
1660         qdisc_put_rtab(rtab);
1661         return err;
1662 }
1663
1664 static int cbq_delete(struct Qdisc *sch, unsigned long arg)
1665 {
1666         struct cbq_sched_data *q = qdisc_priv(sch);
1667         struct cbq_class *cl = (struct cbq_class *)arg;
1668         unsigned int qlen, backlog;
1669
1670         if (cl->filters || cl->children || cl == &q->link)
1671                 return -EBUSY;
1672
1673         sch_tree_lock(sch);
1674
1675         qlen = cl->q->q.qlen;
1676         backlog = cl->q->qstats.backlog;
1677         qdisc_reset(cl->q);
1678         qdisc_tree_reduce_backlog(cl->q, qlen, backlog);
1679
1680         if (cl->next_alive)
1681                 cbq_deactivate_class(cl);
1682
1683         if (q->tx_borrowed == cl)
1684                 q->tx_borrowed = q->tx_class;
1685         if (q->tx_class == cl) {
1686                 q->tx_class = NULL;
1687                 q->tx_borrowed = NULL;
1688         }
1689 #ifdef CONFIG_NET_CLS_ACT
1690         if (q->rx_class == cl)
1691                 q->rx_class = NULL;
1692 #endif
1693
1694         cbq_unlink_class(cl);
1695         cbq_adjust_levels(cl->tparent);
1696         cl->defmap = 0;
1697         cbq_sync_defmap(cl);
1698
1699         cbq_rmprio(q, cl);
1700         sch_tree_unlock(sch);
1701
1702         cbq_destroy_class(sch, cl);
1703         return 0;
1704 }
1705
1706 static struct tcf_block *cbq_tcf_block(struct Qdisc *sch, unsigned long arg,
1707                                        struct netlink_ext_ack *extack)
1708 {
1709         struct cbq_sched_data *q = qdisc_priv(sch);
1710         struct cbq_class *cl = (struct cbq_class *)arg;
1711
1712         if (cl == NULL)
1713                 cl = &q->link;
1714
1715         return cl->block;
1716 }
1717
1718 static unsigned long cbq_bind_filter(struct Qdisc *sch, unsigned long parent,
1719                                      u32 classid)
1720 {
1721         struct cbq_sched_data *q = qdisc_priv(sch);
1722         struct cbq_class *p = (struct cbq_class *)parent;
1723         struct cbq_class *cl = cbq_class_lookup(q, classid);
1724
1725         if (cl) {
1726                 if (p && p->level <= cl->level)
1727                         return 0;
1728                 cl->filters++;
1729                 return (unsigned long)cl;
1730         }
1731         return 0;
1732 }
1733
1734 static void cbq_unbind_filter(struct Qdisc *sch, unsigned long arg)
1735 {
1736         struct cbq_class *cl = (struct cbq_class *)arg;
1737
1738         cl->filters--;
1739 }
1740
1741 static void cbq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1742 {
1743         struct cbq_sched_data *q = qdisc_priv(sch);
1744         struct cbq_class *cl;
1745         unsigned int h;
1746
1747         if (arg->stop)
1748                 return;
1749
1750         for (h = 0; h < q->clhash.hashsize; h++) {
1751                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1752                         if (arg->count < arg->skip) {
1753                                 arg->count++;
1754                                 continue;
1755                         }
1756                         if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1757                                 arg->stop = 1;
1758                                 return;
1759                         }
1760                         arg->count++;
1761                 }
1762         }
1763 }
1764
1765 static const struct Qdisc_class_ops cbq_class_ops = {
1766         .graft          =       cbq_graft,
1767         .leaf           =       cbq_leaf,
1768         .qlen_notify    =       cbq_qlen_notify,
1769         .find           =       cbq_find,
1770         .change         =       cbq_change_class,
1771         .delete         =       cbq_delete,
1772         .walk           =       cbq_walk,
1773         .tcf_block      =       cbq_tcf_block,
1774         .bind_tcf       =       cbq_bind_filter,
1775         .unbind_tcf     =       cbq_unbind_filter,
1776         .dump           =       cbq_dump_class,
1777         .dump_stats     =       cbq_dump_class_stats,
1778 };
1779
1780 static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
1781         .next           =       NULL,
1782         .cl_ops         =       &cbq_class_ops,
1783         .id             =       "cbq",
1784         .priv_size      =       sizeof(struct cbq_sched_data),
1785         .enqueue        =       cbq_enqueue,
1786         .dequeue        =       cbq_dequeue,
1787         .peek           =       qdisc_peek_dequeued,
1788         .init           =       cbq_init,
1789         .reset          =       cbq_reset,
1790         .destroy        =       cbq_destroy,
1791         .change         =       NULL,
1792         .dump           =       cbq_dump,
1793         .dump_stats     =       cbq_dump_stats,
1794         .owner          =       THIS_MODULE,
1795 };
1796
1797 static int __init cbq_module_init(void)
1798 {
1799         return register_qdisc(&cbq_qdisc_ops);
1800 }
1801 static void __exit cbq_module_exit(void)
1802 {
1803         unregister_qdisc(&cbq_qdisc_ops);
1804 }
1805 module_init(cbq_module_init)
1806 module_exit(cbq_module_exit)
1807 MODULE_LICENSE("GPL");