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, bool enable) 146 { 147 struct prio_sched_data *q = qdisc_priv(sch); 148 struct net_device *dev = qdisc_dev(sch); 149 struct tc_prio_qopt_offload opt = { 150 .handle = sch->handle, 151 .parent = sch->parent, 152 }; 153 154 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 155 return -EOPNOTSUPP; 156 157 if (enable) { 158 opt.command = TC_PRIO_REPLACE; 159 opt.replace_params.bands = q->bands; 160 memcpy(&opt.replace_params.priomap, q->prio2band, 161 TC_PRIO_MAX + 1); 162 opt.replace_params.qstats = &sch->qstats; 163 } else { 164 opt.command = TC_PRIO_DESTROY; 165 } 166 167 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt); 168 } 169 170 static void 171 prio_destroy(struct Qdisc *sch) 172 { 173 int prio; 174 struct prio_sched_data *q = qdisc_priv(sch); 175 176 tcf_block_put(q->block); 177 prio_offload(sch, false); 178 for (prio = 0; prio < q->bands; prio++) 179 qdisc_destroy(q->queues[prio]); 180 } 181 182 static int prio_tune(struct Qdisc *sch, struct nlattr *opt, 183 struct netlink_ext_ack *extack) 184 { 185 struct prio_sched_data *q = qdisc_priv(sch); 186 struct Qdisc *queues[TCQ_PRIO_BANDS]; 187 int oldbands = q->bands, i; 188 struct tc_prio_qopt *qopt; 189 190 if (nla_len(opt) < sizeof(*qopt)) 191 return -EINVAL; 192 qopt = nla_data(opt); 193 194 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 195 return -EINVAL; 196 197 for (i = 0; i <= TC_PRIO_MAX; i++) { 198 if (qopt->priomap[i] >= qopt->bands) 199 return -EINVAL; 200 } 201 202 /* Before commit, make sure we can allocate all new qdiscs */ 203 for (i = oldbands; i < qopt->bands; i++) { 204 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, 205 TC_H_MAKE(sch->handle, i + 1), 206 extack); 207 if (!queues[i]) { 208 while (i > oldbands) 209 qdisc_destroy(queues[--i]); 210 return -ENOMEM; 211 } 212 } 213 214 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_destroy(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 prio_offload(sch, true); 234 return 0; 235 } 236 237 static int prio_init(struct Qdisc *sch, struct nlattr *opt, 238 struct netlink_ext_ack *extack) 239 { 240 struct prio_sched_data *q = qdisc_priv(sch); 241 int err; 242 243 if (!opt) 244 return -EINVAL; 245 246 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 247 if (err) 248 return err; 249 250 return prio_tune(sch, opt, extack); 251 } 252 253 static int prio_dump_offload(struct Qdisc *sch) 254 { 255 struct net_device *dev = qdisc_dev(sch); 256 struct tc_prio_qopt_offload hw_stats = { 257 .command = TC_PRIO_STATS, 258 .handle = sch->handle, 259 .parent = sch->parent, 260 { 261 .stats = { 262 .bstats = &sch->bstats, 263 .qstats = &sch->qstats, 264 }, 265 }, 266 }; 267 int err; 268 269 sch->flags &= ~TCQ_F_OFFLOADED; 270 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 271 return 0; 272 273 err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, 274 &hw_stats); 275 if (err == -EOPNOTSUPP) 276 return 0; 277 278 if (!err) 279 sch->flags |= TCQ_F_OFFLOADED; 280 281 return err; 282 } 283 284 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 285 { 286 struct prio_sched_data *q = qdisc_priv(sch); 287 unsigned char *b = skb_tail_pointer(skb); 288 struct tc_prio_qopt opt; 289 int err; 290 291 opt.bands = q->bands; 292 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 293 294 err = prio_dump_offload(sch); 295 if (err) 296 goto nla_put_failure; 297 298 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 299 goto nla_put_failure; 300 301 return skb->len; 302 303 nla_put_failure: 304 nlmsg_trim(skb, b); 305 return -1; 306 } 307 308 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 309 struct Qdisc **old, struct netlink_ext_ack *extack) 310 { 311 struct prio_sched_data *q = qdisc_priv(sch); 312 unsigned long band = arg - 1; 313 314 if (new == NULL) 315 new = &noop_qdisc; 316 317 *old = qdisc_replace(sch, new, &q->queues[band]); 318 return 0; 319 } 320 321 static struct Qdisc * 322 prio_leaf(struct Qdisc *sch, unsigned long arg) 323 { 324 struct prio_sched_data *q = qdisc_priv(sch); 325 unsigned long band = arg - 1; 326 327 return q->queues[band]; 328 } 329 330 static unsigned long prio_find(struct Qdisc *sch, u32 classid) 331 { 332 struct prio_sched_data *q = qdisc_priv(sch); 333 unsigned long band = TC_H_MIN(classid); 334 335 if (band - 1 >= q->bands) 336 return 0; 337 return band; 338 } 339 340 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 341 { 342 return prio_find(sch, classid); 343 } 344 345 346 static void prio_unbind(struct Qdisc *q, unsigned long cl) 347 { 348 } 349 350 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 351 struct tcmsg *tcm) 352 { 353 struct prio_sched_data *q = qdisc_priv(sch); 354 355 tcm->tcm_handle |= TC_H_MIN(cl); 356 tcm->tcm_info = q->queues[cl-1]->handle; 357 return 0; 358 } 359 360 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 361 struct gnet_dump *d) 362 { 363 struct prio_sched_data *q = qdisc_priv(sch); 364 struct Qdisc *cl_q; 365 366 cl_q = q->queues[cl - 1]; 367 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 368 d, NULL, &cl_q->bstats) < 0 || 369 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 370 return -1; 371 372 return 0; 373 } 374 375 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 376 { 377 struct prio_sched_data *q = qdisc_priv(sch); 378 int prio; 379 380 if (arg->stop) 381 return; 382 383 for (prio = 0; prio < q->bands; prio++) { 384 if (arg->count < arg->skip) { 385 arg->count++; 386 continue; 387 } 388 if (arg->fn(sch, prio + 1, arg) < 0) { 389 arg->stop = 1; 390 break; 391 } 392 arg->count++; 393 } 394 } 395 396 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl, 397 struct netlink_ext_ack *extack) 398 { 399 struct prio_sched_data *q = qdisc_priv(sch); 400 401 if (cl) 402 return NULL; 403 return q->block; 404 } 405 406 static const struct Qdisc_class_ops prio_class_ops = { 407 .graft = prio_graft, 408 .leaf = prio_leaf, 409 .find = prio_find, 410 .walk = prio_walk, 411 .tcf_block = prio_tcf_block, 412 .bind_tcf = prio_bind, 413 .unbind_tcf = prio_unbind, 414 .dump = prio_dump_class, 415 .dump_stats = prio_dump_class_stats, 416 }; 417 418 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 419 .next = NULL, 420 .cl_ops = &prio_class_ops, 421 .id = "prio", 422 .priv_size = sizeof(struct prio_sched_data), 423 .enqueue = prio_enqueue, 424 .dequeue = prio_dequeue, 425 .peek = prio_peek, 426 .init = prio_init, 427 .reset = prio_reset, 428 .destroy = prio_destroy, 429 .change = prio_tune, 430 .dump = prio_dump, 431 .owner = THIS_MODULE, 432 }; 433 434 static int __init prio_module_init(void) 435 { 436 return register_qdisc(&prio_qdisc_ops); 437 } 438 439 static void __exit prio_module_exit(void) 440 { 441 unregister_qdisc(&prio_qdisc_ops); 442 } 443 444 module_init(prio_module_init) 445 module_exit(prio_module_exit) 446 447 MODULE_LICENSE("GPL"); 448