linux/net/sched/sch_sfb.c
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   1/*
   2 * net/sched/sch_sfb.c    Stochastic Fair Blue
   3 *
   4 * Copyright (c) 2008-2011 Juliusz Chroboczek <jch@pps.jussieu.fr>
   5 * Copyright (c) 2011 Eric Dumazet <eric.dumazet@gmail.com>
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * version 2 as published by the Free Software Foundation.
  10 *
  11 * W. Feng, D. Kandlur, D. Saha, K. Shin. Blue:
  12 * A New Class of Active Queue Management Algorithms.
  13 * U. Michigan CSE-TR-387-99, April 1999.
  14 *
  15 * http://www.thefengs.com/wuchang/blue/CSE-TR-387-99.pdf
  16 *
  17 */
  18
  19#include <linux/module.h>
  20#include <linux/types.h>
  21#include <linux/kernel.h>
  22#include <linux/errno.h>
  23#include <linux/skbuff.h>
  24#include <linux/random.h>
  25#include <linux/jhash.h>
  26#include <net/ip.h>
  27#include <net/pkt_sched.h>
  28#include <net/pkt_cls.h>
  29#include <net/inet_ecn.h>
  30
  31/*
  32 * SFB uses two B[l][n] : L x N arrays of bins (L levels, N bins per level)
  33 * This implementation uses L = 8 and N = 16
  34 * This permits us to split one 32bit hash (provided per packet by rxhash or
  35 * external classifier) into 8 subhashes of 4 bits.
  36 */
  37#define SFB_BUCKET_SHIFT 4
  38#define SFB_NUMBUCKETS  (1 << SFB_BUCKET_SHIFT) /* N bins per Level */
  39#define SFB_BUCKET_MASK (SFB_NUMBUCKETS - 1)
  40#define SFB_LEVELS      (32 / SFB_BUCKET_SHIFT) /* L */
  41
  42/* SFB algo uses a virtual queue, named "bin" */
  43struct sfb_bucket {
  44        u16             qlen; /* length of virtual queue */
  45        u16             p_mark; /* marking probability */
  46};
  47
  48/* We use a double buffering right before hash change
  49 * (Section 4.4 of SFB reference : moving hash functions)
  50 */
  51struct sfb_bins {
  52        u32               perturbation; /* jhash perturbation */
  53        struct sfb_bucket bins[SFB_LEVELS][SFB_NUMBUCKETS];
  54};
  55
  56struct sfb_sched_data {
  57        struct Qdisc    *qdisc;
  58        struct tcf_proto __rcu *filter_list;
  59        struct tcf_block *block;
  60        unsigned long   rehash_interval;
  61        unsigned long   warmup_time;    /* double buffering warmup time in jiffies */
  62        u32             max;
  63        u32             bin_size;       /* maximum queue length per bin */
  64        u32             increment;      /* d1 */
  65        u32             decrement;      /* d2 */
  66        u32             limit;          /* HARD maximal queue length */
  67        u32             penalty_rate;
  68        u32             penalty_burst;
  69        u32             tokens_avail;
  70        unsigned long   rehash_time;
  71        unsigned long   token_time;
  72
  73        u8              slot;           /* current active bins (0 or 1) */
  74        bool            double_buffering;
  75        struct sfb_bins bins[2];
  76
  77        struct {
  78                u32     earlydrop;
  79                u32     penaltydrop;
  80                u32     bucketdrop;
  81                u32     queuedrop;
  82                u32     childdrop;      /* drops in child qdisc */
  83                u32     marked;         /* ECN mark */
  84        } stats;
  85};
  86
  87/*
  88 * Each queued skb might be hashed on one or two bins
  89 * We store in skb_cb the two hash values.
  90 * (A zero value means double buffering was not used)
  91 */
  92struct sfb_skb_cb {
  93        u32 hashes[2];
  94};
  95
  96static inline struct sfb_skb_cb *sfb_skb_cb(const struct sk_buff *skb)
  97{
  98        qdisc_cb_private_validate(skb, sizeof(struct sfb_skb_cb));
  99        return (struct sfb_skb_cb *)qdisc_skb_cb(skb)->data;
 100}
 101
 102/*
 103 * If using 'internal' SFB flow classifier, hash comes from skb rxhash
 104 * If using external classifier, hash comes from the classid.
 105 */
 106static u32 sfb_hash(const struct sk_buff *skb, u32 slot)
 107{
 108        return sfb_skb_cb(skb)->hashes[slot];
 109}
 110
 111/* Probabilities are coded as Q0.16 fixed-point values,
 112 * with 0xFFFF representing 65535/65536 (almost 1.0)
 113 * Addition and subtraction are saturating in [0, 65535]
 114 */
 115static u32 prob_plus(u32 p1, u32 p2)
 116{
 117        u32 res = p1 + p2;
 118
 119        return min_t(u32, res, SFB_MAX_PROB);
 120}
 121
 122static u32 prob_minus(u32 p1, u32 p2)
 123{
 124        return p1 > p2 ? p1 - p2 : 0;
 125}
 126
 127static void increment_one_qlen(u32 sfbhash, u32 slot, struct sfb_sched_data *q)
 128{
 129        int i;
 130        struct sfb_bucket *b = &q->bins[slot].bins[0][0];
 131
 132        for (i = 0; i < SFB_LEVELS; i++) {
 133                u32 hash = sfbhash & SFB_BUCKET_MASK;
 134
 135                sfbhash >>= SFB_BUCKET_SHIFT;
 136                if (b[hash].qlen < 0xFFFF)
 137                        b[hash].qlen++;
 138                b += SFB_NUMBUCKETS; /* next level */
 139        }
 140}
 141
 142static void increment_qlen(const struct sk_buff *skb, struct sfb_sched_data *q)
 143{
 144        u32 sfbhash;
 145
 146        sfbhash = sfb_hash(skb, 0);
 147        if (sfbhash)
 148                increment_one_qlen(sfbhash, 0, q);
 149
 150        sfbhash = sfb_hash(skb, 1);
 151        if (sfbhash)
 152                increment_one_qlen(sfbhash, 1, q);
 153}
 154
 155static void decrement_one_qlen(u32 sfbhash, u32 slot,
 156                               struct sfb_sched_data *q)
 157{
 158        int i;
 159        struct sfb_bucket *b = &q->bins[slot].bins[0][0];
 160
 161        for (i = 0; i < SFB_LEVELS; i++) {
 162                u32 hash = sfbhash & SFB_BUCKET_MASK;
 163
 164                sfbhash >>= SFB_BUCKET_SHIFT;
 165                if (b[hash].qlen > 0)
 166                        b[hash].qlen--;
 167                b += SFB_NUMBUCKETS; /* next level */
 168        }
 169}
 170
 171static void decrement_qlen(const struct sk_buff *skb, struct sfb_sched_data *q)
 172{
 173        u32 sfbhash;
 174
 175        sfbhash = sfb_hash(skb, 0);
 176        if (sfbhash)
 177                decrement_one_qlen(sfbhash, 0, q);
 178
 179        sfbhash = sfb_hash(skb, 1);
 180        if (sfbhash)
 181                decrement_one_qlen(sfbhash, 1, q);
 182}
 183
 184static void decrement_prob(struct sfb_bucket *b, struct sfb_sched_data *q)
 185{
 186        b->p_mark = prob_minus(b->p_mark, q->decrement);
 187}
 188
 189static void increment_prob(struct sfb_bucket *b, struct sfb_sched_data *q)
 190{
 191        b->p_mark = prob_plus(b->p_mark, q->increment);
 192}
 193
 194static void sfb_zero_all_buckets(struct sfb_sched_data *q)
 195{
 196        memset(&q->bins, 0, sizeof(q->bins));
 197}
 198
 199/*
 200 * compute max qlen, max p_mark, and avg p_mark
 201 */
 202static u32 sfb_compute_qlen(u32 *prob_r, u32 *avgpm_r, const struct sfb_sched_data *q)
 203{
 204        int i;
 205        u32 qlen = 0, prob = 0, totalpm = 0;
 206        const struct sfb_bucket *b = &q->bins[q->slot].bins[0][0];
 207
 208        for (i = 0; i < SFB_LEVELS * SFB_NUMBUCKETS; i++) {
 209                if (qlen < b->qlen)
 210                        qlen = b->qlen;
 211                totalpm += b->p_mark;
 212                if (prob < b->p_mark)
 213                        prob = b->p_mark;
 214                b++;
 215        }
 216        *prob_r = prob;
 217        *avgpm_r = totalpm / (SFB_LEVELS * SFB_NUMBUCKETS);
 218        return qlen;
 219}
 220
 221
 222static void sfb_init_perturbation(u32 slot, struct sfb_sched_data *q)
 223{
 224        q->bins[slot].perturbation = prandom_u32();
 225}
 226
 227static void sfb_swap_slot(struct sfb_sched_data *q)
 228{
 229        sfb_init_perturbation(q->slot, q);
 230        q->slot ^= 1;
 231        q->double_buffering = false;
 232}
 233
 234/* Non elastic flows are allowed to use part of the bandwidth, expressed
 235 * in "penalty_rate" packets per second, with "penalty_burst" burst
 236 */
 237static bool sfb_rate_limit(struct sk_buff *skb, struct sfb_sched_data *q)
 238{
 239        if (q->penalty_rate == 0 || q->penalty_burst == 0)
 240                return true;
 241
 242        if (q->tokens_avail < 1) {
 243                unsigned long age = min(10UL * HZ, jiffies - q->token_time);
 244
 245                q->tokens_avail = (age * q->penalty_rate) / HZ;
 246                if (q->tokens_avail > q->penalty_burst)
 247                        q->tokens_avail = q->penalty_burst;
 248                q->token_time = jiffies;
 249                if (q->tokens_avail < 1)
 250                        return true;
 251        }
 252
 253        q->tokens_avail--;
 254        return false;
 255}
 256
 257static bool sfb_classify(struct sk_buff *skb, struct tcf_proto *fl,
 258                         int *qerr, u32 *salt)
 259{
 260        struct tcf_result res;
 261        int result;
 262
 263        result = tcf_classify(skb, fl, &res, false);
 264        if (result >= 0) {
 265#ifdef CONFIG_NET_CLS_ACT
 266                switch (result) {
 267                case TC_ACT_STOLEN:
 268                case TC_ACT_QUEUED:
 269                case TC_ACT_TRAP:
 270                        *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 271                case TC_ACT_SHOT:
 272                        return false;
 273                }
 274#endif
 275                *salt = TC_H_MIN(res.classid);
 276                return true;
 277        }
 278        return false;
 279}
 280
 281static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 282                       struct sk_buff **to_free)
 283{
 284
 285        struct sfb_sched_data *q = qdisc_priv(sch);
 286        struct Qdisc *child = q->qdisc;
 287        struct tcf_proto *fl;
 288        int i;
 289        u32 p_min = ~0;
 290        u32 minqlen = ~0;
 291        u32 r, sfbhash;
 292        u32 slot = q->slot;
 293        int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 294
 295        if (unlikely(sch->q.qlen >= q->limit)) {
 296                qdisc_qstats_overlimit(sch);
 297                q->stats.queuedrop++;
 298                goto drop;
 299        }
 300
 301        if (q->rehash_interval > 0) {
 302                unsigned long limit = q->rehash_time + q->rehash_interval;
 303
 304                if (unlikely(time_after(jiffies, limit))) {
 305                        sfb_swap_slot(q);
 306                        q->rehash_time = jiffies;
 307                } else if (unlikely(!q->double_buffering && q->warmup_time > 0 &&
 308                                    time_after(jiffies, limit - q->warmup_time))) {
 309                        q->double_buffering = true;
 310                }
 311        }
 312
 313        fl = rcu_dereference_bh(q->filter_list);
 314        if (fl) {
 315                u32 salt;
 316
 317                /* If using external classifiers, get result and record it. */
 318                if (!sfb_classify(skb, fl, &ret, &salt))
 319                        goto other_drop;
 320                sfbhash = jhash_1word(salt, q->bins[slot].perturbation);
 321        } else {
 322                sfbhash = skb_get_hash_perturb(skb, q->bins[slot].perturbation);
 323        }
 324
 325
 326        if (!sfbhash)
 327                sfbhash = 1;
 328        sfb_skb_cb(skb)->hashes[slot] = sfbhash;
 329
 330        for (i = 0; i < SFB_LEVELS; i++) {
 331                u32 hash = sfbhash & SFB_BUCKET_MASK;
 332                struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
 333
 334                sfbhash >>= SFB_BUCKET_SHIFT;
 335                if (b->qlen == 0)
 336                        decrement_prob(b, q);
 337                else if (b->qlen >= q->bin_size)
 338                        increment_prob(b, q);
 339                if (minqlen > b->qlen)
 340                        minqlen = b->qlen;
 341                if (p_min > b->p_mark)
 342                        p_min = b->p_mark;
 343        }
 344
 345        slot ^= 1;
 346        sfb_skb_cb(skb)->hashes[slot] = 0;
 347
 348        if (unlikely(minqlen >= q->max)) {
 349                qdisc_qstats_overlimit(sch);
 350                q->stats.bucketdrop++;
 351                goto drop;
 352        }
 353
 354        if (unlikely(p_min >= SFB_MAX_PROB)) {
 355                /* Inelastic flow */
 356                if (q->double_buffering) {
 357                        sfbhash = skb_get_hash_perturb(skb,
 358                            q->bins[slot].perturbation);
 359                        if (!sfbhash)
 360                                sfbhash = 1;
 361                        sfb_skb_cb(skb)->hashes[slot] = sfbhash;
 362
 363                        for (i = 0; i < SFB_LEVELS; i++) {
 364                                u32 hash = sfbhash & SFB_BUCKET_MASK;
 365                                struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
 366
 367                                sfbhash >>= SFB_BUCKET_SHIFT;
 368                                if (b->qlen == 0)
 369                                        decrement_prob(b, q);
 370                                else if (b->qlen >= q->bin_size)
 371                                        increment_prob(b, q);
 372                        }
 373                }
 374                if (sfb_rate_limit(skb, q)) {
 375                        qdisc_qstats_overlimit(sch);
 376                        q->stats.penaltydrop++;
 377                        goto drop;
 378                }
 379                goto enqueue;
 380        }
 381
 382        r = prandom_u32() & SFB_MAX_PROB;
 383
 384        if (unlikely(r < p_min)) {
 385                if (unlikely(p_min > SFB_MAX_PROB / 2)) {
 386                        /* If we're marking that many packets, then either
 387                         * this flow is unresponsive, or we're badly congested.
 388                         * In either case, we want to start dropping packets.
 389                         */
 390                        if (r < (p_min - SFB_MAX_PROB / 2) * 2) {
 391                                q->stats.earlydrop++;
 392                                goto drop;
 393                        }
 394                }
 395                if (INET_ECN_set_ce(skb)) {
 396                        q->stats.marked++;
 397                } else {
 398                        q->stats.earlydrop++;
 399                        goto drop;
 400                }
 401        }
 402
 403enqueue:
 404        ret = qdisc_enqueue(skb, child, to_free);
 405        if (likely(ret == NET_XMIT_SUCCESS)) {
 406                qdisc_qstats_backlog_inc(sch, skb);
 407                sch->q.qlen++;
 408                increment_qlen(skb, q);
 409        } else if (net_xmit_drop_count(ret)) {
 410                q->stats.childdrop++;
 411                qdisc_qstats_drop(sch);
 412        }
 413        return ret;
 414
 415drop:
 416        qdisc_drop(skb, sch, to_free);
 417        return NET_XMIT_CN;
 418other_drop:
 419        if (ret & __NET_XMIT_BYPASS)
 420                qdisc_qstats_drop(sch);
 421        kfree_skb(skb);
 422        return ret;
 423}
 424
 425static struct sk_buff *sfb_dequeue(struct Qdisc *sch)
 426{
 427        struct sfb_sched_data *q = qdisc_priv(sch);
 428        struct Qdisc *child = q->qdisc;
 429        struct sk_buff *skb;
 430
 431        skb = child->dequeue(q->qdisc);
 432
 433        if (skb) {
 434                qdisc_bstats_update(sch, skb);
 435                qdisc_qstats_backlog_dec(sch, skb);
 436                sch->q.qlen--;
 437                decrement_qlen(skb, q);
 438        }
 439
 440        return skb;
 441}
 442
 443static struct sk_buff *sfb_peek(struct Qdisc *sch)
 444{
 445        struct sfb_sched_data *q = qdisc_priv(sch);
 446        struct Qdisc *child = q->qdisc;
 447
 448        return child->ops->peek(child);
 449}
 450
 451/* No sfb_drop -- impossible since the child doesn't return the dropped skb. */
 452
 453static void sfb_reset(struct Qdisc *sch)
 454{
 455        struct sfb_sched_data *q = qdisc_priv(sch);
 456
 457        qdisc_reset(q->qdisc);
 458        sch->qstats.backlog = 0;
 459        sch->q.qlen = 0;
 460        q->slot = 0;
 461        q->double_buffering = false;
 462        sfb_zero_all_buckets(q);
 463        sfb_init_perturbation(0, q);
 464}
 465
 466static void sfb_destroy(struct Qdisc *sch)
 467{
 468        struct sfb_sched_data *q = qdisc_priv(sch);
 469
 470        tcf_block_put(q->block);
 471        qdisc_destroy(q->qdisc);
 472}
 473
 474static const struct nla_policy sfb_policy[TCA_SFB_MAX + 1] = {
 475        [TCA_SFB_PARMS] = { .len = sizeof(struct tc_sfb_qopt) },
 476};
 477
 478static const struct tc_sfb_qopt sfb_default_ops = {
 479        .rehash_interval = 600 * MSEC_PER_SEC,
 480        .warmup_time = 60 * MSEC_PER_SEC,
 481        .limit = 0,
 482        .max = 25,
 483        .bin_size = 20,
 484        .increment = (SFB_MAX_PROB + 500) / 1000, /* 0.1 % */
 485        .decrement = (SFB_MAX_PROB + 3000) / 6000,
 486        .penalty_rate = 10,
 487        .penalty_burst = 20,
 488};
 489
 490static int sfb_change(struct Qdisc *sch, struct nlattr *opt)
 491{
 492        struct sfb_sched_data *q = qdisc_priv(sch);
 493        struct Qdisc *child;
 494        struct nlattr *tb[TCA_SFB_MAX + 1];
 495        const struct tc_sfb_qopt *ctl = &sfb_default_ops;
 496        u32 limit;
 497        int err;
 498
 499        if (opt) {
 500                err = nla_parse_nested(tb, TCA_SFB_MAX, opt, sfb_policy, NULL);
 501                if (err < 0)
 502                        return -EINVAL;
 503
 504                if (tb[TCA_SFB_PARMS] == NULL)
 505                        return -EINVAL;
 506
 507                ctl = nla_data(tb[TCA_SFB_PARMS]);
 508        }
 509
 510        limit = ctl->limit;
 511        if (limit == 0)
 512                limit = qdisc_dev(sch)->tx_queue_len;
 513
 514        child = fifo_create_dflt(sch, &pfifo_qdisc_ops, limit);
 515        if (IS_ERR(child))
 516                return PTR_ERR(child);
 517
 518        if (child != &noop_qdisc)
 519                qdisc_hash_add(child, true);
 520        sch_tree_lock(sch);
 521
 522        qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
 523                                  q->qdisc->qstats.backlog);
 524        qdisc_destroy(q->qdisc);
 525        q->qdisc = child;
 526
 527        q->rehash_interval = msecs_to_jiffies(ctl->rehash_interval);
 528        q->warmup_time = msecs_to_jiffies(ctl->warmup_time);
 529        q->rehash_time = jiffies;
 530        q->limit = limit;
 531        q->increment = ctl->increment;
 532        q->decrement = ctl->decrement;
 533        q->max = ctl->max;
 534        q->bin_size = ctl->bin_size;
 535        q->penalty_rate = ctl->penalty_rate;
 536        q->penalty_burst = ctl->penalty_burst;
 537        q->tokens_avail = ctl->penalty_burst;
 538        q->token_time = jiffies;
 539
 540        q->slot = 0;
 541        q->double_buffering = false;
 542        sfb_zero_all_buckets(q);
 543        sfb_init_perturbation(0, q);
 544        sfb_init_perturbation(1, q);
 545
 546        sch_tree_unlock(sch);
 547
 548        return 0;
 549}
 550
 551static int sfb_init(struct Qdisc *sch, struct nlattr *opt)
 552{
 553        struct sfb_sched_data *q = qdisc_priv(sch);
 554        int err;
 555
 556        err = tcf_block_get(&q->block, &q->filter_list);
 557        if (err)
 558                return err;
 559
 560        q->qdisc = &noop_qdisc;
 561        return sfb_change(sch, opt);
 562}
 563
 564static int sfb_dump(struct Qdisc *sch, struct sk_buff *skb)
 565{
 566        struct sfb_sched_data *q = qdisc_priv(sch);
 567        struct nlattr *opts;
 568        struct tc_sfb_qopt opt = {
 569                .rehash_interval = jiffies_to_msecs(q->rehash_interval),
 570                .warmup_time = jiffies_to_msecs(q->warmup_time),
 571                .limit = q->limit,
 572                .max = q->max,
 573                .bin_size = q->bin_size,
 574                .increment = q->increment,
 575                .decrement = q->decrement,
 576                .penalty_rate = q->penalty_rate,
 577                .penalty_burst = q->penalty_burst,
 578        };
 579
 580        sch->qstats.backlog = q->qdisc->qstats.backlog;
 581        opts = nla_nest_start(skb, TCA_OPTIONS);
 582        if (opts == NULL)
 583                goto nla_put_failure;
 584        if (nla_put(skb, TCA_SFB_PARMS, sizeof(opt), &opt))
 585                goto nla_put_failure;
 586        return nla_nest_end(skb, opts);
 587
 588nla_put_failure:
 589        nla_nest_cancel(skb, opts);
 590        return -EMSGSIZE;
 591}
 592
 593static int sfb_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 594{
 595        struct sfb_sched_data *q = qdisc_priv(sch);
 596        struct tc_sfb_xstats st = {
 597                .earlydrop = q->stats.earlydrop,
 598                .penaltydrop = q->stats.penaltydrop,
 599                .bucketdrop = q->stats.bucketdrop,
 600                .queuedrop = q->stats.queuedrop,
 601                .childdrop = q->stats.childdrop,
 602                .marked = q->stats.marked,
 603        };
 604
 605        st.maxqlen = sfb_compute_qlen(&st.maxprob, &st.avgprob, q);
 606
 607        return gnet_stats_copy_app(d, &st, sizeof(st));
 608}
 609
 610static int sfb_dump_class(struct Qdisc *sch, unsigned long cl,
 611                          struct sk_buff *skb, struct tcmsg *tcm)
 612{
 613        return -ENOSYS;
 614}
 615
 616static int sfb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 617                     struct Qdisc **old)
 618{
 619        struct sfb_sched_data *q = qdisc_priv(sch);
 620
 621        if (new == NULL)
 622                new = &noop_qdisc;
 623
 624        *old = qdisc_replace(sch, new, &q->qdisc);
 625        return 0;
 626}
 627
 628static struct Qdisc *sfb_leaf(struct Qdisc *sch, unsigned long arg)
 629{
 630        struct sfb_sched_data *q = qdisc_priv(sch);
 631
 632        return q->qdisc;
 633}
 634
 635static unsigned long sfb_get(struct Qdisc *sch, u32 classid)
 636{
 637        return 1;
 638}
 639
 640static void sfb_put(struct Qdisc *sch, unsigned long arg)
 641{
 642}
 643
 644static int sfb_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 645                            struct nlattr **tca, unsigned long *arg)
 646{
 647        return -ENOSYS;
 648}
 649
 650static int sfb_delete(struct Qdisc *sch, unsigned long cl)
 651{
 652        return -ENOSYS;
 653}
 654
 655static void sfb_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 656{
 657        if (!walker->stop) {
 658                if (walker->count >= walker->skip)
 659                        if (walker->fn(sch, 1, walker) < 0) {
 660                                walker->stop = 1;
 661                                return;
 662                        }
 663                walker->count++;
 664        }
 665}
 666
 667static struct tcf_block *sfb_tcf_block(struct Qdisc *sch, unsigned long cl)
 668{
 669        struct sfb_sched_data *q = qdisc_priv(sch);
 670
 671        if (cl)
 672                return NULL;
 673        return q->block;
 674}
 675
 676static unsigned long sfb_bind(struct Qdisc *sch, unsigned long parent,
 677                              u32 classid)
 678{
 679        return 0;
 680}
 681
 682
 683static const struct Qdisc_class_ops sfb_class_ops = {
 684        .graft          =       sfb_graft,
 685        .leaf           =       sfb_leaf,
 686        .get            =       sfb_get,
 687        .put            =       sfb_put,
 688        .change         =       sfb_change_class,
 689        .delete         =       sfb_delete,
 690        .walk           =       sfb_walk,
 691        .tcf_block      =       sfb_tcf_block,
 692        .bind_tcf       =       sfb_bind,
 693        .unbind_tcf     =       sfb_put,
 694        .dump           =       sfb_dump_class,
 695};
 696
 697static struct Qdisc_ops sfb_qdisc_ops __read_mostly = {
 698        .id             =       "sfb",
 699        .priv_size      =       sizeof(struct sfb_sched_data),
 700        .cl_ops         =       &sfb_class_ops,
 701        .enqueue        =       sfb_enqueue,
 702        .dequeue        =       sfb_dequeue,
 703        .peek           =       sfb_peek,
 704        .init           =       sfb_init,
 705        .reset          =       sfb_reset,
 706        .destroy        =       sfb_destroy,
 707        .change         =       sfb_change,
 708        .dump           =       sfb_dump,
 709        .dump_stats     =       sfb_dump_stats,
 710        .owner          =       THIS_MODULE,
 711};
 712
 713static int __init sfb_module_init(void)
 714{
 715        return register_qdisc(&sfb_qdisc_ops);
 716}
 717
 718static void __exit sfb_module_exit(void)
 719{
 720        unregister_qdisc(&sfb_qdisc_ops);
 721}
 722
 723module_init(sfb_module_init)
 724module_exit(sfb_module_exit)
 725
 726MODULE_DESCRIPTION("Stochastic Fair Blue queue discipline");
 727MODULE_AUTHOR("Juliusz Chroboczek");
 728MODULE_AUTHOR("Eric Dumazet");
 729MODULE_LICENSE("GPL");
 730