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, 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]; 197 198 sch_tree_unlock(sch); 199 return 0; 200 } 201 202 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 203 { 204 if (!opt) 205 return -EINVAL; 206 207 return prio_tune(sch, opt); 208 } 209 210 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 211 { 212 struct prio_sched_data *q = qdisc_priv(sch); 213 unsigned char *b = skb_tail_pointer(skb); 214 struct tc_prio_qopt opt; 215 216 opt.bands = q->bands; 217 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1); 218 219 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 220 goto nla_put_failure; 221 222 return skb->len; 223 224 nla_put_failure: 225 nlmsg_trim(skb, b); 226 return -1; 227 } 228 229 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 230 struct Qdisc **old) 231 { 232 struct prio_sched_data *q = qdisc_priv(sch); 233 unsigned long band = arg - 1; 234 235 if (new == NULL) 236 new = &noop_qdisc; 237 238 *old = qdisc_replace(sch, new, &q->queues[band]); 239 return 0; 240 } 241 242 static struct Qdisc * 243 prio_leaf(struct Qdisc *sch, unsigned long arg) 244 { 245 struct prio_sched_data *q = qdisc_priv(sch); 246 unsigned long band = arg - 1; 247 248 return q->queues[band]; 249 } 250 251 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 252 { 253 struct prio_sched_data *q = qdisc_priv(sch); 254 unsigned long band = TC_H_MIN(classid); 255 256 if (band - 1 >= q->bands) 257 return 0; 258 return band; 259 } 260 261 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 262 { 263 return prio_get(sch, classid); 264 } 265 266 267 static void prio_put(struct Qdisc *q, unsigned long cl) 268 { 269 } 270 271 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 272 struct tcmsg *tcm) 273 { 274 struct prio_sched_data *q = qdisc_priv(sch); 275 276 tcm->tcm_handle |= TC_H_MIN(cl); 277 tcm->tcm_info = q->queues[cl-1]->handle; 278 return 0; 279 } 280 281 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 282 struct gnet_dump *d) 283 { 284 struct prio_sched_data *q = qdisc_priv(sch); 285 struct Qdisc *cl_q; 286 287 cl_q = q->queues[cl - 1]; 288 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 289 d, NULL, &cl_q->bstats) < 0 || 290 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 291 return -1; 292 293 return 0; 294 } 295 296 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 297 { 298 struct prio_sched_data *q = qdisc_priv(sch); 299 int prio; 300 301 if (arg->stop) 302 return; 303 304 for (prio = 0; prio < q->bands; prio++) { 305 if (arg->count < arg->skip) { 306 arg->count++; 307 continue; 308 } 309 if (arg->fn(sch, prio + 1, arg) < 0) { 310 arg->stop = 1; 311 break; 312 } 313 arg->count++; 314 } 315 } 316 317 static struct tcf_proto __rcu **prio_find_tcf(struct Qdisc *sch, 318 unsigned long cl) 319 { 320 struct prio_sched_data *q = qdisc_priv(sch); 321 322 if (cl) 323 return NULL; 324 return &q->filter_list; 325 } 326 327 static const struct Qdisc_class_ops prio_class_ops = { 328 .graft = prio_graft, 329 .leaf = prio_leaf, 330 .get = prio_get, 331 .put = prio_put, 332 .walk = prio_walk, 333 .tcf_chain = prio_find_tcf, 334 .bind_tcf = prio_bind, 335 .unbind_tcf = prio_put, 336 .dump = prio_dump_class, 337 .dump_stats = prio_dump_class_stats, 338 }; 339 340 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 341 .next = NULL, 342 .cl_ops = &prio_class_ops, 343 .id = "prio", 344 .priv_size = sizeof(struct prio_sched_data), 345 .enqueue = prio_enqueue, 346 .dequeue = prio_dequeue, 347 .peek = prio_peek, 348 .init = prio_init, 349 .reset = prio_reset, 350 .destroy = prio_destroy, 351 .change = prio_tune, 352 .dump = prio_dump, 353 .owner = THIS_MODULE, 354 }; 355 356 static int __init prio_module_init(void) 357 { 358 return register_qdisc(&prio_qdisc_ops); 359 } 360 361 static void __exit prio_module_exit(void) 362 { 363 unregister_qdisc(&prio_qdisc_ops); 364 } 365 366 module_init(prio_module_init) 367 module_exit(prio_module_exit) 368 369 MODULE_LICENSE("GPL"); 370