[NET_SCHED]: Convert packet schedulers from rtnetlink to new netlink API
[linux-2.6.git] / 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         int err;
42
43         *qerr = NET_XMIT_BYPASS;
44         if (TC_H_MAJ(skb->priority) != sch->handle) {
45                 err = tc_classify(skb, q->filter_list, &res);
46 #ifdef CONFIG_NET_CLS_ACT
47                 switch (err) {
48                 case TC_ACT_STOLEN:
49                 case TC_ACT_QUEUED:
50                         *qerr = NET_XMIT_SUCCESS;
51                 case TC_ACT_SHOT:
52                         return NULL;
53                 }
54 #endif
55                 if (!q->filter_list || err < 0) {
56                         if (TC_H_MAJ(band))
57                                 band = 0;
58                         band = q->prio2band[band&TC_PRIO_MAX];
59                         goto out;
60                 }
61                 band = res.classid;
62         }
63         band = TC_H_MIN(band) - 1;
64         if (band >= q->bands)
65                 band = q->prio2band[0];
66 out:
67         if (q->mq)
68                 skb_set_queue_mapping(skb, band);
69         return q->queues[band];
70 }
71
72 static int
73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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                         sch->qstats.drops++;
84                 kfree_skb(skb);
85                 return ret;
86         }
87 #endif
88
89         if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) {
90                 sch->bstats.bytes += skb->len;
91                 sch->bstats.packets++;
92                 sch->q.qlen++;
93                 return NET_XMIT_SUCCESS;
94         }
95         sch->qstats.drops++;
96         return ret;
97 }
98
99
100 static int
101 prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
102 {
103         struct Qdisc *qdisc;
104         int ret;
105
106         qdisc = prio_classify(skb, sch, &ret);
107 #ifdef CONFIG_NET_CLS_ACT
108         if (qdisc == NULL) {
109                 if (ret == NET_XMIT_BYPASS)
110                         sch->qstats.drops++;
111                 kfree_skb(skb);
112                 return ret;
113         }
114 #endif
115
116         if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) {
117                 sch->q.qlen++;
118                 sch->qstats.requeues++;
119                 return 0;
120         }
121         sch->qstats.drops++;
122         return NET_XMIT_DROP;
123 }
124
125
126 static struct sk_buff *
127 prio_dequeue(struct Qdisc* sch)
128 {
129         struct sk_buff *skb;
130         struct prio_sched_data *q = qdisc_priv(sch);
131         int prio;
132         struct Qdisc *qdisc;
133
134         for (prio = 0; prio < q->bands; prio++) {
135                 /* Check if the target subqueue is available before
136                  * pulling an skb.  This way we avoid excessive requeues
137                  * for slower queues.
138                  */
139                 if (!__netif_subqueue_stopped(sch->dev, (q->mq ? prio : 0))) {
140                         qdisc = q->queues[prio];
141                         skb = qdisc->dequeue(qdisc);
142                         if (skb) {
143                                 sch->q.qlen--;
144                                 return skb;
145                         }
146                 }
147         }
148         return NULL;
149
150 }
151
152 static struct sk_buff *rr_dequeue(struct Qdisc* sch)
153 {
154         struct sk_buff *skb;
155         struct prio_sched_data *q = qdisc_priv(sch);
156         struct Qdisc *qdisc;
157         int bandcount;
158
159         /* Only take one pass through the queues.  If nothing is available,
160          * return nothing.
161          */
162         for (bandcount = 0; bandcount < q->bands; bandcount++) {
163                 /* Check if the target subqueue is available before
164                  * pulling an skb.  This way we avoid excessive requeues
165                  * for slower queues.  If the queue is stopped, try the
166                  * next queue.
167                  */
168                 if (!__netif_subqueue_stopped(sch->dev,
169                                             (q->mq ? q->curband : 0))) {
170                         qdisc = q->queues[q->curband];
171                         skb = qdisc->dequeue(qdisc);
172                         if (skb) {
173                                 sch->q.qlen--;
174                                 q->curband++;
175                                 if (q->curband >= q->bands)
176                                         q->curband = 0;
177                                 return skb;
178                         }
179                 }
180                 q->curband++;
181                 if (q->curband >= q->bands)
182                         q->curband = 0;
183         }
184         return NULL;
185 }
186
187 static unsigned int prio_drop(struct Qdisc* sch)
188 {
189         struct prio_sched_data *q = qdisc_priv(sch);
190         int prio;
191         unsigned int len;
192         struct Qdisc *qdisc;
193
194         for (prio = q->bands-1; prio >= 0; prio--) {
195                 qdisc = q->queues[prio];
196                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
197                         sch->q.qlen--;
198                         return len;
199                 }
200         }
201         return 0;
202 }
203
204
205 static void
206 prio_reset(struct Qdisc* sch)
207 {
208         int prio;
209         struct prio_sched_data *q = qdisc_priv(sch);
210
211         for (prio=0; prio<q->bands; prio++)
212                 qdisc_reset(q->queues[prio]);
213         sch->q.qlen = 0;
214 }
215
216 static void
217 prio_destroy(struct Qdisc* sch)
218 {
219         int prio;
220         struct prio_sched_data *q = qdisc_priv(sch);
221
222         tcf_destroy_chain(q->filter_list);
223         for (prio=0; prio<q->bands; prio++)
224                 qdisc_destroy(q->queues[prio]);
225 }
226
227 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
228 {
229         struct prio_sched_data *q = qdisc_priv(sch);
230         struct tc_prio_qopt *qopt;
231         struct nlattr *tb[TCA_PRIO_MAX + 1];
232         int i;
233
234         if (nla_parse_nested_compat(tb, TCA_PRIO_MAX, opt, NULL, qopt,
235                                     sizeof(*qopt)))
236                 return -EINVAL;
237         q->bands = qopt->bands;
238         /* If we're multiqueue, make sure the number of incoming bands
239          * matches the number of queues on the device we're associating with.
240          * If the number of bands requested is zero, then set q->bands to
241          * dev->egress_subqueue_count.  Also, the root qdisc must be the
242          * only one that is enabled for multiqueue, since it's the only one
243          * that interacts with the underlying device.
244          */
245         q->mq = nla_get_flag(tb[TCA_PRIO_MQ]);
246         if (q->mq) {
247                 if (sch->parent != TC_H_ROOT)
248                         return -EINVAL;
249                 if (netif_is_multiqueue(sch->dev)) {
250                         if (q->bands == 0)
251                                 q->bands = sch->dev->egress_subqueue_count;
252                         else if (q->bands != sch->dev->egress_subqueue_count)
253                                 return -EINVAL;
254                 } else
255                         return -EOPNOTSUPP;
256         }
257
258         if (q->bands > TCQ_PRIO_BANDS || q->bands < 2)
259                 return -EINVAL;
260
261         for (i=0; i<=TC_PRIO_MAX; i++) {
262                 if (qopt->priomap[i] >= q->bands)
263                         return -EINVAL;
264         }
265
266         sch_tree_lock(sch);
267         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
268
269         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
270                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
271                 if (child != &noop_qdisc) {
272                         qdisc_tree_decrease_qlen(child, child->q.qlen);
273                         qdisc_destroy(child);
274                 }
275         }
276         sch_tree_unlock(sch);
277
278         for (i=0; i<q->bands; i++) {
279                 if (q->queues[i] == &noop_qdisc) {
280                         struct Qdisc *child;
281                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
282                                                   TC_H_MAKE(sch->handle, i + 1));
283                         if (child) {
284                                 sch_tree_lock(sch);
285                                 child = xchg(&q->queues[i], child);
286
287                                 if (child != &noop_qdisc) {
288                                         qdisc_tree_decrease_qlen(child,
289                                                                  child->q.qlen);
290                                         qdisc_destroy(child);
291                                 }
292                                 sch_tree_unlock(sch);
293                         }
294                 }
295         }
296         return 0;
297 }
298
299 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
300 {
301         struct prio_sched_data *q = qdisc_priv(sch);
302         int i;
303
304         for (i=0; i<TCQ_PRIO_BANDS; i++)
305                 q->queues[i] = &noop_qdisc;
306
307         if (opt == NULL) {
308                 return -EINVAL;
309         } else {
310                 int err;
311
312                 if ((err= prio_tune(sch, opt)) != 0)
313                         return err;
314         }
315         return 0;
316 }
317
318 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
319 {
320         struct prio_sched_data *q = qdisc_priv(sch);
321         unsigned char *b = skb_tail_pointer(skb);
322         struct nlattr *nest;
323         struct tc_prio_qopt opt;
324
325         opt.bands = q->bands;
326         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
327
328         nest = nla_nest_compat_start(skb, TCA_OPTIONS, sizeof(opt), &opt);
329         if (nest == NULL)
330                 goto nla_put_failure;
331         if (q->mq) {
332                 if (nla_put_flag(skb, TCA_PRIO_MQ) < 0)
333                         goto nla_put_failure;
334         }
335         nla_nest_compat_end(skb, nest);
336
337         return skb->len;
338
339 nla_put_failure:
340         nlmsg_trim(skb, b);
341         return -1;
342 }
343
344 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
345                       struct Qdisc **old)
346 {
347         struct prio_sched_data *q = qdisc_priv(sch);
348         unsigned long band = arg - 1;
349
350         if (band >= q->bands)
351                 return -EINVAL;
352
353         if (new == NULL)
354                 new = &noop_qdisc;
355
356         sch_tree_lock(sch);
357         *old = q->queues[band];
358         q->queues[band] = new;
359         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
360         qdisc_reset(*old);
361         sch_tree_unlock(sch);
362
363         return 0;
364 }
365
366 static struct Qdisc *
367 prio_leaf(struct Qdisc *sch, unsigned long arg)
368 {
369         struct prio_sched_data *q = qdisc_priv(sch);
370         unsigned long band = arg - 1;
371
372         if (band >= q->bands)
373                 return NULL;
374
375         return q->queues[band];
376 }
377
378 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
379 {
380         struct prio_sched_data *q = qdisc_priv(sch);
381         unsigned long band = TC_H_MIN(classid);
382
383         if (band - 1 >= q->bands)
384                 return 0;
385         return band;
386 }
387
388 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
389 {
390         return prio_get(sch, classid);
391 }
392
393
394 static void prio_put(struct Qdisc *q, unsigned long cl)
395 {
396         return;
397 }
398
399 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg)
400 {
401         unsigned long cl = *arg;
402         struct prio_sched_data *q = qdisc_priv(sch);
403
404         if (cl - 1 > q->bands)
405                 return -ENOENT;
406         return 0;
407 }
408
409 static int prio_delete(struct Qdisc *sch, unsigned long cl)
410 {
411         struct prio_sched_data *q = qdisc_priv(sch);
412         if (cl - 1 > q->bands)
413                 return -ENOENT;
414         return 0;
415 }
416
417
418 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
419                            struct tcmsg *tcm)
420 {
421         struct prio_sched_data *q = qdisc_priv(sch);
422
423         if (cl - 1 > q->bands)
424                 return -ENOENT;
425         tcm->tcm_handle |= TC_H_MIN(cl);
426         if (q->queues[cl-1])
427                 tcm->tcm_info = q->queues[cl-1]->handle;
428         return 0;
429 }
430
431 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
432                                  struct gnet_dump *d)
433 {
434         struct prio_sched_data *q = qdisc_priv(sch);
435         struct Qdisc *cl_q;
436
437         cl_q = q->queues[cl - 1];
438         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
439             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
440                 return -1;
441
442         return 0;
443 }
444
445 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
446 {
447         struct prio_sched_data *q = qdisc_priv(sch);
448         int prio;
449
450         if (arg->stop)
451                 return;
452
453         for (prio = 0; prio < q->bands; prio++) {
454                 if (arg->count < arg->skip) {
455                         arg->count++;
456                         continue;
457                 }
458                 if (arg->fn(sch, prio+1, arg) < 0) {
459                         arg->stop = 1;
460                         break;
461                 }
462                 arg->count++;
463         }
464 }
465
466 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
467 {
468         struct prio_sched_data *q = qdisc_priv(sch);
469
470         if (cl)
471                 return NULL;
472         return &q->filter_list;
473 }
474
475 static const struct Qdisc_class_ops prio_class_ops = {
476         .graft          =       prio_graft,
477         .leaf           =       prio_leaf,
478         .get            =       prio_get,
479         .put            =       prio_put,
480         .change         =       prio_change,
481         .delete         =       prio_delete,
482         .walk           =       prio_walk,
483         .tcf_chain      =       prio_find_tcf,
484         .bind_tcf       =       prio_bind,
485         .unbind_tcf     =       prio_put,
486         .dump           =       prio_dump_class,
487         .dump_stats     =       prio_dump_class_stats,
488 };
489
490 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
491         .next           =       NULL,
492         .cl_ops         =       &prio_class_ops,
493         .id             =       "prio",
494         .priv_size      =       sizeof(struct prio_sched_data),
495         .enqueue        =       prio_enqueue,
496         .dequeue        =       prio_dequeue,
497         .requeue        =       prio_requeue,
498         .drop           =       prio_drop,
499         .init           =       prio_init,
500         .reset          =       prio_reset,
501         .destroy        =       prio_destroy,
502         .change         =       prio_tune,
503         .dump           =       prio_dump,
504         .owner          =       THIS_MODULE,
505 };
506
507 static struct Qdisc_ops rr_qdisc_ops __read_mostly = {
508         .next           =       NULL,
509         .cl_ops         =       &prio_class_ops,
510         .id             =       "rr",
511         .priv_size      =       sizeof(struct prio_sched_data),
512         .enqueue        =       prio_enqueue,
513         .dequeue        =       rr_dequeue,
514         .requeue        =       prio_requeue,
515         .drop           =       prio_drop,
516         .init           =       prio_init,
517         .reset          =       prio_reset,
518         .destroy        =       prio_destroy,
519         .change         =       prio_tune,
520         .dump           =       prio_dump,
521         .owner          =       THIS_MODULE,
522 };
523
524 static int __init prio_module_init(void)
525 {
526         int err;
527
528         err = register_qdisc(&prio_qdisc_ops);
529         if (err < 0)
530                 return err;
531         err = register_qdisc(&rr_qdisc_ops);
532         if (err < 0)
533                 unregister_qdisc(&prio_qdisc_ops);
534         return err;
535 }
536
537 static void __exit prio_module_exit(void)
538 {
539         unregister_qdisc(&prio_qdisc_ops);
540         unregister_qdisc(&rr_qdisc_ops);
541 }
542
543 module_init(prio_module_init)
544 module_exit(prio_module_exit)
545
546 MODULE_LICENSE("GPL");
547 MODULE_ALIAS("sch_rr");