net/sched/sch_prio.c

   1 /*
   2  * net/sched/sch_prio.c Simple 3-band priority "scheduler".
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  * Fixes:       19990609: J Hadi Salim <hadi@nortelnetworks.com>:
  11  *              Init --  EINVAL when opt undefined
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/skbuff.h>
  20 #include <net/netlink.h>
  21 #include <net/pkt_sched.h>
  22
  23
  24 struct prio_sched_data
  25 {
  26         int bands;
  27         int curband; /* for round-robin */
  28         struct tcf_proto *filter_list;
  29         u8  prio2band[TC_PRIO_MAX+1];
  30         struct Qdisc *queues[TCQ_PRIO_BANDS];
  31         int mq;
  32 };
  33
  34
  35 static struct Qdisc *
  36 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  37 {
  38         struct prio_sched_data *q = qdisc_priv(sch);
  39         u32 band = skb->priority;
  40         struct tcf_result res;
  41
  42         *qerr = NET_XMIT_BYPASS;
  43         if (TC_H_MAJ(skb->priority) != sch->handle) {
  44 #ifdef CONFIG_NET_CLS_ACT
  45                 switch (tc_classify(skb, q->filter_list, &res)) {
  46                 case TC_ACT_STOLEN:
  47                 case TC_ACT_QUEUED:
  48                         *qerr = NET_XMIT_SUCCESS;
  49                 case TC_ACT_SHOT:
  50                         return NULL;
  51                 }
  52
  53                 if (!q->filter_list ) {
  54 #else
  55                 if (!q->filter_list || tc_classify(skb, q->filter_list, &res)) {
  56 #endif
  57                         if (TC_H_MAJ(band))
  58                                 band = 0;
  59                         band = q->prio2band[band&TC_PRIO_MAX];
  60                         goto out;
  61                 }
  62                 band = res.classid;
  63         }
  64         band = TC_H_MIN(band) - 1;
  65         if (band >= q->bands)
  66                 band = q->prio2band[0];
  67 out:
  68         if (q->mq)
  69                 skb_set_queue_mapping(skb, band);
  70         return q->queues[band];
  71 }
  72
  73 static int
  74 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  75 {
  76         struct Qdisc *qdisc;
  77         int ret;
  78
  79         qdisc = prio_classify(skb, sch, &ret);
  80 #ifdef CONFIG_NET_CLS_ACT
  81         if (qdisc == NULL) {
  82
  83                 if (ret == NET_XMIT_BYPASS)
  84                         sch->qstats.drops++;
  85                 kfree_skb(skb);
  86                 return ret;
  87         }
  88 #endif
  89
  90         if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) {
  91                 sch->bstats.bytes += skb->len;
  92                 sch->bstats.packets++;
  93                 sch->q.qlen++;
  94                 return NET_XMIT_SUCCESS;
  95         }
  96         sch->qstats.drops++;
  97         return ret;
  98 }
  99
 100
 101 static int
 102 prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
 103 {
 104         struct Qdisc *qdisc;
 105         int ret;
 106
 107         qdisc = prio_classify(skb, sch, &ret);
 108 #ifdef CONFIG_NET_CLS_ACT
 109         if (qdisc == NULL) {
 110                 if (ret == NET_XMIT_BYPASS)
 111                         sch->qstats.drops++;
 112                 kfree_skb(skb);
 113                 return ret;
 114         }
 115 #endif
 116
 117         if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) {
 118                 sch->q.qlen++;
 119                 sch->qstats.requeues++;
 120                 return 0;
 121         }
 122         sch->qstats.drops++;
 123         return NET_XMIT_DROP;
 124 }
 125
 126
 127 static struct sk_buff *
 128 prio_dequeue(struct Qdisc* sch)
 129 {
 130         struct sk_buff *skb;
 131         struct prio_sched_data *q = qdisc_priv(sch);
 132         int prio;
 133         struct Qdisc *qdisc;
 134
 135         for (prio = 0; prio < q->bands; prio++) {
 136                 /* Check if the target subqueue is available before
 137                  * pulling an skb.  This way we avoid excessive requeues
 138                  * for slower queues.
 139                  */
 140                 if (!netif_subqueue_stopped(sch->dev, (q->mq ? prio : 0))) {
 141                         qdisc = q->queues[prio];
 142                         skb = qdisc->dequeue(qdisc);
 143                         if (skb) {
 144                                 sch->q.qlen--;
 145                                 return skb;
 146                         }
 147                 }
 148         }
 149         return NULL;
 150
 151 }
 152
 153 static struct sk_buff *rr_dequeue(struct Qdisc* sch)
 154 {
 155         struct sk_buff *skb;
 156         struct prio_sched_data *q = qdisc_priv(sch);
 157         struct Qdisc *qdisc;
 158         int bandcount;
 159
 160         /* Only take one pass through the queues.  If nothing is available,
 161          * return nothing.
 162          */
 163         for (bandcount = 0; bandcount < q->bands; bandcount++) {
 164                 /* Check if the target subqueue is available before
 165                  * pulling an skb.  This way we avoid excessive requeues
 166                  * for slower queues.  If the queue is stopped, try the
 167                  * next queue.
 168                  */
 169                 if (!netif_subqueue_stopped(sch->dev,
 170                                             (q->mq ? q->curband : 0))) {
 171                         qdisc = q->queues[q->curband];
 172                         skb = qdisc->dequeue(qdisc);
 173                         if (skb) {
 174                                 sch->q.qlen--;
 175                                 q->curband++;
 176                                 if (q->curband >= q->bands)
 177                                         q->curband = 0;
 178                                 return skb;
 179                         }
 180                 }
 181                 q->curband++;
 182                 if (q->curband >= q->bands)
 183                         q->curband = 0;
 184         }
 185         return NULL;
 186 }
 187
 188 static unsigned int prio_drop(struct Qdisc* sch)
 189 {
 190         struct prio_sched_data *q = qdisc_priv(sch);
 191         int prio;
 192         unsigned int len;
 193         struct Qdisc *qdisc;
 194
 195         for (prio = q->bands-1; prio >= 0; prio--) {
 196                 qdisc = q->queues[prio];
 197                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 198                         sch->q.qlen--;
 199                         return len;
 200                 }
 201         }
 202         return 0;
 203 }
 204
 205
 206 static void
 207 prio_reset(struct Qdisc* sch)
 208 {
 209         int prio;
 210         struct prio_sched_data *q = qdisc_priv(sch);
 211
 212         for (prio=0; prio<q->bands; prio++)
 213                 qdisc_reset(q->queues[prio]);
 214         sch->q.qlen = 0;
 215 }
 216
 217 static void
 218 prio_destroy(struct Qdisc* sch)
 219 {
 220         int prio;
 221         struct prio_sched_data *q = qdisc_priv(sch);
 222
 223         tcf_destroy_chain(q->filter_list);
 224         for (prio=0; prio<q->bands; prio++)
 225                 qdisc_destroy(q->queues[prio]);
 226 }
 227
 228 static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
 229 {
 230         struct prio_sched_data *q = qdisc_priv(sch);
 231         struct tc_prio_qopt *qopt;
 232         struct rtattr *tb[TCA_PRIO_MAX];
 233         int i;
 234
 235         if (rtattr_parse_nested_compat(tb, TCA_PRIO_MAX, opt, qopt,
 236                                        sizeof(*qopt)))
 237                 return -EINVAL;
 238         q->bands = qopt->bands;
 239         /* If we're multiqueue, make sure the number of incoming bands
 240          * matches the number of queues on the device we're associating with.
 241          * If the number of bands requested is zero, then set q->bands to
 242          * dev->egress_subqueue_count.
 243          */
 244         q->mq = RTA_GET_FLAG(tb[TCA_PRIO_MQ - 1]);
 245         if (q->mq) {
 246                 if (sch->handle != TC_H_ROOT)
 247                         return -EINVAL;
 248                 if (netif_is_multiqueue(sch->dev)) {
 249                         if (q->bands == 0)
 250                                 q->bands = sch->dev->egress_subqueue_count;
 251                         else if (q->bands != sch->dev->egress_subqueue_count)
 252                                 return -EINVAL;
 253                 } else
 254                         return -EOPNOTSUPP;
 255         }
 256
 257         if (q->bands > TCQ_PRIO_BANDS || q->bands < 2)
 258                 return -EINVAL;
 259
 260         for (i=0; i<=TC_PRIO_MAX; i++) {
 261                 if (qopt->priomap[i] >= q->bands)
 262                         return -EINVAL;
 263         }
 264
 265         sch_tree_lock(sch);
 266         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 267
 268         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
 269                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 270                 if (child != &noop_qdisc) {
 271                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 272                         qdisc_destroy(child);
 273                 }
 274         }
 275         sch_tree_unlock(sch);
 276
 277         for (i=0; i<q->bands; i++) {
 278                 if (q->queues[i] == &noop_qdisc) {
 279                         struct Qdisc *child;
 280                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
 281                                                   TC_H_MAKE(sch->handle, i + 1));
 282                         if (child) {
 283                                 sch_tree_lock(sch);
 284                                 child = xchg(&q->queues[i], child);
 285
 286                                 if (child != &noop_qdisc) {
 287                                         qdisc_tree_decrease_qlen(child,
 288                                                                  child->q.qlen);
 289                                         qdisc_destroy(child);
 290                                 }
 291                                 sch_tree_unlock(sch);
 292                         }
 293                 }
 294         }
 295         return 0;
 296 }
 297
 298 static int prio_init(struct Qdisc *sch, struct rtattr *opt)
 299 {
 300         struct prio_sched_data *q = qdisc_priv(sch);
 301         int i;
 302
 303         for (i=0; i<TCQ_PRIO_BANDS; i++)
 304                 q->queues[i] = &noop_qdisc;
 305
 306         if (opt == NULL) {
 307                 return -EINVAL;
 308         } else {
 309                 int err;
 310
 311                 if ((err= prio_tune(sch, opt)) != 0)
 312                         return err;
 313         }
 314         return 0;
 315 }
 316
 317 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 318 {
 319         struct prio_sched_data *q = qdisc_priv(sch);
 320         unsigned char *b = skb_tail_pointer(skb);
 321         struct rtattr *nest;
 322         struct tc_prio_qopt opt;
 323
 324         opt.bands = q->bands;
 325         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
 326
 327         nest = RTA_NEST_COMPAT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 328         if (q->mq)
 329                 RTA_PUT_FLAG(skb, TCA_PRIO_MQ);
 330         RTA_NEST_COMPAT_END(skb, nest);
 331
 332         return skb->len;
 333
 334 rtattr_failure:
 335         nlmsg_trim(skb, b);
 336         return -1;
 337 }
 338
 339 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 340                       struct Qdisc **old)
 341 {
 342         struct prio_sched_data *q = qdisc_priv(sch);
 343         unsigned long band = arg - 1;
 344
 345         if (band >= q->bands)
 346                 return -EINVAL;
 347
 348         if (new == NULL)
 349                 new = &noop_qdisc;
 350
 351         sch_tree_lock(sch);
 352         *old = q->queues[band];
 353         q->queues[band] = new;
 354         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 355         qdisc_reset(*old);
 356         sch_tree_unlock(sch);
 357
 358         return 0;
 359 }
 360
 361 static struct Qdisc *
 362 prio_leaf(struct Qdisc *sch, unsigned long arg)
 363 {
 364         struct prio_sched_data *q = qdisc_priv(sch);
 365         unsigned long band = arg - 1;
 366
 367         if (band >= q->bands)
 368                 return NULL;
 369
 370         return q->queues[band];
 371 }
 372
 373 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 374 {
 375         struct prio_sched_data *q = qdisc_priv(sch);
 376         unsigned long band = TC_H_MIN(classid);
 377
 378         if (band - 1 >= q->bands)
 379                 return 0;
 380         return band;
 381 }
 382
 383 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 384 {
 385         return prio_get(sch, classid);
 386 }
 387
 388
 389 static void prio_put(struct Qdisc *q, unsigned long cl)
 390 {
 391         return;
 392 }
 393
 394 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct rtattr **tca, unsigned long *arg)
 395 {
 396         unsigned long cl = *arg;
 397         struct prio_sched_data *q = qdisc_priv(sch);
 398
 399         if (cl - 1 > q->bands)
 400                 return -ENOENT;
 401         return 0;
 402 }
 403
 404 static int prio_delete(struct Qdisc *sch, unsigned long cl)
 405 {
 406         struct prio_sched_data *q = qdisc_priv(sch);
 407         if (cl - 1 > q->bands)
 408                 return -ENOENT;
 409         return 0;
 410 }
 411
 412
 413 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 414                            struct tcmsg *tcm)
 415 {
 416         struct prio_sched_data *q = qdisc_priv(sch);
 417
 418         if (cl - 1 > q->bands)
 419                 return -ENOENT;
 420         tcm->tcm_handle |= TC_H_MIN(cl);
 421         if (q->queues[cl-1])
 422                 tcm->tcm_info = q->queues[cl-1]->handle;
 423         return 0;
 424 }
 425
 426 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 427                                  struct gnet_dump *d)
 428 {
 429         struct prio_sched_data *q = qdisc_priv(sch);
 430         struct Qdisc *cl_q;
 431
 432         cl_q = q->queues[cl - 1];
 433         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 434             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 435                 return -1;
 436
 437         return 0;
 438 }
 439
 440 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 441 {
 442         struct prio_sched_data *q = qdisc_priv(sch);
 443         int prio;
 444
 445         if (arg->stop)
 446                 return;
 447
 448         for (prio = 0; prio < q->bands; prio++) {
 449                 if (arg->count < arg->skip) {
 450                         arg->count++;
 451                         continue;
 452                 }
 453                 if (arg->fn(sch, prio+1, arg) < 0) {
 454                         arg->stop = 1;
 455                         break;
 456                 }
 457                 arg->count++;
 458         }
 459 }
 460
 461 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 462 {
 463         struct prio_sched_data *q = qdisc_priv(sch);
 464
 465         if (cl)
 466                 return NULL;
 467         return &q->filter_list;
 468 }
 469
 470 static struct Qdisc_class_ops prio_class_ops = {
 471         .graft          =       prio_graft,
 472         .leaf           =       prio_leaf,
 473         .get            =       prio_get,
 474         .put            =       prio_put,
 475         .change         =       prio_change,
 476         .delete         =       prio_delete,
 477         .walk           =       prio_walk,
 478         .tcf_chain      =       prio_find_tcf,
 479         .bind_tcf       =       prio_bind,
 480         .unbind_tcf     =       prio_put,
 481         .dump           =       prio_dump_class,
 482         .dump_stats     =       prio_dump_class_stats,
 483 };
 484
 485 static struct Qdisc_ops prio_qdisc_ops = {
 486         .next           =       NULL,
 487         .cl_ops         =       &prio_class_ops,
 488         .id             =       "prio",
 489         .priv_size      =       sizeof(struct prio_sched_data),
 490         .enqueue        =       prio_enqueue,
 491         .dequeue        =       prio_dequeue,
 492         .requeue        =       prio_requeue,
 493         .drop           =       prio_drop,
 494         .init           =       prio_init,
 495         .reset          =       prio_reset,
 496         .destroy        =       prio_destroy,
 497         .change         =       prio_tune,
 498         .dump           =       prio_dump,
 499         .owner          =       THIS_MODULE,
 500 };
 501
 502 static struct Qdisc_ops rr_qdisc_ops = {
 503         .next           =       NULL,
 504         .cl_ops         =       &prio_class_ops,
 505         .id             =       "rr",
 506         .priv_size      =       sizeof(struct prio_sched_data),
 507         .enqueue        =       prio_enqueue,
 508         .dequeue        =       rr_dequeue,
 509         .requeue        =       prio_requeue,
 510         .drop           =       prio_drop,
 511         .init           =       prio_init,
 512         .reset          =       prio_reset,
 513         .destroy        =       prio_destroy,
 514         .change         =       prio_tune,
 515         .dump           =       prio_dump,
 516         .owner          =       THIS_MODULE,
 517 };
 518
 519 static int __init prio_module_init(void)
 520 {
 521         int err;
 522
 523         err = register_qdisc(&prio_qdisc_ops);
 524         if (err < 0)
 525                 return err;
 526         err = register_qdisc(&rr_qdisc_ops);
 527         if (err < 0)
 528                 unregister_qdisc(&prio_qdisc_ops);
 529         return err;
 530 }
 531
 532 static void __exit prio_module_exit(void)
 533 {
 534         unregister_qdisc(&prio_qdisc_ops);
 535         unregister_qdisc(&rr_qdisc_ops);
 536 }
 537
 538 module_init(prio_module_init)
 539 module_exit(prio_module_exit)
 540
 541 MODULE_LICENSE("GPL");
 542 MODULE_ALIAS("sch_rr");