net/sched/sch_cbq.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/sch_cbq.c  Class-Based Queueing discipline.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/string.h>
  13 #include <linux/errno.h>
  14 #include <linux/skbuff.h>
  15 #include <net/netlink.h>
  16 #include <net/pkt_sched.h>
  17 #include <net/pkt_cls.h>
  18
  19
  20 /*      Class-Based Queueing (CBQ) algorithm.
  21         =======================================
  22
  23         Sources: [1] Sally Floyd and Van Jacobson, "Link-sharing and Resource
  24                  Management Models for Packet Networks",
  25                  IEEE/ACM Transactions on Networking, Vol.3, No.4, 1995
  26
  27                  [2] Sally Floyd, "Notes on CBQ and Guaranteed Service", 1995
  28
  29                  [3] Sally Floyd, "Notes on Class-Based Queueing: Setting
  30                  Parameters", 1996
  31
  32                  [4] Sally Floyd and Michael Speer, "Experimental Results
  33                  for Class-Based Queueing", 1998, not published.
  34
  35         -----------------------------------------------------------------------
  36
  37         Algorithm skeleton was taken from NS simulator cbq.cc.
  38         If someone wants to check this code against the LBL version,
  39         he should take into account that ONLY the skeleton was borrowed,
  40         the implementation is different. Particularly:
  41
  42         --- The WRR algorithm is different. Our version looks more
  43         reasonable (I hope) and works when quanta are allowed to be
  44         less than MTU, which is always the case when real time classes
  45         have small rates. Note, that the statement of [3] is
  46         incomplete, delay may actually be estimated even if class
  47         per-round allotment is less than MTU. Namely, if per-round
  48         allotment is W*r_i, and r_1+...+r_k = r < 1
  49
  50         delay_i <= ([MTU/(W*r_i)]*W*r + W*r + k*MTU)/B
  51
  52         In the worst case we have IntServ estimate with D = W*r+k*MTU
  53         and C = MTU*r. The proof (if correct at all) is trivial.
  54
  55
  56         --- It seems that cbq-2.0 is not very accurate. At least, I cannot
  57         interpret some places, which look like wrong translations
  58         from NS. Anyone is advised to find these differences
  59         and explain to me, why I am wrong 8).
  60
  61         --- Linux has no EOI event, so that we cannot estimate true class
  62         idle time. Workaround is to consider the next dequeue event
  63         as sign that previous packet is finished. This is wrong because of
  64         internal device queueing, but on a permanently loaded link it is true.
  65         Moreover, combined with clock integrator, this scheme looks
  66         very close to an ideal solution.  */
  67
  68 struct cbq_sched_data;
  69
  70
  71 struct cbq_class {
  72         struct Qdisc_class_common common;
  73         struct cbq_class        *next_alive;    /* next class with backlog in this priority band */
  74
  75 /* Parameters */
  76         unsigned char           priority;       /* class priority */
  77         unsigned char           priority2;      /* priority to be used after overlimit */
  78         unsigned char           ewma_log;       /* time constant for idle time calculation */
  79
  80         u32                     defmap;
  81
  82         /* Link-sharing scheduler parameters */
  83         long                    maxidle;        /* Class parameters: see below. */
  84         long                    offtime;
  85         long                    minidle;
  86         u32                     avpkt;
  87         struct qdisc_rate_table *R_tab;
  88
  89         /* General scheduler (WRR) parameters */
  90         long                    allot;
  91         long                    quantum;        /* Allotment per WRR round */
  92         long                    weight;         /* Relative allotment: see below */
  93
  94         struct Qdisc            *qdisc;         /* Ptr to CBQ discipline */
  95         struct cbq_class        *split;         /* Ptr to split node */
  96         struct cbq_class        *share;         /* Ptr to LS parent in the class tree */
  97         struct cbq_class        *tparent;       /* Ptr to tree parent in the class tree */
  98         struct cbq_class        *borrow;        /* NULL if class is bandwidth limited;
  99                                                    parent otherwise */
 100         struct cbq_class        *sibling;       /* Sibling chain */
 101         struct cbq_class        *children;      /* Pointer to children chain */
 102
 103         struct Qdisc            *q;             /* Elementary queueing discipline */
 104
 105
 106 /* Variables */
 107         unsigned char           cpriority;      /* Effective priority */
 108         unsigned char           delayed;
 109         unsigned char           level;          /* level of the class in hierarchy:
 110                                                    0 for leaf classes, and maximal
 111                                                    level of children + 1 for nodes.
 112                                                  */
 113
 114         psched_time_t           last;           /* Last end of service */
 115         psched_time_t           undertime;
 116         long                    avgidle;
 117         long                    deficit;        /* Saved deficit for WRR */
 118         psched_time_t           penalized;
 119         struct gnet_stats_basic_sync bstats;
 120         struct gnet_stats_queue qstats;
 121         struct net_rate_estimator __rcu *rate_est;
 122         struct tc_cbq_xstats    xstats;
 123
 124         struct tcf_proto __rcu  *filter_list;
 125         struct tcf_block        *block;
 126
 127         int                     filters;
 128
 129         struct cbq_class        *defaults[TC_PRIO_MAX + 1];
 130 };
 131
 132 struct cbq_sched_data {
 133         struct Qdisc_class_hash clhash;                 /* Hash table of all classes */
 134         int                     nclasses[TC_CBQ_MAXPRIO + 1];
 135         unsigned int            quanta[TC_CBQ_MAXPRIO + 1];
 136
 137         struct cbq_class        link;
 138
 139         unsigned int            activemask;
 140         struct cbq_class        *active[TC_CBQ_MAXPRIO + 1];    /* List of all classes
 141                                                                    with backlog */
 142
 143 #ifdef CONFIG_NET_CLS_ACT
 144         struct cbq_class        *rx_class;
 145 #endif
 146         struct cbq_class        *tx_class;
 147         struct cbq_class        *tx_borrowed;
 148         int                     tx_len;
 149         psched_time_t           now;            /* Cached timestamp */
 150         unsigned int            pmask;
 151
 152         struct qdisc_watchdog   watchdog;       /* Watchdog timer,
 153                                                    started when CBQ has
 154                                                    backlog, but cannot
 155                                                    transmit just now */
 156         psched_tdiff_t          wd_expires;
 157         int                     toplevel;
 158         u32                     hgenerator;
 159 };
 160
 161
 162 #define L2T(cl, len)    qdisc_l2t((cl)->R_tab, len)
 163
 164 static inline struct cbq_class *
 165 cbq_class_lookup(struct cbq_sched_data *q, u32 classid)
 166 {
 167         struct Qdisc_class_common *clc;
 168
 169         clc = qdisc_class_find(&q->clhash, classid);
 170         if (clc == NULL)
 171                 return NULL;
 172         return container_of(clc, struct cbq_class, common);
 173 }
 174
 175 #ifdef CONFIG_NET_CLS_ACT
 176
 177 static struct cbq_class *
 178 cbq_reclassify(struct sk_buff *skb, struct cbq_class *this)
 179 {
 180         struct cbq_class *cl;
 181
 182         for (cl = this->tparent; cl; cl = cl->tparent) {
 183                 struct cbq_class *new = cl->defaults[TC_PRIO_BESTEFFORT];
 184
 185                 if (new != NULL && new != this)
 186                         return new;
 187         }
 188         return NULL;
 189 }
 190
 191 #endif
 192
 193 /* Classify packet. The procedure is pretty complicated, but
 194  * it allows us to combine link sharing and priority scheduling
 195  * transparently.
 196  *
 197  * Namely, you can put link sharing rules (f.e. route based) at root of CBQ,
 198  * so that it resolves to split nodes. Then packets are classified
 199  * by logical priority, or a more specific classifier may be attached
 200  * to the split node.
 201  */
 202
 203 static struct cbq_class *
 204 cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 205 {
 206         struct cbq_sched_data *q = qdisc_priv(sch);
 207         struct cbq_class *head = &q->link;
 208         struct cbq_class **defmap;
 209         struct cbq_class *cl = NULL;
 210         u32 prio = skb->priority;
 211         struct tcf_proto *fl;
 212         struct tcf_result res;
 213
 214         /*
 215          *  Step 1. If skb->priority points to one of our classes, use it.
 216          */
 217         if (TC_H_MAJ(prio ^ sch->handle) == 0 &&
 218             (cl = cbq_class_lookup(q, prio)) != NULL)
 219                 return cl;
 220
 221         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 222         for (;;) {
 223                 int result = 0;
 224                 defmap = head->defaults;
 225
 226                 fl = rcu_dereference_bh(head->filter_list);
 227                 /*
 228                  * Step 2+n. Apply classifier.
 229                  */
 230                 result = tcf_classify(skb, NULL, fl, &res, true);
 231                 if (!fl || result < 0)
 232                         goto fallback;
 233                 if (result == TC_ACT_SHOT)
 234                         return NULL;
 235
 236                 cl = (void *)res.class;
 237                 if (!cl) {
 238                         if (TC_H_MAJ(res.classid))
 239                                 cl = cbq_class_lookup(q, res.classid);
 240                         else if ((cl = defmap[res.classid & TC_PRIO_MAX]) == NULL)
 241                                 cl = defmap[TC_PRIO_BESTEFFORT];
 242
 243                         if (cl == NULL)
 244                                 goto fallback;
 245                 }
 246                 if (cl->level >= head->level)
 247                         goto fallback;
 248 #ifdef CONFIG_NET_CLS_ACT
 249                 switch (result) {
 250                 case TC_ACT_QUEUED:
 251                 case TC_ACT_STOLEN:
 252                 case TC_ACT_TRAP:
 253                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 254                         fallthrough;
 255                 case TC_ACT_RECLASSIFY:
 256                         return cbq_reclassify(skb, cl);
 257                 }
 258 #endif
 259                 if (cl->level == 0)
 260                         return cl;
 261
 262                 /*
 263                  * Step 3+n. If classifier selected a link sharing class,
 264                  *         apply agency specific classifier.
 265                  *         Repeat this procedure until we hit a leaf node.
 266                  */
 267                 head = cl;
 268         }
 269
 270 fallback:
 271         cl = head;
 272
 273         /*
 274          * Step 4. No success...
 275          */
 276         if (TC_H_MAJ(prio) == 0 &&
 277             !(cl = head->defaults[prio & TC_PRIO_MAX]) &&
 278             !(cl = head->defaults[TC_PRIO_BESTEFFORT]))
 279                 return head;
 280
 281         return cl;
 282 }
 283
 284 /*
 285  * A packet has just been enqueued on the empty class.
 286  * cbq_activate_class adds it to the tail of active class list
 287  * of its priority band.
 288  */
 289
 290 static inline void cbq_activate_class(struct cbq_class *cl)
 291 {
 292         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 293         int prio = cl->cpriority;
 294         struct cbq_class *cl_tail;
 295
 296         cl_tail = q->active[prio];
 297         q->active[prio] = cl;
 298
 299         if (cl_tail != NULL) {
 300                 cl->next_alive = cl_tail->next_alive;
 301                 cl_tail->next_alive = cl;
 302         } else {
 303                 cl->next_alive = cl;
 304                 q->activemask |= (1<<prio);
 305         }
 306 }
 307
 308 /*
 309  * Unlink class from active chain.
 310  * Note that this same procedure is done directly in cbq_dequeue*
 311  * during round-robin procedure.
 312  */
 313
 314 static void cbq_deactivate_class(struct cbq_class *this)
 315 {
 316         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
 317         int prio = this->cpriority;
 318         struct cbq_class *cl;
 319         struct cbq_class *cl_prev = q->active[prio];
 320
 321         do {
 322                 cl = cl_prev->next_alive;
 323                 if (cl == this) {
 324                         cl_prev->next_alive = cl->next_alive;
 325                         cl->next_alive = NULL;
 326
 327                         if (cl == q->active[prio]) {
 328                                 q->active[prio] = cl_prev;
 329                                 if (cl == q->active[prio]) {
 330                                         q->active[prio] = NULL;
 331                                         q->activemask &= ~(1<<prio);
 332                                         return;
 333                                 }
 334                         }
 335                         return;
 336                 }
 337         } while ((cl_prev = cl) != q->active[prio]);
 338 }
 339
 340 static void
 341 cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl)
 342 {
 343         int toplevel = q->toplevel;
 344
 345         if (toplevel > cl->level) {
 346                 psched_time_t now = psched_get_time();
 347
 348                 do {
 349                         if (cl->undertime < now) {
 350                                 q->toplevel = cl->level;
 351                                 return;
 352                         }
 353                 } while ((cl = cl->borrow) != NULL && toplevel > cl->level);
 354         }
 355 }
 356
 357 static int
 358 cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 359             struct sk_buff **to_free)
 360 {
 361         struct cbq_sched_data *q = qdisc_priv(sch);
 362         int ret;
 363         struct cbq_class *cl = cbq_classify(skb, sch, &ret);
 364
 365 #ifdef CONFIG_NET_CLS_ACT
 366         q->rx_class = cl;
 367 #endif
 368         if (cl == NULL) {
 369                 if (ret & __NET_XMIT_BYPASS)
 370                         qdisc_qstats_drop(sch);
 371                 __qdisc_drop(skb, to_free);
 372                 return ret;
 373         }
 374
 375         ret = qdisc_enqueue(skb, cl->q, to_free);
 376         if (ret == NET_XMIT_SUCCESS) {
 377                 sch->q.qlen++;
 378                 cbq_mark_toplevel(q, cl);
 379                 if (!cl->next_alive)
 380                         cbq_activate_class(cl);
 381                 return ret;
 382         }
 383
 384         if (net_xmit_drop_count(ret)) {
 385                 qdisc_qstats_drop(sch);
 386                 cbq_mark_toplevel(q, cl);
 387                 cl->qstats.drops++;
 388         }
 389         return ret;
 390 }
 391
 392 /* Overlimit action: penalize leaf class by adding offtime */
 393 static void cbq_overlimit(struct cbq_class *cl)
 394 {
 395         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 396         psched_tdiff_t delay = cl->undertime - q->now;
 397
 398         if (!cl->delayed) {
 399                 delay += cl->offtime;
 400
 401                 /*
 402                  * Class goes to sleep, so that it will have no
 403                  * chance to work avgidle. Let's forgive it 8)
 404                  *
 405                  * BTW cbq-2.0 has a crap in this
 406                  * place, apparently they forgot to shift it by cl->ewma_log.
 407                  */
 408                 if (cl->avgidle < 0)
 409                         delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
 410                 if (cl->avgidle < cl->minidle)
 411                         cl->avgidle = cl->minidle;
 412                 if (delay <= 0)
 413                         delay = 1;
 414                 cl->undertime = q->now + delay;
 415
 416                 cl->xstats.overactions++;
 417                 cl->delayed = 1;
 418         }
 419         if (q->wd_expires == 0 || q->wd_expires > delay)
 420                 q->wd_expires = delay;
 421
 422         /* Dirty work! We must schedule wakeups based on
 423          * real available rate, rather than leaf rate,
 424          * which may be tiny (even zero).
 425          */
 426         if (q->toplevel == TC_CBQ_MAXLEVEL) {
 427                 struct cbq_class *b;
 428                 psched_tdiff_t base_delay = q->wd_expires;
 429
 430                 for (b = cl->borrow; b; b = b->borrow) {
 431                         delay = b->undertime - q->now;
 432                         if (delay < base_delay) {
 433                                 if (delay <= 0)
 434                                         delay = 1;
 435                                 base_delay = delay;
 436                         }
 437                 }
 438
 439                 q->wd_expires = base_delay;
 440         }
 441 }
 442
 443 /*
 444  * It is mission critical procedure.
 445  *
 446  * We "regenerate" toplevel cutoff, if transmitting class
 447  * has backlog and it is not regulated. It is not part of
 448  * original CBQ description, but looks more reasonable.
 449  * Probably, it is wrong. This question needs further investigation.
 450  */
 451
 452 static inline void
 453 cbq_update_toplevel(struct cbq_sched_data *q, struct cbq_class *cl,
 454                     struct cbq_class *borrowed)
 455 {
 456         if (cl && q->toplevel >= borrowed->level) {
 457                 if (cl->q->q.qlen > 1) {
 458                         do {
 459                                 if (borrowed->undertime == PSCHED_PASTPERFECT) {
 460                                         q->toplevel = borrowed->level;
 461                                         return;
 462                                 }
 463                         } while ((borrowed = borrowed->borrow) != NULL);
 464                 }
 465 #if 0
 466         /* It is not necessary now. Uncommenting it
 467            will save CPU cycles, but decrease fairness.
 468          */
 469                 q->toplevel = TC_CBQ_MAXLEVEL;
 470 #endif
 471         }
 472 }
 473
 474 static void
 475 cbq_update(struct cbq_sched_data *q)
 476 {
 477         struct cbq_class *this = q->tx_class;
 478         struct cbq_class *cl = this;
 479         int len = q->tx_len;
 480         psched_time_t now;
 481
 482         q->tx_class = NULL;
 483         /* Time integrator. We calculate EOS time
 484          * by adding expected packet transmission time.
 485          */
 486         now = q->now + L2T(&q->link, len);
 487
 488         for ( ; cl; cl = cl->share) {
 489                 long avgidle = cl->avgidle;
 490                 long idle;
 491
 492                 _bstats_update(&cl->bstats, len, 1);
 493
 494                 /*
 495                  * (now - last) is total time between packet right edges.
 496                  * (last_pktlen/rate) is "virtual" busy time, so that
 497                  *
 498                  *      idle = (now - last) - last_pktlen/rate
 499                  */
 500
 501                 idle = now - cl->last;
 502                 if ((unsigned long)idle > 128*1024*1024) {
 503                         avgidle = cl->maxidle;
 504                 } else {
 505                         idle -= L2T(cl, len);
 506
 507                 /* true_avgidle := (1-W)*true_avgidle + W*idle,
 508                  * where W=2^{-ewma_log}. But cl->avgidle is scaled:
 509                  * cl->avgidle == true_avgidle/W,
 510                  * hence:
 511                  */
 512                         avgidle += idle - (avgidle>>cl->ewma_log);
 513                 }
 514
 515                 if (avgidle <= 0) {
 516                         /* Overlimit or at-limit */
 517
 518                         if (avgidle < cl->minidle)
 519                                 avgidle = cl->minidle;
 520
 521                         cl->avgidle = avgidle;
 522
 523                         /* Calculate expected time, when this class
 524                          * will be allowed to send.
 525                          * It will occur, when:
 526                          * (1-W)*true_avgidle + W*delay = 0, i.e.
 527                          * idle = (1/W - 1)*(-true_avgidle)
 528                          * or
 529                          * idle = (1 - W)*(-cl->avgidle);
 530                          */
 531                         idle = (-avgidle) - ((-avgidle) >> cl->ewma_log);
 532
 533                         /*
 534                          * That is not all.
 535                          * To maintain the rate allocated to the class,
 536                          * we add to undertime virtual clock,
 537                          * necessary to complete transmitted packet.
 538                          * (len/phys_bandwidth has been already passed
 539                          * to the moment of cbq_update)
 540                          */
 541
 542                         idle -= L2T(&q->link, len);
 543                         idle += L2T(cl, len);
 544
 545                         cl->undertime = now + idle;
 546                 } else {
 547                         /* Underlimit */
 548
 549                         cl->undertime = PSCHED_PASTPERFECT;
 550                         if (avgidle > cl->maxidle)
 551                                 cl->avgidle = cl->maxidle;
 552                         else
 553                                 cl->avgidle = avgidle;
 554                 }
 555                 if ((s64)(now - cl->last) > 0)
 556                         cl->last = now;
 557         }
 558
 559         cbq_update_toplevel(q, this, q->tx_borrowed);
 560 }
 561
 562 static inline struct cbq_class *
 563 cbq_under_limit(struct cbq_class *cl)
 564 {
 565         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 566         struct cbq_class *this_cl = cl;
 567
 568         if (cl->tparent == NULL)
 569                 return cl;
 570
 571         if (cl->undertime == PSCHED_PASTPERFECT || q->now >= cl->undertime) {
 572                 cl->delayed = 0;
 573                 return cl;
 574         }
 575
 576         do {
 577                 /* It is very suspicious place. Now overlimit
 578                  * action is generated for not bounded classes
 579                  * only if link is completely congested.
 580                  * Though it is in agree with ancestor-only paradigm,
 581                  * it looks very stupid. Particularly,
 582                  * it means that this chunk of code will either
 583                  * never be called or result in strong amplification
 584                  * of burstiness. Dangerous, silly, and, however,
 585                  * no another solution exists.
 586                  */
 587                 cl = cl->borrow;
 588                 if (!cl) {
 589                         this_cl->qstats.overlimits++;
 590                         cbq_overlimit(this_cl);
 591                         return NULL;
 592                 }
 593                 if (cl->level > q->toplevel)
 594                         return NULL;
 595         } while (cl->undertime != PSCHED_PASTPERFECT && q->now < cl->undertime);
 596
 597         cl->delayed = 0;
 598         return cl;
 599 }
 600
 601 static inline struct sk_buff *
 602 cbq_dequeue_prio(struct Qdisc *sch, int prio)
 603 {
 604         struct cbq_sched_data *q = qdisc_priv(sch);
 605         struct cbq_class *cl_tail, *cl_prev, *cl;
 606         struct sk_buff *skb;
 607         int deficit;
 608
 609         cl_tail = cl_prev = q->active[prio];
 610         cl = cl_prev->next_alive;
 611
 612         do {
 613                 deficit = 0;
 614
 615                 /* Start round */
 616                 do {
 617                         struct cbq_class *borrow = cl;
 618
 619                         if (cl->q->q.qlen &&
 620                             (borrow = cbq_under_limit(cl)) == NULL)
 621                                 goto skip_class;
 622
 623                         if (cl->deficit <= 0) {
 624                                 /* Class exhausted its allotment per
 625                                  * this round. Switch to the next one.
 626                                  */
 627                                 deficit = 1;
 628                                 cl->deficit += cl->quantum;
 629                                 goto next_class;
 630                         }
 631
 632                         skb = cl->q->dequeue(cl->q);
 633
 634                         /* Class did not give us any skb :-(
 635                          * It could occur even if cl->q->q.qlen != 0
 636                          * f.e. if cl->q == "tbf"
 637                          */
 638                         if (skb == NULL)
 639                                 goto skip_class;
 640
 641                         cl->deficit -= qdisc_pkt_len(skb);
 642                         q->tx_class = cl;
 643                         q->tx_borrowed = borrow;
 644                         if (borrow != cl) {
 645 #ifndef CBQ_XSTATS_BORROWS_BYTES
 646                                 borrow->xstats.borrows++;
 647                                 cl->xstats.borrows++;
 648 #else
 649                                 borrow->xstats.borrows += qdisc_pkt_len(skb);
 650                                 cl->xstats.borrows += qdisc_pkt_len(skb);
 651 #endif
 652                         }
 653                         q->tx_len = qdisc_pkt_len(skb);
 654
 655                         if (cl->deficit <= 0) {
 656                                 q->active[prio] = cl;
 657                                 cl = cl->next_alive;
 658                                 cl->deficit += cl->quantum;
 659                         }
 660                         return skb;
 661
 662 skip_class:
 663                         if (cl->q->q.qlen == 0 || prio != cl->cpriority) {
 664                                 /* Class is empty or penalized.
 665                                  * Unlink it from active chain.
 666                                  */
 667                                 cl_prev->next_alive = cl->next_alive;
 668                                 cl->next_alive = NULL;
 669
 670                                 /* Did cl_tail point to it? */
 671                                 if (cl == cl_tail) {
 672                                         /* Repair it! */
 673                                         cl_tail = cl_prev;
 674
 675                                         /* Was it the last class in this band? */
 676                                         if (cl == cl_tail) {
 677                                                 /* Kill the band! */
 678                                                 q->active[prio] = NULL;
 679                                                 q->activemask &= ~(1<<prio);
 680                                                 if (cl->q->q.qlen)
 681                                                         cbq_activate_class(cl);
 682                                                 return NULL;
 683                                         }
 684
 685                                         q->active[prio] = cl_tail;
 686                                 }
 687                                 if (cl->q->q.qlen)
 688                                         cbq_activate_class(cl);
 689
 690                                 cl = cl_prev;
 691                         }
 692
 693 next_class:
 694                         cl_prev = cl;
 695                         cl = cl->next_alive;
 696                 } while (cl_prev != cl_tail);
 697         } while (deficit);
 698
 699         q->active[prio] = cl_prev;
 700
 701         return NULL;
 702 }
 703
 704 static inline struct sk_buff *
 705 cbq_dequeue_1(struct Qdisc *sch)
 706 {
 707         struct cbq_sched_data *q = qdisc_priv(sch);
 708         struct sk_buff *skb;
 709         unsigned int activemask;
 710
 711         activemask = q->activemask & 0xFF;
 712         while (activemask) {
 713                 int prio = ffz(~activemask);
 714                 activemask &= ~(1<<prio);
 715                 skb = cbq_dequeue_prio(sch, prio);
 716                 if (skb)
 717                         return skb;
 718         }
 719         return NULL;
 720 }
 721
 722 static struct sk_buff *
 723 cbq_dequeue(struct Qdisc *sch)
 724 {
 725         struct sk_buff *skb;
 726         struct cbq_sched_data *q = qdisc_priv(sch);
 727         psched_time_t now;
 728
 729         now = psched_get_time();
 730
 731         if (q->tx_class)
 732                 cbq_update(q);
 733
 734         q->now = now;
 735
 736         for (;;) {
 737                 q->wd_expires = 0;
 738
 739                 skb = cbq_dequeue_1(sch);
 740                 if (skb) {
 741                         qdisc_bstats_update(sch, skb);
 742                         sch->q.qlen--;
 743                         return skb;
 744                 }
 745
 746                 /* All the classes are overlimit.
 747                  *
 748                  * It is possible, if:
 749                  *
 750                  * 1. Scheduler is empty.
 751                  * 2. Toplevel cutoff inhibited borrowing.
 752                  * 3. Root class is overlimit.
 753                  *
 754                  * Reset 2d and 3d conditions and retry.
 755                  *
 756                  * Note, that NS and cbq-2.0 are buggy, peeking
 757                  * an arbitrary class is appropriate for ancestor-only
 758                  * sharing, but not for toplevel algorithm.
 759                  *
 760                  * Our version is better, but slower, because it requires
 761                  * two passes, but it is unavoidable with top-level sharing.
 762                  */
 763
 764                 if (q->toplevel == TC_CBQ_MAXLEVEL &&
 765                     q->link.undertime == PSCHED_PASTPERFECT)
 766                         break;
 767
 768                 q->toplevel = TC_CBQ_MAXLEVEL;
 769                 q->link.undertime = PSCHED_PASTPERFECT;
 770         }
 771
 772         /* No packets in scheduler or nobody wants to give them to us :-(
 773          * Sigh... start watchdog timer in the last case.
 774          */
 775
 776         if (sch->q.qlen) {
 777                 qdisc_qstats_overlimit(sch);
 778                 if (q->wd_expires)
 779                         qdisc_watchdog_schedule(&q->watchdog,
 780                                                 now + q->wd_expires);
 781         }
 782         return NULL;
 783 }
 784
 785 /* CBQ class maintenance routines */
 786
 787 static void cbq_adjust_levels(struct cbq_class *this)
 788 {
 789         if (this == NULL)
 790                 return;
 791
 792         do {
 793                 int level = 0;
 794                 struct cbq_class *cl;
 795
 796                 cl = this->children;
 797                 if (cl) {
 798                         do {
 799                                 if (cl->level > level)
 800                                         level = cl->level;
 801                         } while ((cl = cl->sibling) != this->children);
 802                 }
 803                 this->level = level + 1;
 804         } while ((this = this->tparent) != NULL);
 805 }
 806
 807 static void cbq_normalize_quanta(struct cbq_sched_data *q, int prio)
 808 {
 809         struct cbq_class *cl;
 810         unsigned int h;
 811
 812         if (q->quanta[prio] == 0)
 813                 return;
 814
 815         for (h = 0; h < q->clhash.hashsize; h++) {
 816                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
 817                         /* BUGGGG... Beware! This expression suffer of
 818                          * arithmetic overflows!
 819                          */
 820                         if (cl->priority == prio) {
 821                                 cl->quantum = (cl->weight*cl->allot*q->nclasses[prio])/
 822                                         q->quanta[prio];
 823                         }
 824                         if (cl->quantum <= 0 ||
 825                             cl->quantum > 32*qdisc_dev(cl->qdisc)->mtu) {
 826                                 pr_warn("CBQ: class %08x has bad quantum==%ld, repaired.\n",
 827                                         cl->common.classid, cl->quantum);
 828                                 cl->quantum = qdisc_dev(cl->qdisc)->mtu/2 + 1;
 829                         }
 830                 }
 831         }
 832 }
 833
 834 static void cbq_sync_defmap(struct cbq_class *cl)
 835 {
 836         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 837         struct cbq_class *split = cl->split;
 838         unsigned int h;
 839         int i;
 840
 841         if (split == NULL)
 842                 return;
 843
 844         for (i = 0; i <= TC_PRIO_MAX; i++) {
 845                 if (split->defaults[i] == cl && !(cl->defmap & (1<<i)))
 846                         split->defaults[i] = NULL;
 847         }
 848
 849         for (i = 0; i <= TC_PRIO_MAX; i++) {
 850                 int level = split->level;
 851
 852                 if (split->defaults[i])
 853                         continue;
 854
 855                 for (h = 0; h < q->clhash.hashsize; h++) {
 856                         struct cbq_class *c;
 857
 858                         hlist_for_each_entry(c, &q->clhash.hash[h],
 859                                              common.hnode) {
 860                                 if (c->split == split && c->level < level &&
 861                                     c->defmap & (1<<i)) {
 862                                         split->defaults[i] = c;
 863                                         level = c->level;
 864                                 }
 865                         }
 866                 }
 867         }
 868 }
 869
 870 static void cbq_change_defmap(struct cbq_class *cl, u32 splitid, u32 def, u32 mask)
 871 {
 872         struct cbq_class *split = NULL;
 873
 874         if (splitid == 0) {
 875                 split = cl->split;
 876                 if (!split)
 877                         return;
 878                 splitid = split->common.classid;
 879         }
 880
 881         if (split == NULL || split->common.classid != splitid) {
 882                 for (split = cl->tparent; split; split = split->tparent)
 883                         if (split->common.classid == splitid)
 884                                 break;
 885         }
 886
 887         if (split == NULL)
 888                 return;
 889
 890         if (cl->split != split) {
 891                 cl->defmap = 0;
 892                 cbq_sync_defmap(cl);
 893                 cl->split = split;
 894                 cl->defmap = def & mask;
 895         } else
 896                 cl->defmap = (cl->defmap & ~mask) | (def & mask);
 897
 898         cbq_sync_defmap(cl);
 899 }
 900
 901 static void cbq_unlink_class(struct cbq_class *this)
 902 {
 903         struct cbq_class *cl, **clp;
 904         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
 905
 906         qdisc_class_hash_remove(&q->clhash, &this->common);
 907
 908         if (this->tparent) {
 909                 clp = &this->sibling;
 910                 cl = *clp;
 911                 do {
 912                         if (cl == this) {
 913                                 *clp = cl->sibling;
 914                                 break;
 915                         }
 916                         clp = &cl->sibling;
 917                 } while ((cl = *clp) != this->sibling);
 918
 919                 if (this->tparent->children == this) {
 920                         this->tparent->children = this->sibling;
 921                         if (this->sibling == this)
 922                                 this->tparent->children = NULL;
 923                 }
 924         } else {
 925                 WARN_ON(this->sibling != this);
 926         }
 927 }
 928
 929 static void cbq_link_class(struct cbq_class *this)
 930 {
 931         struct cbq_sched_data *q = qdisc_priv(this->qdisc);
 932         struct cbq_class *parent = this->tparent;
 933
 934         this->sibling = this;
 935         qdisc_class_hash_insert(&q->clhash, &this->common);
 936
 937         if (parent == NULL)
 938                 return;
 939
 940         if (parent->children == NULL) {
 941                 parent->children = this;
 942         } else {
 943                 this->sibling = parent->children->sibling;
 944                 parent->children->sibling = this;
 945         }
 946 }
 947
 948 static void
 949 cbq_reset(struct Qdisc *sch)
 950 {
 951         struct cbq_sched_data *q = qdisc_priv(sch);
 952         struct cbq_class *cl;
 953         int prio;
 954         unsigned int h;
 955
 956         q->activemask = 0;
 957         q->pmask = 0;
 958         q->tx_class = NULL;
 959         q->tx_borrowed = NULL;
 960         qdisc_watchdog_cancel(&q->watchdog);
 961         q->toplevel = TC_CBQ_MAXLEVEL;
 962         q->now = psched_get_time();
 963
 964         for (prio = 0; prio <= TC_CBQ_MAXPRIO; prio++)
 965                 q->active[prio] = NULL;
 966
 967         for (h = 0; h < q->clhash.hashsize; h++) {
 968                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
 969                         qdisc_reset(cl->q);
 970
 971                         cl->next_alive = NULL;
 972                         cl->undertime = PSCHED_PASTPERFECT;
 973                         cl->avgidle = cl->maxidle;
 974                         cl->deficit = cl->quantum;
 975                         cl->cpriority = cl->priority;
 976                 }
 977         }
 978 }
 979
 980
 981 static void cbq_set_lss(struct cbq_class *cl, struct tc_cbq_lssopt *lss)
 982 {
 983         if (lss->change & TCF_CBQ_LSS_FLAGS) {
 984                 cl->share = (lss->flags & TCF_CBQ_LSS_ISOLATED) ? NULL : cl->tparent;
 985                 cl->borrow = (lss->flags & TCF_CBQ_LSS_BOUNDED) ? NULL : cl->tparent;
 986         }
 987         if (lss->change & TCF_CBQ_LSS_EWMA)
 988                 cl->ewma_log = lss->ewma_log;
 989         if (lss->change & TCF_CBQ_LSS_AVPKT)
 990                 cl->avpkt = lss->avpkt;
 991         if (lss->change & TCF_CBQ_LSS_MINIDLE)
 992                 cl->minidle = -(long)lss->minidle;
 993         if (lss->change & TCF_CBQ_LSS_MAXIDLE) {
 994                 cl->maxidle = lss->maxidle;
 995                 cl->avgidle = lss->maxidle;
 996         }
 997         if (lss->change & TCF_CBQ_LSS_OFFTIME)
 998                 cl->offtime = lss->offtime;
 999 }
1000
1001 static void cbq_rmprio(struct cbq_sched_data *q, struct cbq_class *cl)
1002 {
1003         q->nclasses[cl->priority]--;
1004         q->quanta[cl->priority] -= cl->weight;
1005         cbq_normalize_quanta(q, cl->priority);
1006 }
1007
1008 static void cbq_addprio(struct cbq_sched_data *q, struct cbq_class *cl)
1009 {
1010         q->nclasses[cl->priority]++;
1011         q->quanta[cl->priority] += cl->weight;
1012         cbq_normalize_quanta(q, cl->priority);
1013 }
1014
1015 static int cbq_set_wrr(struct cbq_class *cl, struct tc_cbq_wrropt *wrr)
1016 {
1017         struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
1018
1019         if (wrr->allot)
1020                 cl->allot = wrr->allot;
1021         if (wrr->weight)
1022                 cl->weight = wrr->weight;
1023         if (wrr->priority) {
1024                 cl->priority = wrr->priority - 1;
1025                 cl->cpriority = cl->priority;
1026                 if (cl->priority >= cl->priority2)
1027                         cl->priority2 = TC_CBQ_MAXPRIO - 1;
1028         }
1029
1030         cbq_addprio(q, cl);
1031         return 0;
1032 }
1033
1034 static int cbq_set_fopt(struct cbq_class *cl, struct tc_cbq_fopt *fopt)
1035 {
1036         cbq_change_defmap(cl, fopt->split, fopt->defmap, fopt->defchange);
1037         return 0;
1038 }
1039
1040 static const struct nla_policy cbq_policy[TCA_CBQ_MAX + 1] = {
1041         [TCA_CBQ_LSSOPT]        = { .len = sizeof(struct tc_cbq_lssopt) },
1042         [TCA_CBQ_WRROPT]        = { .len = sizeof(struct tc_cbq_wrropt) },
1043         [TCA_CBQ_FOPT]          = { .len = sizeof(struct tc_cbq_fopt) },
1044         [TCA_CBQ_OVL_STRATEGY]  = { .len = sizeof(struct tc_cbq_ovl) },
1045         [TCA_CBQ_RATE]          = { .len = sizeof(struct tc_ratespec) },
1046         [TCA_CBQ_RTAB]          = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
1047         [TCA_CBQ_POLICE]        = { .len = sizeof(struct tc_cbq_police) },
1048 };
1049
1050 static int cbq_opt_parse(struct nlattr *tb[TCA_CBQ_MAX + 1],
1051                          struct nlattr *opt,
1052                          struct netlink_ext_ack *extack)
1053 {
1054         int err;
1055
1056         if (!opt) {
1057                 NL_SET_ERR_MSG(extack, "CBQ options are required for this operation");
1058                 return -EINVAL;
1059         }
1060
1061         err = nla_parse_nested_deprecated(tb, TCA_CBQ_MAX, opt,
1062                                           cbq_policy, extack);
1063         if (err < 0)
1064                 return err;
1065
1066         if (tb[TCA_CBQ_WRROPT]) {
1067                 const struct tc_cbq_wrropt *wrr = nla_data(tb[TCA_CBQ_WRROPT]);
1068
1069                 if (wrr->priority > TC_CBQ_MAXPRIO) {
1070                         NL_SET_ERR_MSG(extack, "priority is bigger than TC_CBQ_MAXPRIO");
1071                         err = -EINVAL;
1072                 }
1073         }
1074         return err;
1075 }
1076
1077 static int cbq_init(struct Qdisc *sch, struct nlattr *opt,
1078                     struct netlink_ext_ack *extack)
1079 {
1080         struct cbq_sched_data *q = qdisc_priv(sch);
1081         struct nlattr *tb[TCA_CBQ_MAX + 1];
1082         struct tc_ratespec *r;
1083         int err;
1084
1085         qdisc_watchdog_init(&q->watchdog, sch);
1086
1087         err = cbq_opt_parse(tb, opt, extack);
1088         if (err < 0)
1089                 return err;
1090
1091         if (!tb[TCA_CBQ_RTAB] || !tb[TCA_CBQ_RATE]) {
1092                 NL_SET_ERR_MSG(extack, "Rate specification missing or incomplete");
1093                 return -EINVAL;
1094         }
1095
1096         r = nla_data(tb[TCA_CBQ_RATE]);
1097
1098         q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB], extack);
1099         if (!q->link.R_tab)
1100                 return -EINVAL;
1101
1102         err = tcf_block_get(&q->link.block, &q->link.filter_list, sch, extack);
1103         if (err)
1104                 goto put_rtab;
1105
1106         err = qdisc_class_hash_init(&q->clhash);
1107         if (err < 0)
1108                 goto put_block;
1109
1110         q->link.sibling = &q->link;
1111         q->link.common.classid = sch->handle;
1112         q->link.qdisc = sch;
1113         q->link.q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1114                                       sch->handle, NULL);
1115         if (!q->link.q)
1116                 q->link.q = &noop_qdisc;
1117         else
1118                 qdisc_hash_add(q->link.q, true);
1119
1120         q->link.priority = TC_CBQ_MAXPRIO - 1;
1121         q->link.priority2 = TC_CBQ_MAXPRIO - 1;
1122         q->link.cpriority = TC_CBQ_MAXPRIO - 1;
1123         q->link.allot = psched_mtu(qdisc_dev(sch));
1124         q->link.quantum = q->link.allot;
1125         q->link.weight = q->link.R_tab->rate.rate;
1126
1127         q->link.ewma_log = TC_CBQ_DEF_EWMA;
1128         q->link.avpkt = q->link.allot/2;
1129         q->link.minidle = -0x7FFFFFFF;
1130
1131         q->toplevel = TC_CBQ_MAXLEVEL;
1132         q->now = psched_get_time();
1133
1134         cbq_link_class(&q->link);
1135
1136         if (tb[TCA_CBQ_LSSOPT])
1137                 cbq_set_lss(&q->link, nla_data(tb[TCA_CBQ_LSSOPT]));
1138
1139         cbq_addprio(q, &q->link);
1140         return 0;
1141
1142 put_block:
1143         tcf_block_put(q->link.block);
1144
1145 put_rtab:
1146         qdisc_put_rtab(q->link.R_tab);
1147         return err;
1148 }
1149
1150 static int cbq_dump_rate(struct sk_buff *skb, struct cbq_class *cl)
1151 {
1152         unsigned char *b = skb_tail_pointer(skb);
1153
1154         if (nla_put(skb, TCA_CBQ_RATE, sizeof(cl->R_tab->rate), &cl->R_tab->rate))
1155                 goto nla_put_failure;
1156         return skb->len;
1157
1158 nla_put_failure:
1159         nlmsg_trim(skb, b);
1160         return -1;
1161 }
1162
1163 static int cbq_dump_lss(struct sk_buff *skb, struct cbq_class *cl)
1164 {
1165         unsigned char *b = skb_tail_pointer(skb);
1166         struct tc_cbq_lssopt opt;
1167
1168         opt.flags = 0;
1169         if (cl->borrow == NULL)
1170                 opt.flags |= TCF_CBQ_LSS_BOUNDED;
1171         if (cl->share == NULL)
1172                 opt.flags |= TCF_CBQ_LSS_ISOLATED;
1173         opt.ewma_log = cl->ewma_log;
1174         opt.level = cl->level;
1175         opt.avpkt = cl->avpkt;
1176         opt.maxidle = cl->maxidle;
1177         opt.minidle = (u32)(-cl->minidle);
1178         opt.offtime = cl->offtime;
1179         opt.change = ~0;
1180         if (nla_put(skb, TCA_CBQ_LSSOPT, sizeof(opt), &opt))
1181                 goto nla_put_failure;
1182         return skb->len;
1183
1184 nla_put_failure:
1185         nlmsg_trim(skb, b);
1186         return -1;
1187 }
1188
1189 static int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
1190 {
1191         unsigned char *b = skb_tail_pointer(skb);
1192         struct tc_cbq_wrropt opt;
1193
1194         memset(&opt, 0, sizeof(opt));
1195         opt.flags = 0;
1196         opt.allot = cl->allot;
1197         opt.priority = cl->priority + 1;
1198         opt.cpriority = cl->cpriority + 1;
1199         opt.weight = cl->weight;
1200         if (nla_put(skb, TCA_CBQ_WRROPT, sizeof(opt), &opt))
1201                 goto nla_put_failure;
1202         return skb->len;
1203
1204 nla_put_failure:
1205         nlmsg_trim(skb, b);
1206         return -1;
1207 }
1208
1209 static int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
1210 {
1211         unsigned char *b = skb_tail_pointer(skb);
1212         struct tc_cbq_fopt opt;
1213
1214         if (cl->split || cl->defmap) {
1215                 opt.split = cl->split ? cl->split->common.classid : 0;
1216                 opt.defmap = cl->defmap;
1217                 opt.defchange = ~0;
1218                 if (nla_put(skb, TCA_CBQ_FOPT, sizeof(opt), &opt))
1219                         goto nla_put_failure;
1220         }
1221         return skb->len;
1222
1223 nla_put_failure:
1224         nlmsg_trim(skb, b);
1225         return -1;
1226 }
1227
1228 static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
1229 {
1230         if (cbq_dump_lss(skb, cl) < 0 ||
1231             cbq_dump_rate(skb, cl) < 0 ||
1232             cbq_dump_wrr(skb, cl) < 0 ||
1233             cbq_dump_fopt(skb, cl) < 0)
1234                 return -1;
1235         return 0;
1236 }
1237
1238 static int cbq_dump(struct Qdisc *sch, struct sk_buff *skb)
1239 {
1240         struct cbq_sched_data *q = qdisc_priv(sch);
1241         struct nlattr *nest;
1242
1243         nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
1244         if (nest == NULL)
1245                 goto nla_put_failure;
1246         if (cbq_dump_attr(skb, &q->link) < 0)
1247                 goto nla_put_failure;
1248         return nla_nest_end(skb, nest);
1249
1250 nla_put_failure:
1251         nla_nest_cancel(skb, nest);
1252         return -1;
1253 }
1254
1255 static int
1256 cbq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
1257 {
1258         struct cbq_sched_data *q = qdisc_priv(sch);
1259
1260         q->link.xstats.avgidle = q->link.avgidle;
1261         return gnet_stats_copy_app(d, &q->link.xstats, sizeof(q->link.xstats));
1262 }
1263
1264 static int
1265 cbq_dump_class(struct Qdisc *sch, unsigned long arg,
1266                struct sk_buff *skb, struct tcmsg *tcm)
1267 {
1268         struct cbq_class *cl = (struct cbq_class *)arg;
1269         struct nlattr *nest;
1270
1271         if (cl->tparent)
1272                 tcm->tcm_parent = cl->tparent->common.classid;
1273         else
1274                 tcm->tcm_parent = TC_H_ROOT;
1275         tcm->tcm_handle = cl->common.classid;
1276         tcm->tcm_info = cl->q->handle;
1277
1278         nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
1279         if (nest == NULL)
1280                 goto nla_put_failure;
1281         if (cbq_dump_attr(skb, cl) < 0)
1282                 goto nla_put_failure;
1283         return nla_nest_end(skb, nest);
1284
1285 nla_put_failure:
1286         nla_nest_cancel(skb, nest);
1287         return -1;
1288 }
1289
1290 static int
1291 cbq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
1292         struct gnet_dump *d)
1293 {
1294         struct cbq_sched_data *q = qdisc_priv(sch);
1295         struct cbq_class *cl = (struct cbq_class *)arg;
1296         __u32 qlen;
1297
1298         cl->xstats.avgidle = cl->avgidle;
1299         cl->xstats.undertime = 0;
1300         qdisc_qstats_qlen_backlog(cl->q, &qlen, &cl->qstats.backlog);
1301
1302         if (cl->undertime != PSCHED_PASTPERFECT)
1303                 cl->xstats.undertime = cl->undertime - q->now;
1304
1305         if (gnet_stats_copy_basic(d, NULL, &cl->bstats, true) < 0 ||
1306             gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1307             gnet_stats_copy_queue(d, NULL, &cl->qstats, qlen) < 0)
1308                 return -1;
1309
1310         return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1311 }
1312
1313 static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1314                      struct Qdisc **old, struct netlink_ext_ack *extack)
1315 {
1316         struct cbq_class *cl = (struct cbq_class *)arg;
1317
1318         if (new == NULL) {
1319                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1320                                         cl->common.classid, extack);
1321                 if (new == NULL)
1322                         return -ENOBUFS;
1323         }
1324
1325         *old = qdisc_replace(sch, new, &cl->q);
1326         return 0;
1327 }
1328
1329 static struct Qdisc *cbq_leaf(struct Qdisc *sch, unsigned long arg)
1330 {
1331         struct cbq_class *cl = (struct cbq_class *)arg;
1332
1333         return cl->q;
1334 }
1335
1336 static void cbq_qlen_notify(struct Qdisc *sch, unsigned long arg)
1337 {
1338         struct cbq_class *cl = (struct cbq_class *)arg;
1339
1340         cbq_deactivate_class(cl);
1341 }
1342
1343 static unsigned long cbq_find(struct Qdisc *sch, u32 classid)
1344 {
1345         struct cbq_sched_data *q = qdisc_priv(sch);
1346
1347         return (unsigned long)cbq_class_lookup(q, classid);
1348 }
1349
1350 static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
1351 {
1352         struct cbq_sched_data *q = qdisc_priv(sch);
1353
1354         WARN_ON(cl->filters);
1355
1356         tcf_block_put(cl->block);
1357         qdisc_put(cl->q);
1358         qdisc_put_rtab(cl->R_tab);
1359         gen_kill_estimator(&cl->rate_est);
1360         if (cl != &q->link)
1361                 kfree(cl);
1362 }
1363
1364 static void cbq_destroy(struct Qdisc *sch)
1365 {
1366         struct cbq_sched_data *q = qdisc_priv(sch);
1367         struct hlist_node *next;
1368         struct cbq_class *cl;
1369         unsigned int h;
1370
1371 #ifdef CONFIG_NET_CLS_ACT
1372         q->rx_class = NULL;
1373 #endif
1374         /*
1375          * Filters must be destroyed first because we don't destroy the
1376          * classes from root to leafs which means that filters can still
1377          * be bound to classes which have been destroyed already. --TGR '04
1378          */
1379         for (h = 0; h < q->clhash.hashsize; h++) {
1380                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1381                         tcf_block_put(cl->block);
1382                         cl->block = NULL;
1383                 }
1384         }
1385         for (h = 0; h < q->clhash.hashsize; h++) {
1386                 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[h],
1387                                           common.hnode)
1388                         cbq_destroy_class(sch, cl);
1389         }
1390         qdisc_class_hash_destroy(&q->clhash);
1391 }
1392
1393 static int
1394 cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca,
1395                  unsigned long *arg, struct netlink_ext_ack *extack)
1396 {
1397         int err;
1398         struct cbq_sched_data *q = qdisc_priv(sch);
1399         struct cbq_class *cl = (struct cbq_class *)*arg;
1400         struct nlattr *opt = tca[TCA_OPTIONS];
1401         struct nlattr *tb[TCA_CBQ_MAX + 1];
1402         struct cbq_class *parent;
1403         struct qdisc_rate_table *rtab = NULL;
1404
1405         err = cbq_opt_parse(tb, opt, extack);
1406         if (err < 0)
1407                 return err;
1408
1409         if (tb[TCA_CBQ_OVL_STRATEGY] || tb[TCA_CBQ_POLICE]) {
1410                 NL_SET_ERR_MSG(extack, "Neither overlimit strategy nor policing attributes can be used for changing class params");
1411                 return -EOPNOTSUPP;
1412         }
1413
1414         if (cl) {
1415                 /* Check parent */
1416                 if (parentid) {
1417                         if (cl->tparent &&
1418                             cl->tparent->common.classid != parentid) {
1419                                 NL_SET_ERR_MSG(extack, "Invalid parent id");
1420                                 return -EINVAL;
1421                         }
1422                         if (!cl->tparent && parentid != TC_H_ROOT) {
1423                                 NL_SET_ERR_MSG(extack, "Parent must be root");
1424                                 return -EINVAL;
1425                         }
1426                 }
1427
1428                 if (tb[TCA_CBQ_RATE]) {
1429                         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
1430                                               tb[TCA_CBQ_RTAB], extack);
1431                         if (rtab == NULL)
1432                                 return -EINVAL;
1433                 }
1434
1435                 if (tca[TCA_RATE]) {
1436                         err = gen_replace_estimator(&cl->bstats, NULL,
1437                                                     &cl->rate_est,
1438                                                     NULL,
1439                                                     true,
1440                                                     tca[TCA_RATE]);
1441                         if (err) {
1442                                 NL_SET_ERR_MSG(extack, "Failed to replace specified rate estimator");
1443                                 qdisc_put_rtab(rtab);
1444                                 return err;
1445                         }
1446                 }
1447
1448                 /* Change class parameters */
1449                 sch_tree_lock(sch);
1450
1451                 if (cl->next_alive != NULL)
1452                         cbq_deactivate_class(cl);
1453
1454                 if (rtab) {
1455                         qdisc_put_rtab(cl->R_tab);
1456                         cl->R_tab = rtab;
1457                 }
1458
1459                 if (tb[TCA_CBQ_LSSOPT])
1460                         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1461
1462                 if (tb[TCA_CBQ_WRROPT]) {
1463                         cbq_rmprio(q, cl);
1464                         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1465                 }
1466
1467                 if (tb[TCA_CBQ_FOPT])
1468                         cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1469
1470                 if (cl->q->q.qlen)
1471                         cbq_activate_class(cl);
1472
1473                 sch_tree_unlock(sch);
1474
1475                 return 0;
1476         }
1477
1478         if (parentid == TC_H_ROOT)
1479                 return -EINVAL;
1480
1481         if (!tb[TCA_CBQ_WRROPT] || !tb[TCA_CBQ_RATE] || !tb[TCA_CBQ_LSSOPT]) {
1482                 NL_SET_ERR_MSG(extack, "One of the following attributes MUST be specified: WRR, rate or link sharing");
1483                 return -EINVAL;
1484         }
1485
1486         rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB],
1487                               extack);
1488         if (rtab == NULL)
1489                 return -EINVAL;
1490
1491         if (classid) {
1492                 err = -EINVAL;
1493                 if (TC_H_MAJ(classid ^ sch->handle) ||
1494                     cbq_class_lookup(q, classid)) {
1495                         NL_SET_ERR_MSG(extack, "Specified class not found");
1496                         goto failure;
1497                 }
1498         } else {
1499                 int i;
1500                 classid = TC_H_MAKE(sch->handle, 0x8000);
1501
1502                 for (i = 0; i < 0x8000; i++) {
1503                         if (++q->hgenerator >= 0x8000)
1504                                 q->hgenerator = 1;
1505                         if (cbq_class_lookup(q, classid|q->hgenerator) == NULL)
1506                                 break;
1507                 }
1508                 err = -ENOSR;
1509                 if (i >= 0x8000) {
1510                         NL_SET_ERR_MSG(extack, "Unable to generate classid");
1511                         goto failure;
1512                 }
1513                 classid = classid|q->hgenerator;
1514         }
1515
1516         parent = &q->link;
1517         if (parentid) {
1518                 parent = cbq_class_lookup(q, parentid);
1519                 err = -EINVAL;
1520                 if (!parent) {
1521                         NL_SET_ERR_MSG(extack, "Failed to find parentid");
1522                         goto failure;
1523                 }
1524         }
1525
1526         err = -ENOBUFS;
1527         cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1528         if (cl == NULL)
1529                 goto failure;
1530
1531         gnet_stats_basic_sync_init(&cl->bstats);
1532         err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
1533         if (err) {
1534                 kfree(cl);
1535                 goto failure;
1536         }
1537
1538         if (tca[TCA_RATE]) {
1539                 err = gen_new_estimator(&cl->bstats, NULL, &cl->rate_est,
1540                                         NULL, true, tca[TCA_RATE]);
1541                 if (err) {
1542                         NL_SET_ERR_MSG(extack, "Couldn't create new estimator");
1543                         tcf_block_put(cl->block);
1544                         kfree(cl);
1545                         goto failure;
1546                 }
1547         }
1548
1549         cl->R_tab = rtab;
1550         rtab = NULL;
1551         cl->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid,
1552                                   NULL);
1553         if (!cl->q)
1554                 cl->q = &noop_qdisc;
1555         else
1556                 qdisc_hash_add(cl->q, true);
1557
1558         cl->common.classid = classid;
1559         cl->tparent = parent;
1560         cl->qdisc = sch;
1561         cl->allot = parent->allot;
1562         cl->quantum = cl->allot;
1563         cl->weight = cl->R_tab->rate.rate;
1564
1565         sch_tree_lock(sch);
1566         cbq_link_class(cl);
1567         cl->borrow = cl->tparent;
1568         if (cl->tparent != &q->link)
1569                 cl->share = cl->tparent;
1570         cbq_adjust_levels(parent);
1571         cl->minidle = -0x7FFFFFFF;
1572         cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
1573         cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
1574         if (cl->ewma_log == 0)
1575                 cl->ewma_log = q->link.ewma_log;
1576         if (cl->maxidle == 0)
1577                 cl->maxidle = q->link.maxidle;
1578         if (cl->avpkt == 0)
1579                 cl->avpkt = q->link.avpkt;
1580         if (tb[TCA_CBQ_FOPT])
1581                 cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
1582         sch_tree_unlock(sch);
1583
1584         qdisc_class_hash_grow(sch, &q->clhash);
1585
1586         *arg = (unsigned long)cl;
1587         return 0;
1588
1589 failure:
1590         qdisc_put_rtab(rtab);
1591         return err;
1592 }
1593
1594 static int cbq_delete(struct Qdisc *sch, unsigned long arg,
1595                       struct netlink_ext_ack *extack)
1596 {
1597         struct cbq_sched_data *q = qdisc_priv(sch);
1598         struct cbq_class *cl = (struct cbq_class *)arg;
1599
1600         if (cl->filters || cl->children || cl == &q->link)
1601                 return -EBUSY;
1602
1603         sch_tree_lock(sch);
1604
1605         qdisc_purge_queue(cl->q);
1606
1607         if (cl->next_alive)
1608                 cbq_deactivate_class(cl);
1609
1610         if (q->tx_borrowed == cl)
1611                 q->tx_borrowed = q->tx_class;
1612         if (q->tx_class == cl) {
1613                 q->tx_class = NULL;
1614                 q->tx_borrowed = NULL;
1615         }
1616 #ifdef CONFIG_NET_CLS_ACT
1617         if (q->rx_class == cl)
1618                 q->rx_class = NULL;
1619 #endif
1620
1621         cbq_unlink_class(cl);
1622         cbq_adjust_levels(cl->tparent);
1623         cl->defmap = 0;
1624         cbq_sync_defmap(cl);
1625
1626         cbq_rmprio(q, cl);
1627         sch_tree_unlock(sch);
1628
1629         cbq_destroy_class(sch, cl);
1630         return 0;
1631 }
1632
1633 static struct tcf_block *cbq_tcf_block(struct Qdisc *sch, unsigned long arg,
1634                                        struct netlink_ext_ack *extack)
1635 {
1636         struct cbq_sched_data *q = qdisc_priv(sch);
1637         struct cbq_class *cl = (struct cbq_class *)arg;
1638
1639         if (cl == NULL)
1640                 cl = &q->link;
1641
1642         return cl->block;
1643 }
1644
1645 static unsigned long cbq_bind_filter(struct Qdisc *sch, unsigned long parent,
1646                                      u32 classid)
1647 {
1648         struct cbq_sched_data *q = qdisc_priv(sch);
1649         struct cbq_class *p = (struct cbq_class *)parent;
1650         struct cbq_class *cl = cbq_class_lookup(q, classid);
1651
1652         if (cl) {
1653                 if (p && p->level <= cl->level)
1654                         return 0;
1655                 cl->filters++;
1656                 return (unsigned long)cl;
1657         }
1658         return 0;
1659 }
1660
1661 static void cbq_unbind_filter(struct Qdisc *sch, unsigned long arg)
1662 {
1663         struct cbq_class *cl = (struct cbq_class *)arg;
1664
1665         cl->filters--;
1666 }
1667
1668 static void cbq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1669 {
1670         struct cbq_sched_data *q = qdisc_priv(sch);
1671         struct cbq_class *cl;
1672         unsigned int h;
1673
1674         if (arg->stop)
1675                 return;
1676
1677         for (h = 0; h < q->clhash.hashsize; h++) {
1678                 hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
1679                         if (!tc_qdisc_stats_dump(sch, (unsigned long)cl, arg))
1680                                 return;
1681                 }
1682         }
1683 }
1684
1685 static const struct Qdisc_class_ops cbq_class_ops = {
1686         .graft          =       cbq_graft,
1687         .leaf           =       cbq_leaf,
1688         .qlen_notify    =       cbq_qlen_notify,
1689         .find           =       cbq_find,
1690         .change         =       cbq_change_class,
1691         .delete         =       cbq_delete,
1692         .walk           =       cbq_walk,
1693         .tcf_block      =       cbq_tcf_block,
1694         .bind_tcf       =       cbq_bind_filter,
1695         .unbind_tcf     =       cbq_unbind_filter,
1696         .dump           =       cbq_dump_class,
1697         .dump_stats     =       cbq_dump_class_stats,
1698 };
1699
1700 static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
1701         .next           =       NULL,
1702         .cl_ops         =       &cbq_class_ops,
1703         .id             =       "cbq",
1704         .priv_size      =       sizeof(struct cbq_sched_data),
1705         .enqueue        =       cbq_enqueue,
1706         .dequeue        =       cbq_dequeue,
1707         .peek           =       qdisc_peek_dequeued,
1708         .init           =       cbq_init,
1709         .reset          =       cbq_reset,
1710         .destroy        =       cbq_destroy,
1711         .change         =       NULL,
1712         .dump           =       cbq_dump,
1713         .dump_stats     =       cbq_dump_stats,
1714         .owner          =       THIS_MODULE,
1715 };
1716
1717 static int __init cbq_module_init(void)
1718 {
1719         return register_qdisc(&cbq_qdisc_ops);
1720 }
1721 static void __exit cbq_module_exit(void)
1722 {
1723         unregister_qdisc(&cbq_qdisc_ops);
1724 }
1725 module_init(cbq_module_init)
1726 module_exit(cbq_module_exit)
1727 MODULE_LICENSE("GPL");