linux/net/sched/sch_prio.c
<<
>>
Prefs
   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
  25struct 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
  34static struct Qdisc *
  35prio_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                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
  71static int
  72prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
  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, to_free);
  89        if (ret == NET_XMIT_SUCCESS) {
  90                qdisc_qstats_backlog_inc(sch, skb);
  91                sch->q.qlen++;
  92                return NET_XMIT_SUCCESS;
  93        }
  94        if (net_xmit_drop_count(ret))
  95                qdisc_qstats_drop(sch);
  96        return ret;
  97}
  98
  99static struct sk_buff *prio_peek(struct Qdisc *sch)
 100{
 101        struct prio_sched_data *q = qdisc_priv(sch);
 102        int prio;
 103
 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
 113static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 114{
 115        struct prio_sched_data *q = qdisc_priv(sch);
 116        int prio;
 117
 118        for (prio = 0; prio < q->bands; prio++) {
 119                struct Qdisc *qdisc = q->queues[prio];
 120                struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 121                if (skb) {
 122                        qdisc_bstats_update(sch, skb);
 123                        qdisc_qstats_backlog_dec(sch, skb);
 124                        sch->q.qlen--;
 125                        return skb;
 126                }
 127        }
 128        return NULL;
 129
 130}
 131
 132static void
 133prio_reset(struct Qdisc *sch)
 134{
 135        int prio;
 136        struct prio_sched_data *q = qdisc_priv(sch);
 137
 138        for (prio = 0; prio < q->bands; prio++)
 139                qdisc_reset(q->queues[prio]);
 140        sch->qstats.backlog = 0;
 141        sch->q.qlen = 0;
 142}
 143
 144static void
 145prio_destroy(struct Qdisc *sch)
 146{
 147        int prio;
 148        struct prio_sched_data *q = qdisc_priv(sch);
 149
 150        tcf_block_put(q->block);
 151        for (prio = 0; prio < q->bands; prio++)
 152                qdisc_destroy(q->queues[prio]);
 153}
 154
 155static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 156{
 157        struct prio_sched_data *q = qdisc_priv(sch);
 158        struct Qdisc *queues[TCQ_PRIO_BANDS];
 159        int oldbands = q->bands, i;
 160        struct tc_prio_qopt *qopt;
 161
 162        if (nla_len(opt) < sizeof(*qopt))
 163                return -EINVAL;
 164        qopt = nla_data(opt);
 165
 166        if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 167                return -EINVAL;
 168
 169        for (i = 0; i <= TC_PRIO_MAX; i++) {
 170                if (qopt->priomap[i] >= qopt->bands)
 171                        return -EINVAL;
 172        }
 173
 174        /* Before commit, make sure we can allocate all new qdiscs */
 175        for (i = oldbands; i < qopt->bands; i++) {
 176                queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
 177                                              TC_H_MAKE(sch->handle, i + 1));
 178                if (!queues[i]) {
 179                        while (i > oldbands)
 180                                qdisc_destroy(queues[--i]);
 181                        return -ENOMEM;
 182                }
 183        }
 184
 185        sch_tree_lock(sch);
 186        q->bands = qopt->bands;
 187        memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 188
 189        for (i = q->bands; i < oldbands; i++) {
 190                struct Qdisc *child = q->queues[i];
 191
 192                qdisc_tree_reduce_backlog(child, child->q.qlen,
 193                                          child->qstats.backlog);
 194                qdisc_destroy(child);
 195        }
 196
 197        for (i = oldbands; i < q->bands; i++) {
 198                q->queues[i] = queues[i];
 199                if (q->queues[i] != &noop_qdisc)
 200                        qdisc_hash_add(q->queues[i], true);
 201        }
 202
 203        sch_tree_unlock(sch);
 204        return 0;
 205}
 206
 207static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 208{
 209        struct prio_sched_data *q = qdisc_priv(sch);
 210        int err;
 211
 212        if (!opt)
 213                return -EINVAL;
 214
 215        err = tcf_block_get(&q->block, &q->filter_list);
 216        if (err)
 217                return err;
 218
 219        return prio_tune(sch, opt);
 220}
 221
 222static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 223{
 224        struct prio_sched_data *q = qdisc_priv(sch);
 225        unsigned char *b = skb_tail_pointer(skb);
 226        struct tc_prio_qopt opt;
 227
 228        opt.bands = q->bands;
 229        memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 230
 231        if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 232                goto nla_put_failure;
 233
 234        return skb->len;
 235
 236nla_put_failure:
 237        nlmsg_trim(skb, b);
 238        return -1;
 239}
 240
 241static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 242                      struct Qdisc **old)
 243{
 244        struct prio_sched_data *q = qdisc_priv(sch);
 245        unsigned long band = arg - 1;
 246
 247        if (new == NULL)
 248                new = &noop_qdisc;
 249
 250        *old = qdisc_replace(sch, new, &q->queues[band]);
 251        return 0;
 252}
 253
 254static struct Qdisc *
 255prio_leaf(struct Qdisc *sch, unsigned long arg)
 256{
 257        struct prio_sched_data *q = qdisc_priv(sch);
 258        unsigned long band = arg - 1;
 259
 260        return q->queues[band];
 261}
 262
 263static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 264{
 265        struct prio_sched_data *q = qdisc_priv(sch);
 266        unsigned long band = TC_H_MIN(classid);
 267
 268        if (band - 1 >= q->bands)
 269                return 0;
 270        return band;
 271}
 272
 273static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 274{
 275        return prio_get(sch, classid);
 276}
 277
 278
 279static void prio_put(struct Qdisc *q, unsigned long cl)
 280{
 281}
 282
 283static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 284                           struct tcmsg *tcm)
 285{
 286        struct prio_sched_data *q = qdisc_priv(sch);
 287
 288        tcm->tcm_handle |= TC_H_MIN(cl);
 289        tcm->tcm_info = q->queues[cl-1]->handle;
 290        return 0;
 291}
 292
 293static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 294                                 struct gnet_dump *d)
 295{
 296        struct prio_sched_data *q = qdisc_priv(sch);
 297        struct Qdisc *cl_q;
 298
 299        cl_q = q->queues[cl - 1];
 300        if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 301                                  d, NULL, &cl_q->bstats) < 0 ||
 302            gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 303                return -1;
 304
 305        return 0;
 306}
 307
 308static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 309{
 310        struct prio_sched_data *q = qdisc_priv(sch);
 311        int prio;
 312
 313        if (arg->stop)
 314                return;
 315
 316        for (prio = 0; prio < q->bands; prio++) {
 317                if (arg->count < arg->skip) {
 318                        arg->count++;
 319                        continue;
 320                }
 321                if (arg->fn(sch, prio + 1, arg) < 0) {
 322                        arg->stop = 1;
 323                        break;
 324                }
 325                arg->count++;
 326        }
 327}
 328
 329static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl)
 330{
 331        struct prio_sched_data *q = qdisc_priv(sch);
 332
 333        if (cl)
 334                return NULL;
 335        return q->block;
 336}
 337
 338static const struct Qdisc_class_ops prio_class_ops = {
 339        .graft          =       prio_graft,
 340        .leaf           =       prio_leaf,
 341        .get            =       prio_get,
 342        .put            =       prio_put,
 343        .walk           =       prio_walk,
 344        .tcf_block      =       prio_tcf_block,
 345        .bind_tcf       =       prio_bind,
 346        .unbind_tcf     =       prio_put,
 347        .dump           =       prio_dump_class,
 348        .dump_stats     =       prio_dump_class_stats,
 349};
 350
 351static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 352        .next           =       NULL,
 353        .cl_ops         =       &prio_class_ops,
 354        .id             =       "prio",
 355        .priv_size      =       sizeof(struct prio_sched_data),
 356        .enqueue        =       prio_enqueue,
 357        .dequeue        =       prio_dequeue,
 358        .peek           =       prio_peek,
 359        .init           =       prio_init,
 360        .reset          =       prio_reset,
 361        .destroy        =       prio_destroy,
 362        .change         =       prio_tune,
 363        .dump           =       prio_dump,
 364        .owner          =       THIS_MODULE,
 365};
 366
 367static int __init prio_module_init(void)
 368{
 369        return register_qdisc(&prio_qdisc_ops);
 370}
 371
 372static void __exit prio_module_exit(void)
 373{
 374        unregister_qdisc(&prio_qdisc_ops);
 375}
 376
 377module_init(prio_module_init)
 378module_exit(prio_module_exit)
 379
 380MODULE_LICENSE("GPL");
 381