OMAP: DSS2: DSI Video mode support
[pandora-kernel.git] / 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/slab.h>
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
26         struct gnet_stats_basic_packed          bstats;
27         struct gnet_stats_queue         qstats;
28         struct gnet_stats_rate_est      rate_est;
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;
38         struct tcf_proto                *filter_list;
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;
70         struct nlattr *opt = tca[TCA_OPTIONS];
71         struct nlattr *tb[TCA_DRR_MAX + 1];
72         u32 quantum;
73         int err;
74
75         if (!opt)
76                 return -EINVAL;
77
78         err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy);
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) {
90                 if (tca[TCA_RATE]) {
91                         err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
92                                                     qdisc_root_sleeping_lock(sch),
93                                                     tca[TCA_RATE]);
94                         if (err)
95                                 return err;
96                 }
97
98                 sch_tree_lock(sch);
99                 if (tb[TCA_DRR_QUANTUM])
100                         cl->quantum = quantum;
101                 sch_tree_unlock(sch);
102
103                 return 0;
104         }
105
106         cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
107         if (cl == NULL)
108                 return -ENOBUFS;
109
110         cl->refcnt         = 1;
111         cl->common.classid = classid;
112         cl->quantum        = quantum;
113         cl->qdisc          = qdisc_create_dflt(sch->dev_queue,
114                                                &pfifo_qdisc_ops, classid);
115         if (cl->qdisc == NULL)
116                 cl->qdisc = &noop_qdisc;
117
118         if (tca[TCA_RATE]) {
119                 err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
120                                             qdisc_root_sleeping_lock(sch),
121                                             tca[TCA_RATE]);
122                 if (err) {
123                         qdisc_destroy(cl->qdisc);
124                         kfree(cl);
125                         return err;
126                 }
127         }
128
129         sch_tree_lock(sch);
130         qdisc_class_hash_insert(&q->clhash, &cl->common);
131         sch_tree_unlock(sch);
132
133         qdisc_class_hash_grow(sch, &q->clhash);
134
135         *arg = (unsigned long)cl;
136         return 0;
137 }
138
139 static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
140 {
141         gen_kill_estimator(&cl->bstats, &cl->rate_est);
142         qdisc_destroy(cl->qdisc);
143         kfree(cl);
144 }
145
146 static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
147 {
148         struct drr_sched *q = qdisc_priv(sch);
149         struct drr_class *cl = (struct drr_class *)arg;
150
151         if (cl->filter_cnt > 0)
152                 return -EBUSY;
153
154         sch_tree_lock(sch);
155
156         drr_purge_queue(cl);
157         qdisc_class_hash_remove(&q->clhash, &cl->common);
158
159         BUG_ON(--cl->refcnt == 0);
160         /*
161          * This shouldn't happen: we "hold" one cops->get() when called
162          * from tc_ctl_tclass; the destroy method is done from cops->put().
163          */
164
165         sch_tree_unlock(sch);
166         return 0;
167 }
168
169 static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
170 {
171         struct drr_class *cl = drr_find_class(sch, classid);
172
173         if (cl != NULL)
174                 cl->refcnt++;
175
176         return (unsigned long)cl;
177 }
178
179 static void drr_put_class(struct Qdisc *sch, unsigned long arg)
180 {
181         struct drr_class *cl = (struct drr_class *)arg;
182
183         if (--cl->refcnt == 0)
184                 drr_destroy_class(sch, cl);
185 }
186
187 static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
188 {
189         struct drr_sched *q = qdisc_priv(sch);
190
191         if (cl)
192                 return NULL;
193
194         return &q->filter_list;
195 }
196
197 static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
198                                   u32 classid)
199 {
200         struct drr_class *cl = drr_find_class(sch, classid);
201
202         if (cl != NULL)
203                 cl->filter_cnt++;
204
205         return (unsigned long)cl;
206 }
207
208 static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
209 {
210         struct drr_class *cl = (struct drr_class *)arg;
211
212         cl->filter_cnt--;
213 }
214
215 static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
216                            struct Qdisc *new, struct Qdisc **old)
217 {
218         struct drr_class *cl = (struct drr_class *)arg;
219
220         if (new == NULL) {
221                 new = qdisc_create_dflt(sch->dev_queue,
222                                         &pfifo_qdisc_ops, cl->common.classid);
223                 if (new == NULL)
224                         new = &noop_qdisc;
225         }
226
227         sch_tree_lock(sch);
228         drr_purge_queue(cl);
229         *old = cl->qdisc;
230         cl->qdisc = new;
231         sch_tree_unlock(sch);
232         return 0;
233 }
234
235 static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
236 {
237         struct drr_class *cl = (struct drr_class *)arg;
238
239         return cl->qdisc;
240 }
241
242 static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
243 {
244         struct drr_class *cl = (struct drr_class *)arg;
245
246         if (cl->qdisc->q.qlen == 0)
247                 list_del(&cl->alist);
248 }
249
250 static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
251                           struct sk_buff *skb, struct tcmsg *tcm)
252 {
253         struct drr_class *cl = (struct drr_class *)arg;
254         struct nlattr *nest;
255
256         tcm->tcm_parent = TC_H_ROOT;
257         tcm->tcm_handle = cl->common.classid;
258         tcm->tcm_info   = cl->qdisc->handle;
259
260         nest = nla_nest_start(skb, TCA_OPTIONS);
261         if (nest == NULL)
262                 goto nla_put_failure;
263         NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
264         return nla_nest_end(skb, nest);
265
266 nla_put_failure:
267         nla_nest_cancel(skb, nest);
268         return -EMSGSIZE;
269 }
270
271 static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
272                                 struct gnet_dump *d)
273 {
274         struct drr_class *cl = (struct drr_class *)arg;
275         struct tc_drr_stats xstats;
276
277         memset(&xstats, 0, sizeof(xstats));
278         if (cl->qdisc->q.qlen) {
279                 xstats.deficit = cl->deficit;
280                 cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
281         }
282
283         if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
284             gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
285             gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
286                 return -1;
287
288         return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
289 }
290
291 static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
292 {
293         struct drr_sched *q = qdisc_priv(sch);
294         struct drr_class *cl;
295         struct hlist_node *n;
296         unsigned int i;
297
298         if (arg->stop)
299                 return;
300
301         for (i = 0; i < q->clhash.hashsize; i++) {
302                 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
303                         if (arg->count < arg->skip) {
304                                 arg->count++;
305                                 continue;
306                         }
307                         if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
308                                 arg->stop = 1;
309                                 return;
310                         }
311                         arg->count++;
312                 }
313         }
314 }
315
316 static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
317                                       int *qerr)
318 {
319         struct drr_sched *q = qdisc_priv(sch);
320         struct drr_class *cl;
321         struct tcf_result res;
322         int result;
323
324         if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
325                 cl = drr_find_class(sch, skb->priority);
326                 if (cl != NULL)
327                         return cl;
328         }
329
330         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
331         result = tc_classify(skb, q->filter_list, &res);
332         if (result >= 0) {
333 #ifdef CONFIG_NET_CLS_ACT
334                 switch (result) {
335                 case TC_ACT_QUEUED:
336                 case TC_ACT_STOLEN:
337                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
338                 case TC_ACT_SHOT:
339                         return NULL;
340                 }
341 #endif
342                 cl = (struct drr_class *)res.class;
343                 if (cl == NULL)
344                         cl = drr_find_class(sch, res.classid);
345                 return cl;
346         }
347         return NULL;
348 }
349
350 static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
351 {
352         struct drr_sched *q = qdisc_priv(sch);
353         struct drr_class *cl;
354         int err;
355
356         cl = drr_classify(skb, sch, &err);
357         if (cl == NULL) {
358                 if (err & __NET_XMIT_BYPASS)
359                         sch->qstats.drops++;
360                 kfree_skb(skb);
361                 return err;
362         }
363
364         err = qdisc_enqueue(skb, cl->qdisc);
365         if (unlikely(err != NET_XMIT_SUCCESS)) {
366                 if (net_xmit_drop_count(err)) {
367                         cl->qstats.drops++;
368                         sch->qstats.drops++;
369                 }
370                 return err;
371         }
372
373         if (cl->qdisc->q.qlen == 1) {
374                 list_add_tail(&cl->alist, &q->active);
375                 cl->deficit = cl->quantum;
376         }
377
378         bstats_update(&cl->bstats, skb);
379
380         sch->q.qlen++;
381         return err;
382 }
383
384 static struct sk_buff *drr_dequeue(struct Qdisc *sch)
385 {
386         struct drr_sched *q = qdisc_priv(sch);
387         struct drr_class *cl;
388         struct sk_buff *skb;
389         unsigned int len;
390
391         if (list_empty(&q->active))
392                 goto out;
393         while (1) {
394                 cl = list_first_entry(&q->active, struct drr_class, alist);
395                 skb = cl->qdisc->ops->peek(cl->qdisc);
396                 if (skb == NULL)
397                         goto out;
398
399                 len = qdisc_pkt_len(skb);
400                 if (len <= cl->deficit) {
401                         cl->deficit -= len;
402                         skb = qdisc_dequeue_peeked(cl->qdisc);
403                         if (cl->qdisc->q.qlen == 0)
404                                 list_del(&cl->alist);
405                         qdisc_bstats_update(sch, skb);
406                         sch->q.qlen--;
407                         return skb;
408                 }
409
410                 cl->deficit += cl->quantum;
411                 list_move_tail(&cl->alist, &q->active);
412         }
413 out:
414         return NULL;
415 }
416
417 static unsigned int drr_drop(struct Qdisc *sch)
418 {
419         struct drr_sched *q = qdisc_priv(sch);
420         struct drr_class *cl;
421         unsigned int len;
422
423         list_for_each_entry(cl, &q->active, alist) {
424                 if (cl->qdisc->ops->drop) {
425                         len = cl->qdisc->ops->drop(cl->qdisc);
426                         if (len > 0) {
427                                 sch->q.qlen--;
428                                 if (cl->qdisc->q.qlen == 0)
429                                         list_del(&cl->alist);
430                                 return len;
431                         }
432                 }
433         }
434         return 0;
435 }
436
437 static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
438 {
439         struct drr_sched *q = qdisc_priv(sch);
440         int err;
441
442         err = qdisc_class_hash_init(&q->clhash);
443         if (err < 0)
444                 return err;
445         INIT_LIST_HEAD(&q->active);
446         return 0;
447 }
448
449 static void drr_reset_qdisc(struct Qdisc *sch)
450 {
451         struct drr_sched *q = qdisc_priv(sch);
452         struct drr_class *cl;
453         struct hlist_node *n;
454         unsigned int i;
455
456         for (i = 0; i < q->clhash.hashsize; i++) {
457                 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
458                         if (cl->qdisc->q.qlen)
459                                 list_del(&cl->alist);
460                         qdisc_reset(cl->qdisc);
461                 }
462         }
463         sch->q.qlen = 0;
464 }
465
466 static void drr_destroy_qdisc(struct Qdisc *sch)
467 {
468         struct drr_sched *q = qdisc_priv(sch);
469         struct drr_class *cl;
470         struct hlist_node *n, *next;
471         unsigned int i;
472
473         tcf_destroy_chain(&q->filter_list);
474
475         for (i = 0; i < q->clhash.hashsize; i++) {
476                 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
477                                           common.hnode)
478                         drr_destroy_class(sch, cl);
479         }
480         qdisc_class_hash_destroy(&q->clhash);
481 }
482
483 static const struct Qdisc_class_ops drr_class_ops = {
484         .change         = drr_change_class,
485         .delete         = drr_delete_class,
486         .get            = drr_get_class,
487         .put            = drr_put_class,
488         .tcf_chain      = drr_tcf_chain,
489         .bind_tcf       = drr_bind_tcf,
490         .unbind_tcf     = drr_unbind_tcf,
491         .graft          = drr_graft_class,
492         .leaf           = drr_class_leaf,
493         .qlen_notify    = drr_qlen_notify,
494         .dump           = drr_dump_class,
495         .dump_stats     = drr_dump_class_stats,
496         .walk           = drr_walk,
497 };
498
499 static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
500         .cl_ops         = &drr_class_ops,
501         .id             = "drr",
502         .priv_size      = sizeof(struct drr_sched),
503         .enqueue        = drr_enqueue,
504         .dequeue        = drr_dequeue,
505         .peek           = qdisc_peek_dequeued,
506         .drop           = drr_drop,
507         .init           = drr_init_qdisc,
508         .reset          = drr_reset_qdisc,
509         .destroy        = drr_destroy_qdisc,
510         .owner          = THIS_MODULE,
511 };
512
513 static int __init drr_init(void)
514 {
515         return register_qdisc(&drr_qdisc_ops);
516 }
517
518 static void __exit drr_exit(void)
519 {
520         unregister_qdisc(&drr_qdisc_ops);
521 }
522
523 module_init(drr_init);
524 module_exit(drr_exit);
525 MODULE_LICENSE("GPL");