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 *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 int err; 40 41 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 42 if (TC_H_MAJ(skb->priority) != sch->handle) { 43 err = tc_classify(skb, q->filter_list, &res); 44 #ifdef CONFIG_NET_CLS_ACT 45 switch (err) { 46 case TC_ACT_STOLEN: 47 case TC_ACT_QUEUED: 48 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 49 case TC_ACT_SHOT: 50 return NULL; 51 } 52 #endif 53 if (!q->filter_list || err < 0) { 54 if (TC_H_MAJ(band)) 55 band = 0; 56 return q->queues[q->prio2band[band & TC_PRIO_MAX]]; 57 } 58 band = res.classid; 59 } 60 band = TC_H_MIN(band) - 1; 61 if (band >= q->bands) 62 return q->queues[q->prio2band[0]]; 63 64 return q->queues[band]; 65 } 66 67 static int 68 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch) 69 { 70 struct Qdisc *qdisc; 71 int ret; 72 73 qdisc = prio_classify(skb, sch, &ret); 74 #ifdef CONFIG_NET_CLS_ACT 75 if (qdisc == NULL) { 76 77 if (ret & __NET_XMIT_BYPASS) 78 sch->qstats.drops++; 79 kfree_skb(skb); 80 return ret; 81 } 82 #endif 83 84 ret = qdisc_enqueue(skb, qdisc); 85 if (ret == NET_XMIT_SUCCESS) { 86 sch->q.qlen++; 87 return NET_XMIT_SUCCESS; 88 } 89 if (net_xmit_drop_count(ret)) 90 sch->qstats.drops++; 91 return ret; 92 } 93 94 static struct sk_buff *prio_peek(struct Qdisc *sch) 95 { 96 struct prio_sched_data *q = qdisc_priv(sch); 97 int prio; 98 99 for (prio = 0; prio < q->bands; prio++) { 100 struct Qdisc *qdisc = q->queues[prio]; 101 struct sk_buff *skb = qdisc->ops->peek(qdisc); 102 if (skb) 103 return skb; 104 } 105 return NULL; 106 } 107 108 static struct sk_buff *prio_dequeue(struct Qdisc *sch) 109 { 110 struct prio_sched_data *q = qdisc_priv(sch); 111 int prio; 112 113 for (prio = 0; prio < q->bands; prio++) { 114 struct Qdisc *qdisc = q->queues[prio]; 115 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc); 116 if (skb) { 117 qdisc_bstats_update(sch, skb); 118 sch->q.qlen--; 119 return skb; 120 } 121 } 122 return NULL; 123 124 } 125 126 static unsigned int prio_drop(struct Qdisc *sch) 127 { 128 struct prio_sched_data *q = qdisc_priv(sch); 129 int prio; 130 unsigned int len; 131 struct Qdisc *qdisc; 132 133 for (prio = q->bands-1; prio >= 0; prio--) { 134 qdisc = q->queues[prio]; 135 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) { 136 sch->q.qlen--; 137 return len; 138 } 139 } 140 return 0; 141 } 142 143 144 static void 145 prio_reset(struct Qdisc *sch) 146 { 147 int prio; 148 struct prio_sched_data *q = qdisc_priv(sch); 149 150 for (prio = 0; prio < q->bands; prio++) 151 qdisc_reset(q->queues[prio]); 152 sch->q.qlen = 0; 153 } 154 155 static void 156 prio_destroy(struct Qdisc *sch) 157 { 158 int prio; 159 struct prio_sched_data *q = qdisc_priv(sch); 160 161 tcf_destroy_chain(&q->filter_list); 162 for (prio = 0; prio < q->bands; prio++) 163 qdisc_destroy(q->queues[prio]); 164 } 165 166 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 167 { 168 struct prio_sched_data *q = qdisc_priv(sch); 169 struct tc_prio_qopt *qopt; 170 int i; 171 172 if (nla_len(opt) < sizeof(*qopt)) 173 return -EINVAL; 174 qopt = nla_data(opt); 175 176 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 177 return -EINVAL; 178 179 for (i = 0; i <= TC_PRIO_MAX; i++) { 180 if (qopt->priomap[i] >= qopt->bands) 181 return -EINVAL; 182 } 183 184 sch_tree_lock(sch); 185 q->bands = qopt->bands; 186 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 187 188 for (i = q->bands; i < TCQ_PRIO_BANDS; i++) { 189 struct Qdisc *child = q->queues[i]; 190 q->queues[i] = &noop_qdisc; 191 if (child != &noop_qdisc) { 192 qdisc_tree_decrease_qlen(child, child->q.qlen); 193 qdisc_destroy(child); 194 } 195 } 196 sch_tree_unlock(sch); 197 198 for (i = 0; i < q->bands; i++) { 199 if (q->queues[i] == &noop_qdisc) { 200 struct Qdisc *child, *old; 201 202 child = qdisc_create_dflt(sch->dev_queue, 203 &pfifo_qdisc_ops, 204 TC_H_MAKE(sch->handle, i + 1)); 205 if (child) { 206 sch_tree_lock(sch); 207 old = q->queues[i]; 208 q->queues[i] = child; 209 210 if (old != &noop_qdisc) { 211 qdisc_tree_decrease_qlen(old, 212 old->q.qlen); 213 qdisc_destroy(old); 214 } 215 sch_tree_unlock(sch); 216 } 217 } 218 } 219 return 0; 220 } 221 222 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 223 { 224 struct prio_sched_data *q = qdisc_priv(sch); 225 int i; 226 227 for (i = 0; i < TCQ_PRIO_BANDS; i++) 228 q->queues[i] = &noop_qdisc; 229 230 if (opt == NULL) { 231 return -EINVAL; 232 } else { 233 int err; 234 235 if ((err = prio_tune(sch, opt)) != 0) 236 return err; 237 } 238 return 0; 239 } 240 241 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 242 { 243 struct prio_sched_data *q = qdisc_priv(sch); 244 unsigned char *b = skb_tail_pointer(skb); 245 struct tc_prio_qopt opt; 246 247 opt.bands = q->bands; 248 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 249 250 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 251 goto nla_put_failure; 252 253 return skb->len; 254 255 nla_put_failure: 256 nlmsg_trim(skb, b); 257 return -1; 258 } 259 260 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 261 struct Qdisc **old) 262 { 263 struct prio_sched_data *q = qdisc_priv(sch); 264 unsigned long band = arg - 1; 265 266 if (new == NULL) 267 new = &noop_qdisc; 268 269 sch_tree_lock(sch); 270 *old = q->queues[band]; 271 q->queues[band] = new; 272 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 273 qdisc_reset(*old); 274 sch_tree_unlock(sch); 275 276 return 0; 277 } 278 279 static struct Qdisc * 280 prio_leaf(struct Qdisc *sch, unsigned long arg) 281 { 282 struct prio_sched_data *q = qdisc_priv(sch); 283 unsigned long band = arg - 1; 284 285 return q->queues[band]; 286 } 287 288 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 289 { 290 struct prio_sched_data *q = qdisc_priv(sch); 291 unsigned long band = TC_H_MIN(classid); 292 293 if (band - 1 >= q->bands) 294 return 0; 295 return band; 296 } 297 298 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 299 { 300 return prio_get(sch, classid); 301 } 302 303 304 static void prio_put(struct Qdisc *q, unsigned long cl) 305 { 306 } 307 308 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 309 struct tcmsg *tcm) 310 { 311 struct prio_sched_data *q = qdisc_priv(sch); 312 313 tcm->tcm_handle |= TC_H_MIN(cl); 314 tcm->tcm_info = q->queues[cl-1]->handle; 315 return 0; 316 } 317 318 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 319 struct gnet_dump *d) 320 { 321 struct prio_sched_data *q = qdisc_priv(sch); 322 struct Qdisc *cl_q; 323 324 cl_q = q->queues[cl - 1]; 325 cl_q->qstats.qlen = cl_q->q.qlen; 326 if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 || 327 gnet_stats_copy_queue(d, &cl_q->qstats) < 0) 328 return -1; 329 330 return 0; 331 } 332 333 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 334 { 335 struct prio_sched_data *q = qdisc_priv(sch); 336 int prio; 337 338 if (arg->stop) 339 return; 340 341 for (prio = 0; prio < q->bands; prio++) { 342 if (arg->count < arg->skip) { 343 arg->count++; 344 continue; 345 } 346 if (arg->fn(sch, prio + 1, arg) < 0) { 347 arg->stop = 1; 348 break; 349 } 350 arg->count++; 351 } 352 } 353 354 static struct tcf_proto **prio_find_tcf(struct Qdisc *sch, unsigned long cl) 355 { 356 struct prio_sched_data *q = qdisc_priv(sch); 357 358 if (cl) 359 return NULL; 360 return &q->filter_list; 361 } 362 363 static const struct Qdisc_class_ops prio_class_ops = { 364 .graft = prio_graft, 365 .leaf = prio_leaf, 366 .get = prio_get, 367 .put = prio_put, 368 .walk = prio_walk, 369 .tcf_chain = prio_find_tcf, 370 .bind_tcf = prio_bind, 371 .unbind_tcf = prio_put, 372 .dump = prio_dump_class, 373 .dump_stats = prio_dump_class_stats, 374 }; 375 376 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 377 .next = NULL, 378 .cl_ops = &prio_class_ops, 379 .id = "prio", 380 .priv_size = sizeof(struct prio_sched_data), 381 .enqueue = prio_enqueue, 382 .dequeue = prio_dequeue, 383 .peek = prio_peek, 384 .drop = prio_drop, 385 .init = prio_init, 386 .reset = prio_reset, 387 .destroy = prio_destroy, 388 .change = prio_tune, 389 .dump = prio_dump, 390 .owner = THIS_MODULE, 391 }; 392 393 static int __init prio_module_init(void) 394 { 395 return register_qdisc(&prio_qdisc_ops); 396 } 397 398 static void __exit prio_module_exit(void) 399 { 400 unregister_qdisc(&prio_qdisc_ops); 401 } 402 403 module_init(prio_module_init) 404 module_exit(prio_module_exit) 405 406 MODULE_LICENSE("GPL"); 407