kernel/net/sched/sch_fq_codel.c

   1 /*
   2  * Fair Queue CoDel 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  *  Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/string.h>
  17 #include <linux/in.h>
  18 #include <linux/errno.h>
  19 #include <linux/init.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/jhash.h>
  22 #include <linux/slab.h>
  23 #include <linux/vmalloc.h>
  24 #include <net/netlink.h>
  25 #include <net/pkt_sched.h>
  26 #include <net/codel.h>
  27
  28 /*      Fair Queue CoDel.
  29  *
  30  * Principles :
  31  * Packets are classified (internal classifier or external) on flows.
  32  * This is a Stochastic model (as we use a hash, several flows
  33  *                             might be hashed on same slot)
  34  * Each flow has a CoDel managed queue.
  35  * Flows are linked onto two (Round Robin) lists,
  36  * so that new flows have priority on old ones.
  37  *
  38  * For a given flow, packets are not reordered (CoDel uses a FIFO)
  39  * head drops only.
  40  * ECN capability is on by default.
  41  * Low memory footprint (64 bytes per flow)
  42  */
  43
  44 struct fq_codel_flow {
  45         struct sk_buff    *head;
  46         struct sk_buff    *tail;
  47         struct list_head  flowchain;
  48         int               deficit;
  49         u32               dropped; /* number of drops (or ECN marks) on this flow */
  50         struct codel_vars cvars;
  51 }; /* please try to keep this structure <= 64 bytes */
  52
  53 struct fq_codel_sched_data {
  54         struct tcf_proto __rcu *filter_list; /* optional external classifier */
  55         struct fq_codel_flow *flows;    /* Flows table [flows_cnt] */
  56         u32             *backlogs;      /* backlog table [flows_cnt] */
  57         u32             flows_cnt;      /* number of flows */
  58         u32             perturbation;   /* hash perturbation */
  59         u32             quantum;        /* psched_mtu(qdisc_dev(sch)); */
  60         struct codel_params cparams;
  61         struct codel_stats cstats;
  62         u32             drop_overlimit;
  63         u32             new_flow_count;
  64
  65         struct list_head new_flows;     /* list of new flows */
  66         struct list_head old_flows;     /* list of old flows */
  67 };
  68
  69 static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q,
  70                                   struct sk_buff *skb)
  71 {
  72         u32 hash = skb_get_hash_perturb(skb, q->perturbation);
  73
  74         return reciprocal_scale(hash, q->flows_cnt);
  75 }
  76
  77 static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
  78                                       int *qerr)
  79 {
  80         struct fq_codel_sched_data *q = qdisc_priv(sch);
  81         struct tcf_proto *filter;
  82         struct tcf_result res;
  83         int result;
  84
  85         if (TC_H_MAJ(skb->priority) == sch->handle &&
  86             TC_H_MIN(skb->priority) > 0 &&
  87             TC_H_MIN(skb->priority) <= q->flows_cnt)
  88                 return TC_H_MIN(skb->priority);
  89
  90         filter = rcu_dereference_bh(q->filter_list);
  91         if (!filter)
  92                 return fq_codel_hash(q, skb) + 1;
  93
  94         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  95         result = tc_classify(skb, filter, &res, false);
  96         if (result >= 0) {
  97 #ifdef CONFIG_NET_CLS_ACT
  98                 switch (result) {
  99                 case TC_ACT_STOLEN:
 100                 case TC_ACT_QUEUED:
 101                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 102                 case TC_ACT_SHOT:
 103                         return 0;
 104                 }
 105 #endif
 106                 if (TC_H_MIN(res.classid) <= q->flows_cnt)
 107                         return TC_H_MIN(res.classid);
 108         }
 109         return 0;
 110 }
 111
 112 /* helper functions : might be changed when/if skb use a standard list_head */
 113
 114 /* remove one skb from head of slot queue */
 115 static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow)
 116 {
 117         struct sk_buff *skb = flow->head;
 118
 119         flow->head = skb->next;
 120         skb->next = NULL;
 121         return skb;
 122 }
 123
 124 /* add skb to flow queue (tail add) */
 125 static inline void flow_queue_add(struct fq_codel_flow *flow,
 126                                   struct sk_buff *skb)
 127 {
 128         if (flow->head == NULL)
 129                 flow->head = skb;
 130         else
 131                 flow->tail->next = skb;
 132         flow->tail = skb;
 133         skb->next = NULL;
 134 }
 135
 136 static unsigned int fq_codel_drop(struct Qdisc *sch)
 137 {
 138         struct fq_codel_sched_data *q = qdisc_priv(sch);
 139         struct sk_buff *skb;
 140         unsigned int maxbacklog = 0, idx = 0, i, len;
 141         struct fq_codel_flow *flow;
 142
 143         /* Queue is full! Find the fat flow and drop packet from it.
 144          * This might sound expensive, but with 1024 flows, we scan
 145          * 4KB of memory, and we dont need to handle a complex tree
 146          * in fast path (packet queue/enqueue) with many cache misses.
 147          */
 148         for (i = 0; i < q->flows_cnt; i++) {
 149                 if (q->backlogs[i] > maxbacklog) {
 150                         maxbacklog = q->backlogs[i];
 151                         idx = i;
 152                 }
 153         }
 154         flow = &q->flows[idx];
 155         skb = dequeue_head(flow);
 156         len = qdisc_pkt_len(skb);
 157         q->backlogs[idx] -= len;
 158         sch->q.qlen--;
 159         qdisc_qstats_drop(sch);
 160         qdisc_qstats_backlog_dec(sch, skb);
 161         kfree_skb(skb);
 162         flow->dropped++;
 163         return idx;
 164 }
 165
 166 static unsigned int fq_codel_qdisc_drop(struct Qdisc *sch)
 167 {
 168         unsigned int prev_backlog;
 169
 170         prev_backlog = sch->qstats.backlog;
 171         fq_codel_drop(sch);
 172         return prev_backlog - sch->qstats.backlog;
 173 }
 174
 175 static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 176 {
 177         struct fq_codel_sched_data *q = qdisc_priv(sch);
 178         unsigned int idx, prev_backlog;
 179         struct fq_codel_flow *flow;
 180         int uninitialized_var(ret);
 181
 182         idx = fq_codel_classify(skb, sch, &ret);
 183         if (idx == 0) {
 184                 if (ret & __NET_XMIT_BYPASS)
 185                         qdisc_qstats_drop(sch);
 186                 kfree_skb(skb);
 187                 return ret;
 188         }
 189         idx--;
 190
 191         codel_set_enqueue_time(skb);
 192         flow = &q->flows[idx];
 193         flow_queue_add(flow, skb);
 194         q->backlogs[idx] += qdisc_pkt_len(skb);
 195         qdisc_qstats_backlog_inc(sch, skb);
 196
 197         if (list_empty(&flow->flowchain)) {
 198                 list_add_tail(&flow->flowchain, &q->new_flows);
 199                 q->new_flow_count++;
 200                 flow->deficit = q->quantum;
 201                 flow->dropped = 0;
 202         }
 203         if (++sch->q.qlen <= sch->limit)
 204                 return NET_XMIT_SUCCESS;
 205
 206         prev_backlog = sch->qstats.backlog;
 207         q->drop_overlimit++;
 208         /* Return Congestion Notification only if we dropped a packet
 209          * from this flow.
 210          */
 211         if (fq_codel_drop(sch) == idx)
 212                 return NET_XMIT_CN;
 213
 214         /* As we dropped a packet, better let upper stack know this */
 215         qdisc_tree_reduce_backlog(sch, 1, prev_backlog - sch->qstats.backlog);
 216         return NET_XMIT_SUCCESS;
 217 }
 218
 219 /* This is the specific function called from codel_dequeue()
 220  * to dequeue a packet from queue. Note: backlog is handled in
 221  * codel, we dont need to reduce it here.
 222  */
 223 static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch)
 224 {
 225         struct fq_codel_sched_data *q = qdisc_priv(sch);
 226         struct fq_codel_flow *flow;
 227         struct sk_buff *skb = NULL;
 228
 229         flow = container_of(vars, struct fq_codel_flow, cvars);
 230         if (flow->head) {
 231                 skb = dequeue_head(flow);
 232                 q->backlogs[flow - q->flows] -= qdisc_pkt_len(skb);
 233                 sch->q.qlen--;
 234         }
 235         return skb;
 236 }
 237
 238 static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
 239 {
 240         struct fq_codel_sched_data *q = qdisc_priv(sch);
 241         struct sk_buff *skb;
 242         struct fq_codel_flow *flow;
 243         struct list_head *head;
 244         u32 prev_drop_count, prev_ecn_mark;
 245         unsigned int prev_backlog;
 246
 247 begin:
 248         head = &q->new_flows;
 249         if (list_empty(head)) {
 250                 head = &q->old_flows;
 251                 if (list_empty(head))
 252                         return NULL;
 253         }
 254         flow = list_first_entry(head, struct fq_codel_flow, flowchain);
 255
 256         if (flow->deficit <= 0) {
 257                 flow->deficit += q->quantum;
 258                 list_move_tail(&flow->flowchain, &q->old_flows);
 259                 goto begin;
 260         }
 261
 262         prev_drop_count = q->cstats.drop_count;
 263         prev_ecn_mark = q->cstats.ecn_mark;
 264         prev_backlog = sch->qstats.backlog;
 265
 266         skb = codel_dequeue(sch, &q->cparams, &flow->cvars, &q->cstats,
 267                             dequeue);
 268
 269         flow->dropped += q->cstats.drop_count - prev_drop_count;
 270         flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
 271
 272         if (!skb) {
 273                 /* force a pass through old_flows to prevent starvation */
 274                 if ((head == &q->new_flows) && !list_empty(&q->old_flows))
 275                         list_move_tail(&flow->flowchain, &q->old_flows);
 276                 else
 277                         list_del_init(&flow->flowchain);
 278                 goto begin;
 279         }
 280         qdisc_bstats_update(sch, skb);
 281         flow->deficit -= qdisc_pkt_len(skb);
 282         /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
 283          * or HTB crashes. Defer it for next round.
 284          */
 285         if (q->cstats.drop_count && sch->q.qlen) {
 286                 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
 287                                           q->cstats.drop_len);
 288                 q->cstats.drop_count = 0;
 289                 q->cstats.drop_len = 0;
 290         }
 291         return skb;
 292 }
 293
 294 static void fq_codel_reset(struct Qdisc *sch)
 295 {
 296         struct fq_codel_sched_data *q = qdisc_priv(sch);
 297         int i;
 298
 299         INIT_LIST_HEAD(&q->new_flows);
 300         INIT_LIST_HEAD(&q->old_flows);
 301         for (i = 0; i < q->flows_cnt; i++) {
 302                 struct fq_codel_flow *flow = q->flows + i;
 303
 304                 while (flow->head) {
 305                         struct sk_buff *skb = dequeue_head(flow);
 306
 307                         qdisc_qstats_backlog_dec(sch, skb);
 308                         kfree_skb(skb);
 309                 }
 310
 311                 INIT_LIST_HEAD(&flow->flowchain);
 312                 codel_vars_init(&flow->cvars);
 313         }
 314         memset(q->backlogs, 0, q->flows_cnt * sizeof(u32));
 315         sch->q.qlen = 0;
 316 }
 317
 318 static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
 319         [TCA_FQ_CODEL_TARGET]   = { .type = NLA_U32 },
 320         [TCA_FQ_CODEL_LIMIT]    = { .type = NLA_U32 },
 321         [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 },
 322         [TCA_FQ_CODEL_ECN]      = { .type = NLA_U32 },
 323         [TCA_FQ_CODEL_FLOWS]    = { .type = NLA_U32 },
 324         [TCA_FQ_CODEL_QUANTUM]  = { .type = NLA_U32 },
 325         [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 },
 326 };
 327
 328 static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
 329 {
 330         struct fq_codel_sched_data *q = qdisc_priv(sch);
 331         struct nlattr *tb[TCA_FQ_CODEL_MAX + 1];
 332         int err;
 333
 334         if (!opt)
 335                 return -EINVAL;
 336
 337         err = nla_parse_nested(tb, TCA_FQ_CODEL_MAX, opt, fq_codel_policy);
 338         if (err < 0)
 339                 return err;
 340         if (tb[TCA_FQ_CODEL_FLOWS]) {
 341                 if (q->flows)
 342                         return -EINVAL;
 343                 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]);
 344                 if (!q->flows_cnt ||
 345                     q->flows_cnt > 65536)
 346                         return -EINVAL;
 347         }
 348         sch_tree_lock(sch);
 349
 350         if (tb[TCA_FQ_CODEL_TARGET]) {
 351                 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
 352
 353                 q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
 354         }
 355
 356         if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) {
 357                 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]);
 358
 359                 q->cparams.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
 360         }
 361
 362         if (tb[TCA_FQ_CODEL_INTERVAL]) {
 363                 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
 364
 365                 q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT;
 366         }
 367
 368         if (tb[TCA_FQ_CODEL_LIMIT])
 369                 sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]);
 370
 371         if (tb[TCA_FQ_CODEL_ECN])
 372                 q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]);
 373
 374         if (tb[TCA_FQ_CODEL_QUANTUM])
 375                 q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM]));
 376
 377         while (sch->q.qlen > sch->limit) {
 378                 struct sk_buff *skb = fq_codel_dequeue(sch);
 379
 380                 q->cstats.drop_len += qdisc_pkt_len(skb);
 381                 kfree_skb(skb);
 382                 q->cstats.drop_count++;
 383         }
 384         qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, q->cstats.drop_len);
 385         q->cstats.drop_count = 0;
 386         q->cstats.drop_len = 0;
 387
 388         sch_tree_unlock(sch);
 389         return 0;
 390 }
 391
 392 static void *fq_codel_zalloc(size_t sz)
 393 {
 394         void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN);
 395
 396         if (!ptr)
 397                 ptr = vzalloc(sz);
 398         return ptr;
 399 }
 400
 401 static void fq_codel_free(void *addr)
 402 {
 403         kvfree(addr);
 404 }
 405
 406 static void fq_codel_destroy(struct Qdisc *sch)
 407 {
 408         struct fq_codel_sched_data *q = qdisc_priv(sch);
 409
 410         tcf_destroy_chain(&q->filter_list);
 411         fq_codel_free(q->backlogs);
 412         fq_codel_free(q->flows);
 413 }
 414
 415 static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt)
 416 {
 417         struct fq_codel_sched_data *q = qdisc_priv(sch);
 418         int i;
 419
 420         sch->limit = 10*1024;
 421         q->flows_cnt = 1024;
 422         q->quantum = psched_mtu(qdisc_dev(sch));
 423         q->perturbation = prandom_u32();
 424         INIT_LIST_HEAD(&q->new_flows);
 425         INIT_LIST_HEAD(&q->old_flows);
 426         codel_params_init(&q->cparams, sch);
 427         codel_stats_init(&q->cstats);
 428         q->cparams.ecn = true;
 429
 430         if (opt) {
 431                 int err = fq_codel_change(sch, opt);
 432                 if (err)
 433                         return err;
 434         }
 435
 436         if (!q->flows) {
 437                 q->flows = fq_codel_zalloc(q->flows_cnt *
 438                                            sizeof(struct fq_codel_flow));
 439                 if (!q->flows)
 440                         return -ENOMEM;
 441                 q->backlogs = fq_codel_zalloc(q->flows_cnt * sizeof(u32));
 442                 if (!q->backlogs) {
 443                         fq_codel_free(q->flows);
 444                         return -ENOMEM;
 445                 }
 446                 for (i = 0; i < q->flows_cnt; i++) {
 447                         struct fq_codel_flow *flow = q->flows + i;
 448
 449                         INIT_LIST_HEAD(&flow->flowchain);
 450                         codel_vars_init(&flow->cvars);
 451                 }
 452         }
 453         if (sch->limit >= 1)
 454                 sch->flags |= TCQ_F_CAN_BYPASS;
 455         else
 456                 sch->flags &= ~TCQ_F_CAN_BYPASS;
 457         return 0;
 458 }
 459
 460 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 461 {
 462         struct fq_codel_sched_data *q = qdisc_priv(sch);
 463         struct nlattr *opts;
 464
 465         opts = nla_nest_start(skb, TCA_OPTIONS);
 466         if (opts == NULL)
 467                 goto nla_put_failure;
 468
 469         if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
 470                         codel_time_to_us(q->cparams.target)) ||
 471             nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
 472                         sch->limit) ||
 473             nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
 474                         codel_time_to_us(q->cparams.interval)) ||
 475             nla_put_u32(skb, TCA_FQ_CODEL_ECN,
 476                         q->cparams.ecn) ||
 477             nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
 478                         q->quantum) ||
 479             nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
 480                         q->flows_cnt))
 481                 goto nla_put_failure;
 482
 483         if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD &&
 484             nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD,
 485                         codel_time_to_us(q->cparams.ce_threshold)))
 486                 goto nla_put_failure;
 487
 488         return nla_nest_end(skb, opts);
 489
 490 nla_put_failure:
 491         return -1;
 492 }
 493
 494 static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 495 {
 496         struct fq_codel_sched_data *q = qdisc_priv(sch);
 497         struct tc_fq_codel_xstats st = {
 498                 .type                           = TCA_FQ_CODEL_XSTATS_QDISC,
 499         };
 500         struct list_head *pos;
 501
 502         st.qdisc_stats.maxpacket = q->cstats.maxpacket;
 503         st.qdisc_stats.drop_overlimit = q->drop_overlimit;
 504         st.qdisc_stats.ecn_mark = q->cstats.ecn_mark;
 505         st.qdisc_stats.new_flow_count = q->new_flow_count;
 506         st.qdisc_stats.ce_mark = q->cstats.ce_mark;
 507
 508         list_for_each(pos, &q->new_flows)
 509                 st.qdisc_stats.new_flows_len++;
 510
 511         list_for_each(pos, &q->old_flows)
 512                 st.qdisc_stats.old_flows_len++;
 513
 514         return gnet_stats_copy_app(d, &st, sizeof(st));
 515 }
 516
 517 static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg)
 518 {
 519         return NULL;
 520 }
 521
 522 static unsigned long fq_codel_get(struct Qdisc *sch, u32 classid)
 523 {
 524         return 0;
 525 }
 526
 527 static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent,
 528                               u32 classid)
 529 {
 530         /* we cannot bypass queue discipline anymore */
 531         sch->flags &= ~TCQ_F_CAN_BYPASS;
 532         return 0;
 533 }
 534
 535 static void fq_codel_put(struct Qdisc *q, unsigned long cl)
 536 {
 537 }
 538
 539 static struct tcf_proto __rcu **fq_codel_find_tcf(struct Qdisc *sch,
 540                                                   unsigned long cl)
 541 {
 542         struct fq_codel_sched_data *q = qdisc_priv(sch);
 543
 544         if (cl)
 545                 return NULL;
 546         return &q->filter_list;
 547 }
 548
 549 static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl,
 550                           struct sk_buff *skb, struct tcmsg *tcm)
 551 {
 552         tcm->tcm_handle |= TC_H_MIN(cl);
 553         return 0;
 554 }
 555
 556 static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 557                                      struct gnet_dump *d)
 558 {
 559         struct fq_codel_sched_data *q = qdisc_priv(sch);
 560         u32 idx = cl - 1;
 561         struct gnet_stats_queue qs = { 0 };
 562         struct tc_fq_codel_xstats xstats;
 563
 564         if (idx < q->flows_cnt) {
 565                 const struct fq_codel_flow *flow = &q->flows[idx];
 566                 const struct sk_buff *skb = flow->head;
 567
 568                 memset(&xstats, 0, sizeof(xstats));
 569                 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
 570                 xstats.class_stats.deficit = flow->deficit;
 571                 xstats.class_stats.ldelay =
 572                         codel_time_to_us(flow->cvars.ldelay);
 573                 xstats.class_stats.count = flow->cvars.count;
 574                 xstats.class_stats.lastcount = flow->cvars.lastcount;
 575                 xstats.class_stats.dropping = flow->cvars.dropping;
 576                 if (flow->cvars.dropping) {
 577                         codel_tdiff_t delta = flow->cvars.drop_next -
 578                                               codel_get_time();
 579
 580                         xstats.class_stats.drop_next = (delta >= 0) ?
 581                                 codel_time_to_us(delta) :
 582                                 -codel_time_to_us(-delta);
 583                 }
 584                 while (skb) {
 585                         qs.qlen++;
 586                         skb = skb->next;
 587                 }
 588                 qs.backlog = q->backlogs[idx];
 589                 qs.drops = flow->dropped;
 590         }
 591         if (gnet_stats_copy_queue(d, NULL, &qs, 0) < 0)
 592                 return -1;
 593         if (idx < q->flows_cnt)
 594                 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
 595         return 0;
 596 }
 597
 598 static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 599 {
 600         struct fq_codel_sched_data *q = qdisc_priv(sch);
 601         unsigned int i;
 602
 603         if (arg->stop)
 604                 return;
 605
 606         for (i = 0; i < q->flows_cnt; i++) {
 607                 if (list_empty(&q->flows[i].flowchain) ||
 608                     arg->count < arg->skip) {
 609                         arg->count++;
 610                         continue;
 611                 }
 612                 if (arg->fn(sch, i + 1, arg) < 0) {
 613                         arg->stop = 1;
 614                         break;
 615                 }
 616                 arg->count++;
 617         }
 618 }
 619
 620 static const struct Qdisc_class_ops fq_codel_class_ops = {
 621         .leaf           =       fq_codel_leaf,
 622         .get            =       fq_codel_get,
 623         .put            =       fq_codel_put,
 624         .tcf_chain      =       fq_codel_find_tcf,
 625         .bind_tcf       =       fq_codel_bind,
 626         .unbind_tcf     =       fq_codel_put,
 627         .dump           =       fq_codel_dump_class,
 628         .dump_stats     =       fq_codel_dump_class_stats,
 629         .walk           =       fq_codel_walk,
 630 };
 631
 632 static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = {
 633         .cl_ops         =       &fq_codel_class_ops,
 634         .id             =       "fq_codel",
 635         .priv_size      =       sizeof(struct fq_codel_sched_data),
 636         .enqueue        =       fq_codel_enqueue,
 637         .dequeue        =       fq_codel_dequeue,
 638         .peek           =       qdisc_peek_dequeued,
 639         .drop           =       fq_codel_qdisc_drop,
 640         .init           =       fq_codel_init,
 641         .reset          =       fq_codel_reset,
 642         .destroy        =       fq_codel_destroy,
 643         .change         =       fq_codel_change,
 644         .dump           =       fq_codel_dump,
 645         .dump_stats =   fq_codel_dump_stats,
 646         .owner          =       THIS_MODULE,
 647 };
 648
 649 static int __init fq_codel_module_init(void)
 650 {
 651         return register_qdisc(&fq_codel_qdisc_ops);
 652 }
 653
 654 static void __exit fq_codel_module_exit(void)
 655 {
 656         unregister_qdisc(&fq_codel_qdisc_ops);
 657 }
 658
 659 module_init(fq_codel_module_init)
 660 module_exit(fq_codel_module_exit)
 661 MODULE_AUTHOR("Eric Dumazet");
 662 MODULE_LICENSE("GPL");