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13d2a1d2 PM |
1 | /* |
2 | * net/sched/sch_drr.c Deficit Round Robin scheduler | |
3 | * | |
4 | * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * version 2 as published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
5a0e3ad6 | 12 | #include <linux/slab.h> |
13d2a1d2 PM |
13 | #include <linux/init.h> |
14 | #include <linux/errno.h> | |
15 | #include <linux/netdevice.h> | |
16 | #include <linux/pkt_sched.h> | |
17 | #include <net/sch_generic.h> | |
18 | #include <net/pkt_sched.h> | |
19 | #include <net/pkt_cls.h> | |
20 | ||
21 | struct drr_class { | |
22 | struct Qdisc_class_common common; | |
23 | unsigned int refcnt; | |
24 | unsigned int filter_cnt; | |
25 | ||
c1a8f1f1 | 26 | struct gnet_stats_basic_packed bstats; |
13d2a1d2 | 27 | struct gnet_stats_queue qstats; |
45203a3b | 28 | struct gnet_stats_rate_est64 rate_est; |
13d2a1d2 PM |
29 | struct list_head alist; |
30 | struct Qdisc *qdisc; | |
31 | ||
32 | u32 quantum; | |
33 | u32 deficit; | |
34 | }; | |
35 | ||
36 | struct drr_sched { | |
37 | struct list_head active; | |
25d8c0d5 | 38 | struct tcf_proto __rcu *filter_list; |
13d2a1d2 PM |
39 | struct Qdisc_class_hash clhash; |
40 | }; | |
41 | ||
42 | static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid) | |
43 | { | |
44 | struct drr_sched *q = qdisc_priv(sch); | |
45 | struct Qdisc_class_common *clc; | |
46 | ||
47 | clc = qdisc_class_find(&q->clhash, classid); | |
48 | if (clc == NULL) | |
49 | return NULL; | |
50 | return container_of(clc, struct drr_class, common); | |
51 | } | |
52 | ||
53 | static void drr_purge_queue(struct drr_class *cl) | |
54 | { | |
55 | unsigned int len = cl->qdisc->q.qlen; | |
56 | ||
57 | qdisc_reset(cl->qdisc); | |
58 | qdisc_tree_decrease_qlen(cl->qdisc, len); | |
59 | } | |
60 | ||
61 | static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = { | |
62 | [TCA_DRR_QUANTUM] = { .type = NLA_U32 }, | |
63 | }; | |
64 | ||
65 | static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, | |
66 | struct nlattr **tca, unsigned long *arg) | |
67 | { | |
68 | struct drr_sched *q = qdisc_priv(sch); | |
69 | struct drr_class *cl = (struct drr_class *)*arg; | |
1844f747 | 70 | struct nlattr *opt = tca[TCA_OPTIONS]; |
13d2a1d2 PM |
71 | struct nlattr *tb[TCA_DRR_MAX + 1]; |
72 | u32 quantum; | |
73 | int err; | |
74 | ||
1844f747 JP |
75 | if (!opt) |
76 | return -EINVAL; | |
77 | ||
78 | err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy); | |
13d2a1d2 PM |
79 | if (err < 0) |
80 | return err; | |
81 | ||
82 | if (tb[TCA_DRR_QUANTUM]) { | |
83 | quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]); | |
84 | if (quantum == 0) | |
85 | return -EINVAL; | |
86 | } else | |
87 | quantum = psched_mtu(qdisc_dev(sch)); | |
88 | ||
89 | if (cl != NULL) { | |
71bcb09a | 90 | if (tca[TCA_RATE]) { |
22e0f8b9 JF |
91 | err = gen_replace_estimator(&cl->bstats, NULL, |
92 | &cl->rate_est, | |
71bcb09a SH |
93 | qdisc_root_sleeping_lock(sch), |
94 | tca[TCA_RATE]); | |
95 | if (err) | |
96 | return err; | |
97 | } | |
98 | ||
13d2a1d2 PM |
99 | sch_tree_lock(sch); |
100 | if (tb[TCA_DRR_QUANTUM]) | |
101 | cl->quantum = quantum; | |
102 | sch_tree_unlock(sch); | |
103 | ||
13d2a1d2 PM |
104 | return 0; |
105 | } | |
106 | ||
107 | cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL); | |
108 | if (cl == NULL) | |
109 | return -ENOBUFS; | |
110 | ||
111 | cl->refcnt = 1; | |
112 | cl->common.classid = classid; | |
113 | cl->quantum = quantum; | |
3511c913 | 114 | cl->qdisc = qdisc_create_dflt(sch->dev_queue, |
13d2a1d2 PM |
115 | &pfifo_qdisc_ops, classid); |
116 | if (cl->qdisc == NULL) | |
117 | cl->qdisc = &noop_qdisc; | |
118 | ||
71bcb09a | 119 | if (tca[TCA_RATE]) { |
22e0f8b9 | 120 | err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est, |
71bcb09a SH |
121 | qdisc_root_sleeping_lock(sch), |
122 | tca[TCA_RATE]); | |
123 | if (err) { | |
124 | qdisc_destroy(cl->qdisc); | |
125 | kfree(cl); | |
126 | return err; | |
127 | } | |
128 | } | |
13d2a1d2 PM |
129 | |
130 | sch_tree_lock(sch); | |
131 | qdisc_class_hash_insert(&q->clhash, &cl->common); | |
132 | sch_tree_unlock(sch); | |
133 | ||
134 | qdisc_class_hash_grow(sch, &q->clhash); | |
135 | ||
136 | *arg = (unsigned long)cl; | |
137 | return 0; | |
138 | } | |
139 | ||
140 | static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl) | |
141 | { | |
142 | gen_kill_estimator(&cl->bstats, &cl->rate_est); | |
143 | qdisc_destroy(cl->qdisc); | |
144 | kfree(cl); | |
145 | } | |
146 | ||
147 | static int drr_delete_class(struct Qdisc *sch, unsigned long arg) | |
148 | { | |
149 | struct drr_sched *q = qdisc_priv(sch); | |
150 | struct drr_class *cl = (struct drr_class *)arg; | |
151 | ||
152 | if (cl->filter_cnt > 0) | |
153 | return -EBUSY; | |
154 | ||
155 | sch_tree_lock(sch); | |
156 | ||
157 | drr_purge_queue(cl); | |
158 | qdisc_class_hash_remove(&q->clhash, &cl->common); | |
159 | ||
7cd0a638 JP |
160 | BUG_ON(--cl->refcnt == 0); |
161 | /* | |
162 | * This shouldn't happen: we "hold" one cops->get() when called | |
163 | * from tc_ctl_tclass; the destroy method is done from cops->put(). | |
164 | */ | |
13d2a1d2 PM |
165 | |
166 | sch_tree_unlock(sch); | |
167 | return 0; | |
168 | } | |
169 | ||
170 | static unsigned long drr_get_class(struct Qdisc *sch, u32 classid) | |
171 | { | |
172 | struct drr_class *cl = drr_find_class(sch, classid); | |
173 | ||
174 | if (cl != NULL) | |
175 | cl->refcnt++; | |
176 | ||
177 | return (unsigned long)cl; | |
178 | } | |
179 | ||
180 | static void drr_put_class(struct Qdisc *sch, unsigned long arg) | |
181 | { | |
182 | struct drr_class *cl = (struct drr_class *)arg; | |
183 | ||
184 | if (--cl->refcnt == 0) | |
185 | drr_destroy_class(sch, cl); | |
186 | } | |
187 | ||
25d8c0d5 JF |
188 | static struct tcf_proto __rcu **drr_tcf_chain(struct Qdisc *sch, |
189 | unsigned long cl) | |
13d2a1d2 PM |
190 | { |
191 | struct drr_sched *q = qdisc_priv(sch); | |
192 | ||
193 | if (cl) | |
194 | return NULL; | |
195 | ||
196 | return &q->filter_list; | |
197 | } | |
198 | ||
199 | static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent, | |
200 | u32 classid) | |
201 | { | |
202 | struct drr_class *cl = drr_find_class(sch, classid); | |
203 | ||
204 | if (cl != NULL) | |
205 | cl->filter_cnt++; | |
206 | ||
207 | return (unsigned long)cl; | |
208 | } | |
209 | ||
210 | static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg) | |
211 | { | |
212 | struct drr_class *cl = (struct drr_class *)arg; | |
213 | ||
214 | cl->filter_cnt--; | |
215 | } | |
216 | ||
217 | static int drr_graft_class(struct Qdisc *sch, unsigned long arg, | |
218 | struct Qdisc *new, struct Qdisc **old) | |
219 | { | |
220 | struct drr_class *cl = (struct drr_class *)arg; | |
221 | ||
222 | if (new == NULL) { | |
3511c913 | 223 | new = qdisc_create_dflt(sch->dev_queue, |
13d2a1d2 PM |
224 | &pfifo_qdisc_ops, cl->common.classid); |
225 | if (new == NULL) | |
226 | new = &noop_qdisc; | |
227 | } | |
228 | ||
229 | sch_tree_lock(sch); | |
230 | drr_purge_queue(cl); | |
b94c8afc PM |
231 | *old = cl->qdisc; |
232 | cl->qdisc = new; | |
13d2a1d2 PM |
233 | sch_tree_unlock(sch); |
234 | return 0; | |
235 | } | |
236 | ||
237 | static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg) | |
238 | { | |
239 | struct drr_class *cl = (struct drr_class *)arg; | |
240 | ||
241 | return cl->qdisc; | |
242 | } | |
243 | ||
244 | static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg) | |
245 | { | |
246 | struct drr_class *cl = (struct drr_class *)arg; | |
247 | ||
248 | if (cl->qdisc->q.qlen == 0) | |
249 | list_del(&cl->alist); | |
250 | } | |
251 | ||
252 | static int drr_dump_class(struct Qdisc *sch, unsigned long arg, | |
253 | struct sk_buff *skb, struct tcmsg *tcm) | |
254 | { | |
255 | struct drr_class *cl = (struct drr_class *)arg; | |
256 | struct nlattr *nest; | |
257 | ||
258 | tcm->tcm_parent = TC_H_ROOT; | |
259 | tcm->tcm_handle = cl->common.classid; | |
260 | tcm->tcm_info = cl->qdisc->handle; | |
261 | ||
262 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
263 | if (nest == NULL) | |
264 | goto nla_put_failure; | |
1b34ec43 DM |
265 | if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum)) |
266 | goto nla_put_failure; | |
13d2a1d2 PM |
267 | return nla_nest_end(skb, nest); |
268 | ||
269 | nla_put_failure: | |
270 | nla_nest_cancel(skb, nest); | |
271 | return -EMSGSIZE; | |
272 | } | |
273 | ||
274 | static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, | |
275 | struct gnet_dump *d) | |
276 | { | |
277 | struct drr_class *cl = (struct drr_class *)arg; | |
64015853 | 278 | __u32 qlen = cl->qdisc->q.qlen; |
13d2a1d2 PM |
279 | struct tc_drr_stats xstats; |
280 | ||
281 | memset(&xstats, 0, sizeof(xstats)); | |
64015853 | 282 | if (qlen) |
13d2a1d2 PM |
283 | xstats.deficit = cl->deficit; |
284 | ||
22e0f8b9 | 285 | if (gnet_stats_copy_basic(d, NULL, &cl->bstats) < 0 || |
d250a5f9 | 286 | gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || |
b0ab6f92 | 287 | gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0) |
13d2a1d2 PM |
288 | return -1; |
289 | ||
290 | return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); | |
291 | } | |
292 | ||
293 | static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg) | |
294 | { | |
295 | struct drr_sched *q = qdisc_priv(sch); | |
296 | struct drr_class *cl; | |
13d2a1d2 PM |
297 | unsigned int i; |
298 | ||
299 | if (arg->stop) | |
300 | return; | |
301 | ||
302 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 303 | hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { |
13d2a1d2 PM |
304 | if (arg->count < arg->skip) { |
305 | arg->count++; | |
306 | continue; | |
307 | } | |
308 | if (arg->fn(sch, (unsigned long)cl, arg) < 0) { | |
309 | arg->stop = 1; | |
310 | return; | |
311 | } | |
312 | arg->count++; | |
313 | } | |
314 | } | |
315 | } | |
316 | ||
317 | static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, | |
318 | int *qerr) | |
319 | { | |
320 | struct drr_sched *q = qdisc_priv(sch); | |
321 | struct drr_class *cl; | |
322 | struct tcf_result res; | |
25d8c0d5 | 323 | struct tcf_proto *fl; |
13d2a1d2 PM |
324 | int result; |
325 | ||
326 | if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { | |
327 | cl = drr_find_class(sch, skb->priority); | |
328 | if (cl != NULL) | |
329 | return cl; | |
330 | } | |
331 | ||
332 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; | |
25d8c0d5 JF |
333 | fl = rcu_dereference_bh(q->filter_list); |
334 | result = tc_classify(skb, fl, &res); | |
13d2a1d2 PM |
335 | if (result >= 0) { |
336 | #ifdef CONFIG_NET_CLS_ACT | |
337 | switch (result) { | |
338 | case TC_ACT_QUEUED: | |
339 | case TC_ACT_STOLEN: | |
340 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; | |
341 | case TC_ACT_SHOT: | |
342 | return NULL; | |
343 | } | |
344 | #endif | |
345 | cl = (struct drr_class *)res.class; | |
346 | if (cl == NULL) | |
347 | cl = drr_find_class(sch, res.classid); | |
348 | return cl; | |
349 | } | |
350 | return NULL; | |
351 | } | |
352 | ||
353 | static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) | |
354 | { | |
355 | struct drr_sched *q = qdisc_priv(sch); | |
356 | struct drr_class *cl; | |
f54ba779 | 357 | int err = 0; |
13d2a1d2 PM |
358 | |
359 | cl = drr_classify(skb, sch, &err); | |
360 | if (cl == NULL) { | |
361 | if (err & __NET_XMIT_BYPASS) | |
25331d6c | 362 | qdisc_qstats_drop(sch); |
13d2a1d2 PM |
363 | kfree_skb(skb); |
364 | return err; | |
365 | } | |
366 | ||
13d2a1d2 PM |
367 | err = qdisc_enqueue(skb, cl->qdisc); |
368 | if (unlikely(err != NET_XMIT_SUCCESS)) { | |
369 | if (net_xmit_drop_count(err)) { | |
370 | cl->qstats.drops++; | |
25331d6c | 371 | qdisc_qstats_drop(sch); |
13d2a1d2 PM |
372 | } |
373 | return err; | |
374 | } | |
375 | ||
376 | if (cl->qdisc->q.qlen == 1) { | |
377 | list_add_tail(&cl->alist, &q->active); | |
378 | cl->deficit = cl->quantum; | |
379 | } | |
380 | ||
13d2a1d2 PM |
381 | sch->q.qlen++; |
382 | return err; | |
383 | } | |
384 | ||
385 | static struct sk_buff *drr_dequeue(struct Qdisc *sch) | |
386 | { | |
387 | struct drr_sched *q = qdisc_priv(sch); | |
388 | struct drr_class *cl; | |
389 | struct sk_buff *skb; | |
390 | unsigned int len; | |
391 | ||
3f0947c3 PM |
392 | if (list_empty(&q->active)) |
393 | goto out; | |
394 | while (1) { | |
13d2a1d2 PM |
395 | cl = list_first_entry(&q->active, struct drr_class, alist); |
396 | skb = cl->qdisc->ops->peek(cl->qdisc); | |
6e765a00 FW |
397 | if (skb == NULL) { |
398 | qdisc_warn_nonwc(__func__, cl->qdisc); | |
3f0947c3 | 399 | goto out; |
6e765a00 | 400 | } |
13d2a1d2 PM |
401 | |
402 | len = qdisc_pkt_len(skb); | |
403 | if (len <= cl->deficit) { | |
404 | cl->deficit -= len; | |
405 | skb = qdisc_dequeue_peeked(cl->qdisc); | |
406 | if (cl->qdisc->q.qlen == 0) | |
407 | list_del(&cl->alist); | |
2dd875ff ED |
408 | |
409 | bstats_update(&cl->bstats, skb); | |
9190b3b3 | 410 | qdisc_bstats_update(sch, skb); |
13d2a1d2 PM |
411 | sch->q.qlen--; |
412 | return skb; | |
413 | } | |
414 | ||
415 | cl->deficit += cl->quantum; | |
13d2a1d2 PM |
416 | list_move_tail(&cl->alist, &q->active); |
417 | } | |
3f0947c3 | 418 | out: |
13d2a1d2 PM |
419 | return NULL; |
420 | } | |
421 | ||
422 | static unsigned int drr_drop(struct Qdisc *sch) | |
423 | { | |
424 | struct drr_sched *q = qdisc_priv(sch); | |
425 | struct drr_class *cl; | |
426 | unsigned int len; | |
427 | ||
428 | list_for_each_entry(cl, &q->active, alist) { | |
429 | if (cl->qdisc->ops->drop) { | |
430 | len = cl->qdisc->ops->drop(cl->qdisc); | |
431 | if (len > 0) { | |
98aa9c80 | 432 | sch->q.qlen--; |
13d2a1d2 PM |
433 | if (cl->qdisc->q.qlen == 0) |
434 | list_del(&cl->alist); | |
435 | return len; | |
436 | } | |
437 | } | |
438 | } | |
439 | return 0; | |
440 | } | |
441 | ||
442 | static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt) | |
443 | { | |
444 | struct drr_sched *q = qdisc_priv(sch); | |
445 | int err; | |
446 | ||
447 | err = qdisc_class_hash_init(&q->clhash); | |
448 | if (err < 0) | |
449 | return err; | |
450 | INIT_LIST_HEAD(&q->active); | |
451 | return 0; | |
452 | } | |
453 | ||
454 | static void drr_reset_qdisc(struct Qdisc *sch) | |
455 | { | |
456 | struct drr_sched *q = qdisc_priv(sch); | |
457 | struct drr_class *cl; | |
13d2a1d2 PM |
458 | unsigned int i; |
459 | ||
460 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 461 | hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { |
13d2a1d2 PM |
462 | if (cl->qdisc->q.qlen) |
463 | list_del(&cl->alist); | |
464 | qdisc_reset(cl->qdisc); | |
465 | } | |
466 | } | |
467 | sch->q.qlen = 0; | |
468 | } | |
469 | ||
470 | static void drr_destroy_qdisc(struct Qdisc *sch) | |
471 | { | |
472 | struct drr_sched *q = qdisc_priv(sch); | |
473 | struct drr_class *cl; | |
b67bfe0d | 474 | struct hlist_node *next; |
13d2a1d2 PM |
475 | unsigned int i; |
476 | ||
477 | tcf_destroy_chain(&q->filter_list); | |
478 | ||
479 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 480 | hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], |
13d2a1d2 PM |
481 | common.hnode) |
482 | drr_destroy_class(sch, cl); | |
483 | } | |
484 | qdisc_class_hash_destroy(&q->clhash); | |
485 | } | |
486 | ||
487 | static const struct Qdisc_class_ops drr_class_ops = { | |
488 | .change = drr_change_class, | |
489 | .delete = drr_delete_class, | |
490 | .get = drr_get_class, | |
491 | .put = drr_put_class, | |
492 | .tcf_chain = drr_tcf_chain, | |
493 | .bind_tcf = drr_bind_tcf, | |
494 | .unbind_tcf = drr_unbind_tcf, | |
495 | .graft = drr_graft_class, | |
496 | .leaf = drr_class_leaf, | |
497 | .qlen_notify = drr_qlen_notify, | |
498 | .dump = drr_dump_class, | |
499 | .dump_stats = drr_dump_class_stats, | |
500 | .walk = drr_walk, | |
501 | }; | |
502 | ||
503 | static struct Qdisc_ops drr_qdisc_ops __read_mostly = { | |
504 | .cl_ops = &drr_class_ops, | |
505 | .id = "drr", | |
506 | .priv_size = sizeof(struct drr_sched), | |
507 | .enqueue = drr_enqueue, | |
508 | .dequeue = drr_dequeue, | |
509 | .peek = qdisc_peek_dequeued, | |
510 | .drop = drr_drop, | |
511 | .init = drr_init_qdisc, | |
512 | .reset = drr_reset_qdisc, | |
513 | .destroy = drr_destroy_qdisc, | |
514 | .owner = THIS_MODULE, | |
515 | }; | |
516 | ||
517 | static int __init drr_init(void) | |
518 | { | |
519 | return register_qdisc(&drr_qdisc_ops); | |
520 | } | |
521 | ||
522 | static void __exit drr_exit(void) | |
523 | { | |
524 | unregister_qdisc(&drr_qdisc_ops); | |
525 | } | |
526 | ||
527 | module_init(drr_init); | |
528 | module_exit(drr_exit); | |
529 | MODULE_LICENSE("GPL"); |