summaryrefslogtreecommitdiffstats
path: root/net/sched/sch_taprio.c
blob: 6b37ffda23ecd821c9192913a832b44673bfa523 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
// SPDX-License-Identifier: GPL-2.0

/* net/sched/sch_taprio.c	 Time Aware Priority Scheduler
 *
 * Authors:	Vinicius Costa Gomes <vinicius.gomes@intel.com>
 *
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/sch_generic.h>

static LIST_HEAD(taprio_list);
static DEFINE_SPINLOCK(taprio_list_lock);

#define TAPRIO_ALL_GATES_OPEN -1

struct sched_entry {
	struct list_head list;

	/* The instant that this entry "closes" and the next one
	 * should open, the qdisc will make some effort so that no
	 * packet leaves after this time.
	 */
	ktime_t close_time;
	atomic_t budget;
	int index;
	u32 gate_mask;
	u32 interval;
	u8 command;
};

struct sched_gate_list {
	struct rcu_head rcu;
	struct list_head entries;
	size_t num_entries;
	ktime_t cycle_close_time;
	s64 cycle_time;
	s64 base_time;
};

struct taprio_sched {
	struct Qdisc **qdiscs;
	struct Qdisc *root;
	int clockid;
	atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+
				    * speeds it's sub-nanoseconds per byte
				    */

	/* Protects the update side of the RCU protected current_entry */
	spinlock_t current_entry_lock;
	struct sched_entry __rcu *current_entry;
	struct sched_gate_list __rcu *oper_sched;
	struct sched_gate_list __rcu *admin_sched;
	ktime_t (*get_time)(void);
	struct hrtimer advance_timer;
	struct list_head taprio_list;
};

static ktime_t sched_base_time(const struct sched_gate_list *sched)
{
	if (!sched)
		return KTIME_MAX;

	return ns_to_ktime(sched->base_time);
}

static void taprio_free_sched_cb(struct rcu_head *head)
{
	struct sched_gate_list *sched = container_of(head, struct sched_gate_list, rcu);
	struct sched_entry *entry, *n;

	if (!sched)
		return;

	list_for_each_entry_safe(entry, n, &sched->entries, list) {
		list_del(&entry->list);
		kfree(entry);
	}

	kfree(sched);
}

static void switch_schedules(struct taprio_sched *q,
			     struct sched_gate_list **admin,
			     struct sched_gate_list **oper)
{
	rcu_assign_pointer(q->oper_sched, *admin);
	rcu_assign_pointer(q->admin_sched, NULL);

	if (*oper)
		call_rcu(&(*oper)->rcu, taprio_free_sched_cb);

	*oper = *admin;
	*admin = NULL;
}

static ktime_t get_cycle_time(struct sched_gate_list *sched)
{
	struct sched_entry *entry;
	ktime_t cycle = 0;

	if (sched->cycle_time != 0)
		return sched->cycle_time;

	list_for_each_entry(entry, &sched->entries, list)
		cycle = ktime_add_ns(cycle, entry->interval);

	sched->cycle_time = cycle;

	return cycle;
}

static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
			  struct sk_buff **to_free)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct Qdisc *child;
	int queue;

	queue = skb_get_queue_mapping(skb);

	child = q->qdiscs[queue];
	if (unlikely(!child))
		return qdisc_drop(skb, sch, to_free);

	qdisc_qstats_backlog_inc(sch, skb);
	sch->q.qlen++;

	return qdisc_enqueue(skb, child, to_free);
}

static struct sk_buff *taprio_peek(struct Qdisc *sch)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct sched_entry *entry;
	struct sk_buff *skb;
	u32 gate_mask;
	int i;

	rcu_read_lock();
	entry = rcu_dereference(q->current_entry);
	gate_mask = entry ? entry->gate_mask : TAPRIO_ALL_GATES_OPEN;
	rcu_read_unlock();

	if (!gate_mask)
		return NULL;

	for (i = 0; i < dev->num_tx_queues; i++) {
		struct Qdisc *child = q->qdiscs[i];
		int prio;
		u8 tc;

		if (unlikely(!child))
			continue;

		skb = child->ops->peek(child);
		if (!skb)
			continue;

		prio = skb->priority;
		tc = netdev_get_prio_tc_map(dev, prio);

		if (!(gate_mask & BIT(tc)))
			continue;

		return skb;
	}

	return NULL;
}

static inline int length_to_duration(struct taprio_sched *q, int len)
{
	return div_u64(len * atomic64_read(&q->picos_per_byte), 1000);
}

static void taprio_set_budget(struct taprio_sched *q, struct sched_entry *entry)
{
	atomic_set(&entry->budget,
		   div64_u64((u64)entry->interval * 1000,
			     atomic64_read(&q->picos_per_byte)));
}

static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct sk_buff *skb = NULL;
	struct sched_entry *entry;
	u32 gate_mask;
	int i;

	if (atomic64_read(&q->picos_per_byte) == -1) {
		WARN_ONCE(1, "taprio: dequeue() called with unknown picos per byte.");
		return NULL;
	}

	rcu_read_lock();
	entry = rcu_dereference(q->current_entry);
	/* if there's no entry, it means that the schedule didn't
	 * start yet, so force all gates to be open, this is in
	 * accordance to IEEE 802.1Qbv-2015 Section 8.6.9.4.5
	 * "AdminGateSates"
	 */
	gate_mask = entry ? entry->gate_mask : TAPRIO_ALL_GATES_OPEN;

	if (!gate_mask)
		goto done;

	for (i = 0; i < dev->num_tx_queues; i++) {
		struct Qdisc *child = q->qdiscs[i];
		ktime_t guard;
		int prio;
		int len;
		u8 tc;

		if (unlikely(!child))
			continue;

		skb = child->ops->peek(child);
		if (!skb)
			continue;

		prio = skb->priority;
		tc = netdev_get_prio_tc_map(dev, prio);

		if (!(gate_mask & BIT(tc)))
			continue;

		len = qdisc_pkt_len(skb);
		guard = ktime_add_ns(q->get_time(),
				     length_to_duration(q, len));

		/* In the case that there's no gate entry, there's no
		 * guard band ...
		 */
		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
		    ktime_after(guard, entry->close_time))
			continue;

		/* ... and no budget. */
		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
		    atomic_sub_return(len, &entry->budget) < 0)
			continue;

		skb = child->ops->dequeue(child);
		if (unlikely(!skb))
			goto done;

		qdisc_bstats_update(sch, skb);
		qdisc_qstats_backlog_dec(sch, skb);
		sch->q.qlen--;

		goto done;
	}

done:
	rcu_read_unlock();

	return skb;
}

static bool should_restart_cycle(const struct sched_gate_list *oper,
				 const struct sched_entry *entry)
{
	if (list_is_last(&entry->list, &oper->entries))
		return true;

	if (ktime_compare(entry->close_time, oper->cycle_close_time) == 0)
		return true;

	return false;
}

static bool should_change_schedules(const struct sched_gate_list *admin,
				    const struct sched_gate_list *oper,
				    ktime_t close_time)
{
	ktime_t next_base_time;

	if (!admin)
		return false;

	next_base_time = sched_base_time(admin);

	/* This is the simple case, the close_time would fall after
	 * the next schedule base_time.
	 */
	if (ktime_compare(next_base_time, close_time) <= 0)
		return true;

	return false;
}

static enum hrtimer_restart advance_sched(struct hrtimer *timer)
{
	struct taprio_sched *q = container_of(timer, struct taprio_sched,
					      advance_timer);
	struct sched_gate_list *oper, *admin;
	struct sched_entry *entry, *next;
	struct Qdisc *sch = q->root;
	ktime_t close_time;

	spin_lock(&q->current_entry_lock);
	entry = rcu_dereference_protected(q->current_entry,
					  lockdep_is_held(&q->current_entry_lock));
	oper = rcu_dereference_protected(q->oper_sched,
					 lockdep_is_held(&q->current_entry_lock));
	admin = rcu_dereference_protected(q->admin_sched,
					  lockdep_is_held(&q->current_entry_lock));

	if (!oper)
		switch_schedules(q, &admin, &oper);

	/* This can happen in two cases: 1. this is the very first run
	 * of this function (i.e. we weren't running any schedule
	 * previously); 2. The previous schedule just ended. The first
	 * entry of all schedules are pre-calculated during the
	 * schedule initialization.
	 */
	if (unlikely(!entry || entry->close_time == oper->base_time)) {
		next = list_first_entry(&oper->entries, struct sched_entry,
					list);
		close_time = next->close_time;
		goto first_run;
	}

	if (should_restart_cycle(oper, entry)) {
		next = list_first_entry(&oper->entries, struct sched_entry,
					list);
		oper->cycle_close_time = ktime_add_ns(oper->cycle_close_time,
						      oper->cycle_time);
	} else {
		next = list_next_entry(entry, list);
	}

	close_time = ktime_add_ns(entry->close_time, next->interval);
	close_time = min_t(ktime_t, close_time, oper->cycle_close_time);

	if (should_change_schedules(admin, oper, close_time)) {
		/* Set things so the next time this runs, the new
		 * schedule runs.
		 */
		close_time = sched_base_time(admin);
		switch_schedules(q, &admin, &oper);
	}

	next->close_time = close_time;
	taprio_set_budget(q, next);

first_run:
	rcu_assign_pointer(q->current_entry, next);
	spin_unlock(&q->current_entry_lock);

	hrtimer_set_expires(&q->advance_timer, close_time);

	rcu_read_lock();
	__netif_schedule(sch);
	rcu_read_unlock();

	return HRTIMER_RESTART;
}

static const struct nla_policy entry_policy[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = {
	[TCA_TAPRIO_SCHED_ENTRY_INDEX]	   = { .type = NLA_U32 },
	[TCA_TAPRIO_SCHED_ENTRY_CMD]	   = { .type = NLA_U8 },
	[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK] = { .type = NLA_U32 },
	[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]  = { .type = NLA_U32 },
};

static const struct nla_policy entry_list_policy[TCA_TAPRIO_SCHED_MAX + 1] = {
	[TCA_TAPRIO_SCHED_ENTRY] = { .type = NLA_NESTED },
};

static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
	[TCA_TAPRIO_ATTR_PRIOMAP]	       = {
		.len = sizeof(struct tc_mqprio_qopt)
	},
	[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST]     = { .type = NLA_NESTED },
	[TCA_TAPRIO_ATTR_SCHED_BASE_TIME]      = { .type = NLA_S64 },
	[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY]   = { .type = NLA_NESTED },
	[TCA_TAPRIO_ATTR_SCHED_CLOCKID]        = { .type = NLA_S32 },
	[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME]     = { .type = NLA_S64 },
};

static int fill_sched_entry(struct nlattr **tb, struct sched_entry *entry,
			    struct netlink_ext_ack *extack)
{
	u32 interval = 0;

	if (tb[TCA_TAPRIO_SCHED_ENTRY_CMD])
		entry->command = nla_get_u8(
			tb[TCA_TAPRIO_SCHED_ENTRY_CMD]);

	if (tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK])
		entry->gate_mask = nla_get_u32(
			tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK]);

	if (tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL])
		interval = nla_get_u32(
			tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]);

	if (interval == 0) {
		NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
		return -EINVAL;
	}

	entry->interval = interval;

	return 0;
}

static int parse_sched_entry(struct nlattr *n, struct sched_entry *entry,
			     int index, struct netlink_ext_ack *extack)
{
	struct nlattr *tb[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = { };
	int err;

	err = nla_parse_nested_deprecated(tb, TCA_TAPRIO_SCHED_ENTRY_MAX, n,
					  entry_policy, NULL);
	if (err < 0) {
		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
		return -EINVAL;
	}

	entry->index = index;

	return fill_sched_entry(tb, entry, extack);
}

static int parse_sched_list(struct nlattr *list,
			    struct sched_gate_list *sched,
			    struct netlink_ext_ack *extack)
{
	struct nlattr *n;
	int err, rem;
	int i = 0;

	if (!list)
		return -EINVAL;

	nla_for_each_nested(n, list, rem) {
		struct sched_entry *entry;

		if (nla_type(n) != TCA_TAPRIO_SCHED_ENTRY) {
			NL_SET_ERR_MSG(extack, "Attribute is not of type 'entry'");
			continue;
		}

		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
		if (!entry) {
			NL_SET_ERR_MSG(extack, "Not enough memory for entry");
			return -ENOMEM;
		}

		err = parse_sched_entry(n, entry, i, extack);
		if (err < 0) {
			kfree(entry);
			return err;
		}

		list_add_tail(&entry->list, &sched->entries);
		i++;
	}

	sched->num_entries = i;

	return i;
}

static int parse_taprio_schedule(struct nlattr **tb,
				 struct sched_gate_list *new,
				 struct netlink_ext_ack *extack)
{
	int err = 0;

	if (tb[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY]) {
		NL_SET_ERR_MSG(extack, "Adding a single entry is not supported");
		return -ENOTSUPP;
	}

	if (tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME])
		new->base_time = nla_get_s64(tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME]);

	if (tb[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME])
		new->cycle_time = nla_get_s64(tb[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME]);

	if (tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST])
		err = parse_sched_list(
			tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST], new, extack);
	if (err < 0)
		return err;

	return 0;
}

static int taprio_parse_mqprio_opt(struct net_device *dev,
				   struct tc_mqprio_qopt *qopt,
				   struct netlink_ext_ack *extack)
{
	int i, j;

	if (!qopt && !dev->num_tc) {
		NL_SET_ERR_MSG(extack, "'mqprio' configuration is necessary");
		return -EINVAL;
	}

	/* If num_tc is already set, it means that the user already
	 * configured the mqprio part
	 */
	if (dev->num_tc)
		return 0;

	/* Verify num_tc is not out of max range */
	if (qopt->num_tc > TC_MAX_QUEUE) {
		NL_SET_ERR_MSG(extack, "Number of traffic classes is outside valid range");
		return -EINVAL;
	}

	/* taprio imposes that traffic classes map 1:n to tx queues */
	if (qopt->num_tc > dev->num_tx_queues) {
		NL_SET_ERR_MSG(extack, "Number of traffic classes is greater than number of HW queues");
		return -EINVAL;
	}

	/* Verify priority mapping uses valid tcs */
	for (i = 0; i < TC_BITMASK + 1; i++) {
		if (qopt->prio_tc_map[i] >= qopt->num_tc) {
			NL_SET_ERR_MSG(extack, "Invalid traffic class in priority to traffic class mapping");
			return -EINVAL;
		}
	}

	for (i = 0; i < qopt->num_tc; i++) {
		unsigned int last = qopt->offset[i] + qopt->count[i];

		/* Verify the queue count is in tx range being equal to the
		 * real_num_tx_queues indicates the last queue is in use.
		 */
		if (qopt->offset[i] >= dev->num_tx_queues ||
		    !qopt->count[i] ||
		    last > dev->real_num_tx_queues) {
			NL_SET_ERR_MSG(extack, "Invalid queue in traffic class to queue mapping");
			return -EINVAL;
		}

		/* Verify that the offset and counts do not overlap */
		for (j = i + 1; j < qopt->num_tc; j++) {
			if (last > qopt->offset[j]) {
				NL_SET_ERR_MSG(extack, "Detected overlap in the traffic class to queue mapping");
				return -EINVAL;
			}
		}
	}

	return 0;
}

static int taprio_get_start_time(struct Qdisc *sch,
				 struct sched_gate_list *sched,
				 ktime_t *start)
{
	struct taprio_sched *q = qdisc_priv(sch);
	ktime_t now, base, cycle;
	s64 n;

	base = sched_base_time(sched);
	now = q->get_time();

	if (ktime_after(base, now)) {
		*start = base;
		return 0;
	}

	cycle = get_cycle_time(sched);

	/* The qdisc is expected to have at least one sched_entry.  Moreover,
	 * any entry must have 'interval' > 0. Thus if the cycle time is zero,
	 * something went really wrong. In that case, we should warn about this
	 * inconsistent state and return error.
	 */
	if (WARN_ON(!cycle))
		return -EFAULT;

	/* Schedule the start time for the beginning of the next
	 * cycle.
	 */
	n = div64_s64(ktime_sub_ns(now, base), cycle);
	*start = ktime_add_ns(base, (n + 1) * cycle);
	return 0;
}

static void setup_first_close_time(struct taprio_sched *q,
				   struct sched_gate_list *sched, ktime_t base)
{
	struct sched_entry *first;
	ktime_t cycle;

	first = list_first_entry(&sched->entries,
				 struct sched_entry, list);

	cycle = get_cycle_time(sched);

	/* FIXME: find a better place to do this */
	sched->cycle_close_time = ktime_add_ns(base, cycle);

	first->close_time = ktime_add_ns(base, first->interval);
	taprio_set_budget(q, first);
	rcu_assign_pointer(q->current_entry, NULL);
}

static void taprio_start_sched(struct Qdisc *sch,
			       ktime_t start, struct sched_gate_list *new)
{
	struct taprio_sched *q = qdisc_priv(sch);
	ktime_t expires;

	expires = hrtimer_get_expires(&q->advance_timer);
	if (expires == 0)
		expires = KTIME_MAX;

	/* If the new schedule starts before the next expiration, we
	 * reprogram it to the earliest one, so we change the admin
	 * schedule to the operational one at the right time.
	 */
	start = min_t(ktime_t, start, expires);

	hrtimer_start(&q->advance_timer, start, HRTIMER_MODE_ABS);
}

static void taprio_set_picos_per_byte(struct net_device *dev,
				      struct taprio_sched *q)
{
	struct ethtool_link_ksettings ecmd;
	int picos_per_byte = -1;

	if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
	    ecmd.base.speed != SPEED_UNKNOWN)
		picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
					   ecmd.base.speed * 1000 * 1000);

	atomic64_set(&q->picos_per_byte, picos_per_byte);
	netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed: %d\n",
		   dev->name, (long long)atomic64_read(&q->picos_per_byte),
		   ecmd.base.speed);
}

static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
			       void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct net_device *qdev;
	struct taprio_sched *q;
	bool found = false;

	ASSERT_RTNL();

	if (event != NETDEV_UP && event != NETDEV_CHANGE)
		return NOTIFY_DONE;

	spin_lock(&taprio_list_lock);
	list_for_each_entry(q, &taprio_list, taprio_list) {
		qdev = qdisc_dev(q->root);
		if (qdev == dev) {
			found = true;
			break;
		}
	}
	spin_unlock(&taprio_list_lock);

	if (found)
		taprio_set_picos_per_byte(dev, q);

	return NOTIFY_DONE;
}

static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
			 struct netlink_ext_ack *extack)
{
	struct nlattr *tb[TCA_TAPRIO_ATTR_MAX + 1] = { };
	struct sched_gate_list *oper, *admin, *new_admin;
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct tc_mqprio_qopt *mqprio = NULL;
	int i, err, clockid;
	unsigned long flags;
	ktime_t start;

	err = nla_parse_nested_deprecated(tb, TCA_TAPRIO_ATTR_MAX, opt,
					  taprio_policy, extack);
	if (err < 0)
		return err;

	if (tb[TCA_TAPRIO_ATTR_PRIOMAP])
		mqprio = nla_data(tb[TCA_TAPRIO_ATTR_PRIOMAP]);

	err = taprio_parse_mqprio_opt(dev, mqprio, extack);
	if (err < 0)
		return err;

	new_admin = kzalloc(sizeof(*new_admin), GFP_KERNEL);
	if (!new_admin) {
		NL_SET_ERR_MSG(extack, "Not enough memory for a new schedule");
		return -ENOMEM;
	}
	INIT_LIST_HEAD(&new_admin->entries);

	rcu_read_lock();
	oper = rcu_dereference(q->oper_sched);
	admin = rcu_dereference(q->admin_sched);
	rcu_read_unlock();

	if (mqprio && (oper || admin)) {
		NL_SET_ERR_MSG(extack, "Changing the traffic mapping of a running schedule is not supported");
		err = -ENOTSUPP;
		goto free_sched;
	}

	err = parse_taprio_schedule(tb, new_admin, extack);
	if (err < 0)
		goto free_sched;

	if (new_admin->num_entries == 0) {
		NL_SET_ERR_MSG(extack, "There should be at least one entry in the schedule");
		err = -EINVAL;
		goto free_sched;
	}

	if (tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]) {
		clockid = nla_get_s32(tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]);

		/* We only support static clockids and we don't allow
		 * for it to be modified after the first init.
		 */
		if (clockid < 0 ||
		    (q->clockid != -1 && q->clockid != clockid)) {
			NL_SET_ERR_MSG(extack, "Changing the 'clockid' of a running schedule is not supported");
			err = -ENOTSUPP;
			goto free_sched;
		}

		q->clockid = clockid;
	}

	if (q->clockid == -1 && !tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]) {
		NL_SET_ERR_MSG(extack, "Specifying a 'clockid' is mandatory");
		err = -EINVAL;
		goto free_sched;
	}

	taprio_set_picos_per_byte(dev, q);

	/* Protects against enqueue()/dequeue() */
	spin_lock_bh(qdisc_lock(sch));

	if (!hrtimer_active(&q->advance_timer)) {
		hrtimer_init(&q->advance_timer, q->clockid, HRTIMER_MODE_ABS);
		q->advance_timer.function = advance_sched;
	}

	if (mqprio) {
		netdev_set_num_tc(dev, mqprio->num_tc);
		for (i = 0; i < mqprio->num_tc; i++)
			netdev_set_tc_queue(dev, i,
					    mqprio->count[i],
					    mqprio->offset[i]);

		/* Always use supplied priority mappings */
		for (i = 0; i < TC_BITMASK + 1; i++)
			netdev_set_prio_tc_map(dev, i,
					       mqprio->prio_tc_map[i]);
	}

	switch (q->clockid) {
	case CLOCK_REALTIME:
		q->get_time = ktime_get_real;
		break;
	case CLOCK_MONOTONIC:
		q->get_time = ktime_get;
		break;
	case CLOCK_BOOTTIME:
		q->get_time = ktime_get_boottime;
		break;
	case CLOCK_TAI:
		q->get_time = ktime_get_clocktai;
		break;
	default:
		NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
		err = -EINVAL;
		goto unlock;
	}

	err = taprio_get_start_time(sch, new_admin, &start);
	if (err < 0) {
		NL_SET_ERR_MSG(extack, "Internal error: failed get start time");
		goto unlock;
	}

	setup_first_close_time(q, new_admin, start);

	/* Protects against advance_sched() */
	spin_lock_irqsave(&q->current_entry_lock, flags);

	taprio_start_sched(sch, start, new_admin);

	rcu_assign_pointer(q->admin_sched, new_admin);
	if (admin)
		call_rcu(&admin->rcu, taprio_free_sched_cb);
	new_admin = NULL;

	spin_unlock_irqrestore(&q->current_entry_lock, flags);

	err = 0;

unlock:
	spin_unlock_bh(qdisc_lock(sch));

free_sched:
	kfree(new_admin);

	return err;
}

static void taprio_destroy(struct Qdisc *sch)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	unsigned int i;

	spin_lock(&taprio_list_lock);
	list_del(&q->taprio_list);
	spin_unlock(&taprio_list_lock);

	hrtimer_cancel(&q->advance_timer);

	if (q->qdiscs) {
		for (i = 0; i < dev->num_tx_queues && q->qdiscs[i]; i++)
			qdisc_put(q->qdiscs[i]);

		kfree(q->qdiscs);
	}
	q->qdiscs = NULL;

	netdev_set_num_tc(dev, 0);

	if (q->oper_sched)
		call_rcu(&q->oper_sched->rcu, taprio_free_sched_cb);

	if (q->admin_sched)
		call_rcu(&q->admin_sched->rcu, taprio_free_sched_cb);
}

static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
		       struct netlink_ext_ack *extack)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	int i;

	spin_lock_init(&q->current_entry_lock);

	hrtimer_init(&q->advance_timer, CLOCK_TAI, HRTIMER_MODE_ABS);
	q->advance_timer.function = advance_sched;

	q->root = sch;

	/* We only support static clockids. Use an invalid value as default
	 * and get the valid one on taprio_change().
	 */
	q->clockid = -1;

	if (sch->parent != TC_H_ROOT)
		return -EOPNOTSUPP;

	if (!netif_is_multiqueue(dev))
		return -EOPNOTSUPP;

	/* pre-allocate qdisc, attachment can't fail */
	q->qdiscs = kcalloc(dev->num_tx_queues,
			    sizeof(q->qdiscs[0]),
			    GFP_KERNEL);

	if (!q->qdiscs)
		return -ENOMEM;

	if (!opt)
		return -EINVAL;

	spin_lock(&taprio_list_lock);
	list_add(&q->taprio_list, &taprio_list);
	spin_unlock(&taprio_list_lock);

	for (i = 0; i < dev->num_tx_queues; i++) {
		struct netdev_queue *dev_queue;
		struct Qdisc *qdisc;

		dev_queue = netdev_get_tx_queue(dev, i);
		qdisc = qdisc_create_dflt(dev_queue,
					  &pfifo_qdisc_ops,
					  TC_H_MAKE(TC_H_MAJ(sch->handle),
						    TC_H_MIN(i + 1)),
					  extack);
		if (!qdisc)
			return -ENOMEM;

		if (i < dev->real_num_tx_queues)
			qdisc_hash_add(qdisc, false);

		q->qdiscs[i] = qdisc;
	}

	return taprio_change(sch, opt, extack);
}

static struct netdev_queue *taprio_queue_get(struct Qdisc *sch,
					     unsigned long cl)
{
	struct net_device *dev = qdisc_dev(sch);
	unsigned long ntx = cl - 1;

	if (ntx >= dev->num_tx_queues)
		return NULL;

	return netdev_get_tx_queue(dev, ntx);
}

static int taprio_graft(struct Qdisc *sch, unsigned long cl,
			struct Qdisc *new, struct Qdisc **old,
			struct netlink_ext_ack *extack)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);

	if (!dev_queue)
		return -EINVAL;

	if (dev->flags & IFF_UP)
		dev_deactivate(dev);

	*old = q->qdiscs[cl - 1];
	q->qdiscs[cl - 1] = new;

	if (new)
		new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;

	if (dev->flags & IFF_UP)
		dev_activate(dev);

	return 0;
}

static int dump_entry(struct sk_buff *msg,
		      const struct sched_entry *entry)
{
	struct nlattr *item;

	item = nla_nest_start_noflag(msg, TCA_TAPRIO_SCHED_ENTRY);
	if (!item)
		return -ENOSPC;

	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_INDEX, entry->index))
		goto nla_put_failure;

	if (nla_put_u8(msg, TCA_TAPRIO_SCHED_ENTRY_CMD, entry->command))
		goto nla_put_failure;

	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_GATE_MASK,
			entry->gate_mask))
		goto nla_put_failure;

	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_INTERVAL,
			entry->interval))
		goto nla_put_failure;

	return nla_nest_end(msg, item);

nla_put_failure:
	nla_nest_cancel(msg, item);
	return -1;
}

static int dump_schedule(struct sk_buff *msg,
			 const struct sched_gate_list *root)
{
	struct nlattr *entry_list;
	struct sched_entry *entry;

	if (nla_put_s64(msg, TCA_TAPRIO_ATTR_SCHED_BASE_TIME,
			root->base_time, TCA_TAPRIO_PAD))
		return -1;

	if (nla_put_s64(msg, TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME,
			root->cycle_time, TCA_TAPRIO_PAD))
		return -1;

	entry_list = nla_nest_start_noflag(msg,
					   TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST);
	if (!entry_list)
		goto error_nest;

	list_for_each_entry(entry, &root->entries, list) {
		if (dump_entry(msg, entry) < 0)
			goto error_nest;
	}

	nla_nest_end(msg, entry_list);
	return 0;

error_nest:
	nla_nest_cancel(msg, entry_list);
	return -1;
}

static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct taprio_sched *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct sched_gate_list *oper, *admin;
	struct tc_mqprio_qopt opt = { 0 };
	struct nlattr *nest, *sched_nest;
	unsigned int i;

	rcu_read_lock();
	oper = rcu_dereference(q->oper_sched);
	admin = rcu_dereference(q->admin_sched);

	opt.num_tc = netdev_get_num_tc(dev);
	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));

	for (i = 0; i < netdev_get_num_tc(dev); i++) {
		opt.count[i] = dev->tc_to_txq[i].count;
		opt.offset[i] = dev->tc_to_txq[i].offset;
	}

	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
	if (!nest)
		goto start_error;

	if (nla_put(skb, TCA_TAPRIO_ATTR_PRIOMAP, sizeof(opt), &opt))
		goto options_error;

	if (nla_put_s32(skb, TCA_TAPRIO_ATTR_SCHED_CLOCKID, q->clockid))
		goto options_error;

	if (oper && dump_schedule(skb, oper))
		goto options_error;

	if (!admin)
		goto done;

	sched_nest = nla_nest_start_noflag(skb, TCA_TAPRIO_ATTR_ADMIN_SCHED);

	if (dump_schedule(skb, admin))
		goto admin_error;

	nla_nest_end(skb, sched_nest);

done:
	rcu_read_unlock();

	return nla_nest_end(skb, nest);

admin_error:
	nla_nest_cancel(skb, sched_nest);

options_error:
	nla_nest_cancel(skb, nest);

start_error:
	rcu_read_unlock();
	return -ENOSPC;
}

static struct Qdisc *taprio_leaf(struct Qdisc *sch, unsigned long cl)
{
	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);

	if (!dev_queue)
		return NULL;

	return dev_queue->qdisc_sleeping;
}

static unsigned long taprio_find(struct Qdisc *sch, u32 classid)
{
	unsigned int ntx = TC_H_MIN(classid);

	if (!taprio_queue_get(sch, ntx))
		return 0;
	return ntx;
}

static int taprio_dump_class(struct Qdisc *sch, unsigned long cl,
			     struct sk_buff *skb, struct tcmsg *tcm)
{
	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);

	tcm->tcm_parent = TC_H_ROOT;
	tcm->tcm_handle |= TC_H_MIN(cl);
	tcm->tcm_info = dev_queue->qdisc_sleeping->handle;

	return 0;
}

static int taprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
				   struct gnet_dump *d)
	__releases(d->lock)
	__acquires(d->lock)
{
	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);

	sch = dev_queue->qdisc_sleeping;
	if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
	    qdisc_qstats_copy(d, sch) < 0)
		return -1;
	return 0;
}

static void taprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
	struct net_device *dev = qdisc_dev(sch);
	unsigned long ntx;

	if (arg->stop)
		return;

	arg->count = arg->skip;
	for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
		if (arg->fn(sch, ntx + 1, arg) < 0) {
			arg->stop = 1;
			break;
		}
		arg->count++;
	}
}

static struct netdev_queue *taprio_select_queue(struct Qdisc *sch,
						struct tcmsg *tcm)
{
	return taprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
}

static const struct Qdisc_class_ops taprio_class_ops = {
	.graft		= taprio_graft,
	.leaf		= taprio_leaf,
	.find		= taprio_find,
	.walk		= taprio_walk,
	.dump		= taprio_dump_class,
	.dump_stats	= taprio_dump_class_stats,
	.select_queue	= taprio_select_queue,
};

static struct Qdisc_ops taprio_qdisc_ops __read_mostly = {
	.cl_ops		= &taprio_class_ops,
	.id		= "taprio",
	.priv_size	= sizeof(struct taprio_sched),
	.init		= taprio_init,
	.change		= taprio_change,
	.destroy	= taprio_destroy,
	.peek		= taprio_peek,
	.dequeue	= taprio_dequeue,
	.enqueue	= taprio_enqueue,
	.dump		= taprio_dump,
	.owner		= THIS_MODULE,
};

static struct notifier_block taprio_device_notifier = {
	.notifier_call = taprio_dev_notifier,
};

static int __init taprio_module_init(void)
{
	int err = register_netdevice_notifier(&taprio_device_notifier);

	if (err)
		return err;

	return register_qdisc(&taprio_qdisc_ops);
}

static void __exit taprio_module_exit(void)
{
	unregister_qdisc(&taprio_qdisc_ops);
	unregister_netdevice_notifier(&taprio_device_notifier);
}

module_init(taprio_module_init);
module_exit(taprio_module_exit);
MODULE_LICENSE("GPL");