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, see <http://www.gnu.org/licenses/>.
  15  *
  16  * Author: Alexander Duyck <alexander.h.duyck@intel.com>
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/slab.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 #include <net/pkt_cls.h>
  29
  30 struct multiq_sched_data {
  31         u16 bands;
  32         u16 max_bands;
  33         u16 curband;
  34         struct tcf_proto __rcu *filter_list;
  35         struct tcf_block *block;
  36         struct Qdisc **queues;
  37 };
  38
  39
  40 static struct Qdisc *
  41 multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  42 {
  43         struct multiq_sched_data *q = qdisc_priv(sch);
  44         u32 band;
  45         struct tcf_result res;
  46         struct tcf_proto *fl = rcu_dereference_bh(q->filter_list);
  47         int err;
  48
  49         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  50         err = tcf_classify(skb, fl, &res, false);
  51 #ifdef CONFIG_NET_CLS_ACT
  52         switch (err) {
  53         case TC_ACT_STOLEN:
  54         case TC_ACT_QUEUED:
  55         case TC_ACT_TRAP:
  56                 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  57         case TC_ACT_SHOT:
  58                 return NULL;
  59         }
  60 #endif
  61         band = skb_get_queue_mapping(skb);
  62
  63         if (band >= q->bands)
  64                 return q->queues[0];
  65
  66         return q->queues[band];
  67 }
  68
  69 static int
  70 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
  71                struct sk_buff **to_free)
  72 {
  73         struct Qdisc *qdisc;
  74         int ret;
  75
  76         qdisc = multiq_classify(skb, sch, &ret);
  77 #ifdef CONFIG_NET_CLS_ACT
  78         if (qdisc == NULL) {
  79
  80                 if (ret & __NET_XMIT_BYPASS)
  81                         qdisc_qstats_drop(sch);
  82                 __qdisc_drop(skb, to_free);
  83                 return ret;
  84         }
  85 #endif
  86
  87         ret = qdisc_enqueue(skb, qdisc, to_free);
  88         if (ret == NET_XMIT_SUCCESS) {
  89                 sch->q.qlen++;
  90                 return NET_XMIT_SUCCESS;
  91         }
  92         if (net_xmit_drop_count(ret))
  93                 qdisc_qstats_drop(sch);
  94         return ret;
  95 }
  96
  97 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
  98 {
  99         struct multiq_sched_data *q = qdisc_priv(sch);
 100         struct Qdisc *qdisc;
 101         struct sk_buff *skb;
 102         int band;
 103
 104         for (band = 0; band < q->bands; band++) {
 105                 /* cycle through bands to ensure fairness */
 106                 q->curband++;
 107                 if (q->curband >= q->bands)
 108                         q->curband = 0;
 109
 110                 /* Check that target subqueue is available before
 111                  * pulling an skb to avoid head-of-line blocking.
 112                  */
 113                 if (!netif_xmit_stopped(
 114                     netdev_get_tx_queue(qdisc_dev(sch), q->curband))) {
 115                         qdisc = q->queues[q->curband];
 116                         skb = qdisc->dequeue(qdisc);
 117                         if (skb) {
 118                                 qdisc_bstats_update(sch, skb);
 119                                 sch->q.qlen--;
 120                                 return skb;
 121                         }
 122                 }
 123         }
 124         return NULL;
 125
 126 }
 127
 128 static struct sk_buff *multiq_peek(struct Qdisc *sch)
 129 {
 130         struct multiq_sched_data *q = qdisc_priv(sch);
 131         unsigned int curband = q->curband;
 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                 curband++;
 139                 if (curband >= q->bands)
 140                         curband = 0;
 141
 142                 /* Check that target subqueue is available before
 143                  * pulling an skb to avoid head-of-line blocking.
 144                  */
 145                 if (!netif_xmit_stopped(
 146                     netdev_get_tx_queue(qdisc_dev(sch), curband))) {
 147                         qdisc = q->queues[curband];
 148                         skb = qdisc->ops->peek(qdisc);
 149                         if (skb)
 150                                 return skb;
 151                 }
 152         }
 153         return NULL;
 154
 155 }
 156
 157 static void
 158 multiq_reset(struct Qdisc *sch)
 159 {
 160         u16 band;
 161         struct multiq_sched_data *q = qdisc_priv(sch);
 162
 163         for (band = 0; band < q->bands; band++)
 164                 qdisc_reset(q->queues[band]);
 165         sch->q.qlen = 0;
 166         q->curband = 0;
 167 }
 168
 169 static void
 170 multiq_destroy(struct Qdisc *sch)
 171 {
 172         int band;
 173         struct multiq_sched_data *q = qdisc_priv(sch);
 174
 175         tcf_block_put(q->block);
 176         for (band = 0; band < q->bands; band++)
 177                 qdisc_destroy(q->queues[band]);
 178
 179         kfree(q->queues);
 180 }
 181
 182 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 183 {
 184         struct multiq_sched_data *q = qdisc_priv(sch);
 185         struct tc_multiq_qopt *qopt;
 186         int i;
 187
 188         if (!netif_is_multiqueue(qdisc_dev(sch)))
 189                 return -EOPNOTSUPP;
 190         if (nla_len(opt) < sizeof(*qopt))
 191                 return -EINVAL;
 192
 193         qopt = nla_data(opt);
 194
 195         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 196
 197         sch_tree_lock(sch);
 198         q->bands = qopt->bands;
 199         for (i = q->bands; i < q->max_bands; i++) {
 200                 if (q->queues[i] != &noop_qdisc) {
 201                         struct Qdisc *child = q->queues[i];
 202                         q->queues[i] = &noop_qdisc;
 203                         qdisc_tree_reduce_backlog(child, child->q.qlen,
 204                                                   child->qstats.backlog);
 205                         qdisc_destroy(child);
 206                 }
 207         }
 208
 209         sch_tree_unlock(sch);
 210
 211         for (i = 0; i < q->bands; i++) {
 212                 if (q->queues[i] == &noop_qdisc) {
 213                         struct Qdisc *child, *old;
 214                         child = qdisc_create_dflt(sch->dev_queue,
 215                                                   &pfifo_qdisc_ops,
 216                                                   TC_H_MAKE(sch->handle,
 217                                                             i + 1));
 218                         if (child) {
 219                                 sch_tree_lock(sch);
 220                                 old = q->queues[i];
 221                                 q->queues[i] = child;
 222                                 if (child != &noop_qdisc)
 223                                         qdisc_hash_add(child, true);
 224
 225                                 if (old != &noop_qdisc) {
 226                                         qdisc_tree_reduce_backlog(old,
 227                                                                   old->q.qlen,
 228                                                                   old->qstats.backlog);
 229                                         qdisc_destroy(old);
 230                                 }
 231                                 sch_tree_unlock(sch);
 232                         }
 233                 }
 234         }
 235         return 0;
 236 }
 237
 238 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 239 {
 240         struct multiq_sched_data *q = qdisc_priv(sch);
 241         int i, err;
 242
 243         q->queues = NULL;
 244
 245         if (opt == NULL)
 246                 return -EINVAL;
 247
 248         err = tcf_block_get(&q->block, &q->filter_list);
 249         if (err)
 250                 return err;
 251
 252         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 253
 254         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 255         if (!q->queues)
 256                 return -ENOBUFS;
 257         for (i = 0; i < q->max_bands; i++)
 258                 q->queues[i] = &noop_qdisc;
 259
 260         err = multiq_tune(sch, opt);
 261
 262         if (err)
 263                 kfree(q->queues);
 264
 265         return err;
 266 }
 267
 268 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 269 {
 270         struct multiq_sched_data *q = qdisc_priv(sch);
 271         unsigned char *b = skb_tail_pointer(skb);
 272         struct tc_multiq_qopt opt;
 273
 274         opt.bands = q->bands;
 275         opt.max_bands = q->max_bands;
 276
 277         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 278                 goto nla_put_failure;
 279
 280         return skb->len;
 281
 282 nla_put_failure:
 283         nlmsg_trim(skb, b);
 284         return -1;
 285 }
 286
 287 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 288                       struct Qdisc **old)
 289 {
 290         struct multiq_sched_data *q = qdisc_priv(sch);
 291         unsigned long band = arg - 1;
 292
 293         if (new == NULL)
 294                 new = &noop_qdisc;
 295
 296         *old = qdisc_replace(sch, new, &q->queues[band]);
 297         return 0;
 298 }
 299
 300 static struct Qdisc *
 301 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 302 {
 303         struct multiq_sched_data *q = qdisc_priv(sch);
 304         unsigned long band = arg - 1;
 305
 306         return q->queues[band];
 307 }
 308
 309 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 310 {
 311         struct multiq_sched_data *q = qdisc_priv(sch);
 312         unsigned long band = TC_H_MIN(classid);
 313
 314         if (band - 1 >= q->bands)
 315                 return 0;
 316         return band;
 317 }
 318
 319 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 320                                  u32 classid)
 321 {
 322         return multiq_get(sch, classid);
 323 }
 324
 325
 326 static void multiq_put(struct Qdisc *q, unsigned long cl)
 327 {
 328 }
 329
 330 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 331                              struct sk_buff *skb, struct tcmsg *tcm)
 332 {
 333         struct multiq_sched_data *q = qdisc_priv(sch);
 334
 335         tcm->tcm_handle |= TC_H_MIN(cl);
 336         tcm->tcm_info = q->queues[cl - 1]->handle;
 337         return 0;
 338 }
 339
 340 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 341                                  struct gnet_dump *d)
 342 {
 343         struct multiq_sched_data *q = qdisc_priv(sch);
 344         struct Qdisc *cl_q;
 345
 346         cl_q = q->queues[cl - 1];
 347         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 348                                   d, NULL, &cl_q->bstats) < 0 ||
 349             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 350                 return -1;
 351
 352         return 0;
 353 }
 354
 355 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 356 {
 357         struct multiq_sched_data *q = qdisc_priv(sch);
 358         int band;
 359
 360         if (arg->stop)
 361                 return;
 362
 363         for (band = 0; band < q->bands; band++) {
 364                 if (arg->count < arg->skip) {
 365                         arg->count++;
 366                         continue;
 367                 }
 368                 if (arg->fn(sch, band + 1, arg) < 0) {
 369                         arg->stop = 1;
 370                         break;
 371                 }
 372                 arg->count++;
 373         }
 374 }
 375
 376 static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl)
 377 {
 378         struct multiq_sched_data *q = qdisc_priv(sch);
 379
 380         if (cl)
 381                 return NULL;
 382         return q->block;
 383 }
 384
 385 static const struct Qdisc_class_ops multiq_class_ops = {
 386         .graft          =       multiq_graft,
 387         .leaf           =       multiq_leaf,
 388         .get            =       multiq_get,
 389         .put            =       multiq_put,
 390         .walk           =       multiq_walk,
 391         .tcf_block      =       multiq_tcf_block,
 392         .bind_tcf       =       multiq_bind,
 393         .unbind_tcf     =       multiq_put,
 394         .dump           =       multiq_dump_class,
 395         .dump_stats     =       multiq_dump_class_stats,
 396 };
 397
 398 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 399         .next           =       NULL,
 400         .cl_ops         =       &multiq_class_ops,
 401         .id             =       "multiq",
 402         .priv_size      =       sizeof(struct multiq_sched_data),
 403         .enqueue        =       multiq_enqueue,
 404         .dequeue        =       multiq_dequeue,
 405         .peek           =       multiq_peek,
 406         .init           =       multiq_init,
 407         .reset          =       multiq_reset,
 408         .destroy        =       multiq_destroy,
 409         .change         =       multiq_tune,
 410         .dump           =       multiq_dump,
 411         .owner          =       THIS_MODULE,
 412 };
 413
 414 static int __init multiq_module_init(void)
 415 {
 416         return register_qdisc(&multiq_qdisc_ops);
 417 }
 418
 419 static void __exit multiq_module_exit(void)
 420 {
 421         unregister_qdisc(&multiq_qdisc_ops);
 422 }
 423
 424 module_init(multiq_module_init)
 425 module_exit(multiq_module_exit)
 426
 427 MODULE_LICENSE("GPL");