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/slab.h> 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/string.h> 19 #include <linux/errno.h> 20 #include <linux/skbuff.h> 21 #include <net/netlink.h> 22 #include <net/pkt_sched.h> 23 #include <net/pkt_cls.h> 24 25 struct prio_sched_data { 26 int bands; 27 struct tcf_proto __rcu *filter_list; 28 struct tcf_block *block; 29 u8 prio2band[TC_PRIO_MAX+1]; 30 struct Qdisc *queues[TCQ_PRIO_BANDS]; 31 }; 32 33 34 static struct Qdisc * 35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 36 { 37 struct prio_sched_data *q = qdisc_priv(sch); 38 u32 band = skb->priority; 39 struct tcf_result res; 40 struct tcf_proto *fl; 41 int err; 42 43 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 44 if (TC_H_MAJ(skb->priority) != sch->handle) { 45 fl = rcu_dereference_bh(q->filter_list); 46 err = tcf_classify(skb, fl, &res, false); 47 #ifdef CONFIG_NET_CLS_ACT 48 switch (err) { 49 case TC_ACT_STOLEN: 50 case TC_ACT_QUEUED: 51 case TC_ACT_TRAP: 52 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 53 /* fall through */ 54 case TC_ACT_SHOT: 55 return NULL; 56 } 57 #endif 58 if (!fl || err < 0) { 59 if (TC_H_MAJ(band)) 60 band = 0; 61 return q->queues[q->prio2band[band & TC_PRIO_MAX]]; 62 } 63 band = res.classid; 64 } 65 band = TC_H_MIN(band) - 1; 66 if (band >= q->bands) 67 return q->queues[q->prio2band[0]]; 68 69 return q->queues[band]; 70 } 71 72 static int 73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) 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 qdisc_qstats_drop(sch); 84 __qdisc_drop(skb, to_free); 85 return ret; 86 } 87 #endif 88 89 ret = qdisc_enqueue(skb, qdisc, to_free); 90 if (ret == NET_XMIT_SUCCESS) { 91 qdisc_qstats_backlog_inc(sch, skb); 92 sch->q.qlen++; 93 return NET_XMIT_SUCCESS; 94 } 95 if (net_xmit_drop_count(ret)) 96 qdisc_qstats_drop(sch); 97 return ret; 98 } 99 100 static struct sk_buff *prio_peek(struct Qdisc *sch) 101 { 102 struct prio_sched_data *q = qdisc_priv(sch); 103 int prio; 104 105 for (prio = 0; prio < q->bands; prio++) { 106 struct Qdisc *qdisc = q->queues[prio]; 107 struct sk_buff *skb = qdisc->ops->peek(qdisc); 108 if (skb) 109 return skb; 110 } 111 return NULL; 112 } 113 114 static struct sk_buff *prio_dequeue(struct Qdisc *sch) 115 { 116 struct prio_sched_data *q = qdisc_priv(sch); 117 int prio; 118 119 for (prio = 0; prio < q->bands; prio++) { 120 struct Qdisc *qdisc = q->queues[prio]; 121 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc); 122 if (skb) { 123 qdisc_bstats_update(sch, skb); 124 qdisc_qstats_backlog_dec(sch, skb); 125 sch->q.qlen--; 126 return skb; 127 } 128 } 129 return NULL; 130 131 } 132 133 static void 134 prio_reset(struct Qdisc *sch) 135 { 136 int prio; 137 struct prio_sched_data *q = qdisc_priv(sch); 138 139 for (prio = 0; prio < q->bands; prio++) 140 qdisc_reset(q->queues[prio]); 141 sch->qstats.backlog = 0; 142 sch->q.qlen = 0; 143 } 144 145 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt) 146 { 147 struct net_device *dev = qdisc_dev(sch); 148 struct tc_prio_qopt_offload opt = { 149 .handle = sch->handle, 150 .parent = sch->parent, 151 }; 152 153 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 154 return -EOPNOTSUPP; 155 156 if (qopt) { 157 opt.command = TC_PRIO_REPLACE; 158 opt.replace_params.bands = qopt->bands; 159 memcpy(&opt.replace_params.priomap, qopt->priomap, 160 TC_PRIO_MAX + 1); 161 opt.replace_params.qstats = &sch->qstats; 162 } else { 163 opt.command = TC_PRIO_DESTROY; 164 } 165 166 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt); 167 } 168 169 static void 170 prio_destroy(struct Qdisc *sch) 171 { 172 int prio; 173 struct prio_sched_data *q = qdisc_priv(sch); 174 175 tcf_block_put(q->block); 176 prio_offload(sch, NULL); 177 for (prio = 0; prio < q->bands; prio++) 178 qdisc_put(q->queues[prio]); 179 } 180 181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt, 182 struct netlink_ext_ack *extack) 183 { 184 struct prio_sched_data *q = qdisc_priv(sch); 185 struct Qdisc *queues[TCQ_PRIO_BANDS]; 186 int oldbands = q->bands, i; 187 struct tc_prio_qopt *qopt; 188 189 if (nla_len(opt) < sizeof(*qopt)) 190 return -EINVAL; 191 qopt = nla_data(opt); 192 193 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 194 return -EINVAL; 195 196 for (i = 0; i <= TC_PRIO_MAX; i++) { 197 if (qopt->priomap[i] >= qopt->bands) 198 return -EINVAL; 199 } 200 201 /* Before commit, make sure we can allocate all new qdiscs */ 202 for (i = oldbands; i < qopt->bands; i++) { 203 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, 204 TC_H_MAKE(sch->handle, i + 1), 205 extack); 206 if (!queues[i]) { 207 while (i > oldbands) 208 qdisc_put(queues[--i]); 209 return -ENOMEM; 210 } 211 } 212 213 prio_offload(sch, qopt); 214 sch_tree_lock(sch); 215 q->bands = qopt->bands; 216 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 217 218 for (i = q->bands; i < oldbands; i++) { 219 struct Qdisc *child = q->queues[i]; 220 221 qdisc_tree_reduce_backlog(child, child->q.qlen, 222 child->qstats.backlog); 223 qdisc_put(child); 224 } 225 226 for (i = oldbands; i < q->bands; i++) { 227 q->queues[i] = queues[i]; 228 if (q->queues[i] != &noop_qdisc) 229 qdisc_hash_add(q->queues[i], true); 230 } 231 232 sch_tree_unlock(sch); 233 return 0; 234 } 235 236 static int prio_init(struct Qdisc *sch, struct nlattr *opt, 237 struct netlink_ext_ack *extack) 238 { 239 struct prio_sched_data *q = qdisc_priv(sch); 240 int err; 241 242 if (!opt) 243 return -EINVAL; 244 245 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 246 if (err) 247 return err; 248 249 return prio_tune(sch, opt, extack); 250 } 251 252 static int prio_dump_offload(struct Qdisc *sch) 253 { 254 struct net_device *dev = qdisc_dev(sch); 255 struct tc_prio_qopt_offload hw_stats = { 256 .command = TC_PRIO_STATS, 257 .handle = sch->handle, 258 .parent = sch->parent, 259 { 260 .stats = { 261 .bstats = &sch->bstats, 262 .qstats = &sch->qstats, 263 }, 264 }, 265 }; 266 int err; 267 268 sch->flags &= ~TCQ_F_OFFLOADED; 269 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 270 return 0; 271 272 err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, 273 &hw_stats); 274 if (err == -EOPNOTSUPP) 275 return 0; 276 277 if (!err) 278 sch->flags |= TCQ_F_OFFLOADED; 279 280 return err; 281 } 282 283 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 284 { 285 struct prio_sched_data *q = qdisc_priv(sch); 286 unsigned char *b = skb_tail_pointer(skb); 287 struct tc_prio_qopt opt; 288 int err; 289 290 opt.bands = q->bands; 291 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 292 293 err = prio_dump_offload(sch); 294 if (err) 295 goto nla_put_failure; 296 297 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 298 goto nla_put_failure; 299 300 return skb->len; 301 302 nla_put_failure: 303 nlmsg_trim(skb, b); 304 return -1; 305 } 306 307 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 308 struct Qdisc **old, struct netlink_ext_ack *extack) 309 { 310 struct prio_sched_data *q = qdisc_priv(sch); 311 struct tc_prio_qopt_offload graft_offload; 312 struct net_device *dev = qdisc_dev(sch); 313 unsigned long band = arg - 1; 314 bool any_qdisc_is_offloaded; 315 int err; 316 317 if (new == NULL) 318 new = &noop_qdisc; 319 320 *old = qdisc_replace(sch, new, &q->queues[band]); 321 322 if (!tc_can_offload(dev)) 323 return 0; 324 325 graft_offload.handle = sch->handle; 326 graft_offload.parent = sch->parent; 327 graft_offload.graft_params.band = band; 328 graft_offload.graft_params.child_handle = new->handle; 329 graft_offload.command = TC_PRIO_GRAFT; 330 331 err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, 332 &graft_offload); 333 334 /* Don't report error if the graft is part of destroy operation. */ 335 if (err && new != &noop_qdisc) { 336 /* Don't report error if the parent, the old child and the new 337 * one are not offloaded. 338 */ 339 any_qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED; 340 any_qdisc_is_offloaded |= new->flags & TCQ_F_OFFLOADED; 341 if (*old) 342 any_qdisc_is_offloaded |= (*old)->flags & 343 TCQ_F_OFFLOADED; 344 345 if (any_qdisc_is_offloaded) 346 NL_SET_ERR_MSG(extack, "Offloading graft operation failed."); 347 } 348 349 return 0; 350 } 351 352 static struct Qdisc * 353 prio_leaf(struct Qdisc *sch, unsigned long arg) 354 { 355 struct prio_sched_data *q = qdisc_priv(sch); 356 unsigned long band = arg - 1; 357 358 return q->queues[band]; 359 } 360 361 static unsigned long prio_find(struct Qdisc *sch, u32 classid) 362 { 363 struct prio_sched_data *q = qdisc_priv(sch); 364 unsigned long band = TC_H_MIN(classid); 365 366 if (band - 1 >= q->bands) 367 return 0; 368 return band; 369 } 370 371 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 372 { 373 return prio_find(sch, classid); 374 } 375 376 377 static void prio_unbind(struct Qdisc *q, unsigned long cl) 378 { 379 } 380 381 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 382 struct tcmsg *tcm) 383 { 384 struct prio_sched_data *q = qdisc_priv(sch); 385 386 tcm->tcm_handle |= TC_H_MIN(cl); 387 tcm->tcm_info = q->queues[cl-1]->handle; 388 return 0; 389 } 390 391 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 392 struct gnet_dump *d) 393 { 394 struct prio_sched_data *q = qdisc_priv(sch); 395 struct Qdisc *cl_q; 396 397 cl_q = q->queues[cl - 1]; 398 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 399 d, NULL, &cl_q->bstats) < 0 || 400 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 401 return -1; 402 403 return 0; 404 } 405 406 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 407 { 408 struct prio_sched_data *q = qdisc_priv(sch); 409 int prio; 410 411 if (arg->stop) 412 return; 413 414 for (prio = 0; prio < q->bands; prio++) { 415 if (arg->count < arg->skip) { 416 arg->count++; 417 continue; 418 } 419 if (arg->fn(sch, prio + 1, arg) < 0) { 420 arg->stop = 1; 421 break; 422 } 423 arg->count++; 424 } 425 } 426 427 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl, 428 struct netlink_ext_ack *extack) 429 { 430 struct prio_sched_data *q = qdisc_priv(sch); 431 432 if (cl) 433 return NULL; 434 return q->block; 435 } 436 437 static const struct Qdisc_class_ops prio_class_ops = { 438 .graft = prio_graft, 439 .leaf = prio_leaf, 440 .find = prio_find, 441 .walk = prio_walk, 442 .tcf_block = prio_tcf_block, 443 .bind_tcf = prio_bind, 444 .unbind_tcf = prio_unbind, 445 .dump = prio_dump_class, 446 .dump_stats = prio_dump_class_stats, 447 }; 448 449 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 450 .next = NULL, 451 .cl_ops = &prio_class_ops, 452 .id = "prio", 453 .priv_size = sizeof(struct prio_sched_data), 454 .enqueue = prio_enqueue, 455 .dequeue = prio_dequeue, 456 .peek = prio_peek, 457 .init = prio_init, 458 .reset = prio_reset, 459 .destroy = prio_destroy, 460 .change = prio_tune, 461 .dump = prio_dump, 462 .owner = THIS_MODULE, 463 }; 464 465 static int __init prio_module_init(void) 466 { 467 return register_qdisc(&prio_qdisc_ops); 468 } 469 470 static void __exit prio_module_exit(void) 471 { 472 unregister_qdisc(&prio_qdisc_ops); 473 } 474 475 module_init(prio_module_init) 476 module_exit(prio_module_exit) 477 478 MODULE_LICENSE("GPL"); 479