Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
[linux-2.6] / net / sched / sch_drr.c
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>
12 #include <linux/init.h>
13 #include <linux/errno.h>
14 #include <linux/netdevice.h>
15 #include <linux/pkt_sched.h>
16 #include <net/sch_generic.h>
17 #include <net/pkt_sched.h>
18 #include <net/pkt_cls.h>
19
20 struct drr_class {
21         struct Qdisc_class_common       common;
22         unsigned int                    refcnt;
23         unsigned int                    filter_cnt;
24
25         struct gnet_stats_basic         bstats;
26         struct gnet_stats_queue         qstats;
27         struct gnet_stats_rate_est      rate_est;
28         struct list_head                alist;
29         struct Qdisc                    *qdisc;
30
31         u32                             quantum;
32         u32                             deficit;
33 };
34
35 struct drr_sched {
36         struct list_head                active;
37         struct tcf_proto                *filter_list;
38         struct Qdisc_class_hash         clhash;
39 };
40
41 static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
42 {
43         struct drr_sched *q = qdisc_priv(sch);
44         struct Qdisc_class_common *clc;
45
46         clc = qdisc_class_find(&q->clhash, classid);
47         if (clc == NULL)
48                 return NULL;
49         return container_of(clc, struct drr_class, common);
50 }
51
52 static void drr_purge_queue(struct drr_class *cl)
53 {
54         unsigned int len = cl->qdisc->q.qlen;
55
56         qdisc_reset(cl->qdisc);
57         qdisc_tree_decrease_qlen(cl->qdisc, len);
58 }
59
60 static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
61         [TCA_DRR_QUANTUM]       = { .type = NLA_U32 },
62 };
63
64 static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
65                             struct nlattr **tca, unsigned long *arg)
66 {
67         struct drr_sched *q = qdisc_priv(sch);
68         struct drr_class *cl = (struct drr_class *)*arg;
69         struct nlattr *opt = tca[TCA_OPTIONS];
70         struct nlattr *tb[TCA_DRR_MAX + 1];
71         u32 quantum;
72         int err;
73
74         if (!opt)
75                 return -EINVAL;
76
77         err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy);
78         if (err < 0)
79                 return err;
80
81         if (tb[TCA_DRR_QUANTUM]) {
82                 quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
83                 if (quantum == 0)
84                         return -EINVAL;
85         } else
86                 quantum = psched_mtu(qdisc_dev(sch));
87
88         if (cl != NULL) {
89                 if (tca[TCA_RATE]) {
90                         err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
91                                                     qdisc_root_sleeping_lock(sch),
92                                                     tca[TCA_RATE]);
93                         if (err)
94                                 return err;
95                 }
96
97                 sch_tree_lock(sch);
98                 if (tb[TCA_DRR_QUANTUM])
99                         cl->quantum = quantum;
100                 sch_tree_unlock(sch);
101
102                 return 0;
103         }
104
105         cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
106         if (cl == NULL)
107                 return -ENOBUFS;
108
109         cl->refcnt         = 1;
110         cl->common.classid = classid;
111         cl->quantum        = quantum;
112         cl->qdisc          = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
113                                                &pfifo_qdisc_ops, classid);
114         if (cl->qdisc == NULL)
115                 cl->qdisc = &noop_qdisc;
116
117         if (tca[TCA_RATE]) {
118                 err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
119                                             qdisc_root_sleeping_lock(sch),
120                                             tca[TCA_RATE]);
121                 if (err) {
122                         qdisc_destroy(cl->qdisc);
123                         kfree(cl);
124                         return err;
125                 }
126         }
127
128         sch_tree_lock(sch);
129         qdisc_class_hash_insert(&q->clhash, &cl->common);
130         sch_tree_unlock(sch);
131
132         qdisc_class_hash_grow(sch, &q->clhash);
133
134         *arg = (unsigned long)cl;
135         return 0;
136 }
137
138 static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
139 {
140         gen_kill_estimator(&cl->bstats, &cl->rate_est);
141         qdisc_destroy(cl->qdisc);
142         kfree(cl);
143 }
144
145 static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
146 {
147         struct drr_sched *q = qdisc_priv(sch);
148         struct drr_class *cl = (struct drr_class *)arg;
149
150         if (cl->filter_cnt > 0)
151                 return -EBUSY;
152
153         sch_tree_lock(sch);
154
155         drr_purge_queue(cl);
156         qdisc_class_hash_remove(&q->clhash, &cl->common);
157
158         if (--cl->refcnt == 0)
159                 drr_destroy_class(sch, cl);
160
161         sch_tree_unlock(sch);
162         return 0;
163 }
164
165 static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
166 {
167         struct drr_class *cl = drr_find_class(sch, classid);
168
169         if (cl != NULL)
170                 cl->refcnt++;
171
172         return (unsigned long)cl;
173 }
174
175 static void drr_put_class(struct Qdisc *sch, unsigned long arg)
176 {
177         struct drr_class *cl = (struct drr_class *)arg;
178
179         if (--cl->refcnt == 0)
180                 drr_destroy_class(sch, cl);
181 }
182
183 static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
184 {
185         struct drr_sched *q = qdisc_priv(sch);
186
187         if (cl)
188                 return NULL;
189
190         return &q->filter_list;
191 }
192
193 static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
194                                   u32 classid)
195 {
196         struct drr_class *cl = drr_find_class(sch, classid);
197
198         if (cl != NULL)
199                 cl->filter_cnt++;
200
201         return (unsigned long)cl;
202 }
203
204 static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
205 {
206         struct drr_class *cl = (struct drr_class *)arg;
207
208         cl->filter_cnt--;
209 }
210
211 static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
212                            struct Qdisc *new, struct Qdisc **old)
213 {
214         struct drr_class *cl = (struct drr_class *)arg;
215
216         if (new == NULL) {
217                 new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
218                                         &pfifo_qdisc_ops, cl->common.classid);
219                 if (new == NULL)
220                         new = &noop_qdisc;
221         }
222
223         sch_tree_lock(sch);
224         drr_purge_queue(cl);
225         *old = cl->qdisc;
226         cl->qdisc = new;
227         sch_tree_unlock(sch);
228         return 0;
229 }
230
231 static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
232 {
233         struct drr_class *cl = (struct drr_class *)arg;
234
235         return cl->qdisc;
236 }
237
238 static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
239 {
240         struct drr_class *cl = (struct drr_class *)arg;
241
242         if (cl->qdisc->q.qlen == 0)
243                 list_del(&cl->alist);
244 }
245
246 static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
247                           struct sk_buff *skb, struct tcmsg *tcm)
248 {
249         struct drr_class *cl = (struct drr_class *)arg;
250         struct nlattr *nest;
251
252         tcm->tcm_parent = TC_H_ROOT;
253         tcm->tcm_handle = cl->common.classid;
254         tcm->tcm_info   = cl->qdisc->handle;
255
256         nest = nla_nest_start(skb, TCA_OPTIONS);
257         if (nest == NULL)
258                 goto nla_put_failure;
259         NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
260         return nla_nest_end(skb, nest);
261
262 nla_put_failure:
263         nla_nest_cancel(skb, nest);
264         return -EMSGSIZE;
265 }
266
267 static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
268                                 struct gnet_dump *d)
269 {
270         struct drr_class *cl = (struct drr_class *)arg;
271         struct tc_drr_stats xstats;
272
273         memset(&xstats, 0, sizeof(xstats));
274         if (cl->qdisc->q.qlen)
275                 xstats.deficit = cl->deficit;
276
277         if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
278             gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
279             gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
280                 return -1;
281
282         return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
283 }
284
285 static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
286 {
287         struct drr_sched *q = qdisc_priv(sch);
288         struct drr_class *cl;
289         struct hlist_node *n;
290         unsigned int i;
291
292         if (arg->stop)
293                 return;
294
295         for (i = 0; i < q->clhash.hashsize; i++) {
296                 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
297                         if (arg->count < arg->skip) {
298                                 arg->count++;
299                                 continue;
300                         }
301                         if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
302                                 arg->stop = 1;
303                                 return;
304                         }
305                         arg->count++;
306                 }
307         }
308 }
309
310 static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
311                                       int *qerr)
312 {
313         struct drr_sched *q = qdisc_priv(sch);
314         struct drr_class *cl;
315         struct tcf_result res;
316         int result;
317
318         if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
319                 cl = drr_find_class(sch, skb->priority);
320                 if (cl != NULL)
321                         return cl;
322         }
323
324         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
325         result = tc_classify(skb, q->filter_list, &res);
326         if (result >= 0) {
327 #ifdef CONFIG_NET_CLS_ACT
328                 switch (result) {
329                 case TC_ACT_QUEUED:
330                 case TC_ACT_STOLEN:
331                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
332                 case TC_ACT_SHOT:
333                         return NULL;
334                 }
335 #endif
336                 cl = (struct drr_class *)res.class;
337                 if (cl == NULL)
338                         cl = drr_find_class(sch, res.classid);
339                 return cl;
340         }
341         return NULL;
342 }
343
344 static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
345 {
346         struct drr_sched *q = qdisc_priv(sch);
347         struct drr_class *cl;
348         unsigned int len;
349         int err;
350
351         cl = drr_classify(skb, sch, &err);
352         if (cl == NULL) {
353                 if (err & __NET_XMIT_BYPASS)
354                         sch->qstats.drops++;
355                 kfree_skb(skb);
356                 return err;
357         }
358
359         len = qdisc_pkt_len(skb);
360         err = qdisc_enqueue(skb, cl->qdisc);
361         if (unlikely(err != NET_XMIT_SUCCESS)) {
362                 if (net_xmit_drop_count(err)) {
363                         cl->qstats.drops++;
364                         sch->qstats.drops++;
365                 }
366                 return err;
367         }
368
369         if (cl->qdisc->q.qlen == 1) {
370                 list_add_tail(&cl->alist, &q->active);
371                 cl->deficit = cl->quantum;
372         }
373
374         cl->bstats.packets++;
375         cl->bstats.bytes += len;
376         sch->bstats.packets++;
377         sch->bstats.bytes += len;
378
379         sch->q.qlen++;
380         return err;
381 }
382
383 static struct sk_buff *drr_dequeue(struct Qdisc *sch)
384 {
385         struct drr_sched *q = qdisc_priv(sch);
386         struct drr_class *cl;
387         struct sk_buff *skb;
388         unsigned int len;
389
390         if (list_empty(&q->active))
391                 goto out;
392         while (1) {
393                 cl = list_first_entry(&q->active, struct drr_class, alist);
394                 skb = cl->qdisc->ops->peek(cl->qdisc);
395                 if (skb == NULL)
396                         goto out;
397
398                 len = qdisc_pkt_len(skb);
399                 if (len <= cl->deficit) {
400                         cl->deficit -= len;
401                         skb = qdisc_dequeue_peeked(cl->qdisc);
402                         if (cl->qdisc->q.qlen == 0)
403                                 list_del(&cl->alist);
404                         sch->q.qlen--;
405                         return skb;
406                 }
407
408                 cl->deficit += cl->quantum;
409                 list_move_tail(&cl->alist, &q->active);
410         }
411 out:
412         return NULL;
413 }
414
415 static unsigned int drr_drop(struct Qdisc *sch)
416 {
417         struct drr_sched *q = qdisc_priv(sch);
418         struct drr_class *cl;
419         unsigned int len;
420
421         list_for_each_entry(cl, &q->active, alist) {
422                 if (cl->qdisc->ops->drop) {
423                         len = cl->qdisc->ops->drop(cl->qdisc);
424                         if (len > 0) {
425                                 sch->q.qlen--;
426                                 if (cl->qdisc->q.qlen == 0)
427                                         list_del(&cl->alist);
428                                 return len;
429                         }
430                 }
431         }
432         return 0;
433 }
434
435 static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
436 {
437         struct drr_sched *q = qdisc_priv(sch);
438         int err;
439
440         err = qdisc_class_hash_init(&q->clhash);
441         if (err < 0)
442                 return err;
443         INIT_LIST_HEAD(&q->active);
444         return 0;
445 }
446
447 static void drr_reset_qdisc(struct Qdisc *sch)
448 {
449         struct drr_sched *q = qdisc_priv(sch);
450         struct drr_class *cl;
451         struct hlist_node *n;
452         unsigned int i;
453
454         for (i = 0; i < q->clhash.hashsize; i++) {
455                 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
456                         if (cl->qdisc->q.qlen)
457                                 list_del(&cl->alist);
458                         qdisc_reset(cl->qdisc);
459                 }
460         }
461         sch->q.qlen = 0;
462 }
463
464 static void drr_destroy_qdisc(struct Qdisc *sch)
465 {
466         struct drr_sched *q = qdisc_priv(sch);
467         struct drr_class *cl;
468         struct hlist_node *n, *next;
469         unsigned int i;
470
471         tcf_destroy_chain(&q->filter_list);
472
473         for (i = 0; i < q->clhash.hashsize; i++) {
474                 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
475                                           common.hnode)
476                         drr_destroy_class(sch, cl);
477         }
478         qdisc_class_hash_destroy(&q->clhash);
479 }
480
481 static const struct Qdisc_class_ops drr_class_ops = {
482         .change         = drr_change_class,
483         .delete         = drr_delete_class,
484         .get            = drr_get_class,
485         .put            = drr_put_class,
486         .tcf_chain      = drr_tcf_chain,
487         .bind_tcf       = drr_bind_tcf,
488         .unbind_tcf     = drr_unbind_tcf,
489         .graft          = drr_graft_class,
490         .leaf           = drr_class_leaf,
491         .qlen_notify    = drr_qlen_notify,
492         .dump           = drr_dump_class,
493         .dump_stats     = drr_dump_class_stats,
494         .walk           = drr_walk,
495 };
496
497 static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
498         .cl_ops         = &drr_class_ops,
499         .id             = "drr",
500         .priv_size      = sizeof(struct drr_sched),
501         .enqueue        = drr_enqueue,
502         .dequeue        = drr_dequeue,
503         .peek           = qdisc_peek_dequeued,
504         .drop           = drr_drop,
505         .init           = drr_init_qdisc,
506         .reset          = drr_reset_qdisc,
507         .destroy        = drr_destroy_qdisc,
508         .owner          = THIS_MODULE,
509 };
510
511 static int __init drr_init(void)
512 {
513         return register_qdisc(&drr_qdisc_ops);
514 }
515
516 static void __exit drr_exit(void)
517 {
518         unregister_qdisc(&drr_qdisc_ops);
519 }
520
521 module_init(drr_init);
522 module_exit(drr_exit);
523 MODULE_LICENSE("GPL");