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 { 27 int bands; 28 struct tcf_proto *filter_list; 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 int err; 41 42 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 43 if (TC_H_MAJ(skb->priority) != sch->handle) { 44 err = tc_classify(skb, q->filter_list, &res); 45 #ifdef CONFIG_NET_CLS_ACT 46 switch (err) { 47 case TC_ACT_STOLEN: 48 case TC_ACT_QUEUED: 49 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 50 case TC_ACT_SHOT: 51 return NULL; 52 } 53 #endif 54 if (!q->filter_list || err < 0) { 55 if (TC_H_MAJ(band)) 56 band = 0; 57 return q->queues[q->prio2band[band&TC_PRIO_MAX]]; 58 } 59 band = res.classid; 60 } 61 band = TC_H_MIN(band) - 1; 62 if (band >= q->bands) 63 return q->queues[q->prio2band[0]]; 64 65 return q->queues[band]; 66 } 67 68 static int 69 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch) 70 { 71 struct Qdisc *qdisc; 72 int ret; 73 74 qdisc = prio_classify(skb, sch, &ret); 75 #ifdef CONFIG_NET_CLS_ACT 76 if (qdisc == NULL) { 77 78 if (ret & __NET_XMIT_BYPASS) 79 sch->qstats.drops++; 80 kfree_skb(skb); 81 return ret; 82 } 83 #endif 84 85 ret = qdisc_enqueue(skb, qdisc); 86 if (ret == NET_XMIT_SUCCESS) { 87 sch->q.qlen++; 88 return NET_XMIT_SUCCESS; 89 } 90 if (net_xmit_drop_count(ret)) 91 sch->qstats.drops++; 92 return ret; 93 } 94 95 static struct sk_buff *prio_peek(struct Qdisc *sch) 96 { 97 struct prio_sched_data *q = qdisc_priv(sch); 98 int prio; 99 100 for (prio = 0; prio < q->bands; prio++) { 101 struct Qdisc *qdisc = q->queues[prio]; 102 struct sk_buff *skb = qdisc->ops->peek(qdisc); 103 if (skb) 104 return skb; 105 } 106 return NULL; 107 } 108 109 static struct sk_buff *prio_dequeue(struct Qdisc* sch) 110 { 111 struct prio_sched_data *q = qdisc_priv(sch); 112 int prio; 113 114 for (prio = 0; prio < q->bands; prio++) { 115 struct Qdisc *qdisc = q->queues[prio]; 116 struct sk_buff *skb = qdisc->dequeue(qdisc); 117 if (skb) { 118 qdisc_bstats_update(sch, skb); 119 sch->q.qlen--; 120 return skb; 121 } 122 } 123 return NULL; 124 125 } 126 127 static unsigned int prio_drop(struct Qdisc* sch) 128 { 129 struct prio_sched_data *q = qdisc_priv(sch); 130 int prio; 131 unsigned int len; 132 struct Qdisc *qdisc; 133 134 for (prio = q->bands-1; prio >= 0; prio--) { 135 qdisc = q->queues[prio]; 136 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) { 137 sch->q.qlen--; 138 return len; 139 } 140 } 141 return 0; 142 } 143 144 145 static void 146 prio_reset(struct Qdisc* sch) 147 { 148 int prio; 149 struct prio_sched_data *q = qdisc_priv(sch); 150 151 for (prio=0; prio<q->bands; prio++) 152 qdisc_reset(q->queues[prio]); 153 sch->q.qlen = 0; 154 } 155 156 static void 157 prio_destroy(struct Qdisc* sch) 158 { 159 int prio; 160 struct prio_sched_data *q = qdisc_priv(sch); 161 162 tcf_destroy_chain(&q->filter_list); 163 for (prio=0; prio<q->bands; prio++) 164 qdisc_destroy(q->queues[prio]); 165 } 166 167 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 168 { 169 struct prio_sched_data *q = qdisc_priv(sch); 170 struct tc_prio_qopt *qopt; 171 int i; 172 173 if (nla_len(opt) < sizeof(*qopt)) 174 return -EINVAL; 175 qopt = nla_data(opt); 176 177 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 178 return -EINVAL; 179 180 for (i=0; i<=TC_PRIO_MAX; i++) { 181 if (qopt->priomap[i] >= qopt->bands) 182 return -EINVAL; 183 } 184 185 sch_tree_lock(sch); 186 q->bands = qopt->bands; 187 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 188 189 for (i=q->bands; i<TCQ_PRIO_BANDS; i++) { 190 struct Qdisc *child = q->queues[i]; 191 q->queues[i] = &noop_qdisc; 192 if (child != &noop_qdisc) { 193 qdisc_tree_decrease_qlen(child, child->q.qlen); 194 qdisc_destroy(child); 195 } 196 } 197 sch_tree_unlock(sch); 198 199 for (i=0; i<q->bands; i++) { 200 if (q->queues[i] == &noop_qdisc) { 201 struct Qdisc *child, *old; 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 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); 251 252 return skb->len; 253 254 nla_put_failure: 255 nlmsg_trim(skb, b); 256 return -1; 257 } 258 259 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 260 struct Qdisc **old) 261 { 262 struct prio_sched_data *q = qdisc_priv(sch); 263 unsigned long band = arg - 1; 264 265 if (new == NULL) 266 new = &noop_qdisc; 267 268 sch_tree_lock(sch); 269 *old = q->queues[band]; 270 q->queues[band] = new; 271 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 272 qdisc_reset(*old); 273 sch_tree_unlock(sch); 274 275 return 0; 276 } 277 278 static struct Qdisc * 279 prio_leaf(struct Qdisc *sch, unsigned long arg) 280 { 281 struct prio_sched_data *q = qdisc_priv(sch); 282 unsigned long band = arg - 1; 283 284 return q->queues[band]; 285 } 286 287 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 288 { 289 struct prio_sched_data *q = qdisc_priv(sch); 290 unsigned long band = TC_H_MIN(classid); 291 292 if (band - 1 >= q->bands) 293 return 0; 294 return band; 295 } 296 297 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 298 { 299 return prio_get(sch, classid); 300 } 301 302 303 static void prio_put(struct Qdisc *q, unsigned long cl) 304 { 305 } 306 307 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 308 struct tcmsg *tcm) 309 { 310 struct prio_sched_data *q = qdisc_priv(sch); 311 312 tcm->tcm_handle |= TC_H_MIN(cl); 313 tcm->tcm_info = q->queues[cl-1]->handle; 314 return 0; 315 } 316 317 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 318 struct gnet_dump *d) 319 { 320 struct prio_sched_data *q = qdisc_priv(sch); 321 struct Qdisc *cl_q; 322 323 cl_q = q->queues[cl - 1]; 324 cl_q->qstats.qlen = cl_q->q.qlen; 325 if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 || 326 gnet_stats_copy_queue(d, &cl_q->qstats) < 0) 327 return -1; 328 329 return 0; 330 } 331 332 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 333 { 334 struct prio_sched_data *q = qdisc_priv(sch); 335 int prio; 336 337 if (arg->stop) 338 return; 339 340 for (prio = 0; prio < q->bands; prio++) { 341 if (arg->count < arg->skip) { 342 arg->count++; 343 continue; 344 } 345 if (arg->fn(sch, prio+1, arg) < 0) { 346 arg->stop = 1; 347 break; 348 } 349 arg->count++; 350 } 351 } 352 353 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl) 354 { 355 struct prio_sched_data *q = qdisc_priv(sch); 356 357 if (cl) 358 return NULL; 359 return &q->filter_list; 360 } 361 362 static const struct Qdisc_class_ops prio_class_ops = { 363 .graft = prio_graft, 364 .leaf = prio_leaf, 365 .get = prio_get, 366 .put = prio_put, 367 .walk = prio_walk, 368 .tcf_chain = prio_find_tcf, 369 .bind_tcf = prio_bind, 370 .unbind_tcf = prio_put, 371 .dump = prio_dump_class, 372 .dump_stats = prio_dump_class_stats, 373 }; 374 375 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 376 .next = NULL, 377 .cl_ops = &prio_class_ops, 378 .id = "prio", 379 .priv_size = sizeof(struct prio_sched_data), 380 .enqueue = prio_enqueue, 381 .dequeue = prio_dequeue, 382 .peek = prio_peek, 383 .drop = prio_drop, 384 .init = prio_init, 385 .reset = prio_reset, 386 .destroy = prio_destroy, 387 .change = prio_tune, 388 .dump = prio_dump, 389 .owner = THIS_MODULE, 390 }; 391 392 static int __init prio_module_init(void) 393 { 394 return register_qdisc(&prio_qdisc_ops); 395 } 396 397 static void __exit prio_module_exit(void) 398 { 399 unregister_qdisc(&prio_qdisc_ops); 400 } 401 402 module_init(prio_module_init) 403 module_exit(prio_module_exit) 404 405 MODULE_LICENSE("GPL"); 406