1 /* 2 * net/sched/sch_prio.c Simple 3-band priority "scheduler". 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 * Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>: 11 * Init -- EINVAL when opt undefined 12 */ 13 14 #include <linux/module.h> 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/string.h> 18 #include <linux/errno.h> 19 #include <linux/skbuff.h> 20 #include <net/netlink.h> 21 #include <net/pkt_sched.h> 22 23 24 struct prio_sched_data 25 { 26 int bands; 27 int curband; /* for round-robin */ 28 struct tcf_proto *filter_list; 29 u8 prio2band[TC_PRIO_MAX+1]; 30 struct Qdisc *queues[TCQ_PRIO_BANDS]; 31 int mq; 32 }; 33 34 35 static struct Qdisc * 36 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 37 { 38 struct prio_sched_data *q = qdisc_priv(sch); 39 u32 band = skb->priority; 40 struct tcf_result res; 41 int err; 42 43 *qerr = NET_XMIT_BYPASS; 44 if (TC_H_MAJ(skb->priority) != sch->handle) { 45 err = tc_classify(skb, q->filter_list, &res); 46 #ifdef CONFIG_NET_CLS_ACT 47 switch (err) { 48 case TC_ACT_STOLEN: 49 case TC_ACT_QUEUED: 50 *qerr = NET_XMIT_SUCCESS; 51 case TC_ACT_SHOT: 52 return NULL; 53 } 54 #endif 55 if (!q->filter_list || err < 0) { 56 if (TC_H_MAJ(band)) 57 band = 0; 58 band = q->prio2band[band&TC_PRIO_MAX]; 59 goto out; 60 } 61 band = res.classid; 62 } 63 band = TC_H_MIN(band) - 1; 64 if (band >= q->bands) 65 band = q->prio2band[0]; 66 out: 67 if (q->mq) 68 skb_set_queue_mapping(skb, band); 69 return q->queues[band]; 70 } 71 72 static int 73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch) 74 { 75 struct Qdisc *qdisc; 76 int ret; 77 78 qdisc = prio_classify(skb, sch, &ret); 79 #ifdef CONFIG_NET_CLS_ACT 80 if (qdisc == NULL) { 81 82 if (ret == NET_XMIT_BYPASS) 83 sch->qstats.drops++; 84 kfree_skb(skb); 85 return ret; 86 } 87 #endif 88 89 if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) { 90 sch->bstats.bytes += skb->len; 91 sch->bstats.packets++; 92 sch->q.qlen++; 93 return NET_XMIT_SUCCESS; 94 } 95 sch->qstats.drops++; 96 return ret; 97 } 98 99 100 static int 101 prio_requeue(struct sk_buff *skb, struct Qdisc* sch) 102 { 103 struct Qdisc *qdisc; 104 int ret; 105 106 qdisc = prio_classify(skb, sch, &ret); 107 #ifdef CONFIG_NET_CLS_ACT 108 if (qdisc == NULL) { 109 if (ret == NET_XMIT_BYPASS) 110 sch->qstats.drops++; 111 kfree_skb(skb); 112 return ret; 113 } 114 #endif 115 116 if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) { 117 sch->q.qlen++; 118 sch->qstats.requeues++; 119 return 0; 120 } 121 sch->qstats.drops++; 122 return NET_XMIT_DROP; 123 } 124 125 126 static struct sk_buff * 127 prio_dequeue(struct Qdisc* sch) 128 { 129 struct sk_buff *skb; 130 struct prio_sched_data *q = qdisc_priv(sch); 131 int prio; 132 struct Qdisc *qdisc; 133 134 for (prio = 0; prio < q->bands; prio++) { 135 /* Check if the target subqueue is available before 136 * pulling an skb. This way we avoid excessive requeues 137 * for slower queues. 138 */ 139 if (!__netif_subqueue_stopped(sch->dev, (q->mq ? prio : 0))) { 140 qdisc = q->queues[prio]; 141 skb = qdisc->dequeue(qdisc); 142 if (skb) { 143 sch->q.qlen--; 144 return skb; 145 } 146 } 147 } 148 return NULL; 149 150 } 151 152 static struct sk_buff *rr_dequeue(struct Qdisc* sch) 153 { 154 struct sk_buff *skb; 155 struct prio_sched_data *q = qdisc_priv(sch); 156 struct Qdisc *qdisc; 157 int bandcount; 158 159 /* Only take one pass through the queues. If nothing is available, 160 * return nothing. 161 */ 162 for (bandcount = 0; bandcount < q->bands; bandcount++) { 163 /* Check if the target subqueue is available before 164 * pulling an skb. This way we avoid excessive requeues 165 * for slower queues. If the queue is stopped, try the 166 * next queue. 167 */ 168 if (!__netif_subqueue_stopped(sch->dev, 169 (q->mq ? q->curband : 0))) { 170 qdisc = q->queues[q->curband]; 171 skb = qdisc->dequeue(qdisc); 172 if (skb) { 173 sch->q.qlen--; 174 q->curband++; 175 if (q->curband >= q->bands) 176 q->curband = 0; 177 return skb; 178 } 179 } 180 q->curband++; 181 if (q->curband >= q->bands) 182 q->curband = 0; 183 } 184 return NULL; 185 } 186 187 static unsigned int prio_drop(struct Qdisc* sch) 188 { 189 struct prio_sched_data *q = qdisc_priv(sch); 190 int prio; 191 unsigned int len; 192 struct Qdisc *qdisc; 193 194 for (prio = q->bands-1; prio >= 0; prio--) { 195 qdisc = q->queues[prio]; 196 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) { 197 sch->q.qlen--; 198 return len; 199 } 200 } 201 return 0; 202 } 203 204 205 static void 206 prio_reset(struct Qdisc* sch) 207 { 208 int prio; 209 struct prio_sched_data *q = qdisc_priv(sch); 210 211 for (prio=0; prio<q->bands; prio++) 212 qdisc_reset(q->queues[prio]); 213 sch->q.qlen = 0; 214 } 215 216 static void 217 prio_destroy(struct Qdisc* sch) 218 { 219 int prio; 220 struct prio_sched_data *q = qdisc_priv(sch); 221 222 tcf_destroy_chain(q->filter_list); 223 for (prio=0; prio<q->bands; prio++) 224 qdisc_destroy(q->queues[prio]); 225 } 226 227 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 228 { 229 struct prio_sched_data *q = qdisc_priv(sch); 230 struct tc_prio_qopt *qopt; 231 struct nlattr *tb[TCA_PRIO_MAX + 1]; 232 int err; 233 int i; 234 235 err = nla_parse_nested_compat(tb, TCA_PRIO_MAX, opt, NULL, qopt, 236 sizeof(*qopt)); 237 if (err < 0) 238 return err; 239 240 q->bands = qopt->bands; 241 /* If we're multiqueue, make sure the number of incoming bands 242 * matches the number of queues on the device we're associating with. 243 * If the number of bands requested is zero, then set q->bands to 244 * dev->egress_subqueue_count. Also, the root qdisc must be the 245 * only one that is enabled for multiqueue, since it's the only one 246 * that interacts with the underlying device. 247 */ 248 q->mq = nla_get_flag(tb[TCA_PRIO_MQ]); 249 if (q->mq) { 250 if (sch->parent != TC_H_ROOT) 251 return -EINVAL; 252 if (netif_is_multiqueue(sch->dev)) { 253 if (q->bands == 0) 254 q->bands = sch->dev->egress_subqueue_count; 255 else if (q->bands != sch->dev->egress_subqueue_count) 256 return -EINVAL; 257 } else 258 return -EOPNOTSUPP; 259 } 260 261 if (q->bands > TCQ_PRIO_BANDS || q->bands < 2) 262 return -EINVAL; 263 264 for (i=0; i<=TC_PRIO_MAX; i++) { 265 if (qopt->priomap[i] >= q->bands) 266 return -EINVAL; 267 } 268 269 sch_tree_lock(sch); 270 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 271 272 for (i=q->bands; i<TCQ_PRIO_BANDS; i++) { 273 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc); 274 if (child != &noop_qdisc) { 275 qdisc_tree_decrease_qlen(child, child->q.qlen); 276 qdisc_destroy(child); 277 } 278 } 279 sch_tree_unlock(sch); 280 281 for (i=0; i<q->bands; i++) { 282 if (q->queues[i] == &noop_qdisc) { 283 struct Qdisc *child; 284 child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, 285 TC_H_MAKE(sch->handle, i + 1)); 286 if (child) { 287 sch_tree_lock(sch); 288 child = xchg(&q->queues[i], child); 289 290 if (child != &noop_qdisc) { 291 qdisc_tree_decrease_qlen(child, 292 child->q.qlen); 293 qdisc_destroy(child); 294 } 295 sch_tree_unlock(sch); 296 } 297 } 298 } 299 return 0; 300 } 301 302 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 303 { 304 struct prio_sched_data *q = qdisc_priv(sch); 305 int i; 306 307 for (i=0; i<TCQ_PRIO_BANDS; i++) 308 q->queues[i] = &noop_qdisc; 309 310 if (opt == NULL) { 311 return -EINVAL; 312 } else { 313 int err; 314 315 if ((err= prio_tune(sch, opt)) != 0) 316 return err; 317 } 318 return 0; 319 } 320 321 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 322 { 323 struct prio_sched_data *q = qdisc_priv(sch); 324 unsigned char *b = skb_tail_pointer(skb); 325 struct nlattr *nest; 326 struct tc_prio_qopt opt; 327 328 opt.bands = q->bands; 329 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1); 330 331 nest = nla_nest_compat_start(skb, TCA_OPTIONS, sizeof(opt), &opt); 332 if (nest == NULL) 333 goto nla_put_failure; 334 if (q->mq) { 335 if (nla_put_flag(skb, TCA_PRIO_MQ) < 0) 336 goto nla_put_failure; 337 } 338 nla_nest_compat_end(skb, nest); 339 340 return skb->len; 341 342 nla_put_failure: 343 nlmsg_trim(skb, b); 344 return -1; 345 } 346 347 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 348 struct Qdisc **old) 349 { 350 struct prio_sched_data *q = qdisc_priv(sch); 351 unsigned long band = arg - 1; 352 353 if (band >= q->bands) 354 return -EINVAL; 355 356 if (new == NULL) 357 new = &noop_qdisc; 358 359 sch_tree_lock(sch); 360 *old = q->queues[band]; 361 q->queues[band] = new; 362 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 363 qdisc_reset(*old); 364 sch_tree_unlock(sch); 365 366 return 0; 367 } 368 369 static struct Qdisc * 370 prio_leaf(struct Qdisc *sch, unsigned long arg) 371 { 372 struct prio_sched_data *q = qdisc_priv(sch); 373 unsigned long band = arg - 1; 374 375 if (band >= q->bands) 376 return NULL; 377 378 return q->queues[band]; 379 } 380 381 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 382 { 383 struct prio_sched_data *q = qdisc_priv(sch); 384 unsigned long band = TC_H_MIN(classid); 385 386 if (band - 1 >= q->bands) 387 return 0; 388 return band; 389 } 390 391 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 392 { 393 return prio_get(sch, classid); 394 } 395 396 397 static void prio_put(struct Qdisc *q, unsigned long cl) 398 { 399 return; 400 } 401 402 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg) 403 { 404 unsigned long cl = *arg; 405 struct prio_sched_data *q = qdisc_priv(sch); 406 407 if (cl - 1 > q->bands) 408 return -ENOENT; 409 return 0; 410 } 411 412 static int prio_delete(struct Qdisc *sch, unsigned long cl) 413 { 414 struct prio_sched_data *q = qdisc_priv(sch); 415 if (cl - 1 > q->bands) 416 return -ENOENT; 417 return 0; 418 } 419 420 421 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 422 struct tcmsg *tcm) 423 { 424 struct prio_sched_data *q = qdisc_priv(sch); 425 426 if (cl - 1 > q->bands) 427 return -ENOENT; 428 tcm->tcm_handle |= TC_H_MIN(cl); 429 if (q->queues[cl-1]) 430 tcm->tcm_info = q->queues[cl-1]->handle; 431 return 0; 432 } 433 434 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 435 struct gnet_dump *d) 436 { 437 struct prio_sched_data *q = qdisc_priv(sch); 438 struct Qdisc *cl_q; 439 440 cl_q = q->queues[cl - 1]; 441 if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 || 442 gnet_stats_copy_queue(d, &cl_q->qstats) < 0) 443 return -1; 444 445 return 0; 446 } 447 448 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 449 { 450 struct prio_sched_data *q = qdisc_priv(sch); 451 int prio; 452 453 if (arg->stop) 454 return; 455 456 for (prio = 0; prio < q->bands; prio++) { 457 if (arg->count < arg->skip) { 458 arg->count++; 459 continue; 460 } 461 if (arg->fn(sch, prio+1, arg) < 0) { 462 arg->stop = 1; 463 break; 464 } 465 arg->count++; 466 } 467 } 468 469 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl) 470 { 471 struct prio_sched_data *q = qdisc_priv(sch); 472 473 if (cl) 474 return NULL; 475 return &q->filter_list; 476 } 477 478 static const struct Qdisc_class_ops prio_class_ops = { 479 .graft = prio_graft, 480 .leaf = prio_leaf, 481 .get = prio_get, 482 .put = prio_put, 483 .change = prio_change, 484 .delete = prio_delete, 485 .walk = prio_walk, 486 .tcf_chain = prio_find_tcf, 487 .bind_tcf = prio_bind, 488 .unbind_tcf = prio_put, 489 .dump = prio_dump_class, 490 .dump_stats = prio_dump_class_stats, 491 }; 492 493 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 494 .next = NULL, 495 .cl_ops = &prio_class_ops, 496 .id = "prio", 497 .priv_size = sizeof(struct prio_sched_data), 498 .enqueue = prio_enqueue, 499 .dequeue = prio_dequeue, 500 .requeue = prio_requeue, 501 .drop = prio_drop, 502 .init = prio_init, 503 .reset = prio_reset, 504 .destroy = prio_destroy, 505 .change = prio_tune, 506 .dump = prio_dump, 507 .owner = THIS_MODULE, 508 }; 509 510 static struct Qdisc_ops rr_qdisc_ops __read_mostly = { 511 .next = NULL, 512 .cl_ops = &prio_class_ops, 513 .id = "rr", 514 .priv_size = sizeof(struct prio_sched_data), 515 .enqueue = prio_enqueue, 516 .dequeue = rr_dequeue, 517 .requeue = prio_requeue, 518 .drop = prio_drop, 519 .init = prio_init, 520 .reset = prio_reset, 521 .destroy = prio_destroy, 522 .change = prio_tune, 523 .dump = prio_dump, 524 .owner = THIS_MODULE, 525 }; 526 527 static int __init prio_module_init(void) 528 { 529 int err; 530 531 err = register_qdisc(&prio_qdisc_ops); 532 if (err < 0) 533 return err; 534 err = register_qdisc(&rr_qdisc_ops); 535 if (err < 0) 536 unregister_qdisc(&prio_qdisc_ops); 537 return err; 538 } 539 540 static void __exit prio_module_exit(void) 541 { 542 unregister_qdisc(&prio_qdisc_ops); 543 unregister_qdisc(&rr_qdisc_ops); 544 } 545 546 module_init(prio_module_init) 547 module_exit(prio_module_exit) 548 549 MODULE_LICENSE("GPL"); 550 MODULE_ALIAS("sch_rr"); 551