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/slab.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/string.h>
  25 #include <linux/errno.h>
  26 #include <linux/skbuff.h>
  27 #include <net/netlink.h>
  28 #include <net/pkt_sched.h>
  29
  30
  31 struct multiq_sched_data {
  32         u16 bands;
  33         u16 max_bands;
  34         u16 curband;
  35         struct tcf_proto *filter_list;
  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         int err;
  47
  48         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  49         err = tc_classify(skb, q->filter_list, &res);
  50 #ifdef CONFIG_NET_CLS_ACT
  51         switch (err) {
  52         case TC_ACT_STOLEN:
  53         case TC_ACT_QUEUED:
  54                 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  55         case TC_ACT_SHOT:
  56                 return NULL;
  57         }
  58 #endif
  59         band = skb_get_queue_mapping(skb);
  60
  61         if (band >= q->bands)
  62                 return q->queues[0];
  63
  64         return q->queues[band];
  65 }
  66
  67 static int
  68 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  69 {
  70         struct Qdisc *qdisc;
  71         int ret;
  72
  73         qdisc = multiq_classify(skb, sch, &ret);
  74 #ifdef CONFIG_NET_CLS_ACT
  75         if (qdisc == NULL) {
  76
  77                 if (ret & __NET_XMIT_BYPASS)
  78                         sch->qstats.drops++;
  79                 kfree_skb(skb);
  80                 return ret;
  81         }
  82 #endif
  83
  84         ret = qdisc_enqueue(skb, qdisc);
  85         if (ret == NET_XMIT_SUCCESS) {
  86                 sch->q.qlen++;
  87                 return NET_XMIT_SUCCESS;
  88         }
  89         if (net_xmit_drop_count(ret))
  90                 sch->qstats.drops++;
  91         return ret;
  92 }
  93
  94 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
  95 {
  96         struct multiq_sched_data *q = qdisc_priv(sch);
  97         struct Qdisc *qdisc;
  98         struct sk_buff *skb;
  99         int band;
 100
 101         for (band = 0; band < q->bands; band++) {
 102                 /* cycle through bands to ensure fairness */
 103                 q->curband++;
 104                 if (q->curband >= q->bands)
 105                         q->curband = 0;
 106
 107                 /* Check that target subqueue is available before
 108                  * pulling an skb to avoid head-of-line blocking.
 109                  */
 110                 if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
 111                         qdisc = q->queues[q->curband];
 112                         skb = qdisc->dequeue(qdisc);
 113                         if (skb) {
 114                                 qdisc_bstats_update(sch, skb);
 115                                 sch->q.qlen--;
 116                                 return skb;
 117                         }
 118                 }
 119         }
 120         return NULL;
 121
 122 }
 123
 124 static struct sk_buff *multiq_peek(struct Qdisc *sch)
 125 {
 126         struct multiq_sched_data *q = qdisc_priv(sch);
 127         unsigned int curband = q->curband;
 128         struct Qdisc *qdisc;
 129         struct sk_buff *skb;
 130         int band;
 131
 132         for (band = 0; band < q->bands; band++) {
 133                 /* cycle through bands to ensure fairness */
 134                 curband++;
 135                 if (curband >= q->bands)
 136                         curband = 0;
 137
 138                 /* Check that target subqueue is available before
 139                  * pulling an skb to avoid head-of-line blocking.
 140                  */
 141                 if (!__netif_subqueue_stopped(qdisc_dev(sch), curband)) {
 142                         qdisc = q->queues[curband];
 143                         skb = qdisc->ops->peek(qdisc);
 144                         if (skb)
 145                                 return skb;
 146                 }
 147         }
 148         return NULL;
 149
 150 }
 151
 152 static unsigned int multiq_drop(struct Qdisc *sch)
 153 {
 154         struct multiq_sched_data *q = qdisc_priv(sch);
 155         int band;
 156         unsigned int len;
 157         struct Qdisc *qdisc;
 158
 159         for (band = q->bands - 1; band >= 0; band--) {
 160                 qdisc = q->queues[band];
 161                 if (qdisc->ops->drop) {
 162                         len = qdisc->ops->drop(qdisc);
 163                         if (len != 0) {
 164                                 sch->q.qlen--;
 165                                 return len;
 166                         }
 167                 }
 168         }
 169         return 0;
 170 }
 171
 172
 173 static void
 174 multiq_reset(struct Qdisc *sch)
 175 {
 176         u16 band;
 177         struct multiq_sched_data *q = qdisc_priv(sch);
 178
 179         for (band = 0; band < q->bands; band++)
 180                 qdisc_reset(q->queues[band]);
 181         sch->q.qlen = 0;
 182         q->curband = 0;
 183 }
 184
 185 static void
 186 multiq_destroy(struct Qdisc *sch)
 187 {
 188         int band;
 189         struct multiq_sched_data *q = qdisc_priv(sch);
 190
 191         tcf_destroy_chain(&q->filter_list);
 192         for (band = 0; band < q->bands; band++)
 193                 qdisc_destroy(q->queues[band]);
 194
 195         kfree(q->queues);
 196 }
 197
 198 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
 199 {
 200         struct multiq_sched_data *q = qdisc_priv(sch);
 201         struct tc_multiq_qopt *qopt;
 202         int i;
 203
 204         if (!netif_is_multiqueue(qdisc_dev(sch)))
 205                 return -EOPNOTSUPP;
 206         if (nla_len(opt) < sizeof(*qopt))
 207                 return -EINVAL;
 208
 209         qopt = nla_data(opt);
 210
 211         qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
 212
 213         sch_tree_lock(sch);
 214         q->bands = qopt->bands;
 215         for (i = q->bands; i < q->max_bands; i++) {
 216                 if (q->queues[i] != &noop_qdisc) {
 217                         struct Qdisc *child = q->queues[i];
 218                         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, *old;
 229                         child = qdisc_create_dflt(sch->dev_queue,
 230                                                   &pfifo_qdisc_ops,
 231                                                   TC_H_MAKE(sch->handle,
 232                                                             i + 1));
 233                         if (child) {
 234                                 sch_tree_lock(sch);
 235                                 old = q->queues[i];
 236                                 q->queues[i] = child;
 237
 238                                 if (old != &noop_qdisc) {
 239                                         qdisc_tree_decrease_qlen(old,
 240                                                                  old->q.qlen);
 241                                         qdisc_destroy(old);
 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 (new == NULL)
 301                 new = &noop_qdisc;
 302
 303         sch_tree_lock(sch);
 304         *old = q->queues[band];
 305         q->queues[band] = new;
 306         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 307         qdisc_reset(*old);
 308         sch_tree_unlock(sch);
 309
 310         return 0;
 311 }
 312
 313 static struct Qdisc *
 314 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 315 {
 316         struct multiq_sched_data *q = qdisc_priv(sch);
 317         unsigned long band = arg - 1;
 318
 319         return q->queues[band];
 320 }
 321
 322 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 323 {
 324         struct multiq_sched_data *q = qdisc_priv(sch);
 325         unsigned long band = TC_H_MIN(classid);
 326
 327         if (band - 1 >= q->bands)
 328                 return 0;
 329         return band;
 330 }
 331
 332 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 333                                  u32 classid)
 334 {
 335         return multiq_get(sch, classid);
 336 }
 337
 338
 339 static void multiq_put(struct Qdisc *q, unsigned long cl)
 340 {
 341 }
 342
 343 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 344                              struct sk_buff *skb, struct tcmsg *tcm)
 345 {
 346         struct multiq_sched_data *q = qdisc_priv(sch);
 347
 348         tcm->tcm_handle |= TC_H_MIN(cl);
 349         tcm->tcm_info = q->queues[cl - 1]->handle;
 350         return 0;
 351 }
 352
 353 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 354                                  struct gnet_dump *d)
 355 {
 356         struct multiq_sched_data *q = qdisc_priv(sch);
 357         struct Qdisc *cl_q;
 358
 359         cl_q = q->queues[cl - 1];
 360         cl_q->qstats.qlen = cl_q->q.qlen;
 361         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 362             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 363                 return -1;
 364
 365         return 0;
 366 }
 367
 368 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 369 {
 370         struct multiq_sched_data *q = qdisc_priv(sch);
 371         int band;
 372
 373         if (arg->stop)
 374                 return;
 375
 376         for (band = 0; band < q->bands; band++) {
 377                 if (arg->count < arg->skip) {
 378                         arg->count++;
 379                         continue;
 380                 }
 381                 if (arg->fn(sch, band + 1, arg) < 0) {
 382                         arg->stop = 1;
 383                         break;
 384                 }
 385                 arg->count++;
 386         }
 387 }
 388
 389 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
 390 {
 391         struct multiq_sched_data *q = qdisc_priv(sch);
 392
 393         if (cl)
 394                 return NULL;
 395         return &q->filter_list;
 396 }
 397
 398 static const struct Qdisc_class_ops multiq_class_ops = {
 399         .graft          =       multiq_graft,
 400         .leaf           =       multiq_leaf,
 401         .get            =       multiq_get,
 402         .put            =       multiq_put,
 403         .walk           =       multiq_walk,
 404         .tcf_chain      =       multiq_find_tcf,
 405         .bind_tcf       =       multiq_bind,
 406         .unbind_tcf     =       multiq_put,
 407         .dump           =       multiq_dump_class,
 408         .dump_stats     =       multiq_dump_class_stats,
 409 };
 410
 411 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 412         .next           =       NULL,
 413         .cl_ops         =       &multiq_class_ops,
 414         .id             =       "multiq",
 415         .priv_size      =       sizeof(struct multiq_sched_data),
 416         .enqueue        =       multiq_enqueue,
 417         .dequeue        =       multiq_dequeue,
 418         .peek           =       multiq_peek,
 419         .drop           =       multiq_drop,
 420         .init           =       multiq_init,
 421         .reset          =       multiq_reset,
 422         .destroy        =       multiq_destroy,
 423         .change         =       multiq_tune,
 424         .dump           =       multiq_dump,
 425         .owner          =       THIS_MODULE,
 426 };
 427
 428 static int __init multiq_module_init(void)
 429 {
 430         return register_qdisc(&multiq_qdisc_ops);
 431 }
 432
 433 static void __exit multiq_module_exit(void)
 434 {
 435         unregister_qdisc(&multiq_qdisc_ops);
 436 }
 437
 438 module_init(multiq_module_init)
 439 module_exit(multiq_module_exit)
 440
 441 MODULE_LICENSE("GPL");