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         struct Qdisc *qdisc;
  76         int ret;
  77
  78         qdisc = prio_classify(skb, sch, &ret);
  79 #ifdef CONFIG_NET_CLS_ACT
  80         if (qdisc == NULL) {
  81
  82                 if (ret & __NET_XMIT_BYPASS)
  83                         qdisc_qstats_drop(sch);
  84                 __qdisc_drop(skb, to_free);
  85                 return ret;
  86         }
  87 #endif
  88
  89         ret = qdisc_enqueue(skb, qdisc, to_free);
  90         if (ret == NET_XMIT_SUCCESS) {
  91                 qdisc_qstats_backlog_inc(sch, skb);
  92                 sch->q.qlen++;
  93                 return NET_XMIT_SUCCESS;
  94         }
  95         if (net_xmit_drop_count(ret))
  96                 qdisc_qstats_drop(sch);
  97         return ret;
  98 }
  99
 100 static struct sk_buff *prio_peek(struct Qdisc *sch)
 101 {
 102         struct prio_sched_data *q = qdisc_priv(sch);
 103         int prio;
 104
 105         for (prio = 0; prio < q->bands; prio++) {
 106                 struct Qdisc *qdisc = q->queues[prio];
 107                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 108                 if (skb)
 109                         return skb;
 110         }
 111         return NULL;
 112 }
 113
 114 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 115 {
 116         struct prio_sched_data *q = qdisc_priv(sch);
 117         int prio;
 118
 119         for (prio = 0; prio < q->bands; prio++) {
 120                 struct Qdisc *qdisc = q->queues[prio];
 121                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 122                 if (skb) {
 123                         qdisc_bstats_update(sch, skb);
 124                         qdisc_qstats_backlog_dec(sch, skb);
 125                         sch->q.qlen--;
 126                         return skb;
 127                 }
 128         }
 129         return NULL;
 130
 131 }
 132
 133 static void
 134 prio_reset(struct Qdisc *sch)
 135 {
 136         int prio;
 137         struct prio_sched_data *q = qdisc_priv(sch);
 138
 139         for (prio = 0; prio < q->bands; prio++)
 140                 qdisc_reset(q->queues[prio]);
 141         sch->qstats.backlog = 0;
 142         sch->q.qlen = 0;
 143 }
 144
 145 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
 146 {
 147         struct net_device *dev = qdisc_dev(sch);
 148         struct tc_prio_qopt_offload opt = {
 149                 .handle = sch->handle,
 150                 .parent = sch->parent,
 151         };
 152
 153         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 154                 return -EOPNOTSUPP;
 155
 156         if (qopt) {
 157                 opt.command = TC_PRIO_REPLACE;
 158                 opt.replace_params.bands = qopt->bands;
 159                 memcpy(&opt.replace_params.priomap, qopt->priomap,
 160                        TC_PRIO_MAX + 1);
 161                 opt.replace_params.qstats = &sch->qstats;
 162         } else {
 163                 opt.command = TC_PRIO_DESTROY;
 164         }
 165
 166         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt);
 167 }
 168
 169 static void
 170 prio_destroy(struct Qdisc *sch)
 171 {
 172         int prio;
 173         struct prio_sched_data *q = qdisc_priv(sch);
 174
 175         tcf_block_put(q->block);
 176         prio_offload(sch, NULL);
 177         for (prio = 0; prio < q->bands; prio++)
 178                 qdisc_put(q->queues[prio]);
 179 }
 180
 181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt,
 182                      struct netlink_ext_ack *extack)
 183 {
 184         struct prio_sched_data *q = qdisc_priv(sch);
 185         struct Qdisc *queues[TCQ_PRIO_BANDS];
 186         int oldbands = q->bands, i;
 187         struct tc_prio_qopt *qopt;
 188
 189         if (nla_len(opt) < sizeof(*qopt))
 190                 return -EINVAL;
 191         qopt = nla_data(opt);
 192
 193         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 194                 return -EINVAL;
 195
 196         for (i = 0; i <= TC_PRIO_MAX; i++) {
 197                 if (qopt->priomap[i] >= qopt->bands)
 198                         return -EINVAL;
 199         }
 200
 201         /* Before commit, make sure we can allocate all new qdiscs */
 202         for (i = oldbands; i < qopt->bands; i++) {
 203                 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
 204                                               TC_H_MAKE(sch->handle, i + 1),
 205                                               extack);
 206                 if (!queues[i]) {
 207                         while (i > oldbands)
 208                                 qdisc_put(queues[--i]);
 209                         return -ENOMEM;
 210                 }
 211         }
 212
 213         prio_offload(sch, qopt);
 214         sch_tree_lock(sch);
 215         q->bands = qopt->bands;
 216         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 217
 218         for (i = q->bands; i < oldbands; i++) {
 219                 struct Qdisc *child = q->queues[i];
 220
 221                 qdisc_tree_reduce_backlog(child, child->q.qlen,
 222                                           child->qstats.backlog);
 223         }
 224
 225         for (i = oldbands; i < q->bands; i++) {
 226                 q->queues[i] = queues[i];
 227                 if (q->queues[i] != &noop_qdisc)
 228                         qdisc_hash_add(q->queues[i], true);
 229         }
 230
 231         sch_tree_unlock(sch);
 232
 233         for (i = q->bands; i < oldbands; i++)
 234                 qdisc_put(q->queues[i]);
 235         return 0;
 236 }
 237
 238 static int prio_init(struct Qdisc *sch, struct nlattr *opt,
 239                      struct netlink_ext_ack *extack)
 240 {
 241         struct prio_sched_data *q = qdisc_priv(sch);
 242         int err;
 243
 244         if (!opt)
 245                 return -EINVAL;
 246
 247         err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
 248         if (err)
 249                 return err;
 250
 251         return prio_tune(sch, opt, extack);
 252 }
 253
 254 static int prio_dump_offload(struct Qdisc *sch)
 255 {
 256         struct tc_prio_qopt_offload hw_stats = {
 257                 .command = TC_PRIO_STATS,
 258                 .handle = sch->handle,
 259                 .parent = sch->parent,
 260                 {
 261                         .stats = {
 262                                 .bstats = &sch->bstats,
 263                                 .qstats = &sch->qstats,
 264                         },
 265                 },
 266         };
 267
 268         return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_PRIO, &hw_stats);
 269 }
 270
 271 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 272 {
 273         struct prio_sched_data *q = qdisc_priv(sch);
 274         unsigned char *b = skb_tail_pointer(skb);
 275         struct tc_prio_qopt opt;
 276         int err;
 277
 278         opt.bands = q->bands;
 279         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 280
 281         err = prio_dump_offload(sch);
 282         if (err)
 283                 goto nla_put_failure;
 284
 285         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 286                 goto nla_put_failure;
 287
 288         return skb->len;
 289
 290 nla_put_failure:
 291         nlmsg_trim(skb, b);
 292         return -1;
 293 }
 294
 295 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 296                       struct Qdisc **old, struct netlink_ext_ack *extack)
 297 {
 298         struct prio_sched_data *q = qdisc_priv(sch);
 299         struct tc_prio_qopt_offload graft_offload;
 300         unsigned long band = arg - 1;
 301
 302         if (new == NULL)
 303                 new = &noop_qdisc;
 304
 305         *old = qdisc_replace(sch, new, &q->queues[band]);
 306
 307         graft_offload.handle = sch->handle;
 308         graft_offload.parent = sch->parent;
 309         graft_offload.graft_params.band = band;
 310         graft_offload.graft_params.child_handle = new->handle;
 311         graft_offload.command = TC_PRIO_GRAFT;
 312
 313         qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
 314                                    TC_SETUP_QDISC_PRIO, &graft_offload,
 315                                    extack);
 316         return 0;
 317 }
 318
 319 static struct Qdisc *
 320 prio_leaf(struct Qdisc *sch, unsigned long arg)
 321 {
 322         struct prio_sched_data *q = qdisc_priv(sch);
 323         unsigned long band = arg - 1;
 324
 325         return q->queues[band];
 326 }
 327
 328 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
 329 {
 330         struct prio_sched_data *q = qdisc_priv(sch);
 331         unsigned long band = TC_H_MIN(classid);
 332
 333         if (band - 1 >= q->bands)
 334                 return 0;
 335         return band;
 336 }
 337
 338 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 339 {
 340         return prio_find(sch, classid);
 341 }
 342
 343
 344 static void prio_unbind(struct Qdisc *q, unsigned long cl)
 345 {
 346 }
 347
 348 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 349                            struct tcmsg *tcm)
 350 {
 351         struct prio_sched_data *q = qdisc_priv(sch);
 352
 353         tcm->tcm_handle |= TC_H_MIN(cl);
 354         tcm->tcm_info = q->queues[cl-1]->handle;
 355         return 0;
 356 }
 357
 358 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 359                                  struct gnet_dump *d)
 360 {
 361         struct prio_sched_data *q = qdisc_priv(sch);
 362         struct Qdisc *cl_q;
 363
 364         cl_q = q->queues[cl - 1];
 365         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 366                                   d, NULL, &cl_q->bstats) < 0 ||
 367             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 368                 return -1;
 369
 370         return 0;
 371 }
 372
 373 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 374 {
 375         struct prio_sched_data *q = qdisc_priv(sch);
 376         int prio;
 377
 378         if (arg->stop)
 379                 return;
 380
 381         for (prio = 0; prio < q->bands; prio++) {
 382                 if (arg->count < arg->skip) {
 383                         arg->count++;
 384                         continue;
 385                 }
 386                 if (arg->fn(sch, prio + 1, arg) < 0) {
 387                         arg->stop = 1;
 388                         break;
 389                 }
 390                 arg->count++;
 391         }
 392 }
 393
 394 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
 395                                         struct netlink_ext_ack *extack)
 396 {
 397         struct prio_sched_data *q = qdisc_priv(sch);
 398
 399         if (cl)
 400                 return NULL;
 401         return q->block;
 402 }
 403
 404 static const struct Qdisc_class_ops prio_class_ops = {
 405         .graft          =       prio_graft,
 406         .leaf           =       prio_leaf,
 407         .find           =       prio_find,
 408         .walk           =       prio_walk,
 409         .tcf_block      =       prio_tcf_block,
 410         .bind_tcf       =       prio_bind,
 411         .unbind_tcf     =       prio_unbind,
 412         .dump           =       prio_dump_class,
 413         .dump_stats     =       prio_dump_class_stats,
 414 };
 415
 416 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 417         .next           =       NULL,
 418         .cl_ops         =       &prio_class_ops,
 419         .id             =       "prio",
 420         .priv_size      =       sizeof(struct prio_sched_data),
 421         .enqueue        =       prio_enqueue,
 422         .dequeue        =       prio_dequeue,
 423         .peek           =       prio_peek,
 424         .init           =       prio_init,
 425         .reset          =       prio_reset,
 426         .destroy        =       prio_destroy,
 427         .change         =       prio_tune,
 428         .dump           =       prio_dump,
 429         .owner          =       THIS_MODULE,
 430 };
 431
 432 static int __init prio_module_init(void)
 433 {
 434         return register_qdisc(&prio_qdisc_ops);
 435 }
 436
 437 static void __exit prio_module_exit(void)
 438 {
 439         unregister_qdisc(&prio_qdisc_ops);
 440 }
 441
 442 module_init(prio_module_init)
 443 module_exit(prio_module_exit)
 444
 445 MODULE_LICENSE("GPL");