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, <[email protected]>
  10  * Fixes:       19990609: J Hadi Salim <[email protected]>:
  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
  24
  25 struct prio_sched_data {
  26         int bands;
  27         struct tcf_proto __rcu *filter_list;
  28         u8  prio2band[TC_PRIO_MAX+1];
  29         struct Qdisc *queues[TCQ_PRIO_BANDS];
  30 };
  31
  32
  33 static struct Qdisc *
  34 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  35 {
  36         struct prio_sched_data *q = qdisc_priv(sch);
  37         u32 band = skb->priority;
  38         struct tcf_result res;
  39         struct tcf_proto *fl;
  40         int err;
  41
  42         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  43         if (TC_H_MAJ(skb->priority) != sch->handle) {
  44                 fl = rcu_dereference_bh(q->filter_list);
  45                 err = tc_classify(skb, fl, &res);
  46 #ifdef CONFIG_NET_CLS_ACT
  47                 switch (err) {
  48                 case TC_ACT_STOLEN:
  49                 case TC_ACT_QUEUED:
  50                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  51                 case TC_ACT_SHOT:
  52                         return NULL;
  53                 }
  54 #endif
  55                 if (!fl || err < 0) {
  56                         if (TC_H_MAJ(band))
  57                                 band = 0;
  58                         return q->queues[q->prio2band[band & TC_PRIO_MAX]];
  59                 }
  60                 band = res.classid;
  61         }
  62         band = TC_H_MIN(band) - 1;
  63         if (band >= q->bands)
  64                 return q->queues[q->prio2band[0]];
  65
  66         return q->queues[band];
  67 }
  68
  69 static int
  70 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  71 {
  72         struct Qdisc *qdisc;
  73         int ret;
  74
  75         qdisc = prio_classify(skb, sch, &ret);
  76 #ifdef CONFIG_NET_CLS_ACT
  77         if (qdisc == NULL) {
  78
  79                 if (ret & __NET_XMIT_BYPASS)
  80                         qdisc_qstats_drop(sch);
  81                 kfree_skb(skb);
  82                 return ret;
  83         }
  84 #endif
  85
  86         ret = qdisc_enqueue(skb, qdisc);
  87         if (ret == NET_XMIT_SUCCESS) {
  88                 sch->q.qlen++;
  89                 return NET_XMIT_SUCCESS;
  90         }
  91         if (net_xmit_drop_count(ret))
  92                 qdisc_qstats_drop(sch);
  93         return ret;
  94 }
  95
  96 static struct sk_buff *prio_peek(struct Qdisc *sch)
  97 {
  98         struct prio_sched_data *q = qdisc_priv(sch);
  99         int prio;
 100
 101         for (prio = 0; prio < q->bands; prio++) {
 102                 struct Qdisc *qdisc = q->queues[prio];
 103                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 104                 if (skb)
 105                         return skb;
 106         }
 107         return NULL;
 108 }
 109
 110 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 111 {
 112         struct prio_sched_data *q = qdisc_priv(sch);
 113         int prio;
 114
 115         for (prio = 0; prio < q->bands; prio++) {
 116                 struct Qdisc *qdisc = q->queues[prio];
 117                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 118                 if (skb) {
 119                         qdisc_bstats_update(sch, skb);
 120                         sch->q.qlen--;
 121                         return skb;
 122                 }
 123         }
 124         return NULL;
 125
 126 }
 127
 128 static unsigned int prio_drop(struct Qdisc *sch)
 129 {
 130         struct prio_sched_data *q = qdisc_priv(sch);
 131         int prio;
 132         unsigned int len;
 133         struct Qdisc *qdisc;
 134
 135         for (prio = q->bands-1; prio >= 0; prio--) {
 136                 qdisc = q->queues[prio];
 137                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 138                         sch->q.qlen--;
 139                         return len;
 140                 }
 141         }
 142         return 0;
 143 }
 144
 145
 146 static void
 147 prio_reset(struct Qdisc *sch)
 148 {
 149         int prio;
 150         struct prio_sched_data *q = qdisc_priv(sch);
 151
 152         for (prio = 0; prio < q->bands; prio++)
 153                 qdisc_reset(q->queues[prio]);
 154         sch->q.qlen = 0;
 155 }
 156
 157 static void
 158 prio_destroy(struct Qdisc *sch)
 159 {
 160         int prio;
 161         struct prio_sched_data *q = qdisc_priv(sch);
 162
 163         tcf_destroy_chain(&q->filter_list);
 164         for (prio = 0; prio < q->bands; prio++)
 165                 qdisc_destroy(q->queues[prio]);
 166 }
 167
 168 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 169 {
 170         struct prio_sched_data *q = qdisc_priv(sch);
 171         struct tc_prio_qopt *qopt;
 172         int i;
 173
 174         if (nla_len(opt) < sizeof(*qopt))
 175                 return -EINVAL;
 176         qopt = nla_data(opt);
 177
 178         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 179                 return -EINVAL;
 180
 181         for (i = 0; i <= TC_PRIO_MAX; i++) {
 182                 if (qopt->priomap[i] >= qopt->bands)
 183                         return -EINVAL;
 184         }
 185
 186         sch_tree_lock(sch);
 187         q->bands = qopt->bands;
 188         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 189
 190         for (i = q->bands; i < TCQ_PRIO_BANDS; i++) {
 191                 struct Qdisc *child = q->queues[i];
 192                 q->queues[i] = &noop_qdisc;
 193                 if (child != &noop_qdisc) {
 194                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 195                         qdisc_destroy(child);
 196                 }
 197         }
 198         sch_tree_unlock(sch);
 199
 200         for (i = 0; i < q->bands; i++) {
 201                 if (q->queues[i] == &noop_qdisc) {
 202                         struct Qdisc *child, *old;
 203
 204                         child = qdisc_create_dflt(sch->dev_queue,
 205                                                   &pfifo_qdisc_ops,
 206                                                   TC_H_MAKE(sch->handle, i + 1));
 207                         if (child) {
 208                                 sch_tree_lock(sch);
 209                                 old = q->queues[i];
 210                                 q->queues[i] = child;
 211
 212                                 if (old != &noop_qdisc) {
 213                                         qdisc_tree_decrease_qlen(old,
 214                                                                  old->q.qlen);
 215                                         qdisc_destroy(old);
 216                                 }
 217                                 sch_tree_unlock(sch);
 218                         }
 219                 }
 220         }
 221         return 0;
 222 }
 223
 224 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 225 {
 226         struct prio_sched_data *q = qdisc_priv(sch);
 227         int i;
 228
 229         for (i = 0; i < TCQ_PRIO_BANDS; i++)
 230                 q->queues[i] = &noop_qdisc;
 231
 232         if (opt == NULL) {
 233                 return -EINVAL;
 234         } else {
 235                 int err;
 236
 237                 if ((err = prio_tune(sch, opt)) != 0)
 238                         return err;
 239         }
 240         return 0;
 241 }
 242
 243 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 244 {
 245         struct prio_sched_data *q = qdisc_priv(sch);
 246         unsigned char *b = skb_tail_pointer(skb);
 247         struct tc_prio_qopt opt;
 248
 249         opt.bands = q->bands;
 250         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 251
 252         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 253                 goto nla_put_failure;
 254
 255         return skb->len;
 256
 257 nla_put_failure:
 258         nlmsg_trim(skb, b);
 259         return -1;
 260 }
 261
 262 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 263                       struct Qdisc **old)
 264 {
 265         struct prio_sched_data *q = qdisc_priv(sch);
 266         unsigned long band = arg - 1;
 267
 268         if (new == NULL)
 269                 new = &noop_qdisc;
 270
 271         sch_tree_lock(sch);
 272         *old = q->queues[band];
 273         q->queues[band] = new;
 274         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 275         qdisc_reset(*old);
 276         sch_tree_unlock(sch);
 277
 278         return 0;
 279 }
 280
 281 static struct Qdisc *
 282 prio_leaf(struct Qdisc *sch, unsigned long arg)
 283 {
 284         struct prio_sched_data *q = qdisc_priv(sch);
 285         unsigned long band = arg - 1;
 286
 287         return q->queues[band];
 288 }
 289
 290 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 291 {
 292         struct prio_sched_data *q = qdisc_priv(sch);
 293         unsigned long band = TC_H_MIN(classid);
 294
 295         if (band - 1 >= q->bands)
 296                 return 0;
 297         return band;
 298 }
 299
 300 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 301 {
 302         return prio_get(sch, classid);
 303 }
 304
 305
 306 static void prio_put(struct Qdisc *q, unsigned long cl)
 307 {
 308 }
 309
 310 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 311                            struct tcmsg *tcm)
 312 {
 313         struct prio_sched_data *q = qdisc_priv(sch);
 314
 315         tcm->tcm_handle |= TC_H_MIN(cl);
 316         tcm->tcm_info = q->queues[cl-1]->handle;
 317         return 0;
 318 }
 319
 320 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 321                                  struct gnet_dump *d)
 322 {
 323         struct prio_sched_data *q = qdisc_priv(sch);
 324         struct Qdisc *cl_q;
 325
 326         cl_q = q->queues[cl - 1];
 327         if (gnet_stats_copy_basic(d, NULL, &cl_q->bstats) < 0 ||
 328             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 329                 return -1;
 330
 331         return 0;
 332 }
 333
 334 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 335 {
 336         struct prio_sched_data *q = qdisc_priv(sch);
 337         int prio;
 338
 339         if (arg->stop)
 340                 return;
 341
 342         for (prio = 0; prio < q->bands; prio++) {
 343                 if (arg->count < arg->skip) {
 344                         arg->count++;
 345                         continue;
 346                 }
 347                 if (arg->fn(sch, prio + 1, arg) < 0) {
 348                         arg->stop = 1;
 349                         break;
 350                 }
 351                 arg->count++;
 352         }
 353 }
 354
 355 static struct tcf_proto __rcu **prio_find_tcf(struct Qdisc *sch,
 356                                               unsigned long cl)
 357 {
 358         struct prio_sched_data *q = qdisc_priv(sch);
 359
 360         if (cl)
 361                 return NULL;
 362         return &q->filter_list;
 363 }
 364
 365 static const struct Qdisc_class_ops prio_class_ops = {
 366         .graft          =       prio_graft,
 367         .leaf           =       prio_leaf,
 368         .get            =       prio_get,
 369         .put            =       prio_put,
 370         .walk           =       prio_walk,
 371         .tcf_chain      =       prio_find_tcf,
 372         .bind_tcf       =       prio_bind,
 373         .unbind_tcf     =       prio_put,
 374         .dump           =       prio_dump_class,
 375         .dump_stats     =       prio_dump_class_stats,
 376 };
 377
 378 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 379         .next           =       NULL,
 380         .cl_ops         =       &prio_class_ops,
 381         .id             =       "prio",
 382         .priv_size      =       sizeof(struct prio_sched_data),
 383         .enqueue        =       prio_enqueue,
 384         .dequeue        =       prio_dequeue,
 385         .peek           =       prio_peek,
 386         .drop           =       prio_drop,
 387         .init           =       prio_init,
 388         .reset          =       prio_reset,
 389         .destroy        =       prio_destroy,
 390         .change         =       prio_tune,
 391         .dump           =       prio_dump,
 392         .owner          =       THIS_MODULE,
 393 };
 394
 395 static int __init prio_module_init(void)
 396 {
 397         return register_qdisc(&prio_qdisc_ops);
 398 }
 399
 400 static void __exit prio_module_exit(void)
 401 {
 402         unregister_qdisc(&prio_qdisc_ops);
 403 }
 404
 405 module_init(prio_module_init)
 406 module_exit(prio_module_exit)
 407
 408 MODULE_LICENSE("GPL");