Pull video into release branch
[linux-2.6] / net / sched / sch_prio.c
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/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <net/netlink.h>
21 #include <net/pkt_sched.h>
22
23
24 struct prio_sched_data
25 {
26         int bands;
27         int curband; /* for round-robin */
28         struct tcf_proto *filter_list;
29         u8  prio2band[TC_PRIO_MAX+1];
30         struct Qdisc *queues[TCQ_PRIO_BANDS];
31         int mq;
32 };
33
34
35 static struct Qdisc *
36 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
37 {
38         struct prio_sched_data *q = qdisc_priv(sch);
39         u32 band = skb->priority;
40         struct tcf_result res;
41
42         *qerr = NET_XMIT_BYPASS;
43         if (TC_H_MAJ(skb->priority) != sch->handle) {
44 #ifdef CONFIG_NET_CLS_ACT
45                 switch (tc_classify(skb, q->filter_list, &res)) {
46                 case TC_ACT_STOLEN:
47                 case TC_ACT_QUEUED:
48                         *qerr = NET_XMIT_SUCCESS;
49                 case TC_ACT_SHOT:
50                         return NULL;
51                 }
52
53                 if (!q->filter_list ) {
54 #else
55                 if (!q->filter_list || tc_classify(skb, q->filter_list, &res)) {
56 #endif
57                         if (TC_H_MAJ(band))
58                                 band = 0;
59                         band = q->prio2band[band&TC_PRIO_MAX];
60                         goto out;
61                 }
62                 band = res.classid;
63         }
64         band = TC_H_MIN(band) - 1;
65         if (band >= q->bands)
66                 band = q->prio2band[0];
67 out:
68         if (q->mq)
69                 skb_set_queue_mapping(skb, band);
70         return q->queues[band];
71 }
72
73 static int
74 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
75 {
76         struct Qdisc *qdisc;
77         int ret;
78
79         qdisc = prio_classify(skb, sch, &ret);
80 #ifdef CONFIG_NET_CLS_ACT
81         if (qdisc == NULL) {
82
83                 if (ret == NET_XMIT_BYPASS)
84                         sch->qstats.drops++;
85                 kfree_skb(skb);
86                 return ret;
87         }
88 #endif
89
90         if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) {
91                 sch->bstats.bytes += skb->len;
92                 sch->bstats.packets++;
93                 sch->q.qlen++;
94                 return NET_XMIT_SUCCESS;
95         }
96         sch->qstats.drops++;
97         return ret;
98 }
99
100
101 static int
102 prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
103 {
104         struct Qdisc *qdisc;
105         int ret;
106
107         qdisc = prio_classify(skb, sch, &ret);
108 #ifdef CONFIG_NET_CLS_ACT
109         if (qdisc == NULL) {
110                 if (ret == NET_XMIT_BYPASS)
111                         sch->qstats.drops++;
112                 kfree_skb(skb);
113                 return ret;
114         }
115 #endif
116
117         if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) {
118                 sch->q.qlen++;
119                 sch->qstats.requeues++;
120                 return 0;
121         }
122         sch->qstats.drops++;
123         return NET_XMIT_DROP;
124 }
125
126
127 static struct sk_buff *
128 prio_dequeue(struct Qdisc* sch)
129 {
130         struct sk_buff *skb;
131         struct prio_sched_data *q = qdisc_priv(sch);
132         int prio;
133         struct Qdisc *qdisc;
134
135         for (prio = 0; prio < q->bands; prio++) {
136                 /* Check if the target subqueue is available before
137                  * pulling an skb.  This way we avoid excessive requeues
138                  * for slower queues.
139                  */
140                 if (!netif_subqueue_stopped(sch->dev, (q->mq ? prio : 0))) {
141                         qdisc = q->queues[prio];
142                         skb = qdisc->dequeue(qdisc);
143                         if (skb) {
144                                 sch->q.qlen--;
145                                 return skb;
146                         }
147                 }
148         }
149         return NULL;
150
151 }
152
153 static struct sk_buff *rr_dequeue(struct Qdisc* sch)
154 {
155         struct sk_buff *skb;
156         struct prio_sched_data *q = qdisc_priv(sch);
157         struct Qdisc *qdisc;
158         int bandcount;
159
160         /* Only take one pass through the queues.  If nothing is available,
161          * return nothing.
162          */
163         for (bandcount = 0; bandcount < q->bands; bandcount++) {
164                 /* Check if the target subqueue is available before
165                  * pulling an skb.  This way we avoid excessive requeues
166                  * for slower queues.  If the queue is stopped, try the
167                  * next queue.
168                  */
169                 if (!netif_subqueue_stopped(sch->dev,
170                                             (q->mq ? q->curband : 0))) {
171                         qdisc = q->queues[q->curband];
172                         skb = qdisc->dequeue(qdisc);
173                         if (skb) {
174                                 sch->q.qlen--;
175                                 q->curband++;
176                                 if (q->curband >= q->bands)
177                                         q->curband = 0;
178                                 return skb;
179                         }
180                 }
181                 q->curband++;
182                 if (q->curband >= q->bands)
183                         q->curband = 0;
184         }
185         return NULL;
186 }
187
188 static unsigned int prio_drop(struct Qdisc* sch)
189 {
190         struct prio_sched_data *q = qdisc_priv(sch);
191         int prio;
192         unsigned int len;
193         struct Qdisc *qdisc;
194
195         for (prio = q->bands-1; prio >= 0; prio--) {
196                 qdisc = q->queues[prio];
197                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
198                         sch->q.qlen--;
199                         return len;
200                 }
201         }
202         return 0;
203 }
204
205
206 static void
207 prio_reset(struct Qdisc* sch)
208 {
209         int prio;
210         struct prio_sched_data *q = qdisc_priv(sch);
211
212         for (prio=0; prio<q->bands; prio++)
213                 qdisc_reset(q->queues[prio]);
214         sch->q.qlen = 0;
215 }
216
217 static void
218 prio_destroy(struct Qdisc* sch)
219 {
220         int prio;
221         struct prio_sched_data *q = qdisc_priv(sch);
222
223         tcf_destroy_chain(q->filter_list);
224         for (prio=0; prio<q->bands; prio++)
225                 qdisc_destroy(q->queues[prio]);
226 }
227
228 static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
229 {
230         struct prio_sched_data *q = qdisc_priv(sch);
231         struct tc_prio_qopt *qopt;
232         struct rtattr *tb[TCA_PRIO_MAX];
233         int i;
234
235         if (rtattr_parse_nested_compat(tb, TCA_PRIO_MAX, opt, qopt,
236                                        sizeof(*qopt)))
237                 return -EINVAL;
238         q->bands = qopt->bands;
239         /* If we're multiqueue, make sure the number of incoming bands
240          * matches the number of queues on the device we're associating with.
241          * If the number of bands requested is zero, then set q->bands to
242          * dev->egress_subqueue_count.
243          */
244         q->mq = RTA_GET_FLAG(tb[TCA_PRIO_MQ - 1]);
245         if (q->mq) {
246                 if (sch->handle != TC_H_ROOT)
247                         return -EINVAL;
248                 if (netif_is_multiqueue(sch->dev)) {
249                         if (q->bands == 0)
250                                 q->bands = sch->dev->egress_subqueue_count;
251                         else if (q->bands != sch->dev->egress_subqueue_count)
252                                 return -EINVAL;
253                 } else
254                         return -EOPNOTSUPP;
255         }
256
257         if (q->bands > TCQ_PRIO_BANDS || q->bands < 2)
258                 return -EINVAL;
259
260         for (i=0; i<=TC_PRIO_MAX; i++) {
261                 if (qopt->priomap[i] >= q->bands)
262                         return -EINVAL;
263         }
264
265         sch_tree_lock(sch);
266         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
267
268         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
269                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
270                 if (child != &noop_qdisc) {
271                         qdisc_tree_decrease_qlen(child, child->q.qlen);
272                         qdisc_destroy(child);
273                 }
274         }
275         sch_tree_unlock(sch);
276
277         for (i=0; i<q->bands; i++) {
278                 if (q->queues[i] == &noop_qdisc) {
279                         struct Qdisc *child;
280                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
281                                                   TC_H_MAKE(sch->handle, i + 1));
282                         if (child) {
283                                 sch_tree_lock(sch);
284                                 child = xchg(&q->queues[i], child);
285
286                                 if (child != &noop_qdisc) {
287                                         qdisc_tree_decrease_qlen(child,
288                                                                  child->q.qlen);
289                                         qdisc_destroy(child);
290                                 }
291                                 sch_tree_unlock(sch);
292                         }
293                 }
294         }
295         return 0;
296 }
297
298 static int prio_init(struct Qdisc *sch, struct rtattr *opt)
299 {
300         struct prio_sched_data *q = qdisc_priv(sch);
301         int i;
302
303         for (i=0; i<TCQ_PRIO_BANDS; i++)
304                 q->queues[i] = &noop_qdisc;
305
306         if (opt == NULL) {
307                 return -EINVAL;
308         } else {
309                 int err;
310
311                 if ((err= prio_tune(sch, opt)) != 0)
312                         return err;
313         }
314         return 0;
315 }
316
317 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
318 {
319         struct prio_sched_data *q = qdisc_priv(sch);
320         unsigned char *b = skb_tail_pointer(skb);
321         struct rtattr *nest;
322         struct tc_prio_qopt opt;
323
324         opt.bands = q->bands;
325         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
326
327         nest = RTA_NEST_COMPAT(skb, TCA_OPTIONS, sizeof(opt), &opt);
328         if (q->mq)
329                 RTA_PUT_FLAG(skb, TCA_PRIO_MQ);
330         RTA_NEST_COMPAT_END(skb, nest);
331
332         return skb->len;
333
334 rtattr_failure:
335         nlmsg_trim(skb, b);
336         return -1;
337 }
338
339 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
340                       struct Qdisc **old)
341 {
342         struct prio_sched_data *q = qdisc_priv(sch);
343         unsigned long band = arg - 1;
344
345         if (band >= q->bands)
346                 return -EINVAL;
347
348         if (new == NULL)
349                 new = &noop_qdisc;
350
351         sch_tree_lock(sch);
352         *old = q->queues[band];
353         q->queues[band] = new;
354         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
355         qdisc_reset(*old);
356         sch_tree_unlock(sch);
357
358         return 0;
359 }
360
361 static struct Qdisc *
362 prio_leaf(struct Qdisc *sch, unsigned long arg)
363 {
364         struct prio_sched_data *q = qdisc_priv(sch);
365         unsigned long band = arg - 1;
366
367         if (band >= q->bands)
368                 return NULL;
369
370         return q->queues[band];
371 }
372
373 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
374 {
375         struct prio_sched_data *q = qdisc_priv(sch);
376         unsigned long band = TC_H_MIN(classid);
377
378         if (band - 1 >= q->bands)
379                 return 0;
380         return band;
381 }
382
383 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
384 {
385         return prio_get(sch, classid);
386 }
387
388
389 static void prio_put(struct Qdisc *q, unsigned long cl)
390 {
391         return;
392 }
393
394 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct rtattr **tca, unsigned long *arg)
395 {
396         unsigned long cl = *arg;
397         struct prio_sched_data *q = qdisc_priv(sch);
398
399         if (cl - 1 > q->bands)
400                 return -ENOENT;
401         return 0;
402 }
403
404 static int prio_delete(struct Qdisc *sch, unsigned long cl)
405 {
406         struct prio_sched_data *q = qdisc_priv(sch);
407         if (cl - 1 > q->bands)
408                 return -ENOENT;
409         return 0;
410 }
411
412
413 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
414                            struct tcmsg *tcm)
415 {
416         struct prio_sched_data *q = qdisc_priv(sch);
417
418         if (cl - 1 > q->bands)
419                 return -ENOENT;
420         tcm->tcm_handle |= TC_H_MIN(cl);
421         if (q->queues[cl-1])
422                 tcm->tcm_info = q->queues[cl-1]->handle;
423         return 0;
424 }
425
426 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
427                                  struct gnet_dump *d)
428 {
429         struct prio_sched_data *q = qdisc_priv(sch);
430         struct Qdisc *cl_q;
431
432         cl_q = q->queues[cl - 1];
433         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
434             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
435                 return -1;
436
437         return 0;
438 }
439
440 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
441 {
442         struct prio_sched_data *q = qdisc_priv(sch);
443         int prio;
444
445         if (arg->stop)
446                 return;
447
448         for (prio = 0; prio < q->bands; prio++) {
449                 if (arg->count < arg->skip) {
450                         arg->count++;
451                         continue;
452                 }
453                 if (arg->fn(sch, prio+1, arg) < 0) {
454                         arg->stop = 1;
455                         break;
456                 }
457                 arg->count++;
458         }
459 }
460
461 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
462 {
463         struct prio_sched_data *q = qdisc_priv(sch);
464
465         if (cl)
466                 return NULL;
467         return &q->filter_list;
468 }
469
470 static struct Qdisc_class_ops prio_class_ops = {
471         .graft          =       prio_graft,
472         .leaf           =       prio_leaf,
473         .get            =       prio_get,
474         .put            =       prio_put,
475         .change         =       prio_change,
476         .delete         =       prio_delete,
477         .walk           =       prio_walk,
478         .tcf_chain      =       prio_find_tcf,
479         .bind_tcf       =       prio_bind,
480         .unbind_tcf     =       prio_put,
481         .dump           =       prio_dump_class,
482         .dump_stats     =       prio_dump_class_stats,
483 };
484
485 static struct Qdisc_ops prio_qdisc_ops = {
486         .next           =       NULL,
487         .cl_ops         =       &prio_class_ops,
488         .id             =       "prio",
489         .priv_size      =       sizeof(struct prio_sched_data),
490         .enqueue        =       prio_enqueue,
491         .dequeue        =       prio_dequeue,
492         .requeue        =       prio_requeue,
493         .drop           =       prio_drop,
494         .init           =       prio_init,
495         .reset          =       prio_reset,
496         .destroy        =       prio_destroy,
497         .change         =       prio_tune,
498         .dump           =       prio_dump,
499         .owner          =       THIS_MODULE,
500 };
501
502 static struct Qdisc_ops rr_qdisc_ops = {
503         .next           =       NULL,
504         .cl_ops         =       &prio_class_ops,
505         .id             =       "rr",
506         .priv_size      =       sizeof(struct prio_sched_data),
507         .enqueue        =       prio_enqueue,
508         .dequeue        =       rr_dequeue,
509         .requeue        =       prio_requeue,
510         .drop           =       prio_drop,
511         .init           =       prio_init,
512         .reset          =       prio_reset,
513         .destroy        =       prio_destroy,
514         .change         =       prio_tune,
515         .dump           =       prio_dump,
516         .owner          =       THIS_MODULE,
517 };
518
519 static int __init prio_module_init(void)
520 {
521         int err;
522
523         err = register_qdisc(&prio_qdisc_ops);
524         if (err < 0)
525                 return err;
526         err = register_qdisc(&rr_qdisc_ops);
527         if (err < 0)
528                 unregister_qdisc(&prio_qdisc_ops);
529         return err;
530 }
531
532 static void __exit prio_module_exit(void)
533 {
534         unregister_qdisc(&prio_qdisc_ops);
535         unregister_qdisc(&rr_qdisc_ops);
536 }
537
538 module_init(prio_module_init)
539 module_exit(prio_module_exit)
540
541 MODULE_LICENSE("GPL");
542 MODULE_ALIAS("sch_rr");