GNU Linux-libre 4.19.211-gnu1
[releases.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/slab.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/string.h>
19 #include <linux/errno.h>
20 #include <linux/skbuff.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23 #include <net/pkt_cls.h>
24
25 struct prio_sched_data {
26         int bands;
27         struct tcf_proto __rcu *filter_list;
28         struct tcf_block *block;
29         u8  prio2band[TC_PRIO_MAX+1];
30         struct Qdisc *queues[TCQ_PRIO_BANDS];
31 };
32
33
34 static struct Qdisc *
35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
36 {
37         struct prio_sched_data *q = qdisc_priv(sch);
38         u32 band = skb->priority;
39         struct tcf_result res;
40         struct tcf_proto *fl;
41         int err;
42
43         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
44         if (TC_H_MAJ(skb->priority) != sch->handle) {
45                 fl = rcu_dereference_bh(q->filter_list);
46                 err = tcf_classify(skb, fl, &res, false);
47 #ifdef CONFIG_NET_CLS_ACT
48                 switch (err) {
49                 case TC_ACT_STOLEN:
50                 case TC_ACT_QUEUED:
51                 case TC_ACT_TRAP:
52                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
53                         /* fall through */
54                 case TC_ACT_SHOT:
55                         return NULL;
56                 }
57 #endif
58                 if (!fl || err < 0) {
59                         if (TC_H_MAJ(band))
60                                 band = 0;
61                         return q->queues[q->prio2band[band & TC_PRIO_MAX]];
62                 }
63                 band = res.classid;
64         }
65         band = TC_H_MIN(band) - 1;
66         if (band >= q->bands)
67                 return q->queues[q->prio2band[0]];
68
69         return q->queues[band];
70 }
71
72 static int
73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
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                         qdisc_qstats_drop(sch);
84                 __qdisc_drop(skb, to_free);
85                 return ret;
86         }
87 #endif
88
89         ret = qdisc_enqueue(skb, qdisc, to_free);
90         if (ret == NET_XMIT_SUCCESS) {
91                 qdisc_qstats_backlog_inc(sch, skb);
92                 sch->q.qlen++;
93                 return NET_XMIT_SUCCESS;
94         }
95         if (net_xmit_drop_count(ret))
96                 qdisc_qstats_drop(sch);
97         return ret;
98 }
99
100 static struct sk_buff *prio_peek(struct Qdisc *sch)
101 {
102         struct prio_sched_data *q = qdisc_priv(sch);
103         int prio;
104
105         for (prio = 0; prio < q->bands; prio++) {
106                 struct Qdisc *qdisc = q->queues[prio];
107                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
108                 if (skb)
109                         return skb;
110         }
111         return NULL;
112 }
113
114 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
115 {
116         struct prio_sched_data *q = qdisc_priv(sch);
117         int prio;
118
119         for (prio = 0; prio < q->bands; prio++) {
120                 struct Qdisc *qdisc = q->queues[prio];
121                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
122                 if (skb) {
123                         qdisc_bstats_update(sch, skb);
124                         qdisc_qstats_backlog_dec(sch, skb);
125                         sch->q.qlen--;
126                         return skb;
127                 }
128         }
129         return NULL;
130
131 }
132
133 static void
134 prio_reset(struct Qdisc *sch)
135 {
136         int prio;
137         struct prio_sched_data *q = qdisc_priv(sch);
138
139         for (prio = 0; prio < q->bands; prio++)
140                 qdisc_reset(q->queues[prio]);
141         sch->qstats.backlog = 0;
142         sch->q.qlen = 0;
143 }
144
145 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
146 {
147         struct net_device *dev = qdisc_dev(sch);
148         struct tc_prio_qopt_offload opt = {
149                 .handle = sch->handle,
150                 .parent = sch->parent,
151         };
152
153         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
154                 return -EOPNOTSUPP;
155
156         if (qopt) {
157                 opt.command = TC_PRIO_REPLACE;
158                 opt.replace_params.bands = qopt->bands;
159                 memcpy(&opt.replace_params.priomap, qopt->priomap,
160                        TC_PRIO_MAX + 1);
161                 opt.replace_params.qstats = &sch->qstats;
162         } else {
163                 opt.command = TC_PRIO_DESTROY;
164         }
165
166         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt);
167 }
168
169 static void
170 prio_destroy(struct Qdisc *sch)
171 {
172         int prio;
173         struct prio_sched_data *q = qdisc_priv(sch);
174
175         tcf_block_put(q->block);
176         prio_offload(sch, NULL);
177         for (prio = 0; prio < q->bands; prio++)
178                 qdisc_destroy(q->queues[prio]);
179 }
180
181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt,
182                      struct netlink_ext_ack *extack)
183 {
184         struct prio_sched_data *q = qdisc_priv(sch);
185         struct Qdisc *queues[TCQ_PRIO_BANDS];
186         int oldbands = q->bands, i;
187         struct tc_prio_qopt *qopt;
188
189         if (nla_len(opt) < sizeof(*qopt))
190                 return -EINVAL;
191         qopt = nla_data(opt);
192
193         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
194                 return -EINVAL;
195
196         for (i = 0; i <= TC_PRIO_MAX; i++) {
197                 if (qopt->priomap[i] >= qopt->bands)
198                         return -EINVAL;
199         }
200
201         /* Before commit, make sure we can allocate all new qdiscs */
202         for (i = oldbands; i < qopt->bands; i++) {
203                 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
204                                               TC_H_MAKE(sch->handle, i + 1),
205                                               extack);
206                 if (!queues[i]) {
207                         while (i > oldbands)
208                                 qdisc_destroy(queues[--i]);
209                         return -ENOMEM;
210                 }
211         }
212
213         prio_offload(sch, qopt);
214         sch_tree_lock(sch);
215         q->bands = qopt->bands;
216         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
217
218         for (i = q->bands; i < oldbands; i++) {
219                 struct Qdisc *child = q->queues[i];
220
221                 qdisc_tree_reduce_backlog(child, child->q.qlen,
222                                           child->qstats.backlog);
223                 qdisc_destroy(child);
224         }
225
226         for (i = oldbands; i < q->bands; i++) {
227                 q->queues[i] = queues[i];
228                 if (q->queues[i] != &noop_qdisc)
229                         qdisc_hash_add(q->queues[i], true);
230         }
231
232         sch_tree_unlock(sch);
233         return 0;
234 }
235
236 static int prio_init(struct Qdisc *sch, struct nlattr *opt,
237                      struct netlink_ext_ack *extack)
238 {
239         struct prio_sched_data *q = qdisc_priv(sch);
240         int err;
241
242         if (!opt)
243                 return -EINVAL;
244
245         err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
246         if (err)
247                 return err;
248
249         return prio_tune(sch, opt, extack);
250 }
251
252 static int prio_dump_offload(struct Qdisc *sch)
253 {
254         struct net_device *dev = qdisc_dev(sch);
255         struct tc_prio_qopt_offload hw_stats = {
256                 .command = TC_PRIO_STATS,
257                 .handle = sch->handle,
258                 .parent = sch->parent,
259                 {
260                         .stats = {
261                                 .bstats = &sch->bstats,
262                                 .qstats = &sch->qstats,
263                         },
264                 },
265         };
266         int err;
267
268         sch->flags &= ~TCQ_F_OFFLOADED;
269         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
270                 return 0;
271
272         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
273                                             &hw_stats);
274         if (err == -EOPNOTSUPP)
275                 return 0;
276
277         if (!err)
278                 sch->flags |= TCQ_F_OFFLOADED;
279
280         return err;
281 }
282
283 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
284 {
285         struct prio_sched_data *q = qdisc_priv(sch);
286         unsigned char *b = skb_tail_pointer(skb);
287         struct tc_prio_qopt opt;
288         int err;
289
290         opt.bands = q->bands;
291         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
292
293         err = prio_dump_offload(sch);
294         if (err)
295                 goto nla_put_failure;
296
297         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
298                 goto nla_put_failure;
299
300         return skb->len;
301
302 nla_put_failure:
303         nlmsg_trim(skb, b);
304         return -1;
305 }
306
307 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
308                       struct Qdisc **old, struct netlink_ext_ack *extack)
309 {
310         struct prio_sched_data *q = qdisc_priv(sch);
311         struct tc_prio_qopt_offload graft_offload;
312         struct net_device *dev = qdisc_dev(sch);
313         unsigned long band = arg - 1;
314         bool any_qdisc_is_offloaded;
315         int err;
316
317         if (!new) {
318                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
319                                         TC_H_MAKE(sch->handle, arg), extack);
320                 if (!new)
321                         new = &noop_qdisc;
322                 else
323                         qdisc_hash_add(new, true);
324         }
325
326         *old = qdisc_replace(sch, new, &q->queues[band]);
327
328         if (!tc_can_offload(dev))
329                 return 0;
330
331         graft_offload.handle = sch->handle;
332         graft_offload.parent = sch->parent;
333         graft_offload.graft_params.band = band;
334         graft_offload.graft_params.child_handle = new->handle;
335         graft_offload.command = TC_PRIO_GRAFT;
336
337         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
338                                             &graft_offload);
339
340         /* Don't report error if the graft is part of destroy operation. */
341         if (err && new != &noop_qdisc) {
342                 /* Don't report error if the parent, the old child and the new
343                  * one are not offloaded.
344                  */
345                 any_qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
346                 any_qdisc_is_offloaded |= new->flags & TCQ_F_OFFLOADED;
347                 if (*old)
348                         any_qdisc_is_offloaded |= (*old)->flags &
349                                                    TCQ_F_OFFLOADED;
350
351                 if (any_qdisc_is_offloaded)
352                         NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
353         }
354
355         return 0;
356 }
357
358 static struct Qdisc *
359 prio_leaf(struct Qdisc *sch, unsigned long arg)
360 {
361         struct prio_sched_data *q = qdisc_priv(sch);
362         unsigned long band = arg - 1;
363
364         return q->queues[band];
365 }
366
367 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
368 {
369         struct prio_sched_data *q = qdisc_priv(sch);
370         unsigned long band = TC_H_MIN(classid);
371
372         if (band - 1 >= q->bands)
373                 return 0;
374         return band;
375 }
376
377 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
378 {
379         return prio_find(sch, classid);
380 }
381
382
383 static void prio_unbind(struct Qdisc *q, unsigned long cl)
384 {
385 }
386
387 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
388                            struct tcmsg *tcm)
389 {
390         struct prio_sched_data *q = qdisc_priv(sch);
391
392         tcm->tcm_handle |= TC_H_MIN(cl);
393         tcm->tcm_info = q->queues[cl-1]->handle;
394         return 0;
395 }
396
397 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
398                                  struct gnet_dump *d)
399 {
400         struct prio_sched_data *q = qdisc_priv(sch);
401         struct Qdisc *cl_q;
402
403         cl_q = q->queues[cl - 1];
404         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
405                                   d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
406             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
407                 return -1;
408
409         return 0;
410 }
411
412 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
413 {
414         struct prio_sched_data *q = qdisc_priv(sch);
415         int prio;
416
417         if (arg->stop)
418                 return;
419
420         for (prio = 0; prio < q->bands; prio++) {
421                 if (arg->count < arg->skip) {
422                         arg->count++;
423                         continue;
424                 }
425                 if (arg->fn(sch, prio + 1, arg) < 0) {
426                         arg->stop = 1;
427                         break;
428                 }
429                 arg->count++;
430         }
431 }
432
433 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
434                                         struct netlink_ext_ack *extack)
435 {
436         struct prio_sched_data *q = qdisc_priv(sch);
437
438         if (cl)
439                 return NULL;
440         return q->block;
441 }
442
443 static const struct Qdisc_class_ops prio_class_ops = {
444         .graft          =       prio_graft,
445         .leaf           =       prio_leaf,
446         .find           =       prio_find,
447         .walk           =       prio_walk,
448         .tcf_block      =       prio_tcf_block,
449         .bind_tcf       =       prio_bind,
450         .unbind_tcf     =       prio_unbind,
451         .dump           =       prio_dump_class,
452         .dump_stats     =       prio_dump_class_stats,
453 };
454
455 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
456         .next           =       NULL,
457         .cl_ops         =       &prio_class_ops,
458         .id             =       "prio",
459         .priv_size      =       sizeof(struct prio_sched_data),
460         .enqueue        =       prio_enqueue,
461         .dequeue        =       prio_dequeue,
462         .peek           =       prio_peek,
463         .init           =       prio_init,
464         .reset          =       prio_reset,
465         .destroy        =       prio_destroy,
466         .change         =       prio_tune,
467         .dump           =       prio_dump,
468         .owner          =       THIS_MODULE,
469 };
470
471 static int __init prio_module_init(void)
472 {
473         return register_qdisc(&prio_qdisc_ops);
474 }
475
476 static void __exit prio_module_exit(void)
477 {
478         unregister_qdisc(&prio_qdisc_ops);
479 }
480
481 module_init(prio_module_init)
482 module_exit(prio_module_exit)
483
484 MODULE_LICENSE("GPL");