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                 /* fall through */
  58         case TC_ACT_SHOT:
  59                 return NULL;
  60         }
  61 #endif
  62         band = skb_get_queue_mapping(skb);
  63
  64         if (band >= q->bands)
  65                 return q->queues[0];
  66
  67         return q->queues[band];
  68 }
  69
  70 static int
  71 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
  72                struct sk_buff **to_free)
  73 {
  74         struct Qdisc *qdisc;
  75         int ret;
  76
  77         qdisc = multiq_classify(skb, sch, &ret);
  78 #ifdef CONFIG_NET_CLS_ACT
  79         if (qdisc == NULL) {
  80
  81                 if (ret & __NET_XMIT_BYPASS)
  82                         qdisc_qstats_drop(sch);
  83                 __qdisc_drop(skb, to_free);
  84                 return ret;
  85         }
  86 #endif
  87
  88         ret = qdisc_enqueue(skb, qdisc, to_free);
  89         if (ret == NET_XMIT_SUCCESS) {
  90                 sch->q.qlen++;
  91                 return NET_XMIT_SUCCESS;
  92         }
  93         if (net_xmit_drop_count(ret))
  94                 qdisc_qstats_drop(sch);
  95         return ret;
  96 }
  97
  98 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
  99 {
 100         struct multiq_sched_data *q = qdisc_priv(sch);
 101         struct Qdisc *qdisc;
 102         struct sk_buff *skb;
 103         int band;
 104
 105         for (band = 0; band < q->bands; band++) {
 106                 /* cycle through bands to ensure fairness */
 107                 q->curband++;
 108                 if (q->curband >= q->bands)
 109                         q->curband = 0;
 110
 111                 /* Check that target subqueue is available before
 112                  * pulling an skb to avoid head-of-line blocking.
 113                  */
 114                 if (!netif_xmit_stopped(
 115                     netdev_get_tx_queue(qdisc_dev(sch), q->curband))) {
 116                         qdisc = q->queues[q->curband];
 117                         skb = qdisc->dequeue(qdisc);
 118                         if (skb) {
 119                                 qdisc_bstats_update(sch, skb);
 120                                 sch->q.qlen--;
 121                                 return skb;
 122                         }
 123                 }
 124         }
 125         return NULL;
 126
 127 }
 128
 129 static struct sk_buff *multiq_peek(struct Qdisc *sch)
 130 {
 131         struct multiq_sched_data *q = qdisc_priv(sch);
 132         unsigned int curband = q->curband;
 133         struct Qdisc *qdisc;
 134         struct sk_buff *skb;
 135         int band;
 136
 137         for (band = 0; band < q->bands; band++) {
 138                 /* cycle through bands to ensure fairness */
 139                 curband++;
 140                 if (curband >= q->bands)
 141                         curband = 0;
 142
 143                 /* Check that target subqueue is available before
 144                  * pulling an skb to avoid head-of-line blocking.
 145                  */
 146                 if (!netif_xmit_stopped(
 147                     netdev_get_tx_queue(qdisc_dev(sch), curband))) {
 148                         qdisc = q->queues[curband];
 149                         skb = qdisc->ops->peek(qdisc);
 150                         if (skb)
 151                                 return skb;
 152                 }
 153         }
 154         return NULL;
 155
 156 }
 157
 158 static void
 159 multiq_reset(struct Qdisc *sch)
 160 {
 161         u16 band;
 162         struct multiq_sched_data *q = qdisc_priv(sch);
 163
 164         for (band = 0; band < q->bands; band++)
 165                 qdisc_reset(q->queues[band]);
 166         sch->q.qlen = 0;
 167         q->curband = 0;
 168 }
 169
 170 static void
 171 multiq_destroy(struct Qdisc *sch)
 172 {
 173         int band;
 174         struct multiq_sched_data *q = qdisc_priv(sch);
 175
 176         tcf_block_put(q->block);
 177         for (band = 0; band < q->bands; band++)
 178                 qdisc_destroy(q->queues[band]);
 179
 180         kfree(q->queues);
 181 }
 182
 183 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 184 {
 185         struct multiq_sched_data *q = qdisc_priv(sch);
 186         struct tc_multiq_qopt *qopt;
 187         int i;
 188
 189         if (!netif_is_multiqueue(qdisc_dev(sch)))
 190                 return -EOPNOTSUPP;
 191         if (nla_len(opt) < sizeof(*qopt))
 192                 return -EINVAL;
 193
 194         qopt = nla_data(opt);
 195
 196         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 197
 198         sch_tree_lock(sch);
 199         q->bands = qopt->bands;
 200         for (i = q->bands; i < q->max_bands; i++) {
 201                 if (q->queues[i] != &noop_qdisc) {
 202                         struct Qdisc *child = q->queues[i];
 203                         q->queues[i] = &noop_qdisc;
 204                         qdisc_tree_reduce_backlog(child, child->q.qlen,
 205                                                   child->qstats.backlog);
 206                         qdisc_destroy(child);
 207                 }
 208         }
 209
 210         sch_tree_unlock(sch);
 211
 212         for (i = 0; i < q->bands; i++) {
 213                 if (q->queues[i] == &noop_qdisc) {
 214                         struct Qdisc *child, *old;
 215                         child = qdisc_create_dflt(sch->dev_queue,
 216                                                   &pfifo_qdisc_ops,
 217                                                   TC_H_MAKE(sch->handle,
 218                                                             i + 1));
 219                         if (child) {
 220                                 sch_tree_lock(sch);
 221                                 old = q->queues[i];
 222                                 q->queues[i] = child;
 223                                 if (child != &noop_qdisc)
 224                                         qdisc_hash_add(child, true);
 225
 226                                 if (old != &noop_qdisc) {
 227                                         qdisc_tree_reduce_backlog(old,
 228                                                                   old->q.qlen,
 229                                                                   old->qstats.backlog);
 230                                         qdisc_destroy(old);
 231                                 }
 232                                 sch_tree_unlock(sch);
 233                         }
 234                 }
 235         }
 236         return 0;
 237 }
 238
 239 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 240 {
 241         struct multiq_sched_data *q = qdisc_priv(sch);
 242         int i, err;
 243
 244         q->queues = NULL;
 245
 246         if (opt == NULL)
 247                 return -EINVAL;
 248
 249         err = tcf_block_get(&q->block, &q->filter_list, sch);
 250         if (err)
 251                 return err;
 252
 253         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 254
 255         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 256         if (!q->queues)
 257                 return -ENOBUFS;
 258         for (i = 0; i < q->max_bands; i++)
 259                 q->queues[i] = &noop_qdisc;
 260
 261         return multiq_tune(sch, opt);
 262 }
 263
 264 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 265 {
 266         struct multiq_sched_data *q = qdisc_priv(sch);
 267         unsigned char *b = skb_tail_pointer(skb);
 268         struct tc_multiq_qopt opt;
 269
 270         opt.bands = q->bands;
 271         opt.max_bands = q->max_bands;
 272
 273         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 274                 goto nla_put_failure;
 275
 276         return skb->len;
 277
 278 nla_put_failure:
 279         nlmsg_trim(skb, b);
 280         return -1;
 281 }
 282
 283 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 284                       struct Qdisc **old)
 285 {
 286         struct multiq_sched_data *q = qdisc_priv(sch);
 287         unsigned long band = arg - 1;
 288
 289         if (new == NULL)
 290                 new = &noop_qdisc;
 291
 292         *old = qdisc_replace(sch, new, &q->queues[band]);
 293         return 0;
 294 }
 295
 296 static struct Qdisc *
 297 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 298 {
 299         struct multiq_sched_data *q = qdisc_priv(sch);
 300         unsigned long band = arg - 1;
 301
 302         return q->queues[band];
 303 }
 304
 305 static unsigned long multiq_find(struct Qdisc *sch, u32 classid)
 306 {
 307         struct multiq_sched_data *q = qdisc_priv(sch);
 308         unsigned long band = TC_H_MIN(classid);
 309
 310         if (band - 1 >= q->bands)
 311                 return 0;
 312         return band;
 313 }
 314
 315 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 316                                  u32 classid)
 317 {
 318         return multiq_find(sch, classid);
 319 }
 320
 321
 322 static void multiq_unbind(struct Qdisc *q, unsigned long cl)
 323 {
 324 }
 325
 326 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 327                              struct sk_buff *skb, struct tcmsg *tcm)
 328 {
 329         struct multiq_sched_data *q = qdisc_priv(sch);
 330
 331         tcm->tcm_handle |= TC_H_MIN(cl);
 332         tcm->tcm_info = q->queues[cl - 1]->handle;
 333         return 0;
 334 }
 335
 336 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 337                                  struct gnet_dump *d)
 338 {
 339         struct multiq_sched_data *q = qdisc_priv(sch);
 340         struct Qdisc *cl_q;
 341
 342         cl_q = q->queues[cl - 1];
 343         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 344                                   d, NULL, &cl_q->bstats) < 0 ||
 345             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 346                 return -1;
 347
 348         return 0;
 349 }
 350
 351 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 352 {
 353         struct multiq_sched_data *q = qdisc_priv(sch);
 354         int band;
 355
 356         if (arg->stop)
 357                 return;
 358
 359         for (band = 0; band < q->bands; band++) {
 360                 if (arg->count < arg->skip) {
 361                         arg->count++;
 362                         continue;
 363                 }
 364                 if (arg->fn(sch, band + 1, arg) < 0) {
 365                         arg->stop = 1;
 366                         break;
 367                 }
 368                 arg->count++;
 369         }
 370 }
 371
 372 static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl)
 373 {
 374         struct multiq_sched_data *q = qdisc_priv(sch);
 375
 376         if (cl)
 377                 return NULL;
 378         return q->block;
 379 }
 380
 381 static const struct Qdisc_class_ops multiq_class_ops = {
 382         .graft          =       multiq_graft,
 383         .leaf           =       multiq_leaf,
 384         .find           =       multiq_find,
 385         .walk           =       multiq_walk,
 386         .tcf_block      =       multiq_tcf_block,
 387         .bind_tcf       =       multiq_bind,
 388         .unbind_tcf     =       multiq_unbind,
 389         .dump           =       multiq_dump_class,
 390         .dump_stats     =       multiq_dump_class_stats,
 391 };
 392
 393 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 394         .next           =       NULL,
 395         .cl_ops         =       &multiq_class_ops,
 396         .id             =       "multiq",
 397         .priv_size      =       sizeof(struct multiq_sched_data),
 398         .enqueue        =       multiq_enqueue,
 399         .dequeue        =       multiq_dequeue,
 400         .peek           =       multiq_peek,
 401         .init           =       multiq_init,
 402         .reset          =       multiq_reset,
 403         .destroy        =       multiq_destroy,
 404         .change         =       multiq_tune,
 405         .dump           =       multiq_dump,
 406         .owner          =       THIS_MODULE,
 407 };
 408
 409 static int __init multiq_module_init(void)
 410 {
 411         return register_qdisc(&multiq_qdisc_ops);
 412 }
 413
 414 static void __exit multiq_module_exit(void)
 415 {
 416         unregister_qdisc(&multiq_qdisc_ops);
 417 }
 418
 419 module_init(multiq_module_init)
 420 module_exit(multiq_module_exit)
 421
 422 MODULE_LICENSE("GPL");