[NET_SCHED]: Propagate nla_parse return value
[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 err;
233         int i;
234
235         err = nla_parse_nested_compat(tb, TCA_PRIO_MAX, opt, NULL, qopt,
236                                       sizeof(*qopt));
237         if (err < 0)
238                 return err;
239
240         q->bands = qopt->bands;
241         /* If we're multiqueue, make sure the number of incoming bands
242          * matches the number of queues on the device we're associating with.
243          * If the number of bands requested is zero, then set q->bands to
244          * dev->egress_subqueue_count.  Also, the root qdisc must be the
245          * only one that is enabled for multiqueue, since it's the only one
246          * that interacts with the underlying device.
247          */
248         q->mq = nla_get_flag(tb[TCA_PRIO_MQ]);
249         if (q->mq) {
250                 if (sch->parent != TC_H_ROOT)
251                         return -EINVAL;
252                 if (netif_is_multiqueue(sch->dev)) {
253                         if (q->bands == 0)
254                                 q->bands = sch->dev->egress_subqueue_count;
255                         else if (q->bands != sch->dev->egress_subqueue_count)
256                                 return -EINVAL;
257                 } else
258                         return -EOPNOTSUPP;
259         }
260
261         if (q->bands > TCQ_PRIO_BANDS || q->bands < 2)
262                 return -EINVAL;
263
264         for (i=0; i<=TC_PRIO_MAX; i++) {
265                 if (qopt->priomap[i] >= q->bands)
266                         return -EINVAL;
267         }
268
269         sch_tree_lock(sch);
270         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
271
272         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
273                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
274                 if (child != &noop_qdisc) {
275                         qdisc_tree_decrease_qlen(child, child->q.qlen);
276                         qdisc_destroy(child);
277                 }
278         }
279         sch_tree_unlock(sch);
280
281         for (i=0; i<q->bands; i++) {
282                 if (q->queues[i] == &noop_qdisc) {
283                         struct Qdisc *child;
284                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
285                                                   TC_H_MAKE(sch->handle, i + 1));
286                         if (child) {
287                                 sch_tree_lock(sch);
288                                 child = xchg(&q->queues[i], child);
289
290                                 if (child != &noop_qdisc) {
291                                         qdisc_tree_decrease_qlen(child,
292                                                                  child->q.qlen);
293                                         qdisc_destroy(child);
294                                 }
295                                 sch_tree_unlock(sch);
296                         }
297                 }
298         }
299         return 0;
300 }
301
302 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
303 {
304         struct prio_sched_data *q = qdisc_priv(sch);
305         int i;
306
307         for (i=0; i<TCQ_PRIO_BANDS; i++)
308                 q->queues[i] = &noop_qdisc;
309
310         if (opt == NULL) {
311                 return -EINVAL;
312         } else {
313                 int err;
314
315                 if ((err= prio_tune(sch, opt)) != 0)
316                         return err;
317         }
318         return 0;
319 }
320
321 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
322 {
323         struct prio_sched_data *q = qdisc_priv(sch);
324         unsigned char *b = skb_tail_pointer(skb);
325         struct nlattr *nest;
326         struct tc_prio_qopt opt;
327
328         opt.bands = q->bands;
329         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
330
331         nest = nla_nest_compat_start(skb, TCA_OPTIONS, sizeof(opt), &opt);
332         if (nest == NULL)
333                 goto nla_put_failure;
334         if (q->mq) {
335                 if (nla_put_flag(skb, TCA_PRIO_MQ) < 0)
336                         goto nla_put_failure;
337         }
338         nla_nest_compat_end(skb, nest);
339
340         return skb->len;
341
342 nla_put_failure:
343         nlmsg_trim(skb, b);
344         return -1;
345 }
346
347 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
348                       struct Qdisc **old)
349 {
350         struct prio_sched_data *q = qdisc_priv(sch);
351         unsigned long band = arg - 1;
352
353         if (band >= q->bands)
354                 return -EINVAL;
355
356         if (new == NULL)
357                 new = &noop_qdisc;
358
359         sch_tree_lock(sch);
360         *old = q->queues[band];
361         q->queues[band] = new;
362         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
363         qdisc_reset(*old);
364         sch_tree_unlock(sch);
365
366         return 0;
367 }
368
369 static struct Qdisc *
370 prio_leaf(struct Qdisc *sch, unsigned long arg)
371 {
372         struct prio_sched_data *q = qdisc_priv(sch);
373         unsigned long band = arg - 1;
374
375         if (band >= q->bands)
376                 return NULL;
377
378         return q->queues[band];
379 }
380
381 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
382 {
383         struct prio_sched_data *q = qdisc_priv(sch);
384         unsigned long band = TC_H_MIN(classid);
385
386         if (band - 1 >= q->bands)
387                 return 0;
388         return band;
389 }
390
391 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
392 {
393         return prio_get(sch, classid);
394 }
395
396
397 static void prio_put(struct Qdisc *q, unsigned long cl)
398 {
399         return;
400 }
401
402 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg)
403 {
404         unsigned long cl = *arg;
405         struct prio_sched_data *q = qdisc_priv(sch);
406
407         if (cl - 1 > q->bands)
408                 return -ENOENT;
409         return 0;
410 }
411
412 static int prio_delete(struct Qdisc *sch, unsigned long cl)
413 {
414         struct prio_sched_data *q = qdisc_priv(sch);
415         if (cl - 1 > q->bands)
416                 return -ENOENT;
417         return 0;
418 }
419
420
421 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
422                            struct tcmsg *tcm)
423 {
424         struct prio_sched_data *q = qdisc_priv(sch);
425
426         if (cl - 1 > q->bands)
427                 return -ENOENT;
428         tcm->tcm_handle |= TC_H_MIN(cl);
429         if (q->queues[cl-1])
430                 tcm->tcm_info = q->queues[cl-1]->handle;
431         return 0;
432 }
433
434 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
435                                  struct gnet_dump *d)
436 {
437         struct prio_sched_data *q = qdisc_priv(sch);
438         struct Qdisc *cl_q;
439
440         cl_q = q->queues[cl - 1];
441         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
442             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
443                 return -1;
444
445         return 0;
446 }
447
448 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
449 {
450         struct prio_sched_data *q = qdisc_priv(sch);
451         int prio;
452
453         if (arg->stop)
454                 return;
455
456         for (prio = 0; prio < q->bands; prio++) {
457                 if (arg->count < arg->skip) {
458                         arg->count++;
459                         continue;
460                 }
461                 if (arg->fn(sch, prio+1, arg) < 0) {
462                         arg->stop = 1;
463                         break;
464                 }
465                 arg->count++;
466         }
467 }
468
469 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
470 {
471         struct prio_sched_data *q = qdisc_priv(sch);
472
473         if (cl)
474                 return NULL;
475         return &q->filter_list;
476 }
477
478 static const struct Qdisc_class_ops prio_class_ops = {
479         .graft          =       prio_graft,
480         .leaf           =       prio_leaf,
481         .get            =       prio_get,
482         .put            =       prio_put,
483         .change         =       prio_change,
484         .delete         =       prio_delete,
485         .walk           =       prio_walk,
486         .tcf_chain      =       prio_find_tcf,
487         .bind_tcf       =       prio_bind,
488         .unbind_tcf     =       prio_put,
489         .dump           =       prio_dump_class,
490         .dump_stats     =       prio_dump_class_stats,
491 };
492
493 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
494         .next           =       NULL,
495         .cl_ops         =       &prio_class_ops,
496         .id             =       "prio",
497         .priv_size      =       sizeof(struct prio_sched_data),
498         .enqueue        =       prio_enqueue,
499         .dequeue        =       prio_dequeue,
500         .requeue        =       prio_requeue,
501         .drop           =       prio_drop,
502         .init           =       prio_init,
503         .reset          =       prio_reset,
504         .destroy        =       prio_destroy,
505         .change         =       prio_tune,
506         .dump           =       prio_dump,
507         .owner          =       THIS_MODULE,
508 };
509
510 static struct Qdisc_ops rr_qdisc_ops __read_mostly = {
511         .next           =       NULL,
512         .cl_ops         =       &prio_class_ops,
513         .id             =       "rr",
514         .priv_size      =       sizeof(struct prio_sched_data),
515         .enqueue        =       prio_enqueue,
516         .dequeue        =       rr_dequeue,
517         .requeue        =       prio_requeue,
518         .drop           =       prio_drop,
519         .init           =       prio_init,
520         .reset          =       prio_reset,
521         .destroy        =       prio_destroy,
522         .change         =       prio_tune,
523         .dump           =       prio_dump,
524         .owner          =       THIS_MODULE,
525 };
526
527 static int __init prio_module_init(void)
528 {
529         int err;
530
531         err = register_qdisc(&prio_qdisc_ops);
532         if (err < 0)
533                 return err;
534         err = register_qdisc(&rr_qdisc_ops);
535         if (err < 0)
536                 unregister_qdisc(&prio_qdisc_ops);
537         return err;
538 }
539
540 static void __exit prio_module_exit(void)
541 {
542         unregister_qdisc(&prio_qdisc_ops);
543         unregister_qdisc(&rr_qdisc_ops);
544 }
545
546 module_init(prio_module_init)
547 module_exit(prio_module_exit)
548
549 MODULE_LICENSE("GPL");
550 MODULE_ALIAS("sch_rr");