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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         int ret;
 101
 102         qdisc = multiq_classify(skb, sch, &ret);
 103 #ifdef CONFIG_NET_CLS_ACT
 104         if (qdisc == NULL) {
 105                 if (ret & __NET_XMIT_BYPASS)
 106                         sch->qstats.drops++;
 107                 kfree_skb(skb);
 108                 return ret;
 109         }
 110 #endif
 111
 112         ret = qdisc->ops->requeue(skb, qdisc);
 113         if (ret == NET_XMIT_SUCCESS) {
 114                 sch->q.qlen++;
 115                 sch->qstats.requeues++;
 116                 return NET_XMIT_SUCCESS;
 117         }
 118         if (net_xmit_drop_count(ret))
 119                 sch->qstats.drops++;
 120         return ret;
 121 }
 122
 123
 124 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
 125 {
 126         struct multiq_sched_data *q = qdisc_priv(sch);
 127         struct Qdisc *qdisc;
 128         struct sk_buff *skb;
 129         int band;
 130
 131         for (band = 0; band < q->bands; band++) {
 132                 /* cycle through bands to ensure fairness */
 133                 q->curband++;
 134                 if (q->curband >= q->bands)
 135                         q->curband = 0;
 136
 137                 /* Check that target subqueue is available before
 138                  * pulling an skb to avoid excessive requeues
 139                  */
 140                 if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
 141                         qdisc = q->queues[q->curband];
 142                         skb = qdisc->dequeue(qdisc);
 143                         if (skb) {
 144                                 sch->q.qlen--;
 145                                 return skb;
 146                         }
 147                 }
 148         }
 149         return NULL;
 150
 151 }
 152
 153 static unsigned int multiq_drop(struct Qdisc *sch)
 154 {
 155         struct multiq_sched_data *q = qdisc_priv(sch);
 156         int band;
 157         unsigned int len;
 158         struct Qdisc *qdisc;
 159
 160         for (band = q->bands-1; band >= 0; band--) {
 161                 qdisc = q->queues[band];
 162                 if (qdisc->ops->drop) {
 163                         len = qdisc->ops->drop(qdisc);
 164                         if (len != 0) {
 165                                 sch->q.qlen--;
 166                                 return len;
 167                         }
 168                 }
 169         }
 170         return 0;
 171 }
 172
 173
 174 static void
 175 multiq_reset(struct Qdisc *sch)
 176 {
 177         u16 band;
 178         struct multiq_sched_data *q = qdisc_priv(sch);
 179
 180         for (band = 0; band < q->bands; band++)
 181                 qdisc_reset(q->queues[band]);
 182         sch->q.qlen = 0;
 183         q->curband = 0;
 184 }
 185
 186 static void
 187 multiq_destroy(struct Qdisc *sch)
 188 {
 189         int band;
 190         struct multiq_sched_data *q = qdisc_priv(sch);
 191
 192         tcf_destroy_chain(&q->filter_list);
 193         for (band = 0; band < q->bands; band++)
 194                 qdisc_destroy(q->queues[band]);
 195
 196         kfree(q->queues);
 197 }
 198
 199 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 200 {
 201         struct multiq_sched_data *q = qdisc_priv(sch);
 202         struct tc_multiq_qopt *qopt;
 203         int i;
 204
 205         if (!netif_is_multiqueue(qdisc_dev(sch)))
 206                 return -EINVAL;
 207         if (nla_len(opt) < sizeof(*qopt))
 208                 return -EINVAL;
 209
 210         qopt = nla_data(opt);
 211
 212         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 213
 214         sch_tree_lock(sch);
 215         q->bands = qopt->bands;
 216         for (i = q->bands; i < q->max_bands; i++) {
 217                 if (q->queues[i] != &noop_qdisc) {
 218                         struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 219                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 220                         qdisc_destroy(child);
 221                 }
 222         }
 223
 224         sch_tree_unlock(sch);
 225
 226         for (i = 0; i < q->bands; i++) {
 227                 if (q->queues[i] == &noop_qdisc) {
 228                         struct Qdisc *child;
 229                         child = qdisc_create_dflt(qdisc_dev(sch),
 230                                                   sch->dev_queue,
 231                                                   &pfifo_qdisc_ops,
 232                                                   TC_H_MAKE(sch->handle,
 233                                                             i + 1));
 234                         if (child) {
 235                                 sch_tree_lock(sch);
 236                                 child = xchg(&q->queues[i], child);
 237
 238                                 if (child != &noop_qdisc) {
 239                                         qdisc_tree_decrease_qlen(child,
 240                                                                  child->q.qlen);
 241                                         qdisc_destroy(child);
 242                                 }
 243                                 sch_tree_unlock(sch);
 244                         }
 245                 }
 246         }
 247         return 0;
 248 }
 249
 250 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 251 {
 252         struct multiq_sched_data *q = qdisc_priv(sch);
 253         int i, err;
 254
 255         q->queues = NULL;
 256
 257         if (opt == NULL)
 258                 return -EINVAL;
 259
 260         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 261
 262         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 263         if (!q->queues)
 264                 return -ENOBUFS;
 265         for (i = 0; i < q->max_bands; i++)
 266                 q->queues[i] = &noop_qdisc;
 267
 268         err = multiq_tune(sch,opt);
 269
 270         if (err)
 271                 kfree(q->queues);
 272
 273         return err;
 274 }
 275
 276 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 277 {
 278         struct multiq_sched_data *q = qdisc_priv(sch);
 279         unsigned char *b = skb_tail_pointer(skb);
 280         struct tc_multiq_qopt opt;
 281
 282         opt.bands = q->bands;
 283         opt.max_bands = q->max_bands;
 284
 285         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 286
 287         return skb->len;
 288
 289 nla_put_failure:
 290         nlmsg_trim(skb, b);
 291         return -1;
 292 }
 293
 294 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 295                       struct Qdisc **old)
 296 {
 297         struct multiq_sched_data *q = qdisc_priv(sch);
 298         unsigned long band = arg - 1;
 299
 300         if (band >= q->bands)
 301                 return -EINVAL;
 302
 303         if (new == NULL)
 304                 new = &noop_qdisc;
 305
 306         sch_tree_lock(sch);
 307         *old = q->queues[band];
 308         q->queues[band] = new;
 309         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 310         qdisc_reset(*old);
 311         sch_tree_unlock(sch);
 312
 313         return 0;
 314 }
 315
 316 static struct Qdisc *
 317 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 318 {
 319         struct multiq_sched_data *q = qdisc_priv(sch);
 320         unsigned long band = arg - 1;
 321
 322         if (band >= q->bands)
 323                 return NULL;
 324
 325         return q->queues[band];
 326 }
 327
 328 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 329 {
 330         struct multiq_sched_data *q = qdisc_priv(sch);
 331         unsigned long band = TC_H_MIN(classid);
 332
 333         if (band - 1 >= q->bands)
 334                 return 0;
 335         return band;
 336 }
 337
 338 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 339                                  u32 classid)
 340 {
 341         return multiq_get(sch, classid);
 342 }
 343
 344
 345 static void multiq_put(struct Qdisc *q, unsigned long cl)
 346 {
 347         return;
 348 }
 349
 350 static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent,
 351                          struct nlattr **tca, unsigned long *arg)
 352 {
 353         unsigned long cl = *arg;
 354         struct multiq_sched_data *q = qdisc_priv(sch);
 355
 356         if (cl - 1 > q->bands)
 357                 return -ENOENT;
 358         return 0;
 359 }
 360
 361 static int multiq_delete(struct Qdisc *sch, unsigned long cl)
 362 {
 363         struct multiq_sched_data *q = qdisc_priv(sch);
 364         if (cl - 1 > q->bands)
 365                 return -ENOENT;
 366         return 0;
 367 }
 368
 369
 370 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 371                              struct sk_buff *skb, struct tcmsg *tcm)
 372 {
 373         struct multiq_sched_data *q = qdisc_priv(sch);
 374
 375         if (cl - 1 > q->bands)
 376                 return -ENOENT;
 377         tcm->tcm_handle |= TC_H_MIN(cl);
 378         if (q->queues[cl-1])
 379                 tcm->tcm_info = q->queues[cl-1]->handle;
 380         return 0;
 381 }
 382
 383 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 384                                  struct gnet_dump *d)
 385 {
 386         struct multiq_sched_data *q = qdisc_priv(sch);
 387         struct Qdisc *cl_q;
 388
 389         cl_q = q->queues[cl - 1];
 390         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 391             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 392                 return -1;
 393
 394         return 0;
 395 }
 396
 397 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 398 {
 399         struct multiq_sched_data *q = qdisc_priv(sch);
 400         int band;
 401
 402         if (arg->stop)
 403                 return;
 404
 405         for (band = 0; band < q->bands; band++) {
 406                 if (arg->count < arg->skip) {
 407                         arg->count++;
 408                         continue;
 409                 }
 410                 if (arg->fn(sch, band+1, arg) < 0) {
 411                         arg->stop = 1;
 412                         break;
 413                 }
 414                 arg->count++;
 415         }
 416 }
 417
 418 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
 419 {
 420         struct multiq_sched_data *q = qdisc_priv(sch);
 421
 422         if (cl)
 423                 return NULL;
 424         return &q->filter_list;
 425 }
 426
 427 static const struct Qdisc_class_ops multiq_class_ops = {
 428         .graft          =       multiq_graft,
 429         .leaf           =       multiq_leaf,
 430         .get            =       multiq_get,
 431         .put            =       multiq_put,
 432         .change         =       multiq_change,
 433         .delete         =       multiq_delete,
 434         .walk           =       multiq_walk,
 435         .tcf_chain      =       multiq_find_tcf,
 436         .bind_tcf       =       multiq_bind,
 437         .unbind_tcf     =       multiq_put,
 438         .dump           =       multiq_dump_class,
 439         .dump_stats     =       multiq_dump_class_stats,
 440 };
 441
 442 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 443         .next           =       NULL,
 444         .cl_ops         =       &multiq_class_ops,
 445         .id             =       "multiq",
 446         .priv_size      =       sizeof(struct multiq_sched_data),
 447         .enqueue        =       multiq_enqueue,
 448         .dequeue        =       multiq_dequeue,
 449         .requeue        =       multiq_requeue,
 450         .drop           =       multiq_drop,
 451         .init           =       multiq_init,
 452         .reset          =       multiq_reset,
 453         .destroy        =       multiq_destroy,
 454         .change         =       multiq_tune,
 455         .dump           =       multiq_dump,
 456         .owner          =       THIS_MODULE,
 457 };
 458
 459 static int __init multiq_module_init(void)
 460 {
 461         return register_qdisc(&multiq_qdisc_ops);
 462 }
 463
 464 static void __exit multiq_module_exit(void)
 465 {
 466         unregister_qdisc(&multiq_qdisc_ops);
 467 }
 468
 469 module_init(multiq_module_init)
 470 module_exit(multiq_module_exit)
 471
 472 MODULE_LICENSE("GPL");