net/sched/sch_multiq.c

   1 /*
   2  * Copyright (c) 2008, Intel Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Author: Alexander Duyck <alexander.h.duyck@intel.com>
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/string.h>
  24 #include <linux/errno.h>
  25 #include <linux/skbuff.h>
  26 #include <net/netlink.h>
  27 #include <net/pkt_sched.h>
  28
  29
  30 struct multiq_sched_data {
  31         u16 bands;
  32         u16 max_bands;
  33         u16 curband;
  34         struct tcf_proto *filter_list;
  35         struct Qdisc **queues;
  36 };
  37
  38
  39 static struct Qdisc *
  40 multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  41 {
  42         struct multiq_sched_data *q = qdisc_priv(sch);
  43         u32 band;
  44         struct tcf_result res;
  45         int err;
  46
  47         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  48         err = tc_classify(skb, q->filter_list, &res);
  49 #ifdef CONFIG_NET_CLS_ACT
  50         switch (err) {
  51         case TC_ACT_STOLEN:
  52         case TC_ACT_QUEUED:
  53                 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  54         case TC_ACT_SHOT:
  55                 return NULL;
  56         }
  57 #endif
  58         band = skb_get_queue_mapping(skb);
  59
  60         if (band >= q->bands)
  61                 return q->queues[0];
  62
  63         return q->queues[band];
  64 }
  65
  66 static int
  67 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  68 {
  69         struct Qdisc *qdisc;
  70         int ret;
  71
  72         qdisc = multiq_classify(skb, sch, &ret);
  73 #ifdef CONFIG_NET_CLS_ACT
  74         if (qdisc == NULL) {
  75
  76                 if (ret & __NET_XMIT_BYPASS)
  77                         sch->qstats.drops++;
  78                 kfree_skb(skb);
  79                 return ret;
  80         }
  81 #endif
  82
  83         ret = qdisc_enqueue(skb, qdisc);
  84         if (ret == NET_XMIT_SUCCESS) {
  85                 sch->bstats.bytes += qdisc_pkt_len(skb);
  86                 sch->bstats.packets++;
  87                 sch->q.qlen++;
  88                 return NET_XMIT_SUCCESS;
  89         }
  90         if (net_xmit_drop_count(ret))
  91                 sch->qstats.drops++;
  92         return ret;
  93 }
  94
  95
  96 static int
  97 multiq_requeue(struct sk_buff *skb, struct Qdisc *sch)
  98 {
  99         struct Qdisc *qdisc;
 100         struct multiq_sched_data *q = qdisc_priv(sch);
 101         int ret;
 102
 103         qdisc = multiq_classify(skb, sch, &ret);
 104 #ifdef CONFIG_NET_CLS_ACT
 105         if (qdisc == NULL) {
 106                 if (ret & __NET_XMIT_BYPASS)
 107                         sch->qstats.drops++;
 108                 kfree_skb(skb);
 109                 return ret;
 110         }
 111 #endif
 112
 113         ret = qdisc->ops->requeue(skb, qdisc);
 114         if (ret == NET_XMIT_SUCCESS) {
 115                 sch->q.qlen++;
 116                 sch->qstats.requeues++;
 117                 if (q->curband)
 118                         q->curband--;
 119                 else
 120                         q->curband = q->bands - 1;
 121                 return NET_XMIT_SUCCESS;
 122         }
 123         if (net_xmit_drop_count(ret))
 124                 sch->qstats.drops++;
 125         return ret;
 126 }
 127
 128
 129 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
 130 {
 131         struct multiq_sched_data *q = qdisc_priv(sch);
 132         struct Qdisc *qdisc;
 133         struct sk_buff *skb;
 134         int band;
 135
 136         for (band = 0; band < q->bands; band++) {
 137                 /* cycle through bands to ensure fairness */
 138                 q->curband++;
 139                 if (q->curband >= q->bands)
 140                         q->curband = 0;
 141
 142                 /* Check that target subqueue is available before
 143                  * pulling an skb to avoid excessive requeues
 144                  */
 145                 if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
 146                         qdisc = q->queues[q->curband];
 147                         skb = qdisc->dequeue(qdisc);
 148                         if (skb) {
 149                                 sch->q.qlen--;
 150                                 return skb;
 151                         }
 152                 }
 153         }
 154         return NULL;
 155
 156 }
 157
 158 static unsigned int multiq_drop(struct Qdisc *sch)
 159 {
 160         struct multiq_sched_data *q = qdisc_priv(sch);
 161         int band;
 162         unsigned int len;
 163         struct Qdisc *qdisc;
 164
 165         for (band = q->bands-1; band >= 0; band--) {
 166                 qdisc = q->queues[band];
 167                 if (qdisc->ops->drop) {
 168                         len = qdisc->ops->drop(qdisc);
 169                         if (len != 0) {
 170                                 sch->q.qlen--;
 171                                 return len;
 172                         }
 173                 }
 174         }
 175         return 0;
 176 }
 177
 178
 179 static void
 180 multiq_reset(struct Qdisc *sch)
 181 {
 182         u16 band;
 183         struct multiq_sched_data *q = qdisc_priv(sch);
 184
 185         for (band = 0; band < q->bands; band++)
 186                 qdisc_reset(q->queues[band]);
 187         sch->q.qlen = 0;
 188         q->curband = 0;
 189 }
 190
 191 static void
 192 multiq_destroy(struct Qdisc *sch)
 193 {
 194         int band;
 195         struct multiq_sched_data *q = qdisc_priv(sch);
 196
 197         tcf_destroy_chain(&q->filter_list);
 198         for (band = 0; band < q->bands; band++)
 199                 qdisc_destroy(q->queues[band]);
 200
 201         kfree(q->queues);
 202 }
 203
 204 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 205 {
 206         struct multiq_sched_data *q = qdisc_priv(sch);
 207         struct tc_multiq_qopt *qopt;
 208         int i;
 209
 210         if (!netif_is_multiqueue(qdisc_dev(sch)))
 211                 return -EINVAL;
 212         if (nla_len(opt) < sizeof(*qopt))
 213                 return -EINVAL;
 214
 215         qopt = nla_data(opt);
 216
 217         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 218
 219         sch_tree_lock(sch);
 220         q->bands = qopt->bands;
 221         for (i = q->bands; i < q->max_bands; i++) {
 222                 if (q->queues[i] != &noop_qdisc) {
 223                         struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 224                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 225                         qdisc_destroy(child);
 226                 }
 227         }
 228
 229         sch_tree_unlock(sch);
 230
 231         for (i = 0; i < q->bands; i++) {
 232                 if (q->queues[i] == &noop_qdisc) {
 233                         struct Qdisc *child;
 234                         child = qdisc_create_dflt(qdisc_dev(sch),
 235                                                   sch->dev_queue,
 236                                                   &pfifo_qdisc_ops,
 237                                                   TC_H_MAKE(sch->handle,
 238                                                             i + 1));
 239                         if (child) {
 240                                 sch_tree_lock(sch);
 241                                 child = xchg(&q->queues[i], child);
 242
 243                                 if (child != &noop_qdisc) {
 244                                         qdisc_tree_decrease_qlen(child,
 245                                                                  child->q.qlen);
 246                                         qdisc_destroy(child);
 247                                 }
 248                                 sch_tree_unlock(sch);
 249                         }
 250                 }
 251         }
 252         return 0;
 253 }
 254
 255 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 256 {
 257         struct multiq_sched_data *q = qdisc_priv(sch);
 258         int i, err;
 259
 260         q->queues = NULL;
 261
 262         if (opt == NULL)
 263                 return -EINVAL;
 264
 265         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 266
 267         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 268         if (!q->queues)
 269                 return -ENOBUFS;
 270         for (i = 0; i < q->max_bands; i++)
 271                 q->queues[i] = &noop_qdisc;
 272
 273         err = multiq_tune(sch,opt);
 274
 275         if (err)
 276                 kfree(q->queues);
 277
 278         return err;
 279 }
 280
 281 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 282 {
 283         struct multiq_sched_data *q = qdisc_priv(sch);
 284         unsigned char *b = skb_tail_pointer(skb);
 285         struct tc_multiq_qopt opt;
 286
 287         opt.bands = q->bands;
 288         opt.max_bands = q->max_bands;
 289
 290         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 291
 292         return skb->len;
 293
 294 nla_put_failure:
 295         nlmsg_trim(skb, b);
 296         return -1;
 297 }
 298
 299 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 300                       struct Qdisc **old)
 301 {
 302         struct multiq_sched_data *q = qdisc_priv(sch);
 303         unsigned long band = arg - 1;
 304
 305         if (band >= q->bands)
 306                 return -EINVAL;
 307
 308         if (new == NULL)
 309                 new = &noop_qdisc;
 310
 311         sch_tree_lock(sch);
 312         *old = q->queues[band];
 313         q->queues[band] = new;
 314         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 315         qdisc_reset(*old);
 316         sch_tree_unlock(sch);
 317
 318         return 0;
 319 }
 320
 321 static struct Qdisc *
 322 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 323 {
 324         struct multiq_sched_data *q = qdisc_priv(sch);
 325         unsigned long band = arg - 1;
 326
 327         if (band >= q->bands)
 328                 return NULL;
 329
 330         return q->queues[band];
 331 }
 332
 333 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 334 {
 335         struct multiq_sched_data *q = qdisc_priv(sch);
 336         unsigned long band = TC_H_MIN(classid);
 337
 338         if (band - 1 >= q->bands)
 339                 return 0;
 340         return band;
 341 }
 342
 343 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 344                                  u32 classid)
 345 {
 346         return multiq_get(sch, classid);
 347 }
 348
 349
 350 static void multiq_put(struct Qdisc *q, unsigned long cl)
 351 {
 352         return;
 353 }
 354
 355 static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent,
 356                          struct nlattr **tca, unsigned long *arg)
 357 {
 358         unsigned long cl = *arg;
 359         struct multiq_sched_data *q = qdisc_priv(sch);
 360
 361         if (cl - 1 > q->bands)
 362                 return -ENOENT;
 363         return 0;
 364 }
 365
 366 static int multiq_delete(struct Qdisc *sch, unsigned long cl)
 367 {
 368         struct multiq_sched_data *q = qdisc_priv(sch);
 369         if (cl - 1 > q->bands)
 370                 return -ENOENT;
 371         return 0;
 372 }
 373
 374
 375 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 376                              struct sk_buff *skb, struct tcmsg *tcm)
 377 {
 378         struct multiq_sched_data *q = qdisc_priv(sch);
 379
 380         if (cl - 1 > q->bands)
 381                 return -ENOENT;
 382         tcm->tcm_handle |= TC_H_MIN(cl);
 383         if (q->queues[cl-1])
 384                 tcm->tcm_info = q->queues[cl-1]->handle;
 385         return 0;
 386 }
 387
 388 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 389                                  struct gnet_dump *d)
 390 {
 391         struct multiq_sched_data *q = qdisc_priv(sch);
 392         struct Qdisc *cl_q;
 393
 394         cl_q = q->queues[cl - 1];
 395         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 396             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 397                 return -1;
 398
 399         return 0;
 400 }
 401
 402 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 403 {
 404         struct multiq_sched_data *q = qdisc_priv(sch);
 405         int band;
 406
 407         if (arg->stop)
 408                 return;
 409
 410         for (band = 0; band < q->bands; band++) {
 411                 if (arg->count < arg->skip) {
 412                         arg->count++;
 413                         continue;
 414                 }
 415                 if (arg->fn(sch, band+1, arg) < 0) {
 416                         arg->stop = 1;
 417                         break;
 418                 }
 419                 arg->count++;
 420         }
 421 }
 422
 423 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
 424 {
 425         struct multiq_sched_data *q = qdisc_priv(sch);
 426
 427         if (cl)
 428                 return NULL;
 429         return &q->filter_list;
 430 }
 431
 432 static const struct Qdisc_class_ops multiq_class_ops = {
 433         .graft          =       multiq_graft,
 434         .leaf           =       multiq_leaf,
 435         .get            =       multiq_get,
 436         .put            =       multiq_put,
 437         .change         =       multiq_change,
 438         .delete         =       multiq_delete,
 439         .walk           =       multiq_walk,
 440         .tcf_chain      =       multiq_find_tcf,
 441         .bind_tcf       =       multiq_bind,
 442         .unbind_tcf     =       multiq_put,
 443         .dump           =       multiq_dump_class,
 444         .dump_stats     =       multiq_dump_class_stats,
 445 };
 446
 447 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 448         .next           =       NULL,
 449         .cl_ops         =       &multiq_class_ops,
 450         .id             =       "multiq",
 451         .priv_size      =       sizeof(struct multiq_sched_data),
 452         .enqueue        =       multiq_enqueue,
 453         .dequeue        =       multiq_dequeue,
 454         .requeue        =       multiq_requeue,
 455         .drop           =       multiq_drop,
 456         .init           =       multiq_init,
 457         .reset          =       multiq_reset,
 458         .destroy        =       multiq_destroy,
 459         .change         =       multiq_tune,
 460         .dump           =       multiq_dump,
 461         .owner          =       THIS_MODULE,
 462 };
 463
 464 static int __init multiq_module_init(void)
 465 {
 466         return register_qdisc(&multiq_qdisc_ops);
 467 }
 468
 469 static void __exit multiq_module_exit(void)
 470 {
 471         unregister_qdisc(&multiq_qdisc_ops);
 472 }
 473
 474 module_init(multiq_module_init)
 475 module_exit(multiq_module_exit)
 476
 477 MODULE_LICENSE("GPL");