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   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 struct sk_buff *multiq_peek(struct Qdisc *sch)
 159 {
 160         struct multiq_sched_data *q = qdisc_priv(sch);
 161         unsigned int curband = q->curband;
 162         struct Qdisc *qdisc;
 163         struct sk_buff *skb;
 164         int band;
 165
 166         for (band = 0; band < q->bands; band++) {
 167                 /* cycle through bands to ensure fairness */
 168                 curband++;
 169                 if (curband >= q->bands)
 170                         curband = 0;
 171
 172                 /* Check that target subqueue is available before
 173                  * pulling an skb to avoid excessive requeues
 174                  */
 175                 if (!__netif_subqueue_stopped(qdisc_dev(sch), curband)) {
 176                         qdisc = q->queues[curband];
 177                         skb = qdisc->ops->peek(qdisc);
 178                         if (skb)
 179                                 return skb;
 180                 }
 181         }
 182         return NULL;
 183
 184 }
 185
 186 static unsigned int multiq_drop(struct Qdisc *sch)
 187 {
 188         struct multiq_sched_data *q = qdisc_priv(sch);
 189         int band;
 190         unsigned int len;
 191         struct Qdisc *qdisc;
 192
 193         for (band = q->bands-1; band >= 0; band--) {
 194                 qdisc = q->queues[band];
 195                 if (qdisc->ops->drop) {
 196                         len = qdisc->ops->drop(qdisc);
 197                         if (len != 0) {
 198                                 sch->q.qlen--;
 199                                 return len;
 200                         }
 201                 }
 202         }
 203         return 0;
 204 }
 205
 206
 207 static void
 208 multiq_reset(struct Qdisc *sch)
 209 {
 210         u16 band;
 211         struct multiq_sched_data *q = qdisc_priv(sch);
 212
 213         for (band = 0; band < q->bands; band++)
 214                 qdisc_reset(q->queues[band]);
 215         sch->q.qlen = 0;
 216         q->curband = 0;
 217 }
 218
 219 static void
 220 multiq_destroy(struct Qdisc *sch)
 221 {
 222         int band;
 223         struct multiq_sched_data *q = qdisc_priv(sch);
 224
 225         tcf_destroy_chain(&q->filter_list);
 226         for (band = 0; band < q->bands; band++)
 227                 qdisc_destroy(q->queues[band]);
 228
 229         kfree(q->queues);
 230 }
 231
 232 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 233 {
 234         struct multiq_sched_data *q = qdisc_priv(sch);
 235         struct tc_multiq_qopt *qopt;
 236         int i;
 237
 238         if (!netif_is_multiqueue(qdisc_dev(sch)))
 239                 return -EINVAL;
 240         if (nla_len(opt) < sizeof(*qopt))
 241                 return -EINVAL;
 242
 243         qopt = nla_data(opt);
 244
 245         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 246
 247         sch_tree_lock(sch);
 248         q->bands = qopt->bands;
 249         for (i = q->bands; i < q->max_bands; i++) {
 250                 if (q->queues[i] != &noop_qdisc) {
 251                         struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 252                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 253                         qdisc_destroy(child);
 254                 }
 255         }
 256
 257         sch_tree_unlock(sch);
 258
 259         for (i = 0; i < q->bands; i++) {
 260                 if (q->queues[i] == &noop_qdisc) {
 261                         struct Qdisc *child;
 262                         child = qdisc_create_dflt(qdisc_dev(sch),
 263                                                   sch->dev_queue,
 264                                                   &pfifo_qdisc_ops,
 265                                                   TC_H_MAKE(sch->handle,
 266                                                             i + 1));
 267                         if (child) {
 268                                 sch_tree_lock(sch);
 269                                 child = xchg(&q->queues[i], child);
 270
 271                                 if (child != &noop_qdisc) {
 272                                         qdisc_tree_decrease_qlen(child,
 273                                                                  child->q.qlen);
 274                                         qdisc_destroy(child);
 275                                 }
 276                                 sch_tree_unlock(sch);
 277                         }
 278                 }
 279         }
 280         return 0;
 281 }
 282
 283 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 284 {
 285         struct multiq_sched_data *q = qdisc_priv(sch);
 286         int i, err;
 287
 288         q->queues = NULL;
 289
 290         if (opt == NULL)
 291                 return -EINVAL;
 292
 293         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 294
 295         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 296         if (!q->queues)
 297                 return -ENOBUFS;
 298         for (i = 0; i < q->max_bands; i++)
 299                 q->queues[i] = &noop_qdisc;
 300
 301         err = multiq_tune(sch,opt);
 302
 303         if (err)
 304                 kfree(q->queues);
 305
 306         return err;
 307 }
 308
 309 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 310 {
 311         struct multiq_sched_data *q = qdisc_priv(sch);
 312         unsigned char *b = skb_tail_pointer(skb);
 313         struct tc_multiq_qopt opt;
 314
 315         opt.bands = q->bands;
 316         opt.max_bands = q->max_bands;
 317
 318         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 319
 320         return skb->len;
 321
 322 nla_put_failure:
 323         nlmsg_trim(skb, b);
 324         return -1;
 325 }
 326
 327 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 328                       struct Qdisc **old)
 329 {
 330         struct multiq_sched_data *q = qdisc_priv(sch);
 331         unsigned long band = arg - 1;
 332
 333         if (band >= q->bands)
 334                 return -EINVAL;
 335
 336         if (new == NULL)
 337                 new = &noop_qdisc;
 338
 339         sch_tree_lock(sch);
 340         *old = q->queues[band];
 341         q->queues[band] = new;
 342         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 343         qdisc_reset(*old);
 344         sch_tree_unlock(sch);
 345
 346         return 0;
 347 }
 348
 349 static struct Qdisc *
 350 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 351 {
 352         struct multiq_sched_data *q = qdisc_priv(sch);
 353         unsigned long band = arg - 1;
 354
 355         if (band >= q->bands)
 356                 return NULL;
 357
 358         return q->queues[band];
 359 }
 360
 361 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 362 {
 363         struct multiq_sched_data *q = qdisc_priv(sch);
 364         unsigned long band = TC_H_MIN(classid);
 365
 366         if (band - 1 >= q->bands)
 367                 return 0;
 368         return band;
 369 }
 370
 371 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 372                                  u32 classid)
 373 {
 374         return multiq_get(sch, classid);
 375 }
 376
 377
 378 static void multiq_put(struct Qdisc *q, unsigned long cl)
 379 {
 380         return;
 381 }
 382
 383 static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent,
 384                          struct nlattr **tca, unsigned long *arg)
 385 {
 386         unsigned long cl = *arg;
 387         struct multiq_sched_data *q = qdisc_priv(sch);
 388
 389         if (cl - 1 > q->bands)
 390                 return -ENOENT;
 391         return 0;
 392 }
 393
 394 static int multiq_delete(struct Qdisc *sch, unsigned long cl)
 395 {
 396         struct multiq_sched_data *q = qdisc_priv(sch);
 397         if (cl - 1 > q->bands)
 398                 return -ENOENT;
 399         return 0;
 400 }
 401
 402
 403 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 404                              struct sk_buff *skb, struct tcmsg *tcm)
 405 {
 406         struct multiq_sched_data *q = qdisc_priv(sch);
 407
 408         if (cl - 1 > q->bands)
 409                 return -ENOENT;
 410         tcm->tcm_handle |= TC_H_MIN(cl);
 411         if (q->queues[cl-1])
 412                 tcm->tcm_info = q->queues[cl-1]->handle;
 413         return 0;
 414 }
 415
 416 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 417                                  struct gnet_dump *d)
 418 {
 419         struct multiq_sched_data *q = qdisc_priv(sch);
 420         struct Qdisc *cl_q;
 421
 422         cl_q = q->queues[cl - 1];
 423         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 424             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 425                 return -1;
 426
 427         return 0;
 428 }
 429
 430 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 431 {
 432         struct multiq_sched_data *q = qdisc_priv(sch);
 433         int band;
 434
 435         if (arg->stop)
 436                 return;
 437
 438         for (band = 0; band < q->bands; band++) {
 439                 if (arg->count < arg->skip) {
 440                         arg->count++;
 441                         continue;
 442                 }
 443                 if (arg->fn(sch, band+1, arg) < 0) {
 444                         arg->stop = 1;
 445                         break;
 446                 }
 447                 arg->count++;
 448         }
 449 }
 450
 451 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
 452 {
 453         struct multiq_sched_data *q = qdisc_priv(sch);
 454
 455         if (cl)
 456                 return NULL;
 457         return &q->filter_list;
 458 }
 459
 460 static const struct Qdisc_class_ops multiq_class_ops = {
 461         .graft          =       multiq_graft,
 462         .leaf           =       multiq_leaf,
 463         .get            =       multiq_get,
 464         .put            =       multiq_put,
 465         .change         =       multiq_change,
 466         .delete         =       multiq_delete,
 467         .walk           =       multiq_walk,
 468         .tcf_chain      =       multiq_find_tcf,
 469         .bind_tcf       =       multiq_bind,
 470         .unbind_tcf     =       multiq_put,
 471         .dump           =       multiq_dump_class,
 472         .dump_stats     =       multiq_dump_class_stats,
 473 };
 474
 475 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 476         .next           =       NULL,
 477         .cl_ops         =       &multiq_class_ops,
 478         .id             =       "multiq",
 479         .priv_size      =       sizeof(struct multiq_sched_data),
 480         .enqueue        =       multiq_enqueue,
 481         .dequeue        =       multiq_dequeue,
 482         .peek           =       multiq_peek,
 483         .requeue        =       multiq_requeue,
 484         .drop           =       multiq_drop,
 485         .init           =       multiq_init,
 486         .reset          =       multiq_reset,
 487         .destroy        =       multiq_destroy,
 488         .change         =       multiq_tune,
 489         .dump           =       multiq_dump,
 490         .owner          =       THIS_MODULE,
 491 };
 492
 493 static int __init multiq_module_init(void)
 494 {
 495         return register_qdisc(&multiq_qdisc_ops);
 496 }
 497
 498 static void __exit multiq_module_exit(void)
 499 {
 500         unregister_qdisc(&multiq_qdisc_ops);
 501 }
 502
 503 module_init(multiq_module_init)
 504 module_exit(multiq_module_exit)
 505
 506 MODULE_LICENSE("GPL");