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 24 25 struct prio_sched_data { 26 int bands; 27 struct tcf_proto __rcu *filter_list; 28 u8 prio2band[TC_PRIO_MAX+1]; 29 struct Qdisc *queues[TCQ_PRIO_BANDS]; 30 }; 31 32 33 static struct Qdisc * 34 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 35 { 36 struct prio_sched_data *q = qdisc_priv(sch); 37 u32 band = skb->priority; 38 struct tcf_result res; 39 struct tcf_proto *fl; 40 int err; 41 42 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 43 if (TC_H_MAJ(skb->priority) != sch->handle) { 44 fl = rcu_dereference_bh(q->filter_list); 45 err = tc_classify(skb, fl, &res, false); 46 #ifdef CONFIG_NET_CLS_ACT 47 switch (err) { 48 case TC_ACT_STOLEN: 49 case TC_ACT_QUEUED: 50 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 51 case TC_ACT_SHOT: 52 return NULL; 53 } 54 #endif 55 if (!fl || err < 0) { 56 if (TC_H_MAJ(band)) 57 band = 0; 58 return q->queues[q->prio2band[band & TC_PRIO_MAX]]; 59 } 60 band = res.classid; 61 } 62 band = TC_H_MIN(band) - 1; 63 if (band >= q->bands) 64 return q->queues[q->prio2band[0]]; 65 66 return q->queues[band]; 67 } 68 69 static int 70 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch) 71 { 72 struct Qdisc *qdisc; 73 int ret; 74 75 qdisc = prio_classify(skb, sch, &ret); 76 #ifdef CONFIG_NET_CLS_ACT 77 if (qdisc == NULL) { 78 79 if (ret & __NET_XMIT_BYPASS) 80 qdisc_qstats_drop(sch); 81 kfree_skb(skb); 82 return ret; 83 } 84 #endif 85 86 ret = qdisc_enqueue(skb, qdisc); 87 if (ret == NET_XMIT_SUCCESS) { 88 sch->q.qlen++; 89 return NET_XMIT_SUCCESS; 90 } 91 if (net_xmit_drop_count(ret)) 92 qdisc_qstats_drop(sch); 93 return ret; 94 } 95 96 static struct sk_buff *prio_peek(struct Qdisc *sch) 97 { 98 struct prio_sched_data *q = qdisc_priv(sch); 99 int prio; 100 101 for (prio = 0; prio < q->bands; prio++) { 102 struct Qdisc *qdisc = q->queues[prio]; 103 struct sk_buff *skb = qdisc->ops->peek(qdisc); 104 if (skb) 105 return skb; 106 } 107 return NULL; 108 } 109 110 static struct sk_buff *prio_dequeue(struct Qdisc *sch) 111 { 112 struct prio_sched_data *q = qdisc_priv(sch); 113 int prio; 114 115 for (prio = 0; prio < q->bands; prio++) { 116 struct Qdisc *qdisc = q->queues[prio]; 117 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc); 118 if (skb) { 119 qdisc_bstats_update(sch, skb); 120 sch->q.qlen--; 121 return skb; 122 } 123 } 124 return NULL; 125 126 } 127 128 static unsigned int prio_drop(struct Qdisc *sch) 129 { 130 struct prio_sched_data *q = qdisc_priv(sch); 131 int prio; 132 unsigned int len; 133 struct Qdisc *qdisc; 134 135 for (prio = q->bands-1; prio >= 0; prio--) { 136 qdisc = q->queues[prio]; 137 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) { 138 sch->q.qlen--; 139 return len; 140 } 141 } 142 return 0; 143 } 144 145 146 static void 147 prio_reset(struct Qdisc *sch) 148 { 149 int prio; 150 struct prio_sched_data *q = qdisc_priv(sch); 151 152 for (prio = 0; prio < q->bands; prio++) 153 qdisc_reset(q->queues[prio]); 154 sch->q.qlen = 0; 155 } 156 157 static void 158 prio_destroy(struct Qdisc *sch) 159 { 160 int prio; 161 struct prio_sched_data *q = qdisc_priv(sch); 162 163 tcf_destroy_chain(&q->filter_list); 164 for (prio = 0; prio < q->bands; prio++) 165 qdisc_destroy(q->queues[prio]); 166 } 167 168 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 169 { 170 struct prio_sched_data *q = qdisc_priv(sch); 171 struct tc_prio_qopt *qopt; 172 int i; 173 174 if (nla_len(opt) < sizeof(*qopt)) 175 return -EINVAL; 176 qopt = nla_data(opt); 177 178 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 179 return -EINVAL; 180 181 for (i = 0; i <= TC_PRIO_MAX; i++) { 182 if (qopt->priomap[i] >= qopt->bands) 183 return -EINVAL; 184 } 185 186 sch_tree_lock(sch); 187 q->bands = qopt->bands; 188 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 189 190 for (i = q->bands; i < TCQ_PRIO_BANDS; i++) { 191 struct Qdisc *child = q->queues[i]; 192 q->queues[i] = &noop_qdisc; 193 if (child != &noop_qdisc) { 194 qdisc_tree_reduce_backlog(child, child->q.qlen, child->qstats.backlog); 195 qdisc_destroy(child); 196 } 197 } 198 sch_tree_unlock(sch); 199 200 for (i = 0; i < q->bands; i++) { 201 if (q->queues[i] == &noop_qdisc) { 202 struct Qdisc *child, *old; 203 204 child = qdisc_create_dflt(sch->dev_queue, 205 &pfifo_qdisc_ops, 206 TC_H_MAKE(sch->handle, i + 1)); 207 if (child) { 208 sch_tree_lock(sch); 209 old = q->queues[i]; 210 q->queues[i] = child; 211 212 if (old != &noop_qdisc) { 213 qdisc_tree_reduce_backlog(old, 214 old->q.qlen, 215 old->qstats.backlog); 216 qdisc_destroy(old); 217 } 218 sch_tree_unlock(sch); 219 } 220 } 221 } 222 return 0; 223 } 224 225 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 226 { 227 struct prio_sched_data *q = qdisc_priv(sch); 228 int i; 229 230 for (i = 0; i < TCQ_PRIO_BANDS; i++) 231 q->queues[i] = &noop_qdisc; 232 233 if (opt == NULL) { 234 return -EINVAL; 235 } else { 236 int err; 237 238 if ((err = prio_tune(sch, opt)) != 0) 239 return err; 240 } 241 return 0; 242 } 243 244 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 245 { 246 struct prio_sched_data *q = qdisc_priv(sch); 247 unsigned char *b = skb_tail_pointer(skb); 248 struct tc_prio_qopt opt; 249 250 opt.bands = q->bands; 251 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 252 253 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 254 goto nla_put_failure; 255 256 return skb->len; 257 258 nla_put_failure: 259 nlmsg_trim(skb, b); 260 return -1; 261 } 262 263 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 264 struct Qdisc **old) 265 { 266 struct prio_sched_data *q = qdisc_priv(sch); 267 unsigned long band = arg - 1; 268 269 if (new == NULL) 270 new = &noop_qdisc; 271 272 *old = qdisc_replace(sch, new, &q->queues[band]); 273 return 0; 274 } 275 276 static struct Qdisc * 277 prio_leaf(struct Qdisc *sch, unsigned long arg) 278 { 279 struct prio_sched_data *q = qdisc_priv(sch); 280 unsigned long band = arg - 1; 281 282 return q->queues[band]; 283 } 284 285 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 286 { 287 struct prio_sched_data *q = qdisc_priv(sch); 288 unsigned long band = TC_H_MIN(classid); 289 290 if (band - 1 >= q->bands) 291 return 0; 292 return band; 293 } 294 295 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 296 { 297 return prio_get(sch, classid); 298 } 299 300 301 static void prio_put(struct Qdisc *q, unsigned long cl) 302 { 303 } 304 305 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 306 struct tcmsg *tcm) 307 { 308 struct prio_sched_data *q = qdisc_priv(sch); 309 310 tcm->tcm_handle |= TC_H_MIN(cl); 311 tcm->tcm_info = q->queues[cl-1]->handle; 312 return 0; 313 } 314 315 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 316 struct gnet_dump *d) 317 { 318 struct prio_sched_data *q = qdisc_priv(sch); 319 struct Qdisc *cl_q; 320 321 cl_q = q->queues[cl - 1]; 322 if (gnet_stats_copy_basic(d, NULL, &cl_q->bstats) < 0 || 323 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 324 return -1; 325 326 return 0; 327 } 328 329 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 330 { 331 struct prio_sched_data *q = qdisc_priv(sch); 332 int prio; 333 334 if (arg->stop) 335 return; 336 337 for (prio = 0; prio < q->bands; prio++) { 338 if (arg->count < arg->skip) { 339 arg->count++; 340 continue; 341 } 342 if (arg->fn(sch, prio + 1, arg) < 0) { 343 arg->stop = 1; 344 break; 345 } 346 arg->count++; 347 } 348 } 349 350 static struct tcf_proto __rcu **prio_find_tcf(struct Qdisc *sch, 351 unsigned long cl) 352 { 353 struct prio_sched_data *q = qdisc_priv(sch); 354 355 if (cl) 356 return NULL; 357 return &q->filter_list; 358 } 359 360 static const struct Qdisc_class_ops prio_class_ops = { 361 .graft = prio_graft, 362 .leaf = prio_leaf, 363 .get = prio_get, 364 .put = prio_put, 365 .walk = prio_walk, 366 .tcf_chain = prio_find_tcf, 367 .bind_tcf = prio_bind, 368 .unbind_tcf = prio_put, 369 .dump = prio_dump_class, 370 .dump_stats = prio_dump_class_stats, 371 }; 372 373 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 374 .next = NULL, 375 .cl_ops = &prio_class_ops, 376 .id = "prio", 377 .priv_size = sizeof(struct prio_sched_data), 378 .enqueue = prio_enqueue, 379 .dequeue = prio_dequeue, 380 .peek = prio_peek, 381 .drop = prio_drop, 382 .init = prio_init, 383 .reset = prio_reset, 384 .destroy = prio_destroy, 385 .change = prio_tune, 386 .dump = prio_dump, 387 .owner = THIS_MODULE, 388 }; 389 390 static int __init prio_module_init(void) 391 { 392 return register_qdisc(&prio_qdisc_ops); 393 } 394 395 static void __exit prio_module_exit(void) 396 { 397 unregister_qdisc(&prio_qdisc_ops); 398 } 399 400 module_init(prio_module_init) 401 module_exit(prio_module_exit) 402 403 MODULE_LICENSE("GPL"); 404