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                 qdisc_tree_flush_backlog(q->queues[i]);
 221
 222         for (i = oldbands; i < q->bands; i++) {
 223                 q->queues[i] = queues[i];
 224                 if (q->queues[i] != &noop_qdisc)
 225                         qdisc_hash_add(q->queues[i], true);
 226         }
 227
 228         sch_tree_unlock(sch);
 229
 230         for (i = q->bands; i < oldbands; i++)
 231                 qdisc_put(q->queues[i]);
 232         return 0;
 233 }
 234
 235 static int prio_init(struct Qdisc *sch, struct nlattr *opt,
 236                      struct netlink_ext_ack *extack)
 237 {
 238         struct prio_sched_data *q = qdisc_priv(sch);
 239         int err;
 240
 241         if (!opt)
 242                 return -EINVAL;
 243
 244         err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
 245         if (err)
 246                 return err;
 247
 248         return prio_tune(sch, opt, extack);
 249 }
 250
 251 static int prio_dump_offload(struct Qdisc *sch)
 252 {
 253         struct tc_prio_qopt_offload hw_stats = {
 254                 .command = TC_PRIO_STATS,
 255                 .handle = sch->handle,
 256                 .parent = sch->parent,
 257                 {
 258                         .stats = {
 259                                 .bstats = &sch->bstats,
 260                                 .qstats = &sch->qstats,
 261                         },
 262                 },
 263         };
 264
 265         return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_PRIO, &hw_stats);
 266 }
 267
 268 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 269 {
 270         struct prio_sched_data *q = qdisc_priv(sch);
 271         unsigned char *b = skb_tail_pointer(skb);
 272         struct tc_prio_qopt opt;
 273         int err;
 274
 275         opt.bands = q->bands;
 276         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 277
 278         err = prio_dump_offload(sch);
 279         if (err)
 280                 goto nla_put_failure;
 281
 282         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 283                 goto nla_put_failure;
 284
 285         return skb->len;
 286
 287 nla_put_failure:
 288         nlmsg_trim(skb, b);
 289         return -1;
 290 }
 291
 292 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 293                       struct Qdisc **old, struct netlink_ext_ack *extack)
 294 {
 295         struct prio_sched_data *q = qdisc_priv(sch);
 296         struct tc_prio_qopt_offload graft_offload;
 297         unsigned long band = arg - 1;
 298
 299         if (new == NULL)
 300                 new = &noop_qdisc;
 301
 302         *old = qdisc_replace(sch, new, &q->queues[band]);
 303
 304         graft_offload.handle = sch->handle;
 305         graft_offload.parent = sch->parent;
 306         graft_offload.graft_params.band = band;
 307         graft_offload.graft_params.child_handle = new->handle;
 308         graft_offload.command = TC_PRIO_GRAFT;
 309
 310         qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
 311                                    TC_SETUP_QDISC_PRIO, &graft_offload,
 312                                    extack);
 313         return 0;
 314 }
 315
 316 static struct Qdisc *
 317 prio_leaf(struct Qdisc *sch, unsigned long arg)
 318 {
 319         struct prio_sched_data *q = qdisc_priv(sch);
 320         unsigned long band = arg - 1;
 321
 322         return q->queues[band];
 323 }
 324
 325 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
 326 {
 327         struct prio_sched_data *q = qdisc_priv(sch);
 328         unsigned long band = TC_H_MIN(classid);
 329
 330         if (band - 1 >= q->bands)
 331                 return 0;
 332         return band;
 333 }
 334
 335 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 336 {
 337         return prio_find(sch, classid);
 338 }
 339
 340
 341 static void prio_unbind(struct Qdisc *q, unsigned long cl)
 342 {
 343 }
 344
 345 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 346                            struct tcmsg *tcm)
 347 {
 348         struct prio_sched_data *q = qdisc_priv(sch);
 349
 350         tcm->tcm_handle |= TC_H_MIN(cl);
 351         tcm->tcm_info = q->queues[cl-1]->handle;
 352         return 0;
 353 }
 354
 355 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 356                                  struct gnet_dump *d)
 357 {
 358         struct prio_sched_data *q = qdisc_priv(sch);
 359         struct Qdisc *cl_q;
 360
 361         cl_q = q->queues[cl - 1];
 362         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 363                                   d, NULL, &cl_q->bstats) < 0 ||
 364             qdisc_qstats_copy(d, cl_q) < 0)
 365                 return -1;
 366
 367         return 0;
 368 }
 369
 370 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 371 {
 372         struct prio_sched_data *q = qdisc_priv(sch);
 373         int prio;
 374
 375         if (arg->stop)
 376                 return;
 377
 378         for (prio = 0; prio < q->bands; prio++) {
 379                 if (arg->count < arg->skip) {
 380                         arg->count++;
 381                         continue;
 382                 }
 383                 if (arg->fn(sch, prio + 1, arg) < 0) {
 384                         arg->stop = 1;
 385                         break;
 386                 }
 387                 arg->count++;
 388         }
 389 }
 390
 391 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
 392                                         struct netlink_ext_ack *extack)
 393 {
 394         struct prio_sched_data *q = qdisc_priv(sch);
 395
 396         if (cl)
 397                 return NULL;
 398         return q->block;
 399 }
 400
 401 static const struct Qdisc_class_ops prio_class_ops = {
 402         .graft          =       prio_graft,
 403         .leaf           =       prio_leaf,
 404         .find           =       prio_find,
 405         .walk           =       prio_walk,
 406         .tcf_block      =       prio_tcf_block,
 407         .bind_tcf       =       prio_bind,
 408         .unbind_tcf     =       prio_unbind,
 409         .dump           =       prio_dump_class,
 410         .dump_stats     =       prio_dump_class_stats,
 411 };
 412
 413 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 414         .next           =       NULL,
 415         .cl_ops         =       &prio_class_ops,
 416         .id             =       "prio",
 417         .priv_size      =       sizeof(struct prio_sched_data),
 418         .enqueue        =       prio_enqueue,
 419         .dequeue        =       prio_dequeue,
 420         .peek           =       prio_peek,
 421         .init           =       prio_init,
 422         .reset          =       prio_reset,
 423         .destroy        =       prio_destroy,
 424         .change         =       prio_tune,
 425         .dump           =       prio_dump,
 426         .owner          =       THIS_MODULE,
 427 };
 428
 429 static int __init prio_module_init(void)
 430 {
 431         return register_qdisc(&prio_qdisc_ops);
 432 }
 433
 434 static void __exit prio_module_exit(void)
 435 {
 436         unregister_qdisc(&prio_qdisc_ops);
 437 }
 438
 439 module_init(prio_module_init)
 440 module_exit(prio_module_exit)
 441
 442 MODULE_LICENSE("GPL");