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