aboutsummaryrefslogtreecommitdiffstats
path: root/net/sched/sch_hfsc.c
blob: 874452c41a0172ef25bce549c97d60f38ca91daf (plain) (blame)
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
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
/*
 * Copyright (c) 2003 Patrick McHardy, <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 2003-10-17 - Ported from altq
 */
/*
 * Copyright (c) 1997-1999 Carnegie Mellon University. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation is hereby granted (including for commercial or
 * for-profit use), provided that both the copyright notice and this
 * permission notice appear in all copies of the software, derivative
 * works, or modified versions, and any portions thereof.
 *
 * THIS SOFTWARE IS EXPERIMENTAL AND IS KNOWN TO HAVE BUGS, SOME OF
 * WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON PROVIDES THIS
 * SOFTWARE IN ITS ``AS IS'' CONDITION, AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * Carnegie Mellon encourages (but does not require) users of this
 * software to return any improvements or extensions that they make,
 * and to grant Carnegie Mellon the rights to redistribute these
 * changes without encumbrance.
 */
/*
 * H-FSC is described in Proceedings of SIGCOMM'97,
 * "A Hierarchical Fair Service Curve Algorithm for Link-Sharing,
 * Real-Time and Priority Service"
 * by Ion Stoica, Hui Zhang, and T. S. Eugene Ng.
 *
 * Oleg Cherevko <olwi@aq.ml.com.ua> added the upperlimit for link-sharing.
 * when a class has an upperlimit, the fit-time is computed from the
 * upperlimit service curve.  the link-sharing scheduler does not schedule
 * a class whose fit-time exceeds the current time.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_sched.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <asm/div64.h>

/*
 * kernel internal service curve representation:
 *   coordinates are given by 64 bit unsigned integers.
 *   x-axis: unit is clock count.
 *   y-axis: unit is byte.
 *
 *   The service curve parameters are converted to the internal
 *   representation. The slope values are scaled to avoid overflow.
 *   the inverse slope values as well as the y-projection of the 1st
 *   segment are kept in order to to avoid 64-bit divide operations
 *   that are expensive on 32-bit architectures.
 */

struct internal_sc
{
	u64	sm1;	/* scaled slope of the 1st segment */
	u64	ism1;	/* scaled inverse-slope of the 1st segment */
	u64	dx;	/* the x-projection of the 1st segment */
	u64	dy;	/* the y-projection of the 1st segment */
	u64	sm2;	/* scaled slope of the 2nd segment */
	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
};

/* runtime service curve */
struct runtime_sc
{
	u64	x;	/* current starting position on x-axis */
	u64	y;	/* current starting position on y-axis */
	u64	sm1;	/* scaled slope of the 1st segment */
	u64	ism1;	/* scaled inverse-slope of the 1st segment */
	u64	dx;	/* the x-projection of the 1st segment */
	u64	dy;	/* the y-projection of the 1st segment */
	u64	sm2;	/* scaled slope of the 2nd segment */
	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
};

enum hfsc_class_flags
{
	HFSC_RSC = 0x1,
	HFSC_FSC = 0x2,
	HFSC_USC = 0x4
};

struct hfsc_class
{
	u32		classid;	/* class id */
	unsigned int	refcnt;		/* usage count */

	struct gnet_stats_basic bstats;
	struct gnet_stats_queue qstats;
	struct gnet_stats_rate_est rate_est;
	unsigned int	level;		/* class level in hierarchy */
	struct tcf_proto *filter_list;	/* filter list */
	unsigned int	filter_cnt;	/* filter count */

	struct hfsc_sched *sched;	/* scheduler data */
	struct hfsc_class *cl_parent;	/* parent class */
	struct list_head siblings;	/* sibling classes */
	struct list_head children;	/* child classes */
	struct Qdisc	*qdisc;		/* leaf qdisc */

	struct rb_node el_node;		/* qdisc's eligible tree member */
	struct rb_root vt_tree;		/* active children sorted by cl_vt */
	struct rb_node vt_node;		/* parent's vt_tree member */
	struct rb_root cf_tree;		/* active children sorted by cl_f */
	struct rb_node cf_node;		/* parent's cf_heap member */
	struct list_head hlist;		/* hash list member */
	struct list_head dlist;		/* drop list member */

	u64	cl_total;		/* total work in bytes */
	u64	cl_cumul;		/* cumulative work in bytes done by
					   real-time criteria */

	u64 	cl_d;			/* deadline*/
	u64 	cl_e;			/* eligible time */
	u64	cl_vt;			/* virtual time */
	u64	cl_f;			/* time when this class will fit for
					   link-sharing, max(myf, cfmin) */
	u64	cl_myf;			/* my fit-time (calculated from this
					   class's own upperlimit curve) */
	u64	cl_myfadj;		/* my fit-time adjustment (to cancel
					   history dependence) */
	u64	cl_cfmin;		/* earliest children's fit-time (used
					   with cl_myf to obtain cl_f) */
	u64	cl_cvtmin;		/* minimal virtual time among the
					   children fit for link-sharing
					   (monotonic within a period) */
	u64	cl_vtadj;		/* intra-period cumulative vt
					   adjustment */
	u64	cl_vtoff;		/* inter-period cumulative vt offset */
	u64	cl_cvtmax;		/* max child's vt in the last period */
	u64	cl_cvtoff;		/* cumulative cvtmax of all periods */
	u64	cl_pcvtoff;		/* parent's cvtoff at initalization
					   time */

	struct internal_sc cl_rsc;	/* internal real-time service curve */
	struct internal_sc cl_fsc;	/* internal fair service curve */
	struct internal_sc cl_usc;	/* internal upperlimit service curve */
	struct runtime_sc cl_deadline;	/* deadline curve */
	struct runtime_sc cl_eligible;	/* eligible curve */
	struct runtime_sc cl_virtual;	/* virtual curve */
	struct runtime_sc cl_ulimit;	/* upperlimit curve */

	unsigned long	cl_flags;	/* which curves are valid */
	unsigned long	cl_vtperiod;	/* vt period sequence number */
	unsigned long	cl_parentperiod;/* parent's vt period sequence number*/
	unsigned long	cl_nactive;	/* number of active children */
};

#define HFSC_HSIZE	16

struct hfsc_sched
{
	u16	defcls;				/* default class id */
	struct hfsc_class root;			/* root class */
	struct list_head clhash[HFSC_HSIZE];	/* class hash */
	struct rb_root eligible;		/* eligible tree */
	struct list_head droplist;		/* active leaf class list (for
						   dropping) */
	struct sk_buff_head requeue;		/* requeued packet */
	struct qdisc_watchdog watchdog;		/* watchdog timer */
};

#define	HT_INFINITY	0xffffffffffffffffULL	/* infinite time value */


/*
 * eligible tree holds backlogged classes being sorted by their eligible times.
 * there is one eligible tree per hfsc instance.
 */

static void
eltree_insert(struct hfsc_class *cl)
{
	struct rb_node **p = &cl->sched->eligible.rb_node;
	struct rb_node *parent = NULL;
	struct hfsc_class *cl1;

	while (*p != NULL) {
		parent = *p;
		cl1 = rb_entry(parent, struct hfsc_class, el_node);
		if (cl->cl_e >= cl1->cl_e)
			p = &parent->rb_right;
		else
			p = &parent->rb_left;
	}
	rb_link_node(&cl->el_node, parent, p);
	rb_insert_color(&cl->el_node, &cl->sched->eligible);
}

static inline void
eltree_remove(struct hfsc_class *cl)
{
	rb_erase(&cl->el_node, &cl->sched->eligible);
}

static inline void
eltree_update(struct hfsc_class *cl)
{
	eltree_remove(cl);
	eltree_insert(cl);
}

/* find the class with the minimum deadline among the eligible classes */
static inline struct hfsc_class *
eltree_get_mindl(struct hfsc_sched *q, u64 cur_time)
{
	struct hfsc_class *p, *cl = NULL;
	struct rb_node *n;

	for (n = rb_first(&q->eligible); n != NULL; n = rb_next(n)) {
		p = rb_entry(n, struct hfsc_class, el_node);
		if (p->cl_e > cur_time)
			break;
		if (cl == NULL || p->cl_d < cl->cl_d)
			cl = p;
	}
	return cl;
}

/* find the class with minimum eligible time among the eligible classes */
static inline struct hfsc_class *
eltree_get_minel(struct hfsc_sched *q)
{
	struct rb_node *n;

	n = rb_first(&q->eligible);
	if (n == NULL)
		return NULL;
	return rb_entry(n, struct hfsc_class, el_node);
}

/*
 * vttree holds holds backlogged child classes being sorted by their virtual
 * time. each intermediate class has one vttree.
 */
static void
vttree_insert(struct hfsc_class *cl)
{
	struct rb_node **p = &cl->cl_parent->vt_tree.rb_node;
	struct rb_node *parent = NULL;
	struct hfsc_class *cl1;

	while (*p != NULL) {
		parent = *p;
		cl1 = rb_entry(parent, struct hfsc_class, vt_node);
		if (cl->cl_vt >= cl1->cl_vt)
			p = &parent->rb_right;
		else
			p = &parent->rb_left;
	}
	rb_link_node(&cl->vt_node, parent, p);
	rb_insert_color(&cl->vt_node, &cl->cl_parent->vt_tree);
}

static inline void
vttree_remove(struct hfsc_class *cl)
{
	rb_erase(&cl->vt_node, &cl->cl_parent->vt_tree);
}

static inline void
vttree_update(struct hfsc_class *cl)
{
	vttree_remove(cl);
	vttree_insert(cl);
}

static inline struct hfsc_class *
vttree_firstfit(struct hfsc_class *cl, u64 cur_time)
{
	struct hfsc_class *p;
	struct rb_node *n;

	for (n = rb_first(&cl->vt_tree); n != NULL; n = rb_next(n)) {
		p = rb_entry(n, struct hfsc_class, vt_node);
		if (p->cl_f <= cur_time)
			return p;
	}
	return NULL;
}

/*
 * get the leaf class with the minimum vt in the hierarchy
 */
static struct hfsc_class *
vttree_get_minvt(struct hfsc_class *cl, u64 cur_time)
{
	/* if root-class's cfmin is bigger than cur_time nothing to do */
	if (cl->cl_cfmin > cur_time)
		return NULL;

	while (cl->level > 0) {
		cl = vttree_firstfit(cl, cur_time);
		if (cl == NULL)
			return NULL;
		/*
		 * update parent's cl_cvtmin.
		 */
		if (cl->cl_parent->cl_cvtmin < cl->cl_vt)
			cl->cl_parent->cl_cvtmin = cl->cl_vt;
	}
	return cl;
}

static void
cftree_insert(struct hfsc_class *cl)
{
	struct rb_node **p = &cl->cl_parent->cf_tree.rb_node;
	struct rb_node *parent = NULL;
	struct hfsc_class *cl1;

	while (*p != NULL) {
		parent = *p;
		cl1 = rb_entry(parent, struct hfsc_class, cf_node);
		if (cl->cl_f >= cl1->cl_f)
			p = &parent->rb_right;
		else
			p = &parent->rb_left;
	}
	rb_link_node(&cl->cf_node, parent, p);
	rb_insert_color(&cl->cf_node, &cl->cl_parent->cf_tree);
}

static inline void
cftree_remove(struct hfsc_class *cl)
{
	rb_erase(&cl->cf_node, &cl->cl_parent->cf_tree);
}

static inline void
cftree_update(struct hfsc_class *cl)
{
	cftree_remove(cl);
	cftree_insert(cl);
}

/*
 * service curve support functions
 *
 *  external service curve parameters
 *	m: bps
 *	d: us
 *  internal service curve parameters
 *	sm: (bytes/psched_us) << SM_SHIFT
 *	ism: (psched_us/byte) << ISM_SHIFT
 *	dx: psched_us
 *
 * The clock source resolution with ktime is 1.024us.
 *
 * sm and ism are scaled in order to keep effective digits.
 * SM_SHIFT and ISM_SHIFT are selected to keep at least 4 effective
 * digits in decimal using the following table.
 *
 *  bits/sec      100Kbps     1Mbps     10Mbps     100Mbps    1Gbps
 *  ------------+-------------------------------------------------------
 *  bytes/1.024us 12.8e-3    128e-3     1280e-3    12800e-3   128000e-3
 *
 *  1.024us/byte  78.125     7.8125     0.78125    0.078125   0.0078125
 */
#define	SM_SHIFT	20
#define	ISM_SHIFT	18

#define	SM_MASK		((1ULL << SM_SHIFT) - 1)
#define	ISM_MASK	((1ULL << ISM_SHIFT) - 1)

static inline u64
seg_x2y(u64 x, u64 sm)
{
	u64 y;

	/*
	 * compute
	 *	y = x * sm >> SM_SHIFT
	 * but divide it for the upper and lower bits to avoid overflow
	 */
	y = (x >> SM_SHIFT) * sm + (((x & SM_MASK) * sm) >> SM_SHIFT);
	return y;
}

static inline u64
seg_y2x(u64 y, u64 ism)
{
	u64 x;

	if (y == 0)
		x = 0;
	else if (ism == HT_INFINITY)
		x = HT_INFINITY;
	else {
		x = (y >> ISM_SHIFT) * ism
		    + (((y & ISM_MASK) * ism) >> ISM_SHIFT);
	}
	return x;
}

/* Convert m (bps) into sm (bytes/psched us) */
static u64
m2sm(u32 m)
{
	u64 sm;

	sm = ((u64)m << SM_SHIFT);
	sm += PSCHED_TICKS_PER_SEC - 1;
	do_div(sm, PSCHED_TICKS_PER_SEC);
	return sm;
}

/* convert m (bps) into ism (psched us/byte) */
static u64
m2ism(u32 m)
{
	u64 ism;

	if (m == 0)
		ism = HT_INFINITY;
	else {
		ism = ((u64)PSCHED_TICKS_PER_SEC << ISM_SHIFT);
		ism += m - 1;
		do_div(ism, m);
	}
	return ism;
}

/* convert d (us) into dx (psched us) */
static u64
d2dx(u32 d)
{
	u64 dx;

	dx = ((u64)d * PSCHED_TICKS_PER_SEC);
	dx += USEC_PER_SEC - 1;
	do_div(dx, USEC_PER_SEC);
	return dx;
}

/* convert sm (bytes/psched us) into m (bps) */
static u32
sm2m(u64 sm)
{
	u64 m;

	m = (sm * PSCHED_TICKS_PER_SEC) >> SM_SHIFT;
	return (u32)m;
}

/* convert dx (psched us) into d (us) */
static u32
dx2d(u64 dx)
{
	u64 d;

	d = dx * USEC_PER_SEC;
	do_div(d, PSCHED_TICKS_PER_SEC);
	return (u32)d;
}

static void
sc2isc(struct tc_service_curve *sc, struct internal_sc *isc)
{
	isc->sm1  = m2sm(sc->m1);
	isc->ism1 = m2ism(sc->m1);
	isc->dx   = d2dx(sc->d);
	isc->dy   = seg_x2y(isc->dx, isc->sm1);
	isc->sm2  = m2sm(sc->m2);
	isc->ism2 = m2ism(sc->m2);
}

/*
 * initialize the runtime service curve with the given internal
 * service curve starting at (x, y).
 */
static void
rtsc_init(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
{
	rtsc->x	   = x;
	rtsc->y    = y;
	rtsc->sm1  = isc->sm1;
	rtsc->ism1 = isc->ism1;
	rtsc->dx   = isc->dx;
	rtsc->dy   = isc->dy;
	rtsc->sm2  = isc->sm2;
	rtsc->ism2 = isc->ism2;
}

/*
 * calculate the y-projection of the runtime service curve by the
 * given x-projection value
 */
static u64
rtsc_y2x(struct runtime_sc *rtsc, u64 y)
{
	u64 x;

	if (y < rtsc->y)
		x = rtsc->x;
	else if (y <= rtsc->y + rtsc->dy) {
		/* x belongs to the 1st segment */
		if (rtsc->dy == 0)
			x = rtsc->x + rtsc->dx;
		else
			x = rtsc->x + seg_y2x(y - rtsc->y, rtsc->ism1);
	} else {
		/* x belongs to the 2nd segment */
		x = rtsc->x + rtsc->dx
		    + seg_y2x(y - rtsc->y - rtsc->dy, rtsc->ism2);
	}
	return x;
}

static u64
rtsc_x2y(struct runtime_sc *rtsc, u64 x)
{
	u64 y;

	if (x <= rtsc->x)
		y = rtsc->y;
	else if (x <= rtsc->x + rtsc->dx)
		/* y belongs to the 1st segment */
		y = rtsc->y + seg_x2y(x - rtsc->x, rtsc->sm1);
	else
		/* y belongs to the 2nd segment */
		y = rtsc->y + rtsc->dy
		    + seg_x2y(x - rtsc->x - rtsc->dx, rtsc->sm2);
	return y;
}

/*
 * update the runtime service curve by taking the minimum of the current
 * runtime service curve and the service curve starting at (x, y).
 */
static void
rtsc_min(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
{
	u64 y1, y2, dx, dy;
	u32 dsm;

	if (isc->sm1 <= isc->sm2) {
		/* service curve is convex */
		y1 = rtsc_x2y(rtsc, x);
		if (y1 < y)
			/* the current rtsc is smaller */
			return;
		rtsc->x = x;
		rtsc->y = y;
		return;
	}

	/*
	 * service curve is concave
	 * compute the two y values of the current rtsc
	 *	y1: at x
	 *	y2: at (x + dx)
	 */
	y1 = rtsc_x2y(rtsc, x);
	if (y1 <= y) {
		/* rtsc is below isc, no change to rtsc */
		return;
	}

	y2 = rtsc_x2y(rtsc, x + isc->dx);
	if (y2 >= y + isc->dy) {
		/* rtsc is above isc, replace rtsc by isc */
		rtsc->x = x;
		rtsc->y = y;
		rtsc->dx = isc->dx;
		rtsc->dy = isc->dy;
		return;
	}

	/*
	 * the two curves intersect
	 * compute the offsets (dx, dy) using the reverse
	 * function of seg_x2y()
	 *	seg_x2y(dx, sm1) == seg_x2y(dx, sm2) + (y1 - y)
	 */
	dx = (y1 - y) << SM_SHIFT;
	dsm = isc->sm1 - isc->sm2;
	do_div(dx, dsm);
	/*
	 * check if (x, y1) belongs to the 1st segment of rtsc.
	 * if so, add the offset.
	 */
	if (rtsc->x + rtsc->dx > x)
		dx += rtsc->x + rtsc->dx - x;
	dy = seg_x2y(dx, isc->sm1);

	rtsc->x = x;
	rtsc->y = y;
	rtsc->dx = dx;
	rtsc->dy = dy;
	return;
}

static void
init_ed(struct hfsc_class *cl, unsigned int next_len)
{
	u64 cur_time = psched_get_time();

	/* update the deadline curve */
	rtsc_min(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);

	/*
	 * update the eligible curve.
	 * for concave, it is equal to the deadline curve.
	 * for convex, it is a linear curve with slope m2.
	 */
	cl->cl_eligible = cl->cl_deadline;
	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
		cl->cl_eligible.dx = 0;
		cl->cl_eligible.dy = 0;
	}

	/* compute e and d */
	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);

	eltree_insert(cl);
}

static void
update_ed(struct hfsc_class *cl, unsigned int next_len)
{
	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);

	eltree_update(cl);
}

static inline void
update_d(struct hfsc_class *cl, unsigned int next_len)
{
	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
}

static inline void
update_cfmin(struct hfsc_class *cl)
{
	struct rb_node *n = rb_first(&cl->cf_tree);
	struct hfsc_class *p;

	if (n == NULL) {
		cl->cl_cfmin = 0;
		return;
	}
	p = rb_entry(n, struct hfsc_class, cf_node);
	cl->cl_cfmin = p->cl_f;
}

static void
init_vf(struct hfsc_class *cl, unsigned int len)
{
	struct hfsc_class *max_cl;
	struct rb_node *n;
	u64 vt, f, cur_time;
	int go_active;

	cur_time = 0;
	go_active = 1;
	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
		if (go_active && cl->cl_nactive++ == 0)
			go_active = 1;
		else
			go_active = 0;

		if (go_active) {
			n = rb_last(&cl->cl_parent->vt_tree);
			if (n != NULL) {
				max_cl = rb_entry(n, struct hfsc_class,vt_node);
				/*
				 * set vt to the average of the min and max
				 * classes.  if the parent's period didn't
				 * change, don't decrease vt of the class.
				 */
				vt = max_cl->cl_vt;
				if (cl->cl_parent->cl_cvtmin != 0)
					vt = (cl->cl_parent->cl_cvtmin + vt)/2;

				if (cl->cl_parent->cl_vtperiod !=
				    cl->cl_parentperiod || vt > cl->cl_vt)
					cl->cl_vt = vt;
			} else {
				/*
				 * first child for a new parent backlog period.
				 * add parent's cvtmax to cvtoff to make a new
				 * vt (vtoff + vt) larger than the vt in the
				 * last period for all children.
				 */
				vt = cl->cl_parent->cl_cvtmax;
				cl->cl_parent->cl_cvtoff += vt;
				cl->cl_parent->cl_cvtmax = 0;
				cl->cl_parent->cl_cvtmin = 0;
				cl->cl_vt = 0;
			}

			cl->cl_vtoff = cl->cl_parent->cl_cvtoff -
							cl->cl_pcvtoff;

			/* update the virtual curve */
			vt = cl->cl_vt + cl->cl_vtoff;
			rtsc_min(&cl->cl_virtual, &cl->cl_fsc, vt,
						      cl->cl_total);
			if (cl->cl_virtual.x == vt) {
				cl->cl_virtual.x -= cl->cl_vtoff;
				cl->cl_vtoff = 0;
			}
			cl->cl_vtadj = 0;

			cl->cl_vtperiod++;  /* increment vt period */
			cl->cl_parentperiod = cl->cl_parent->cl_vtperiod;
			if (cl->cl_parent->cl_nactive == 0)
				cl->cl_parentperiod++;
			cl->cl_f = 0;

			vttree_insert(cl);
			cftree_insert(cl);

			if (cl->cl_flags & HFSC_USC) {
				/* class has upper limit curve */
				if (cur_time == 0)
					cur_time = psched_get_time();

				/* update the ulimit curve */
				rtsc_min(&cl->cl_ulimit, &cl->cl_usc, cur_time,
					 cl->cl_total);
				/* compute myf */
				cl->cl_myf = rtsc_y2x(&cl->cl_ulimit,
						      cl->cl_total);
				cl->cl_myfadj = 0;
			}
		}

		f = max(cl->cl_myf, cl->cl_cfmin);
		if (f != cl->cl_f) {
			cl->cl_f = f;
			cftree_update(cl);
			update_cfmin(cl->cl_parent);
		}
	}
}

static void
update_vf(struct hfsc_class *cl, unsigned int len, u64 cur_time)
{
	u64 f; /* , myf_bound, delta; */
	int go_passive = 0;

	if (cl->qdisc->q.qlen == 0 && cl->cl_flags & HFSC_FSC)
		go_passive = 1;

	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
		cl->cl_total += len;

		if (!(cl->cl_flags & HFSC_FSC) || cl->cl_nactive == 0)
			continue;

		if (go_passive && --cl->cl_nactive == 0)
			go_passive = 1;
		else
			go_passive = 0;

		if (go_passive) {
			/* no more active child, going passive */

			/* update cvtmax of the parent class */
			if (cl->cl_vt > cl->cl_parent->cl_cvtmax)
				cl->cl_parent->cl_cvtmax = cl->cl_vt;

			/* remove this class from the vt tree */
			vttree_remove(cl);

			cftree_remove(cl);
			update_cfmin(cl->cl_parent);

			continue;
		}

		/*
		 * update vt and f
		 */
		cl->cl_vt = rtsc_y2x(&cl->cl_virtual, cl->cl_total)
			    - cl->cl_vtoff + cl->cl_vtadj;

		/*
		 * if vt of the class is smaller than cvtmin,
		 * the class was skipped in the past due to non-fit.
		 * if so, we need to adjust vtadj.
		 */
		if (cl->cl_vt < cl->cl_parent->cl_cvtmin) {
			cl->cl_vtadj += cl->cl_parent->cl_cvtmin - cl->cl_vt;
			cl->cl_vt = cl->cl_parent->cl_cvtmin;
		}

		/* update the vt tree */
		vttree_update(cl);

		if (cl->cl_flags & HFSC_USC) {
			cl->cl_myf = cl->cl_myfadj + rtsc_y2x(&cl->cl_ulimit,
							      cl->cl_total);
#if 0
			/*
			 * This code causes classes to stay way under their
			 * limit when multiple classes are used at gigabit
			 * speed. needs investigation. -kaber
			 */
			/*
			 * if myf lags behind by more than one clock tick
			 * from the current time, adjust myfadj to prevent
			 * a rate-limited class from going greedy.
			 * in a steady state under rate-limiting, myf
			 * fluctuates within one clock tick.
			 */
			myf_bound = cur_time - PSCHED_JIFFIE2US(1);
			if (cl->cl_myf < myf_bound) {
				delta = cur_time - cl->cl_myf;
				cl->cl_myfadj += delta;
				cl->cl_myf += delta;
			}
#endif
		}

		f = max(cl->cl_myf, cl->cl_cfmin);
		if (f != cl->cl_f) {
			cl->cl_f = f;
			cftree_update(cl);
			update_cfmin(cl->cl_parent);
		}
	}
}

static void
set_active(struct hfsc_class *cl, unsigned int len)
{
	if (cl->cl_flags & HFSC_RSC)
		init_ed(cl, len);
	if (cl->cl_flags & HFSC_FSC)
		init_vf(cl, len);

	list_add_tail(&cl->dlist, &cl->sched->droplist);
}

static void
set_passive(struct hfsc_class *cl)
{
	if (cl->cl_flags & HFSC_RSC)
		eltree_remove(cl);

	list_del(&cl->dlist);

	/*
	 * vttree is now handled in update_vf() so that update_vf(cl, 0, 0)
	 * needs to be called explicitly to remove a class from vttree.
	 */
}

/*
 * hack to get length of first packet in queue.
 */
static unsigned int
qdisc_peek_len(struct Qdisc *sch)
{
	struct sk_buff *skb;
	unsigned int len;

	skb = sch->dequeue(sch);
	if (skb == NULL) {
		if (net_ratelimit())
			printk("qdisc_peek_len: non work-conserving qdisc ?\n");
		return 0;
	}
	len = skb->len;
	if (unlikely(sch->ops->requeue(skb, sch) != NET_XMIT_SUCCESS)) {
		if (net_ratelimit())
			printk("qdisc_peek_len: failed to requeue\n");
		qdisc_tree_decrease_qlen(sch, 1);
		return 0;
	}
	return len;
}

static void
hfsc_purge_queue(struct Qdisc *sch, struct hfsc_class *cl)
{
	unsigned int len = cl->qdisc->q.qlen;

	qdisc_reset(cl->qdisc);
	qdisc_tree_decrease_qlen(cl->qdisc, len);
}

static void
hfsc_adjust_levels(struct hfsc_class *cl)
{
	struct hfsc_class *p;
	unsigned int level;

	do {
		level = 0;
		list_for_each_entry(p, &cl->children, siblings) {
			if (p->level >= level)
				level = p->level + 1;
		}
		cl->level = level;
	} while ((cl = cl->cl_parent) != NULL);
}

static inline unsigned int
hfsc_hash(u32 h)
{
	h ^= h >> 8;
	h ^= h >> 4;

	return h & (HFSC_HSIZE - 1);
}

static inline struct hfsc_class *
hfsc_find_class(u32 classid, struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;

	list_for_each_entry(cl, &q->clhash[hfsc_hash(classid)], hlist) {
		if (cl->classid == classid)
			return cl;
	}
	return NULL;
}

static void
hfsc_change_rsc(struct hfsc_class *cl, struct tc_service_curve *rsc,
		u64 cur_time)
{
	sc2isc(rsc, &cl->cl_rsc);
	rtsc_init(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);
	cl->cl_eligible = cl->cl_deadline;
	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
		cl->cl_eligible.dx = 0;
		cl->cl_eligible.dy = 0;
	}
	cl->cl_flags |= HFSC_RSC;
}

static void
hfsc_change_fsc(struct hfsc_class *cl, struct tc_service_curve *fsc)
{
	sc2isc(fsc, &cl->cl_fsc);
	rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
	cl->cl_flags |= HFSC_FSC;
}

static void
hfsc_change_usc(struct hfsc_class *cl, struct tc_service_curve *usc,
		u64 cur_time)
{
	sc2isc(usc, &cl->cl_usc);
	rtsc_init(&cl->cl_ulimit, &cl->cl_usc, cur_time, cl->cl_total);
	cl->cl_flags |= HFSC_USC;
}

static int
hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
		  struct rtattr **tca, unsigned long *arg)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl = (struct hfsc_class *)*arg;
	struct hfsc_class *parent = NULL;
	struct rtattr *opt = tca[TCA_OPTIONS-1];
	struct rtattr *tb[TCA_HFSC_MAX];
	struct tc_service_curve *rsc = NULL, *fsc = NULL, *usc = NULL;
	u64 cur_time;

	if (opt == NULL || rtattr_parse_nested(tb, TCA_HFSC_MAX, opt))
		return -EINVAL;

	if (tb[TCA_HFSC_RSC-1]) {
		if (RTA_PAYLOAD(tb[TCA_HFSC_RSC-1]) < sizeof(*rsc))
			return -EINVAL;
		rsc = RTA_DATA(tb[TCA_HFSC_RSC-1]);
		if (rsc->m1 == 0 && rsc->m2 == 0)
			rsc = NULL;
	}

	if (tb[TCA_HFSC_FSC-1]) {
		if (RTA_PAYLOAD(tb[TCA_HFSC_FSC-1]) < sizeof(*fsc))
			return -EINVAL;
		fsc = RTA_DATA(tb[TCA_HFSC_FSC-1]);
		if (fsc->m1 == 0 && fsc->m2 == 0)
			fsc = NULL;
	}

	if (tb[TCA_HFSC_USC-1]) {
		if (RTA_PAYLOAD(tb[TCA_HFSC_USC-1]) < sizeof(*usc))
			return -EINVAL;
		usc = RTA_DATA(tb[TCA_HFSC_USC-1]);
		if (usc->m1 == 0 && usc->m2 == 0)
			usc = NULL;
	}

	if (cl != NULL) {
		if (parentid) {
			if (cl->cl_parent && cl->cl_parent->classid != parentid)
				return -EINVAL;
			if (cl->cl_parent == NULL && parentid != TC_H_ROOT)
				return -EINVAL;
		}
		cur_time = psched_get_time();

		sch_tree_lock(sch);
		if (rsc != NULL)
			hfsc_change_rsc(cl, rsc, cur_time);
		if (fsc != NULL)
			hfsc_change_fsc(cl, fsc);
		if (usc != NULL)
			hfsc_change_usc(cl, usc, cur_time);

		if (cl->qdisc->q.qlen != 0) {
			if (cl->cl_flags & HFSC_RSC)
				update_ed(cl, qdisc_peek_len(cl->qdisc));
			if (cl->cl_flags & HFSC_FSC)
				update_vf(cl, 0, cur_time);
		}
		sch_tree_unlock(sch);

		if (tca[TCA_RATE-1])
			gen_replace_estimator(&cl->bstats, &cl->rate_est,
					      &sch->dev->queue_lock,
					      tca[TCA_RATE-1]);
		return 0;
	}

	if (parentid == TC_H_ROOT)
		return -EEXIST;

	parent = &q->root;
	if (parentid) {
		parent = hfsc_find_class(parentid, sch);
		if (parent == NULL)
			return -ENOENT;
	}

	if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0)
		return -EINVAL;
	if (hfsc_find_class(classid, sch))
		return -EEXIST;

	if (rsc == NULL && fsc == NULL)
		return -EINVAL;

	cl = kzalloc(sizeof(struct hfsc_class), GFP_KERNEL);
	if (cl == NULL)
		return -ENOBUFS;

	if (rsc != NULL)
		hfsc_change_rsc(cl, rsc, 0);
	if (fsc != NULL)
		hfsc_change_fsc(cl, fsc);
	if (usc != NULL)
		hfsc_change_usc(cl, usc, 0);

	cl->refcnt    = 1;
	cl->classid   = classid;
	cl->sched     = q;
	cl->cl_parent = parent;
	cl->qdisc = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, classid);
	if (cl->qdisc == NULL)
		cl->qdisc = &noop_qdisc;
	INIT_LIST_HEAD(&cl->children);
	cl->vt_tree = RB_ROOT;
	cl->cf_tree = RB_ROOT;

	sch_tree_lock(sch);
	list_add_tail(&cl->hlist, &q->clhash[hfsc_hash(classid)]);
	list_add_tail(&cl->siblings, &parent->children);
	if (parent->level == 0)
		hfsc_purge_queue(sch, parent);
	hfsc_adjust_levels(parent);
	cl->cl_pcvtoff = parent->cl_cvtoff;
	sch_tree_unlock(sch);

	if (tca[TCA_RATE-1])
		gen_new_estimator(&cl->bstats, &cl->rate_est,
				  &sch->dev->queue_lock, tca[TCA_RATE-1]);
	*arg = (unsigned long)cl;
	return 0;
}

static void
hfsc_destroy_class(struct Qdisc *sch, struct hfsc_class *cl)
{
	struct hfsc_sched *q = qdisc_priv(sch);

	tcf_destroy_chain(cl->filter_list);
	qdisc_destroy(cl->qdisc);
	gen_kill_estimator(&cl->bstats, &cl->rate_est);
	if (cl != &q->root)
		kfree(cl);
}

static int
hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (cl->level > 0 || cl->filter_cnt > 0 || cl == &q->root)
		return -EBUSY;

	sch_tree_lock(sch);

	list_del(&cl->siblings);
	hfsc_adjust_levels(cl->cl_parent);

	hfsc_purge_queue(sch, cl);
	list_del(&cl->hlist);

	if (--cl->refcnt == 0)
		hfsc_destroy_class(sch, cl);

	sch_tree_unlock(sch);
	return 0;
}

static struct hfsc_class *
hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	struct tcf_result res;
	struct tcf_proto *tcf;
	int result;

	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0 &&
	    (cl = hfsc_find_class(skb->priority, sch)) != NULL)
		if (cl->level == 0)
			return cl;

	*qerr = NET_XMIT_BYPASS;
	tcf = q->root.filter_list;
	while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
#ifdef CONFIG_NET_CLS_ACT
		switch (result) {
		case TC_ACT_QUEUED:
		case TC_ACT_STOLEN:
			*qerr = NET_XMIT_SUCCESS;
		case TC_ACT_SHOT:
			return NULL;
		}
#elif defined(CONFIG_NET_CLS_POLICE)
		if (result == TC_POLICE_SHOT)
			return NULL;
#endif
		if ((cl = (struct hfsc_class *)res.class) == NULL) {
			if ((cl = hfsc_find_class(res.classid, sch)) == NULL)
				break; /* filter selected invalid classid */
		}

		if (cl->level == 0)
			return cl; /* hit leaf class */

		/* apply inner filter chain */
		tcf = cl->filter_list;
	}

	/* classification failed, try default class */
	cl = hfsc_find_class(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
	if (cl == NULL || cl->level > 0)
		return NULL;

	return cl;
}

static int
hfsc_graft_class(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
		 struct Qdisc **old)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (cl == NULL)
		return -ENOENT;
	if (cl->level > 0)
		return -EINVAL;
	if (new == NULL) {
		new = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
					cl->classid);
		if (new == NULL)
			new = &noop_qdisc;
	}

	sch_tree_lock(sch);
	hfsc_purge_queue(sch, cl);
	*old = xchg(&cl->qdisc, new);
	sch_tree_unlock(sch);
	return 0;
}

static struct Qdisc *
hfsc_class_leaf(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (cl != NULL && cl->level == 0)
		return cl->qdisc;

	return NULL;
}

static void
hfsc_qlen_notify(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (cl->qdisc->q.qlen == 0) {
		update_vf(cl, 0, 0);
		set_passive(cl);
	}
}

static unsigned long
hfsc_get_class(struct Qdisc *sch, u32 classid)
{
	struct hfsc_class *cl = hfsc_find_class(classid, sch);

	if (cl != NULL)
		cl->refcnt++;

	return (unsigned long)cl;
}

static void
hfsc_put_class(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (--cl->refcnt == 0)
		hfsc_destroy_class(sch, cl);
}

static unsigned long
hfsc_bind_tcf(struct Qdisc *sch, unsigned long parent, u32 classid)
{
	struct hfsc_class *p = (struct hfsc_class *)parent;
	struct hfsc_class *cl = hfsc_find_class(classid, sch);

	if (cl != NULL) {
		if (p != NULL && p->level <= cl->level)
			return 0;
		cl->filter_cnt++;
	}

	return (unsigned long)cl;
}

static void
hfsc_unbind_tcf(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	cl->filter_cnt--;
}

static struct tcf_proto **
hfsc_tcf_chain(struct Qdisc *sch, unsigned long arg)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl = (struct hfsc_class *)arg;

	if (cl == NULL)
		cl = &q->root;

	return &cl->filter_list;
}

static int
hfsc_dump_sc(struct sk_buff *skb, int attr, struct internal_sc *sc)
{
	struct tc_service_curve tsc;

	tsc.m1 = sm2m(sc->sm1);
	tsc.d  = dx2d(sc->dx);
	tsc.m2 = sm2m(sc->sm2);
	RTA_PUT(skb, attr, sizeof(tsc), &tsc);

	return skb->len;

 rtattr_failure:
	return -1;
}

static inline int
hfsc_dump_curves(struct sk_buff *skb, struct hfsc_class *cl)
{
	if ((cl->cl_flags & HFSC_RSC) &&
	    (hfsc_dump_sc(skb, TCA_HFSC_RSC, &cl->cl_rsc) < 0))
		goto rtattr_failure;

	if ((cl->cl_flags & HFSC_FSC) &&
	    (hfsc_dump_sc(skb, TCA_HFSC_FSC, &cl->cl_fsc) < 0))
		goto rtattr_failure;

	if ((cl->cl_flags & HFSC_USC) &&
	    (hfsc_dump_sc(skb, TCA_HFSC_USC, &cl->cl_usc) < 0))
		goto rtattr_failure;

	return skb->len;

 rtattr_failure:
	return -1;
}

static int
hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,
		struct tcmsg *tcm)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;
	unsigned char *b = skb_tail_pointer(skb);
	struct rtattr *rta = (struct rtattr *)b;

	tcm->tcm_parent = cl->cl_parent ? cl->cl_parent->classid : TC_H_ROOT;
	tcm->tcm_handle = cl->classid;
	if (cl->level == 0)
		tcm->tcm_info = cl->qdisc->handle;

	RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
	if (hfsc_dump_curves(skb, cl) < 0)
		goto rtattr_failure;
	rta->rta_len = skb_tail_pointer(skb) - b;
	return skb->len;

 rtattr_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int
hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
	struct gnet_dump *d)
{
	struct hfsc_class *cl = (struct hfsc_class *)arg;
	struct tc_hfsc_stats xstats;

	cl->qstats.qlen = cl->qdisc->q.qlen;
	xstats.level   = cl->level;
	xstats.period  = cl->cl_vtperiod;
	xstats.work    = cl->cl_total;
	xstats.rtwork  = cl->cl_cumul;

	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
		return -1;

	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
}



static void
hfsc_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	unsigned int i;

	if (arg->stop)
		return;

	for (i = 0; i < HFSC_HSIZE; i++) {
		list_for_each_entry(cl, &q->clhash[i], hlist) {
			if (arg->count < arg->skip) {
				arg->count++;
				continue;
			}
			if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
				arg->stop = 1;
				return;
			}
			arg->count++;
		}
	}
}

static void
hfsc_schedule_watchdog(struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	u64 next_time = 0;

	if ((cl = eltree_get_minel(q)) != NULL)
		next_time = cl->cl_e;
	if (q->root.cl_cfmin != 0) {
		if (next_time == 0 || next_time > q->root.cl_cfmin)
			next_time = q->root.cl_cfmin;
	}
	WARN_ON(next_time == 0);
	qdisc_watchdog_schedule(&q->watchdog, next_time);
}

static int
hfsc_init_qdisc(struct Qdisc *sch, struct rtattr *opt)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct tc_hfsc_qopt *qopt;
	unsigned int i;

	if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
		return -EINVAL;
	qopt = RTA_DATA(opt);

	q->defcls = qopt->defcls;
	for (i = 0; i < HFSC_HSIZE; i++)
		INIT_LIST_HEAD(&q->clhash[i]);
	q->eligible = RB_ROOT;
	INIT_LIST_HEAD(&q->droplist);
	skb_queue_head_init(&q->requeue);

	q->root.refcnt  = 1;
	q->root.classid = sch->handle;
	q->root.sched   = q;
	q->root.qdisc = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
					  sch->handle);
	if (q->root.qdisc == NULL)
		q->root.qdisc = &noop_qdisc;
	INIT_LIST_HEAD(&q->root.children);
	q->root.vt_tree = RB_ROOT;
	q->root.cf_tree = RB_ROOT;

	list_add(&q->root.hlist, &q->clhash[hfsc_hash(q->root.classid)]);

	qdisc_watchdog_init(&q->watchdog, sch);

	return 0;
}

static int
hfsc_change_qdisc(struct Qdisc *sch, struct rtattr *opt)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct tc_hfsc_qopt *qopt;

	if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
		return -EINVAL;
	qopt = RTA_DATA(opt);

	sch_tree_lock(sch);
	q->defcls = qopt->defcls;
	sch_tree_unlock(sch);

	return 0;
}

static void
hfsc_reset_class(struct hfsc_class *cl)
{
	cl->cl_total        = 0;
	cl->cl_cumul        = 0;
	cl->cl_d            = 0;
	cl->cl_e            = 0;
	cl->cl_vt           = 0;
	cl->cl_vtadj        = 0;
	cl->cl_vtoff        = 0;
	cl->cl_cvtmin       = 0;
	cl->cl_cvtmax       = 0;
	cl->cl_cvtoff       = 0;
	cl->cl_pcvtoff      = 0;
	cl->cl_vtperiod     = 0;
	cl->cl_parentperiod = 0;
	cl->cl_f            = 0;
	cl->cl_myf          = 0;
	cl->cl_myfadj       = 0;
	cl->cl_cfmin        = 0;
	cl->cl_nactive      = 0;

	cl->vt_tree = RB_ROOT;
	cl->cf_tree = RB_ROOT;
	qdisc_reset(cl->qdisc);

	if (cl->cl_flags & HFSC_RSC)
		rtsc_init(&cl->cl_deadline, &cl->cl_rsc, 0, 0);
	if (cl->cl_flags & HFSC_FSC)
		rtsc_init(&cl->cl_virtual, &cl->cl_fsc, 0, 0);
	if (cl->cl_flags & HFSC_USC)
		rtsc_init(&cl->cl_ulimit, &cl->cl_usc, 0, 0);
}

static void
hfsc_reset_qdisc(struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	unsigned int i;

	for (i = 0; i < HFSC_HSIZE; i++) {
		list_for_each_entry(cl, &q->clhash[i], hlist)
			hfsc_reset_class(cl);
	}
	__skb_queue_purge(&q->requeue);
	q->eligible = RB_ROOT;
	INIT_LIST_HEAD(&q->droplist);
	qdisc_watchdog_cancel(&q->watchdog);
	sch->q.qlen = 0;
}

static void
hfsc_destroy_qdisc(struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl, *next;
	unsigned int i;

	for (i = 0; i < HFSC_HSIZE; i++) {
		list_for_each_entry_safe(cl, next, &q->clhash[i], hlist)
			hfsc_destroy_class(sch, cl);
	}
	__skb_queue_purge(&q->requeue);
	qdisc_watchdog_cancel(&q->watchdog);
}

static int
hfsc_dump_qdisc(struct Qdisc *sch, struct sk_buff *skb)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	unsigned char *b = skb_tail_pointer(skb);
	struct tc_hfsc_qopt qopt;

	qopt.defcls = q->defcls;
	RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
	return skb->len;

 rtattr_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int
hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct hfsc_class *cl;
	unsigned int len;
	int err;

	cl = hfsc_classify(skb, sch, &err);
	if (cl == NULL) {
		if (err == NET_XMIT_BYPASS)
			sch->qstats.drops++;
		kfree_skb(skb);
		return err;
	}

	len = skb->len;
	err = cl->qdisc->enqueue(skb, cl->qdisc);
	if (unlikely(err != NET_XMIT_SUCCESS)) {
		cl->qstats.drops++;
		sch->qstats.drops++;
		return err;
	}

	if (cl->qdisc->q.qlen == 1)
		set_active(cl, len);

	cl->bstats.packets++;
	cl->bstats.bytes += len;
	sch->bstats.packets++;
	sch->bstats.bytes += len;
	sch->q.qlen++;

	return NET_XMIT_SUCCESS;
}

static struct sk_buff *
hfsc_dequeue(struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	struct sk_buff *skb;
	u64 cur_time;
	unsigned int next_len;
	int realtime = 0;

	if (sch->q.qlen == 0)
		return NULL;
	if ((skb = __skb_dequeue(&q->requeue)))
		goto out;

	cur_time = psched_get_time();

	/*
	 * if there are eligible classes, use real-time criteria.
	 * find the class with the minimum deadline among
	 * the eligible classes.
	 */
	if ((cl = eltree_get_mindl(q, cur_time)) != NULL) {
		realtime = 1;
	} else {
		/*
		 * use link-sharing criteria
		 * get the class with the minimum vt in the hierarchy
		 */
		cl = vttree_get_minvt(&q->root, cur_time);
		if (cl == NULL) {
			sch->qstats.overlimits++;
			hfsc_schedule_watchdog(sch);
			return NULL;
		}
	}

	skb = cl->qdisc->dequeue(cl->qdisc);
	if (skb == NULL) {
		if (net_ratelimit())
			printk("HFSC: Non-work-conserving qdisc ?\n");
		return NULL;
	}

	update_vf(cl, skb->len, cur_time);
	if (realtime)
		cl->cl_cumul += skb->len;

	if (cl->qdisc->q.qlen != 0) {
		if (cl->cl_flags & HFSC_RSC) {
			/* update ed */
			next_len = qdisc_peek_len(cl->qdisc);
			if (realtime)
				update_ed(cl, next_len);
			else
				update_d(cl, next_len);
		}
	} else {
		/* the class becomes passive */
		set_passive(cl);
	}

 out:
	sch->flags &= ~TCQ_F_THROTTLED;
	sch->q.qlen--;

	return skb;
}

static int
hfsc_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);

	__skb_queue_head(&q->requeue, skb);
	sch->q.qlen++;
	sch->qstats.requeues++;
	return NET_XMIT_SUCCESS;
}

static unsigned int
hfsc_drop(struct Qdisc *sch)
{
	struct hfsc_sched *q = qdisc_priv(sch);
	struct hfsc_class *cl;
	unsigned int len;

	list_for_each_entry(cl, &q->droplist, dlist) {
		if (cl->qdisc->ops->drop != NULL &&
		    (len = cl->qdisc->ops->drop(cl->qdisc)) > 0) {
			if (cl->qdisc->q.qlen == 0) {
				update_vf(cl, 0, 0);
				set_passive(cl);
			} else {
				list_move_tail(&cl->dlist, &q->droplist);
			}
			cl->qstats.drops++;
			sch->qstats.drops++;
			sch->q.qlen--;
			return len;
		}
	}
	return 0;
}

static struct Qdisc_class_ops hfsc_class_ops = {
	.change		= hfsc_change_class,
	.delete		= hfsc_delete_class,
	.graft		= hfsc_graft_class,
	.leaf		= hfsc_class_leaf,
	.qlen_notify	= hfsc_qlen_notify,
	.get		= hfsc_get_class,
	.put		= hfsc_put_class,
	.bind_tcf	= hfsc_bind_tcf,
	.unbind_tcf	= hfsc_unbind_tcf,
	.tcf_chain	= hfsc_tcf_chain,
	.dump		= hfsc_dump_class,
	.dump_stats	= hfsc_dump_class_stats,
	.walk		= hfsc_walk
};

static struct Qdisc_ops hfsc_qdisc_ops = {
	.id		= "hfsc",
	.init		= hfsc_init_qdisc,
	.change		= hfsc_change_qdisc,
	.reset		= hfsc_reset_qdisc,
	.destroy	= hfsc_destroy_qdisc,
	.dump		= hfsc_dump_qdisc,
	.enqueue	= hfsc_enqueue,
	.dequeue	= hfsc_dequeue,
	.requeue	= hfsc_requeue,
	.drop		= hfsc_drop,
	.cl_ops		= &hfsc_class_ops,
	.priv_size	= sizeof(struct hfsc_sched),
	.owner		= THIS_MODULE
};

static int __init
hfsc_init(void)
{
	return register_qdisc(&hfsc_qdisc_ops);
}

static void __exit
hfsc_cleanup(void)
{
	unregister_qdisc(&hfsc_qdisc_ops);
}

MODULE_LICENSE("GPL");
module_init(hfsc_init);
module_exit(hfsc_cleanup);