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 unsigned int len = qdisc_pkt_len(skb); 76 struct Qdisc *qdisc; 77 int ret; 78 79 qdisc = prio_classify(skb, sch, &ret); 80 #ifdef CONFIG_NET_CLS_ACT 81 if (qdisc == NULL) { 82 83 if (ret & __NET_XMIT_BYPASS) 84 qdisc_qstats_drop(sch); 85 __qdisc_drop(skb, to_free); 86 return ret; 87 } 88 #endif 89 90 ret = qdisc_enqueue(skb, qdisc, to_free); 91 if (ret == NET_XMIT_SUCCESS) { 92 sch->qstats.backlog += len; 93 sch->q.qlen++; 94 return NET_XMIT_SUCCESS; 95 } 96 if (net_xmit_drop_count(ret)) 97 qdisc_qstats_drop(sch); 98 return ret; 99 } 100 101 static struct sk_buff *prio_peek(struct Qdisc *sch) 102 { 103 struct prio_sched_data *q = qdisc_priv(sch); 104 int prio; 105 106 for (prio = 0; prio < q->bands; prio++) { 107 struct Qdisc *qdisc = q->queues[prio]; 108 struct sk_buff *skb = qdisc->ops->peek(qdisc); 109 if (skb) 110 return skb; 111 } 112 return NULL; 113 } 114 115 static struct sk_buff *prio_dequeue(struct Qdisc *sch) 116 { 117 struct prio_sched_data *q = qdisc_priv(sch); 118 int prio; 119 120 for (prio = 0; prio < q->bands; prio++) { 121 struct Qdisc *qdisc = q->queues[prio]; 122 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc); 123 if (skb) { 124 qdisc_bstats_update(sch, skb); 125 qdisc_qstats_backlog_dec(sch, skb); 126 sch->q.qlen--; 127 return skb; 128 } 129 } 130 return NULL; 131 132 } 133 134 static void 135 prio_reset(struct Qdisc *sch) 136 { 137 int prio; 138 struct prio_sched_data *q = qdisc_priv(sch); 139 140 for (prio = 0; prio < q->bands; prio++) 141 qdisc_reset(q->queues[prio]); 142 sch->qstats.backlog = 0; 143 sch->q.qlen = 0; 144 } 145 146 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt) 147 { 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 (qopt) { 158 opt.command = TC_PRIO_REPLACE; 159 opt.replace_params.bands = qopt->bands; 160 memcpy(&opt.replace_params.priomap, qopt->priomap, 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, NULL); 178 for (prio = 0; prio < q->bands; prio++) 179 qdisc_put(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_put(queues[--i]); 210 return -ENOMEM; 211 } 212 } 213 214 prio_offload(sch, qopt); 215 sch_tree_lock(sch); 216 q->bands = qopt->bands; 217 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 218 219 for (i = q->bands; i < oldbands; i++) 220 qdisc_tree_flush_backlog(q->queues[i]); 221 222 for (i = oldbands; i < q->bands; i++) { 223 q->queues[i] = queues[i]; 224 if (q->queues[i] != &noop_qdisc) 225 qdisc_hash_add(q->queues[i], true); 226 } 227 228 sch_tree_unlock(sch); 229 230 for (i = q->bands; i < oldbands; i++) 231 qdisc_put(q->queues[i]); 232 return 0; 233 } 234 235 static int prio_init(struct Qdisc *sch, struct nlattr *opt, 236 struct netlink_ext_ack *extack) 237 { 238 struct prio_sched_data *q = qdisc_priv(sch); 239 int err; 240 241 if (!opt) 242 return -EINVAL; 243 244 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 245 if (err) 246 return err; 247 248 return prio_tune(sch, opt, extack); 249 } 250 251 static int prio_dump_offload(struct Qdisc *sch) 252 { 253 struct tc_prio_qopt_offload hw_stats = { 254 .command = TC_PRIO_STATS, 255 .handle = sch->handle, 256 .parent = sch->parent, 257 { 258 .stats = { 259 .bstats = &sch->bstats, 260 .qstats = &sch->qstats, 261 }, 262 }, 263 }; 264 265 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_PRIO, &hw_stats); 266 } 267 268 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 269 { 270 struct prio_sched_data *q = qdisc_priv(sch); 271 unsigned char *b = skb_tail_pointer(skb); 272 struct tc_prio_qopt opt; 273 int err; 274 275 opt.bands = q->bands; 276 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 277 278 err = prio_dump_offload(sch); 279 if (err) 280 goto nla_put_failure; 281 282 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 283 goto nla_put_failure; 284 285 return skb->len; 286 287 nla_put_failure: 288 nlmsg_trim(skb, b); 289 return -1; 290 } 291 292 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 293 struct Qdisc **old, struct netlink_ext_ack *extack) 294 { 295 struct prio_sched_data *q = qdisc_priv(sch); 296 struct tc_prio_qopt_offload graft_offload; 297 unsigned long band = arg - 1; 298 299 if (new == NULL) 300 new = &noop_qdisc; 301 302 *old = qdisc_replace(sch, new, &q->queues[band]); 303 304 graft_offload.handle = sch->handle; 305 graft_offload.parent = sch->parent; 306 graft_offload.graft_params.band = band; 307 graft_offload.graft_params.child_handle = new->handle; 308 graft_offload.command = TC_PRIO_GRAFT; 309 310 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old, 311 TC_SETUP_QDISC_PRIO, &graft_offload, 312 extack); 313 return 0; 314 } 315 316 static struct Qdisc * 317 prio_leaf(struct Qdisc *sch, unsigned long arg) 318 { 319 struct prio_sched_data *q = qdisc_priv(sch); 320 unsigned long band = arg - 1; 321 322 return q->queues[band]; 323 } 324 325 static unsigned long prio_find(struct Qdisc *sch, u32 classid) 326 { 327 struct prio_sched_data *q = qdisc_priv(sch); 328 unsigned long band = TC_H_MIN(classid); 329 330 if (band - 1 >= q->bands) 331 return 0; 332 return band; 333 } 334 335 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 336 { 337 return prio_find(sch, classid); 338 } 339 340 341 static void prio_unbind(struct Qdisc *q, unsigned long cl) 342 { 343 } 344 345 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 346 struct tcmsg *tcm) 347 { 348 struct prio_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 prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 356 struct gnet_dump *d) 357 { 358 struct prio_sched_data *q = qdisc_priv(sch); 359 struct Qdisc *cl_q; 360 361 cl_q = q->queues[cl - 1]; 362 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 363 d, NULL, &cl_q->bstats) < 0 || 364 qdisc_qstats_copy(d, cl_q) < 0) 365 return -1; 366 367 return 0; 368 } 369 370 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 371 { 372 struct prio_sched_data *q = qdisc_priv(sch); 373 int prio; 374 375 if (arg->stop) 376 return; 377 378 for (prio = 0; prio < q->bands; prio++) { 379 if (arg->count < arg->skip) { 380 arg->count++; 381 continue; 382 } 383 if (arg->fn(sch, prio + 1, arg) < 0) { 384 arg->stop = 1; 385 break; 386 } 387 arg->count++; 388 } 389 } 390 391 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl, 392 struct netlink_ext_ack *extack) 393 { 394 struct prio_sched_data *q = qdisc_priv(sch); 395 396 if (cl) 397 return NULL; 398 return q->block; 399 } 400 401 static const struct Qdisc_class_ops prio_class_ops = { 402 .graft = prio_graft, 403 .leaf = prio_leaf, 404 .find = prio_find, 405 .walk = prio_walk, 406 .tcf_block = prio_tcf_block, 407 .bind_tcf = prio_bind, 408 .unbind_tcf = prio_unbind, 409 .dump = prio_dump_class, 410 .dump_stats = prio_dump_class_stats, 411 }; 412 413 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 414 .next = NULL, 415 .cl_ops = &prio_class_ops, 416 .id = "prio", 417 .priv_size = sizeof(struct prio_sched_data), 418 .enqueue = prio_enqueue, 419 .dequeue = prio_dequeue, 420 .peek = prio_peek, 421 .init = prio_init, 422 .reset = prio_reset, 423 .destroy = prio_destroy, 424 .change = prio_tune, 425 .dump = prio_dump, 426 .owner = THIS_MODULE, 427 }; 428 429 static int __init prio_module_init(void) 430 { 431 return register_qdisc(&prio_qdisc_ops); 432 } 433 434 static void __exit prio_module_exit(void) 435 { 436 unregister_qdisc(&prio_qdisc_ops); 437 } 438 439 module_init(prio_module_init) 440 module_exit(prio_module_exit) 441 442 MODULE_LICENSE("GPL"); 443