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/slab.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/errno.h>
  20 #include <linux/skbuff.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <net/pkt_cls.h>
  24
  25 struct prio_sched_data {
  26         int bands;
  27         struct tcf_proto __rcu *filter_list;
  28         struct tcf_block *block;
  29         u8  prio2band[TC_PRIO_MAX+1];
  30         struct Qdisc *queues[TCQ_PRIO_BANDS];
  31 };
  32
  33
  34 static struct Qdisc *
  35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  36 {
  37         struct prio_sched_data *q = qdisc_priv(sch);
  38         u32 band = skb->priority;
  39         struct tcf_result res;
  40         struct tcf_proto *fl;
  41         int err;
  42
  43         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  44         if (TC_H_MAJ(skb->priority) != sch->handle) {
  45                 fl = rcu_dereference_bh(q->filter_list);
  46                 err = tcf_classify(skb, fl, &res, false);
  47 #ifdef CONFIG_NET_CLS_ACT
  48                 switch (err) {
  49                 case TC_ACT_STOLEN:
  50                 case TC_ACT_QUEUED:
  51                 case TC_ACT_TRAP:
  52                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  53                         /* fall through */
  54                 case TC_ACT_SHOT:
  55                         return NULL;
  56                 }
  57 #endif
  58                 if (!fl || err < 0) {
  59                         if (TC_H_MAJ(band))
  60                                 band = 0;
  61                         return q->queues[q->prio2band[band & TC_PRIO_MAX]];
  62                 }
  63                 band = res.classid;
  64         }
  65         band = TC_H_MIN(band) - 1;
  66         if (band >= q->bands)
  67                 return q->queues[q->prio2band[0]];
  68
  69         return q->queues[band];
  70 }
  71
  72 static int
  73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
  74 {
  75         unsigned int len = qdisc_pkt_len(skb);
  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                         qdisc_qstats_drop(sch);
  85                 __qdisc_drop(skb, to_free);
  86                 return ret;
  87         }
  88 #endif
  89
  90         ret = qdisc_enqueue(skb, qdisc, to_free);
  91         if (ret == NET_XMIT_SUCCESS) {
  92                 sch->qstats.backlog += len;
  93                 sch->q.qlen++;
  94                 return NET_XMIT_SUCCESS;
  95         }
  96         if (net_xmit_drop_count(ret))
  97                 qdisc_qstats_drop(sch);
  98         return ret;
  99 }
 100
 101 static struct sk_buff *prio_peek(struct Qdisc *sch)
 102 {
 103         struct prio_sched_data *q = qdisc_priv(sch);
 104         int prio;
 105
 106         for (prio = 0; prio < q->bands; prio++) {
 107                 struct Qdisc *qdisc = q->queues[prio];
 108                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 109                 if (skb)
 110                         return skb;
 111         }
 112         return NULL;
 113 }
 114
 115 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 116 {
 117         struct prio_sched_data *q = qdisc_priv(sch);
 118         int prio;
 119
 120         for (prio = 0; prio < q->bands; prio++) {
 121                 struct Qdisc *qdisc = q->queues[prio];
 122                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 123                 if (skb) {
 124                         qdisc_bstats_update(sch, skb);
 125                         qdisc_qstats_backlog_dec(sch, skb);
 126                         sch->q.qlen--;
 127                         return skb;
 128                 }
 129         }
 130         return NULL;
 131
 132 }
 133
 134 static void
 135 prio_reset(struct Qdisc *sch)
 136 {
 137         int prio;
 138         struct prio_sched_data *q = qdisc_priv(sch);
 139
 140         for (prio = 0; prio < q->bands; prio++)
 141                 qdisc_reset(q->queues[prio]);
 142         sch->qstats.backlog = 0;
 143         sch->q.qlen = 0;
 144 }
 145
 146 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
 147 {
 148         struct net_device *dev = qdisc_dev(sch);
 149         struct tc_prio_qopt_offload opt = {
 150                 .handle = sch->handle,
 151                 .parent = sch->parent,
 152         };
 153
 154         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 155                 return -EOPNOTSUPP;
 156
 157         if (qopt) {
 158                 opt.command = TC_PRIO_REPLACE;
 159                 opt.replace_params.bands = qopt->bands;
 160                 memcpy(&opt.replace_params.priomap, qopt->priomap,
 161                        TC_PRIO_MAX + 1);
 162                 opt.replace_params.qstats = &sch->qstats;
 163         } else {
 164                 opt.command = TC_PRIO_DESTROY;
 165         }
 166
 167         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt);
 168 }
 169
 170 static void
 171 prio_destroy(struct Qdisc *sch)
 172 {
 173         int prio;
 174         struct prio_sched_data *q = qdisc_priv(sch);
 175
 176         tcf_block_put(q->block);
 177         prio_offload(sch, NULL);
 178         for (prio = 0; prio < q->bands; prio++)
 179                 qdisc_put(q->queues[prio]);
 180 }
 181
 182 static int prio_tune(struct Qdisc *sch, struct nlattr *opt,
 183                      struct netlink_ext_ack *extack)
 184 {
 185         struct prio_sched_data *q = qdisc_priv(sch);
 186         struct Qdisc *queues[TCQ_PRIO_BANDS];
 187         int oldbands = q->bands, i;
 188         struct tc_prio_qopt *qopt;
 189
 190         if (nla_len(opt) < sizeof(*qopt))
 191                 return -EINVAL;
 192         qopt = nla_data(opt);
 193
 194         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 195                 return -EINVAL;
 196
 197         for (i = 0; i <= TC_PRIO_MAX; i++) {
 198                 if (qopt->priomap[i] >= qopt->bands)
 199                         return -EINVAL;
 200         }
 201
 202         /* Before commit, make sure we can allocate all new qdiscs */
 203         for (i = oldbands; i < qopt->bands; i++) {
 204                 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
 205                                               TC_H_MAKE(sch->handle, i + 1),
 206                                               extack);
 207                 if (!queues[i]) {
 208                         while (i > oldbands)
 209                                 qdisc_put(queues[--i]);
 210                         return -ENOMEM;
 211                 }
 212         }
 213
 214         prio_offload(sch, qopt);
 215         sch_tree_lock(sch);
 216         q->bands = qopt->bands;
 217         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 218
 219         for (i = q->bands; i < oldbands; i++) {
 220                 struct Qdisc *child = q->queues[i];
 221
 222                 qdisc_tree_reduce_backlog(child, child->q.qlen,
 223                                           child->qstats.backlog);
 224         }
 225
 226         for (i = oldbands; i < q->bands; i++) {
 227                 q->queues[i] = queues[i];
 228                 if (q->queues[i] != &noop_qdisc)
 229                         qdisc_hash_add(q->queues[i], true);
 230         }
 231
 232         sch_tree_unlock(sch);
 233
 234         for (i = q->bands; i < oldbands; i++)
 235                 qdisc_put(q->queues[i]);
 236         return 0;
 237 }
 238
 239 static int prio_init(struct Qdisc *sch, struct nlattr *opt,
 240                      struct netlink_ext_ack *extack)
 241 {
 242         struct prio_sched_data *q = qdisc_priv(sch);
 243         int err;
 244
 245         if (!opt)
 246                 return -EINVAL;
 247
 248         err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
 249         if (err)
 250                 return err;
 251
 252         return prio_tune(sch, opt, extack);
 253 }
 254
 255 static int prio_dump_offload(struct Qdisc *sch)
 256 {
 257         struct tc_prio_qopt_offload hw_stats = {
 258                 .command = TC_PRIO_STATS,
 259                 .handle = sch->handle,
 260                 .parent = sch->parent,
 261                 {
 262                         .stats = {
 263                                 .bstats = &sch->bstats,
 264                                 .qstats = &sch->qstats,
 265                         },
 266                 },
 267         };
 268
 269         return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_PRIO, &hw_stats);
 270 }
 271
 272 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 273 {
 274         struct prio_sched_data *q = qdisc_priv(sch);
 275         unsigned char *b = skb_tail_pointer(skb);
 276         struct tc_prio_qopt opt;
 277         int err;
 278
 279         opt.bands = q->bands;
 280         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 281
 282         err = prio_dump_offload(sch);
 283         if (err)
 284                 goto nla_put_failure;
 285
 286         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 287                 goto nla_put_failure;
 288
 289         return skb->len;
 290
 291 nla_put_failure:
 292         nlmsg_trim(skb, b);
 293         return -1;
 294 }
 295
 296 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 297                       struct Qdisc **old, struct netlink_ext_ack *extack)
 298 {
 299         struct prio_sched_data *q = qdisc_priv(sch);
 300         struct tc_prio_qopt_offload graft_offload;
 301         unsigned long band = arg - 1;
 302
 303         if (new == NULL)
 304                 new = &noop_qdisc;
 305
 306         *old = qdisc_replace(sch, new, &q->queues[band]);
 307
 308         graft_offload.handle = sch->handle;
 309         graft_offload.parent = sch->parent;
 310         graft_offload.graft_params.band = band;
 311         graft_offload.graft_params.child_handle = new->handle;
 312         graft_offload.command = TC_PRIO_GRAFT;
 313
 314         qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
 315                                    TC_SETUP_QDISC_PRIO, &graft_offload,
 316                                    extack);
 317         return 0;
 318 }
 319
 320 static struct Qdisc *
 321 prio_leaf(struct Qdisc *sch, unsigned long arg)
 322 {
 323         struct prio_sched_data *q = qdisc_priv(sch);
 324         unsigned long band = arg - 1;
 325
 326         return q->queues[band];
 327 }
 328
 329 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
 330 {
 331         struct prio_sched_data *q = qdisc_priv(sch);
 332         unsigned long band = TC_H_MIN(classid);
 333
 334         if (band - 1 >= q->bands)
 335                 return 0;
 336         return band;
 337 }
 338
 339 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 340 {
 341         return prio_find(sch, classid);
 342 }
 343
 344
 345 static void prio_unbind(struct Qdisc *q, unsigned long cl)
 346 {
 347 }
 348
 349 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 350                            struct tcmsg *tcm)
 351 {
 352         struct prio_sched_data *q = qdisc_priv(sch);
 353
 354         tcm->tcm_handle |= TC_H_MIN(cl);
 355         tcm->tcm_info = q->queues[cl-1]->handle;
 356         return 0;
 357 }
 358
 359 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 360                                  struct gnet_dump *d)
 361 {
 362         struct prio_sched_data *q = qdisc_priv(sch);
 363         struct Qdisc *cl_q;
 364
 365         cl_q = q->queues[cl - 1];
 366         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 367                                   d, NULL, &cl_q->bstats) < 0 ||
 368             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 369                 return -1;
 370
 371         return 0;
 372 }
 373
 374 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 375 {
 376         struct prio_sched_data *q = qdisc_priv(sch);
 377         int prio;
 378
 379         if (arg->stop)
 380                 return;
 381
 382         for (prio = 0; prio < q->bands; prio++) {
 383                 if (arg->count < arg->skip) {
 384                         arg->count++;
 385                         continue;
 386                 }
 387                 if (arg->fn(sch, prio + 1, arg) < 0) {
 388                         arg->stop = 1;
 389                         break;
 390                 }
 391                 arg->count++;
 392         }
 393 }
 394
 395 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
 396                                         struct netlink_ext_ack *extack)
 397 {
 398         struct prio_sched_data *q = qdisc_priv(sch);
 399
 400         if (cl)
 401                 return NULL;
 402         return q->block;
 403 }
 404
 405 static const struct Qdisc_class_ops prio_class_ops = {
 406         .graft          =       prio_graft,
 407         .leaf           =       prio_leaf,
 408         .find           =       prio_find,
 409         .walk           =       prio_walk,
 410         .tcf_block      =       prio_tcf_block,
 411         .bind_tcf       =       prio_bind,
 412         .unbind_tcf     =       prio_unbind,
 413         .dump           =       prio_dump_class,
 414         .dump_stats     =       prio_dump_class_stats,
 415 };
 416
 417 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 418         .next           =       NULL,
 419         .cl_ops         =       &prio_class_ops,
 420         .id             =       "prio",
 421         .priv_size      =       sizeof(struct prio_sched_data),
 422         .enqueue        =       prio_enqueue,
 423         .dequeue        =       prio_dequeue,
 424         .peek           =       prio_peek,
 425         .init           =       prio_init,
 426         .reset          =       prio_reset,
 427         .destroy        =       prio_destroy,
 428         .change         =       prio_tune,
 429         .dump           =       prio_dump,
 430         .owner          =       THIS_MODULE,
 431 };
 432
 433 static int __init prio_module_init(void)
 434 {
 435         return register_qdisc(&prio_qdisc_ops);
 436 }
 437
 438 static void __exit prio_module_exit(void)
 439 {
 440         unregister_qdisc(&prio_qdisc_ops);
 441 }
 442
 443 module_init(prio_module_init)
 444 module_exit(prio_module_exit)
 445
 446 MODULE_LICENSE("GPL");