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 <linux/netdevice.h>
  22 #include <net/netlink.h>
  23 #include <net/pkt_sched.h>
  24
  25
  26 struct prio_sched_data {
  27         int bands;
  28         struct tcf_proto __rcu *filter_list;
  29         u8  prio2band[TC_PRIO_MAX+1];
  30         struct Qdisc *queues[TCQ_PRIO_BANDS];
  31         u8 enable_flow;
  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         struct tcf_proto *fl;
  42         int err;
  43
  44         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  45         if (TC_H_MAJ(skb->priority) != sch->handle) {
  46                 fl = rcu_dereference_bh(q->filter_list);
  47                 err = tc_classify(skb, fl, &res, false);
  48 #ifdef CONFIG_NET_CLS_ACT
  49                 switch (err) {
  50                 case TC_ACT_STOLEN:
  51                 case TC_ACT_QUEUED:
  52                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  53                 case TC_ACT_SHOT:
  54                         return NULL;
  55                 }
  56 #endif
  57                 if (!fl || err < 0) {
  58                         if (TC_H_MAJ(band))
  59                                 band = 0;
  60                         return q->queues[q->prio2band[band & TC_PRIO_MAX]];
  61                 }
  62                 band = res.classid;
  63         }
  64         band = TC_H_MIN(band) - 1;
  65         if (band >= q->bands)
  66                 return q->queues[q->prio2band[0]];
  67
  68         return q->queues[band];
  69 }
  70
  71 static int
  72 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  73 {
  74         struct Qdisc *qdisc;
  75         int ret;
  76
  77         qdisc = prio_classify(skb, sch, &ret);
  78 #ifdef CONFIG_NET_CLS_ACT
  79         if (qdisc == NULL) {
  80
  81                 if (ret & __NET_XMIT_BYPASS)
  82                         qdisc_qstats_drop(sch);
  83                 kfree_skb(skb);
  84                 return ret;
  85         }
  86 #endif
  87
  88         ret = qdisc_enqueue(skb, qdisc);
  89         if (ret == NET_XMIT_SUCCESS) {
  90                 sch->q.qlen++;
  91                 return NET_XMIT_SUCCESS;
  92         }
  93         if (net_xmit_drop_count(ret))
  94                 qdisc_qstats_drop(sch);
  95         return ret;
  96 }
  97
  98 static struct sk_buff *prio_peek(struct Qdisc *sch)
  99 {
 100         struct prio_sched_data *q = qdisc_priv(sch);
 101         int prio;
 102         if (!q->enable_flow)
 103                 return NULL;
 104         for (prio = 0; prio < q->bands; prio++) {
 105                 struct Qdisc *qdisc = q->queues[prio];
 106                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 107                 if (skb)
 108                         return skb;
 109         }
 110         return NULL;
 111 }
 112
 113 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 114 {
 115         struct prio_sched_data *q = qdisc_priv(sch);
 116         int prio;
 117         if (!q->enable_flow)
 118                 return NULL;
 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                         sch->q.qlen--;
 126                         return skb;
 127                 }
 128         }
 129         return NULL;
 130
 131 }
 132
 133 static unsigned int prio_drop(struct Qdisc *sch)
 134 {
 135         struct prio_sched_data *q = qdisc_priv(sch);
 136         int prio;
 137         unsigned int len;
 138         struct Qdisc *qdisc;
 139
 140         for (prio = q->bands-1; prio >= 0; prio--) {
 141                 qdisc = q->queues[prio];
 142                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 143                         sch->q.qlen--;
 144                         return len;
 145                 }
 146         }
 147         return 0;
 148 }
 149
 150
 151 static void
 152 prio_reset(struct Qdisc *sch)
 153 {
 154         int prio;
 155         struct prio_sched_data *q = qdisc_priv(sch);
 156
 157         for (prio = 0; prio < q->bands; prio++)
 158                 qdisc_reset(q->queues[prio]);
 159         sch->q.qlen = 0;
 160         q->enable_flow = 1;
 161 }
 162
 163 static void
 164 prio_destroy(struct Qdisc *sch)
 165 {
 166         int prio;
 167         struct prio_sched_data *q = qdisc_priv(sch);
 168
 169         tcf_destroy_chain(&q->filter_list);
 170         for (prio = 0; prio < q->bands; prio++)
 171                 qdisc_destroy(q->queues[prio]);
 172 }
 173
 174 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 175 {
 176         struct prio_sched_data *q = qdisc_priv(sch);
 177         struct tc_prio_qopt *qopt;
 178         int i;
 179         int flow_change = 0;
 180
 181         if (nla_len(opt) < sizeof(*qopt))
 182                 return -EINVAL;
 183         qopt = nla_data(opt);
 184
 185         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 186                 return -EINVAL;
 187
 188         for (i = 0; i <= TC_PRIO_MAX; i++) {
 189                 if (qopt->priomap[i] >= qopt->bands)
 190                         return -EINVAL;
 191         }
 192
 193         sch_tree_lock(sch);
 194         if (q->enable_flow != qopt->enable_flow) {
 195                 q->enable_flow = qopt->enable_flow;
 196                 flow_change = 1;
 197         }
 198         q->bands = qopt->bands;
 199         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 200
 201         for (i = q->bands; i < TCQ_PRIO_BANDS; i++) {
 202                 struct Qdisc *child = q->queues[i];
 203                 q->queues[i] = &noop_qdisc;
 204                 if (child != &noop_qdisc) {
 205                         qdisc_tree_reduce_backlog(child, child->q.qlen, child->qstats.backlog);
 206                         qdisc_destroy(child);
 207                 }
 208         }
 209         sch_tree_unlock(sch);
 210
 211         for (i = 0; i < q->bands; i++) {
 212                 if (q->queues[i] == &noop_qdisc) {
 213                         struct Qdisc *child, *old;
 214
 215                         child = qdisc_create_dflt(sch->dev_queue,
 216                                                   &pfifo_qdisc_ops,
 217                                                   TC_H_MAKE(sch->handle, i + 1));
 218                         if (child) {
 219                                 sch_tree_lock(sch);
 220                                 old = q->queues[i];
 221                                 q->queues[i] = child;
 222
 223                                 if (old != &noop_qdisc) {
 224                                         qdisc_tree_reduce_backlog(old,
 225                                                                   old->q.qlen,
 226                                                                   old->qstats.backlog);
 227                                         qdisc_destroy(old);
 228                                 }
 229                                 sch_tree_unlock(sch);
 230                         }
 231                 }
 232         }
 233         /* Schedule qdisc when flow re-enabled */
 234         if (flow_change && q->enable_flow) {
 235                 if (!test_bit(__QDISC_STATE_DEACTIVATED,
 236                               &sch->state))
 237                         __netif_schedule(qdisc_root(sch));
 238         }
 239         return 0;
 240 }
 241
 242 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 243 {
 244         struct prio_sched_data *q = qdisc_priv(sch);
 245         int i;
 246
 247         for (i = 0; i < TCQ_PRIO_BANDS; i++)
 248                 q->queues[i] = &noop_qdisc;
 249
 250         if (opt == NULL) {
 251                 return -EINVAL;
 252         } else {
 253                 int err;
 254
 255                 if ((err = prio_tune(sch, opt)) != 0)
 256                         return err;
 257         }
 258         return 0;
 259 }
 260
 261 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 262 {
 263         struct prio_sched_data *q = qdisc_priv(sch);
 264         unsigned char *b = skb_tail_pointer(skb);
 265         struct tc_prio_qopt opt;
 266
 267         opt.bands = q->bands;
 268         opt.enable_flow = q->enable_flow;
 269         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 270
 271         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 272                 goto nla_put_failure;
 273
 274         return skb->len;
 275
 276 nla_put_failure:
 277         nlmsg_trim(skb, b);
 278         return -1;
 279 }
 280
 281 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 282                       struct Qdisc **old)
 283 {
 284         struct prio_sched_data *q = qdisc_priv(sch);
 285         unsigned long band = arg - 1;
 286
 287         if (new == NULL)
 288                 new = &noop_qdisc;
 289
 290         *old = qdisc_replace(sch, new, &q->queues[band]);
 291         return 0;
 292 }
 293
 294 static struct Qdisc *
 295 prio_leaf(struct Qdisc *sch, unsigned long arg)
 296 {
 297         struct prio_sched_data *q = qdisc_priv(sch);
 298         unsigned long band = arg - 1;
 299
 300         return q->queues[band];
 301 }
 302
 303 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 304 {
 305         struct prio_sched_data *q = qdisc_priv(sch);
 306         unsigned long band = TC_H_MIN(classid);
 307
 308         if (band - 1 >= q->bands)
 309                 return 0;
 310         return band;
 311 }
 312
 313 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 314 {
 315         return prio_get(sch, classid);
 316 }
 317
 318
 319 static void prio_put(struct Qdisc *q, unsigned long cl)
 320 {
 321 }
 322
 323 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 324                            struct tcmsg *tcm)
 325 {
 326         struct prio_sched_data *q = qdisc_priv(sch);
 327
 328         tcm->tcm_handle |= TC_H_MIN(cl);
 329         tcm->tcm_info = q->queues[cl-1]->handle;
 330         return 0;
 331 }
 332
 333 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 334                                  struct gnet_dump *d)
 335 {
 336         struct prio_sched_data *q = qdisc_priv(sch);
 337         struct Qdisc *cl_q;
 338
 339         cl_q = q->queues[cl - 1];
 340         if (gnet_stats_copy_basic(d, NULL, &cl_q->bstats) < 0 ||
 341             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 342                 return -1;
 343
 344         return 0;
 345 }
 346
 347 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 348 {
 349         struct prio_sched_data *q = qdisc_priv(sch);
 350         int prio;
 351
 352         if (arg->stop)
 353                 return;
 354
 355         for (prio = 0; prio < q->bands; prio++) {
 356                 if (arg->count < arg->skip) {
 357                         arg->count++;
 358                         continue;
 359                 }
 360                 if (arg->fn(sch, prio + 1, arg) < 0) {
 361                         arg->stop = 1;
 362                         break;
 363                 }
 364                 arg->count++;
 365         }
 366 }
 367
 368 static struct tcf_proto __rcu **prio_find_tcf(struct Qdisc *sch,
 369                                               unsigned long cl)
 370 {
 371         struct prio_sched_data *q = qdisc_priv(sch);
 372
 373         if (cl)
 374                 return NULL;
 375         return &q->filter_list;
 376 }
 377
 378 static const struct Qdisc_class_ops prio_class_ops = {
 379         .graft          =       prio_graft,
 380         .leaf           =       prio_leaf,
 381         .get            =       prio_get,
 382         .put            =       prio_put,
 383         .walk           =       prio_walk,
 384         .tcf_chain      =       prio_find_tcf,
 385         .bind_tcf       =       prio_bind,
 386         .unbind_tcf     =       prio_put,
 387         .dump           =       prio_dump_class,
 388         .dump_stats     =       prio_dump_class_stats,
 389 };
 390
 391 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 392         .next           =       NULL,
 393         .cl_ops         =       &prio_class_ops,
 394         .id             =       "prio",
 395         .priv_size      =       sizeof(struct prio_sched_data),
 396         .enqueue        =       prio_enqueue,
 397         .dequeue        =       prio_dequeue,
 398         .peek           =       prio_peek,
 399         .drop           =       prio_drop,
 400         .init           =       prio_init,
 401         .reset          =       prio_reset,
 402         .destroy        =       prio_destroy,
 403         .change         =       prio_tune,
 404         .dump           =       prio_dump,
 405         .owner          =       THIS_MODULE,
 406 };
 407
 408 static int __init prio_module_init(void)
 409 {
 410         return register_qdisc(&prio_qdisc_ops);
 411 }
 412
 413 static void __exit prio_module_exit(void)
 414 {
 415         unregister_qdisc(&prio_qdisc_ops);
 416 }
 417
 418 module_init(prio_module_init)
 419 module_exit(prio_module_exit)
 420
 421 MODULE_LICENSE("GPL");