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53#include <linux/module.h>
54#include <linux/types.h>
55#include <linux/kernel.h>
56#include <linux/string.h>
57#include <linux/errno.h>
58#include <linux/skbuff.h>
59#include <net/netevent.h>
60#include <net/netlink.h>
61#include <net/sch_generic.h>
62#include <net/pkt_sched.h>
63
64static LIST_HEAD(cbs_list);
65static DEFINE_SPINLOCK(cbs_list_lock);
66
67#define BYTES_PER_KBIT (1000LL / 8)
68
69struct cbs_sched_data {
70 bool offload;
71 int queue;
72 atomic64_t port_rate;
73 s64 last;
74 s64 credits;
75 s32 locredit;
76 s32 hicredit;
77 s64 sendslope;
78 s64 idleslope;
79 struct qdisc_watchdog watchdog;
80 int (*enqueue)(struct sk_buff *skb, struct Qdisc *sch,
81 struct sk_buff **to_free);
82 struct sk_buff *(*dequeue)(struct Qdisc *sch);
83 struct Qdisc *qdisc;
84 struct list_head cbs_list;
85};
86
87static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,
88 struct Qdisc *child,
89 struct sk_buff **to_free)
90{
91 unsigned int len = qdisc_pkt_len(skb);
92 int err;
93
94 err = child->ops->enqueue(skb, child, to_free);
95 if (err != NET_XMIT_SUCCESS)
96 return err;
97
98 sch->qstats.backlog += len;
99 sch->q.qlen++;
100
101 return NET_XMIT_SUCCESS;
102}
103
104static int cbs_enqueue_offload(struct sk_buff *skb, struct Qdisc *sch,
105 struct sk_buff **to_free)
106{
107 struct cbs_sched_data *q = qdisc_priv(sch);
108 struct Qdisc *qdisc = q->qdisc;
109
110 return cbs_child_enqueue(skb, sch, qdisc, to_free);
111}
112
113static int cbs_enqueue_soft(struct sk_buff *skb, struct Qdisc *sch,
114 struct sk_buff **to_free)
115{
116 struct cbs_sched_data *q = qdisc_priv(sch);
117 struct Qdisc *qdisc = q->qdisc;
118
119 if (sch->q.qlen == 0 && q->credits > 0) {
120
121
122
123 q->credits = 0;
124 q->last = ktime_get_ns();
125 }
126
127 return cbs_child_enqueue(skb, sch, qdisc, to_free);
128}
129
130static int cbs_enqueue(struct sk_buff *skb, struct Qdisc *sch,
131 struct sk_buff **to_free)
132{
133 struct cbs_sched_data *q = qdisc_priv(sch);
134
135 return q->enqueue(skb, sch, to_free);
136}
137
138
139static s64 timediff_to_credits(s64 timediff, s64 slope)
140{
141 return div64_s64(timediff * slope, NSEC_PER_SEC);
142}
143
144static s64 delay_from_credits(s64 credits, s64 slope)
145{
146 if (unlikely(slope == 0))
147 return S64_MAX;
148
149 return div64_s64(-credits * NSEC_PER_SEC, slope);
150}
151
152static s64 credits_from_len(unsigned int len, s64 slope, s64 port_rate)
153{
154 if (unlikely(port_rate == 0))
155 return S64_MAX;
156
157 return div64_s64(len * slope, port_rate);
158}
159
160static struct sk_buff *cbs_child_dequeue(struct Qdisc *sch, struct Qdisc *child)
161{
162 struct sk_buff *skb;
163
164 skb = child->ops->dequeue(child);
165 if (!skb)
166 return NULL;
167
168 qdisc_qstats_backlog_dec(sch, skb);
169 qdisc_bstats_update(sch, skb);
170 sch->q.qlen--;
171
172 return skb;
173}
174
175static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
176{
177 struct cbs_sched_data *q = qdisc_priv(sch);
178 struct Qdisc *qdisc = q->qdisc;
179 s64 now = ktime_get_ns();
180 struct sk_buff *skb;
181 s64 credits;
182 int len;
183
184 if (q->credits < 0) {
185 credits = timediff_to_credits(now - q->last, q->idleslope);
186
187 credits = q->credits + credits;
188 q->credits = min_t(s64, credits, q->hicredit);
189
190 if (q->credits < 0) {
191 s64 delay;
192
193 delay = delay_from_credits(q->credits, q->idleslope);
194 qdisc_watchdog_schedule_ns(&q->watchdog, now + delay);
195
196 q->last = now;
197
198 return NULL;
199 }
200 }
201 skb = cbs_child_dequeue(sch, qdisc);
202 if (!skb)
203 return NULL;
204
205 len = qdisc_pkt_len(skb);
206
207
208
209
210 credits = credits_from_len(len, q->sendslope,
211 atomic64_read(&q->port_rate));
212 credits += q->credits;
213
214 q->credits = max_t(s64, credits, q->locredit);
215 q->last = now;
216
217 return skb;
218}
219
220static struct sk_buff *cbs_dequeue_offload(struct Qdisc *sch)
221{
222 struct cbs_sched_data *q = qdisc_priv(sch);
223 struct Qdisc *qdisc = q->qdisc;
224
225 return cbs_child_dequeue(sch, qdisc);
226}
227
228static struct sk_buff *cbs_dequeue(struct Qdisc *sch)
229{
230 struct cbs_sched_data *q = qdisc_priv(sch);
231
232 return q->dequeue(sch);
233}
234
235static const struct nla_policy cbs_policy[TCA_CBS_MAX + 1] = {
236 [TCA_CBS_PARMS] = { .len = sizeof(struct tc_cbs_qopt) },
237};
238
239static void cbs_disable_offload(struct net_device *dev,
240 struct cbs_sched_data *q)
241{
242 struct tc_cbs_qopt_offload cbs = { };
243 const struct net_device_ops *ops;
244 int err;
245
246 if (!q->offload)
247 return;
248
249 q->enqueue = cbs_enqueue_soft;
250 q->dequeue = cbs_dequeue_soft;
251
252 ops = dev->netdev_ops;
253 if (!ops->ndo_setup_tc)
254 return;
255
256 cbs.queue = q->queue;
257 cbs.enable = 0;
258
259 err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_CBS, &cbs);
260 if (err < 0)
261 pr_warn("Couldn't disable CBS offload for queue %d\n",
262 cbs.queue);
263}
264
265static int cbs_enable_offload(struct net_device *dev, struct cbs_sched_data *q,
266 const struct tc_cbs_qopt *opt,
267 struct netlink_ext_ack *extack)
268{
269 const struct net_device_ops *ops = dev->netdev_ops;
270 struct tc_cbs_qopt_offload cbs = { };
271 int err;
272
273 if (!ops->ndo_setup_tc) {
274 NL_SET_ERR_MSG(extack, "Specified device does not support cbs offload");
275 return -EOPNOTSUPP;
276 }
277
278 cbs.queue = q->queue;
279
280 cbs.enable = 1;
281 cbs.hicredit = opt->hicredit;
282 cbs.locredit = opt->locredit;
283 cbs.idleslope = opt->idleslope;
284 cbs.sendslope = opt->sendslope;
285
286 err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_CBS, &cbs);
287 if (err < 0) {
288 NL_SET_ERR_MSG(extack, "Specified device failed to setup cbs hardware offload");
289 return err;
290 }
291
292 q->enqueue = cbs_enqueue_offload;
293 q->dequeue = cbs_dequeue_offload;
294
295 return 0;
296}
297
298static void cbs_set_port_rate(struct net_device *dev, struct cbs_sched_data *q)
299{
300 struct ethtool_link_ksettings ecmd;
301 int speed = SPEED_10;
302 int port_rate = -1;
303 int err;
304
305 err = __ethtool_get_link_ksettings(dev, &ecmd);
306 if (err < 0)
307 goto skip;
308
309 if (ecmd.base.speed != SPEED_UNKNOWN)
310 speed = ecmd.base.speed;
311
312skip:
313 port_rate = speed * 1000 * BYTES_PER_KBIT;
314
315 atomic64_set(&q->port_rate, port_rate);
316 netdev_dbg(dev, "cbs: set %s's port_rate to: %lld, linkspeed: %d\n",
317 dev->name, (long long)atomic64_read(&q->port_rate),
318 ecmd.base.speed);
319}
320
321static int cbs_dev_notifier(struct notifier_block *nb, unsigned long event,
322 void *ptr)
323{
324 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
325 struct cbs_sched_data *q;
326 struct net_device *qdev;
327 bool found = false;
328
329 ASSERT_RTNL();
330
331 if (event != NETDEV_UP && event != NETDEV_CHANGE)
332 return NOTIFY_DONE;
333
334 spin_lock(&cbs_list_lock);
335 list_for_each_entry(q, &cbs_list, cbs_list) {
336 qdev = qdisc_dev(q->qdisc);
337 if (qdev == dev) {
338 found = true;
339 break;
340 }
341 }
342 spin_unlock(&cbs_list_lock);
343
344 if (found)
345 cbs_set_port_rate(dev, q);
346
347 return NOTIFY_DONE;
348}
349
350static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
351 struct netlink_ext_ack *extack)
352{
353 struct cbs_sched_data *q = qdisc_priv(sch);
354 struct net_device *dev = qdisc_dev(sch);
355 struct nlattr *tb[TCA_CBS_MAX + 1];
356 struct tc_cbs_qopt *qopt;
357 int err;
358
359 err = nla_parse_nested_deprecated(tb, TCA_CBS_MAX, opt, cbs_policy,
360 extack);
361 if (err < 0)
362 return err;
363
364 if (!tb[TCA_CBS_PARMS]) {
365 NL_SET_ERR_MSG(extack, "Missing CBS parameter which are mandatory");
366 return -EINVAL;
367 }
368
369 qopt = nla_data(tb[TCA_CBS_PARMS]);
370
371 if (!qopt->offload) {
372 cbs_set_port_rate(dev, q);
373 cbs_disable_offload(dev, q);
374 } else {
375 err = cbs_enable_offload(dev, q, qopt, extack);
376 if (err < 0)
377 return err;
378 }
379
380
381 q->hicredit = qopt->hicredit;
382 q->locredit = qopt->locredit;
383 q->idleslope = qopt->idleslope * BYTES_PER_KBIT;
384 q->sendslope = qopt->sendslope * BYTES_PER_KBIT;
385 q->offload = qopt->offload;
386
387 return 0;
388}
389
390static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
391 struct netlink_ext_ack *extack)
392{
393 struct cbs_sched_data *q = qdisc_priv(sch);
394 struct net_device *dev = qdisc_dev(sch);
395 int err;
396
397 if (!opt) {
398 NL_SET_ERR_MSG(extack, "Missing CBS qdisc options which are mandatory");
399 return -EINVAL;
400 }
401
402 q->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
403 sch->handle, extack);
404 if (!q->qdisc)
405 return -ENOMEM;
406
407 qdisc_hash_add(q->qdisc, false);
408
409 q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
410
411 q->enqueue = cbs_enqueue_soft;
412 q->dequeue = cbs_dequeue_soft;
413
414 qdisc_watchdog_init(&q->watchdog, sch);
415
416 err = cbs_change(sch, opt, extack);
417 if (err)
418 return err;
419
420 if (!q->offload) {
421 spin_lock(&cbs_list_lock);
422 list_add(&q->cbs_list, &cbs_list);
423 spin_unlock(&cbs_list_lock);
424 }
425
426 return 0;
427}
428
429static void cbs_destroy(struct Qdisc *sch)
430{
431 struct cbs_sched_data *q = qdisc_priv(sch);
432 struct net_device *dev = qdisc_dev(sch);
433
434 spin_lock(&cbs_list_lock);
435 list_del(&q->cbs_list);
436 spin_unlock(&cbs_list_lock);
437
438 qdisc_watchdog_cancel(&q->watchdog);
439 cbs_disable_offload(dev, q);
440
441 if (q->qdisc)
442 qdisc_put(q->qdisc);
443}
444
445static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)
446{
447 struct cbs_sched_data *q = qdisc_priv(sch);
448 struct tc_cbs_qopt opt = { };
449 struct nlattr *nest;
450
451 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
452 if (!nest)
453 goto nla_put_failure;
454
455 opt.hicredit = q->hicredit;
456 opt.locredit = q->locredit;
457 opt.sendslope = div64_s64(q->sendslope, BYTES_PER_KBIT);
458 opt.idleslope = div64_s64(q->idleslope, BYTES_PER_KBIT);
459 opt.offload = q->offload;
460
461 if (nla_put(skb, TCA_CBS_PARMS, sizeof(opt), &opt))
462 goto nla_put_failure;
463
464 return nla_nest_end(skb, nest);
465
466nla_put_failure:
467 nla_nest_cancel(skb, nest);
468 return -1;
469}
470
471static int cbs_dump_class(struct Qdisc *sch, unsigned long cl,
472 struct sk_buff *skb, struct tcmsg *tcm)
473{
474 struct cbs_sched_data *q = qdisc_priv(sch);
475
476 if (cl != 1 || !q->qdisc)
477 return -ENOENT;
478
479 tcm->tcm_handle |= TC_H_MIN(1);
480 tcm->tcm_info = q->qdisc->handle;
481
482 return 0;
483}
484
485static int cbs_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
486 struct Qdisc **old, struct netlink_ext_ack *extack)
487{
488 struct cbs_sched_data *q = qdisc_priv(sch);
489
490 if (!new) {
491 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
492 sch->handle, NULL);
493 if (!new)
494 new = &noop_qdisc;
495 }
496
497 *old = qdisc_replace(sch, new, &q->qdisc);
498 return 0;
499}
500
501static struct Qdisc *cbs_leaf(struct Qdisc *sch, unsigned long arg)
502{
503 struct cbs_sched_data *q = qdisc_priv(sch);
504
505 return q->qdisc;
506}
507
508static unsigned long cbs_find(struct Qdisc *sch, u32 classid)
509{
510 return 1;
511}
512
513static void cbs_walk(struct Qdisc *sch, struct qdisc_walker *walker)
514{
515 if (!walker->stop) {
516 if (walker->count >= walker->skip) {
517 if (walker->fn(sch, 1, walker) < 0) {
518 walker->stop = 1;
519 return;
520 }
521 }
522 walker->count++;
523 }
524}
525
526static const struct Qdisc_class_ops cbs_class_ops = {
527 .graft = cbs_graft,
528 .leaf = cbs_leaf,
529 .find = cbs_find,
530 .walk = cbs_walk,
531 .dump = cbs_dump_class,
532};
533
534static struct Qdisc_ops cbs_qdisc_ops __read_mostly = {
535 .id = "cbs",
536 .cl_ops = &cbs_class_ops,
537 .priv_size = sizeof(struct cbs_sched_data),
538 .enqueue = cbs_enqueue,
539 .dequeue = cbs_dequeue,
540 .peek = qdisc_peek_dequeued,
541 .init = cbs_init,
542 .reset = qdisc_reset_queue,
543 .destroy = cbs_destroy,
544 .change = cbs_change,
545 .dump = cbs_dump,
546 .owner = THIS_MODULE,
547};
548
549static struct notifier_block cbs_device_notifier = {
550 .notifier_call = cbs_dev_notifier,
551};
552
553static int __init cbs_module_init(void)
554{
555 int err;
556
557 err = register_netdevice_notifier(&cbs_device_notifier);
558 if (err)
559 return err;
560
561 err = register_qdisc(&cbs_qdisc_ops);
562 if (err)
563 unregister_netdevice_notifier(&cbs_device_notifier);
564
565 return err;
566}
567
568static void __exit cbs_module_exit(void)
569{
570 unregister_qdisc(&cbs_qdisc_ops);
571 unregister_netdevice_notifier(&cbs_device_notifier);
572}
573module_init(cbs_module_init)
574module_exit(cbs_module_exit)
575MODULE_LICENSE("GPL");
576