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 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, struct sk_buff **to_free) 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, to_free); 87 if (ret == NET_XMIT_SUCCESS) { 88 qdisc_qstats_backlog_inc(sch, skb); 89 sch->q.qlen++; 90 return NET_XMIT_SUCCESS; 91 } 92 if (net_xmit_drop_count(ret)) 93 qdisc_qstats_drop(sch); 94 return ret; 95 } 96 97 static struct sk_buff *prio_peek(struct Qdisc *sch) 98 { 99 struct prio_sched_data *q = qdisc_priv(sch); 100 int prio; 101 102 for (prio = 0; prio < q->bands; prio++) { 103 struct Qdisc *qdisc = q->queues[prio]; 104 struct sk_buff *skb = qdisc->ops->peek(qdisc); 105 if (skb) 106 return skb; 107 } 108 return NULL; 109 } 110 111 static struct sk_buff *prio_dequeue(struct Qdisc *sch) 112 { 113 struct prio_sched_data *q = qdisc_priv(sch); 114 int prio; 115 116 for (prio = 0; prio < q->bands; prio++) { 117 struct Qdisc *qdisc = q->queues[prio]; 118 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc); 119 if (skb) { 120 qdisc_bstats_update(sch, skb); 121 qdisc_qstats_backlog_dec(sch, skb); 122 sch->q.qlen--; 123 return skb; 124 } 125 } 126 return NULL; 127 128 } 129 130 static void 131 prio_reset(struct Qdisc *sch) 132 { 133 int prio; 134 struct prio_sched_data *q = qdisc_priv(sch); 135 136 for (prio = 0; prio < q->bands; prio++) 137 qdisc_reset(q->queues[prio]); 138 sch->qstats.backlog = 0; 139 sch->q.qlen = 0; 140 } 141 142 static void 143 prio_destroy(struct Qdisc *sch) 144 { 145 int prio; 146 struct prio_sched_data *q = qdisc_priv(sch); 147 148 tcf_destroy_chain(&q->filter_list); 149 for (prio = 0; prio < q->bands; prio++) 150 qdisc_destroy(q->queues[prio]); 151 } 152 153 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 154 { 155 struct prio_sched_data *q = qdisc_priv(sch); 156 struct Qdisc *queues[TCQ_PRIO_BANDS]; 157 int oldbands = q->bands, i; 158 struct tc_prio_qopt *qopt; 159 160 if (nla_len(opt) < sizeof(*qopt)) 161 return -EINVAL; 162 qopt = nla_data(opt); 163 164 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 165 return -EINVAL; 166 167 for (i = 0; i <= TC_PRIO_MAX; i++) { 168 if (qopt->priomap[i] >= qopt->bands) 169 return -EINVAL; 170 } 171 172 /* Before commit, make sure we can allocate all new qdiscs */ 173 for (i = oldbands; i < qopt->bands; i++) { 174 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, 175 TC_H_MAKE(sch->handle, i + 1)); 176 if (!queues[i]) { 177 while (i > oldbands) 178 qdisc_destroy(queues[--i]); 179 return -ENOMEM; 180 } 181 } 182 183 sch_tree_lock(sch); 184 q->bands = qopt->bands; 185 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 186 187 for (i = q->bands; i < oldbands; i++) { 188 struct Qdisc *child = q->queues[i]; 189 190 qdisc_tree_reduce_backlog(child, child->q.qlen, 191 child->qstats.backlog); 192 qdisc_destroy(child); 193 } 194 195 for (i = oldbands; i < q->bands; i++) { 196 q->queues[i] = queues[i]; 197 if (q->queues[i] != &noop_qdisc) 198 qdisc_hash_add(q->queues[i], true); 199 } 200 201 sch_tree_unlock(sch); 202 return 0; 203 } 204 205 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 206 { 207 if (!opt) 208 return -EINVAL; 209 210 return prio_tune(sch, opt); 211 } 212 213 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 214 { 215 struct prio_sched_data *q = qdisc_priv(sch); 216 unsigned char *b = skb_tail_pointer(skb); 217 struct tc_prio_qopt opt; 218 219 opt.bands = q->bands; 220 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 221 222 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 223 goto nla_put_failure; 224 225 return skb->len; 226 227 nla_put_failure: 228 nlmsg_trim(skb, b); 229 return -1; 230 } 231 232 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 233 struct Qdisc **old) 234 { 235 struct prio_sched_data *q = qdisc_priv(sch); 236 unsigned long band = arg - 1; 237 238 if (new == NULL) 239 new = &noop_qdisc; 240 241 *old = qdisc_replace(sch, new, &q->queues[band]); 242 return 0; 243 } 244 245 static struct Qdisc * 246 prio_leaf(struct Qdisc *sch, unsigned long arg) 247 { 248 struct prio_sched_data *q = qdisc_priv(sch); 249 unsigned long band = arg - 1; 250 251 return q->queues[band]; 252 } 253 254 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 255 { 256 struct prio_sched_data *q = qdisc_priv(sch); 257 unsigned long band = TC_H_MIN(classid); 258 259 if (band - 1 >= q->bands) 260 return 0; 261 return band; 262 } 263 264 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 265 { 266 return prio_get(sch, classid); 267 } 268 269 270 static void prio_put(struct Qdisc *q, unsigned long cl) 271 { 272 } 273 274 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 275 struct tcmsg *tcm) 276 { 277 struct prio_sched_data *q = qdisc_priv(sch); 278 279 tcm->tcm_handle |= TC_H_MIN(cl); 280 tcm->tcm_info = q->queues[cl-1]->handle; 281 return 0; 282 } 283 284 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 285 struct gnet_dump *d) 286 { 287 struct prio_sched_data *q = qdisc_priv(sch); 288 struct Qdisc *cl_q; 289 290 cl_q = q->queues[cl - 1]; 291 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 292 d, NULL, &cl_q->bstats) < 0 || 293 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 294 return -1; 295 296 return 0; 297 } 298 299 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 300 { 301 struct prio_sched_data *q = qdisc_priv(sch); 302 int prio; 303 304 if (arg->stop) 305 return; 306 307 for (prio = 0; prio < q->bands; prio++) { 308 if (arg->count < arg->skip) { 309 arg->count++; 310 continue; 311 } 312 if (arg->fn(sch, prio + 1, arg) < 0) { 313 arg->stop = 1; 314 break; 315 } 316 arg->count++; 317 } 318 } 319 320 static struct tcf_proto __rcu **prio_find_tcf(struct Qdisc *sch, 321 unsigned long cl) 322 { 323 struct prio_sched_data *q = qdisc_priv(sch); 324 325 if (cl) 326 return NULL; 327 return &q->filter_list; 328 } 329 330 static const struct Qdisc_class_ops prio_class_ops = { 331 .graft = prio_graft, 332 .leaf = prio_leaf, 333 .get = prio_get, 334 .put = prio_put, 335 .walk = prio_walk, 336 .tcf_chain = prio_find_tcf, 337 .bind_tcf = prio_bind, 338 .unbind_tcf = prio_put, 339 .dump = prio_dump_class, 340 .dump_stats = prio_dump_class_stats, 341 }; 342 343 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 344 .next = NULL, 345 .cl_ops = &prio_class_ops, 346 .id = "prio", 347 .priv_size = sizeof(struct prio_sched_data), 348 .enqueue = prio_enqueue, 349 .dequeue = prio_dequeue, 350 .peek = prio_peek, 351 .init = prio_init, 352 .reset = prio_reset, 353 .destroy = prio_destroy, 354 .change = prio_tune, 355 .dump = prio_dump, 356 .owner = THIS_MODULE, 357 }; 358 359 static int __init prio_module_init(void) 360 { 361 return register_qdisc(&prio_qdisc_ops); 362 } 363 364 static void __exit prio_module_exit(void) 365 { 366 unregister_qdisc(&prio_qdisc_ops); 367 } 368 369 module_init(prio_module_init) 370 module_exit(prio_module_exit) 371 372 MODULE_LICENSE("GPL"); 373