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
  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->q.qlen++;
  86                 return NET_XMIT_SUCCESS;
  87         }
  88         if (net_xmit_drop_count(ret))
  89                 sch->qstats.drops++;
  90         return ret;
  91 }
  92
  93 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
  94 {
  95         struct multiq_sched_data *q = qdisc_priv(sch);
  96         struct Qdisc *qdisc;
  97         struct sk_buff *skb;
  98         int band;
  99
 100         for (band = 0; band < q->bands; band++) {
 101                 /* cycle through bands to ensure fairness */
 102                 q->curband++;
 103                 if (q->curband >= q->bands)
 104                         q->curband = 0;
 105
 106                 /* Check that target subqueue is available before
 107                  * pulling an skb to avoid head-of-line blocking.
 108                  */
 109                 if (!netif_xmit_stopped(
 110                     netdev_get_tx_queue(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_xmit_stopped(
 142                     netdev_get_tx_queue(qdisc_dev(sch), curband))) {
 143                         qdisc = q->queues[curband];
 144                         skb = qdisc->ops->peek(qdisc);
 145                         if (skb)
 146                                 return skb;
 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 -EOPNOTSUPP;
 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 = q->queues[i];
 219                         q->queues[i] = &noop_qdisc;
 220                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 221                         qdisc_destroy(child);
 222                 }
 223         }
 224
 225         sch_tree_unlock(sch);
 226
 227         for (i = 0; i < q->bands; i++) {
 228                 if (q->queues[i] == &noop_qdisc) {
 229                         struct Qdisc *child, *old;
 230                         child = qdisc_create_dflt(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                                 old = q->queues[i];
 237                                 q->queues[i] = child;
 238
 239                                 if (old != &noop_qdisc) {
 240                                         qdisc_tree_decrease_qlen(old,
 241                                                                  old->q.qlen);
 242                                         qdisc_destroy(old);
 243                                 }
 244                                 sch_tree_unlock(sch);
 245                         }
 246                 }
 247         }
 248         return 0;
 249 }
 250
 251 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
 252 {
 253         struct multiq_sched_data *q = qdisc_priv(sch);
 254         int i, err;
 255
 256         q->queues = NULL;
 257
 258         if (opt == NULL)
 259                 return -EINVAL;
 260
 261         q->max_bands = qdisc_dev(sch)->num_tx_queues;
 262
 263         q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
 264         if (!q->queues)
 265                 return -ENOBUFS;
 266         for (i = 0; i < q->max_bands; i++)
 267                 q->queues[i] = &noop_qdisc;
 268
 269         err = multiq_tune(sch, opt);
 270
 271         if (err)
 272                 kfree(q->queues);
 273
 274         return err;
 275 }
 276
 277 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
 278 {
 279         struct multiq_sched_data *q = qdisc_priv(sch);
 280         unsigned char *b = skb_tail_pointer(skb);
 281         struct tc_multiq_qopt opt;
 282
 283         opt.bands = q->bands;
 284         opt.max_bands = q->max_bands;
 285
 286         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 287                 goto nla_put_failure;
 288
 289         return skb->len;
 290
 291 nla_put_failure:
 292         nlmsg_trim(skb, b);
 293         return -1;
 294 }
 295
 296 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 297                       struct Qdisc **old)
 298 {
 299         struct multiq_sched_data *q = qdisc_priv(sch);
 300         unsigned long band = arg - 1;
 301
 302         if (new == NULL)
 303                 new = &noop_qdisc;
 304
 305         sch_tree_lock(sch);
 306         *old = q->queues[band];
 307         q->queues[band] = new;
 308         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 309         qdisc_reset(*old);
 310         sch_tree_unlock(sch);
 311
 312         return 0;
 313 }
 314
 315 static struct Qdisc *
 316 multiq_leaf(struct Qdisc *sch, unsigned long arg)
 317 {
 318         struct multiq_sched_data *q = qdisc_priv(sch);
 319         unsigned long band = arg - 1;
 320
 321         return q->queues[band];
 322 }
 323
 324 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
 325 {
 326         struct multiq_sched_data *q = qdisc_priv(sch);
 327         unsigned long band = TC_H_MIN(classid);
 328
 329         if (band - 1 >= q->bands)
 330                 return 0;
 331         return band;
 332 }
 333
 334 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
 335                                  u32 classid)
 336 {
 337         return multiq_get(sch, classid);
 338 }
 339
 340
 341 static void multiq_put(struct Qdisc *q, unsigned long cl)
 342 {
 343 }
 344
 345 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
 346                              struct sk_buff *skb, struct tcmsg *tcm)
 347 {
 348         struct multiq_sched_data *q = qdisc_priv(sch);
 349
 350         tcm->tcm_handle |= TC_H_MIN(cl);
 351         tcm->tcm_info = q->queues[cl - 1]->handle;
 352         return 0;
 353 }
 354
 355 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 356                                  struct gnet_dump *d)
 357 {
 358         struct multiq_sched_data *q = qdisc_priv(sch);
 359         struct Qdisc *cl_q;
 360
 361         cl_q = q->queues[cl - 1];
 362         cl_q->qstats.qlen = cl_q->q.qlen;
 363         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 364             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 365                 return -1;
 366
 367         return 0;
 368 }
 369
 370 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 371 {
 372         struct multiq_sched_data *q = qdisc_priv(sch);
 373         int band;
 374
 375         if (arg->stop)
 376                 return;
 377
 378         for (band = 0; band < q->bands; band++) {
 379                 if (arg->count < arg->skip) {
 380                         arg->count++;
 381                         continue;
 382                 }
 383                 if (arg->fn(sch, band + 1, arg) < 0) {
 384                         arg->stop = 1;
 385                         break;
 386                 }
 387                 arg->count++;
 388         }
 389 }
 390
 391 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
 392 {
 393         struct multiq_sched_data *q = qdisc_priv(sch);
 394
 395         if (cl)
 396                 return NULL;
 397         return &q->filter_list;
 398 }
 399
 400 static const struct Qdisc_class_ops multiq_class_ops = {
 401         .graft          =       multiq_graft,
 402         .leaf           =       multiq_leaf,
 403         .get            =       multiq_get,
 404         .put            =       multiq_put,
 405         .walk           =       multiq_walk,
 406         .tcf_chain      =       multiq_find_tcf,
 407         .bind_tcf       =       multiq_bind,
 408         .unbind_tcf     =       multiq_put,
 409         .dump           =       multiq_dump_class,
 410         .dump_stats     =       multiq_dump_class_stats,
 411 };
 412
 413 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
 414         .next           =       NULL,
 415         .cl_ops         =       &multiq_class_ops,
 416         .id             =       "multiq",
 417         .priv_size      =       sizeof(struct multiq_sched_data),
 418         .enqueue        =       multiq_enqueue,
 419         .dequeue        =       multiq_dequeue,
 420         .peek           =       multiq_peek,
 421         .drop           =       multiq_drop,
 422         .init           =       multiq_init,
 423         .reset          =       multiq_reset,
 424         .destroy        =       multiq_destroy,
 425         .change         =       multiq_tune,
 426         .dump           =       multiq_dump,
 427         .owner          =       THIS_MODULE,
 428 };
 429
 430 static int __init multiq_module_init(void)
 431 {
 432         return register_qdisc(&multiq_qdisc_ops);
 433 }
 434
 435 static void __exit multiq_module_exit(void)
 436 {
 437         unregister_qdisc(&multiq_qdisc_ops);
 438 }
 439
 440 module_init(multiq_module_init)
 441 module_exit(multiq_module_exit)
 442
 443 MODULE_LICENSE("GPL");