summaryrefslogtreecommitdiffstats
path: root/net/sunrpc/svc.c
blob: 0de918cb3d90da4842fdb0facc54ac2f8b0ddc5a (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
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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/net/sunrpc/svc.c
 *
 * High-level RPC service routines
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 *
 * Multiple threads pools and NUMAisation
 * Copyright (c) 2006 Silicon Graphics, Inc.
 * by Greg Banks <gnb@melbourne.sgi.com>
 */

#include <linux/linkage.h>
#include <linux/sched/signal.h>
#include <linux/errno.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/slab.h>

#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/bc_xprt.h>

#include <trace/events/sunrpc.h>

#define RPCDBG_FACILITY	RPCDBG_SVCDSP

static void svc_unregister(const struct svc_serv *serv, struct net *net);

#define svc_serv_is_pooled(serv)    ((serv)->sv_ops->svo_function)

#define SVC_POOL_DEFAULT	SVC_POOL_GLOBAL

/*
 * Structure for mapping cpus to pools and vice versa.
 * Setup once during sunrpc initialisation.
 */
struct svc_pool_map svc_pool_map = {
	.mode = SVC_POOL_DEFAULT
};
EXPORT_SYMBOL_GPL(svc_pool_map);

static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */

static int
param_set_pool_mode(const char *val, const struct kernel_param *kp)
{
	int *ip = (int *)kp->arg;
	struct svc_pool_map *m = &svc_pool_map;
	int err;

	mutex_lock(&svc_pool_map_mutex);

	err = -EBUSY;
	if (m->count)
		goto out;

	err = 0;
	if (!strncmp(val, "auto", 4))
		*ip = SVC_POOL_AUTO;
	else if (!strncmp(val, "global", 6))
		*ip = SVC_POOL_GLOBAL;
	else if (!strncmp(val, "percpu", 6))
		*ip = SVC_POOL_PERCPU;
	else if (!strncmp(val, "pernode", 7))
		*ip = SVC_POOL_PERNODE;
	else
		err = -EINVAL;

out:
	mutex_unlock(&svc_pool_map_mutex);
	return err;
}

static int
param_get_pool_mode(char *buf, const struct kernel_param *kp)
{
	int *ip = (int *)kp->arg;

	switch (*ip)
	{
	case SVC_POOL_AUTO:
		return strlcpy(buf, "auto\n", 20);
	case SVC_POOL_GLOBAL:
		return strlcpy(buf, "global\n", 20);
	case SVC_POOL_PERCPU:
		return strlcpy(buf, "percpu\n", 20);
	case SVC_POOL_PERNODE:
		return strlcpy(buf, "pernode\n", 20);
	default:
		return sprintf(buf, "%d\n", *ip);
	}
}

module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
		 &svc_pool_map.mode, 0644);

/*
 * Detect best pool mapping mode heuristically,
 * according to the machine's topology.
 */
static int
svc_pool_map_choose_mode(void)
{
	unsigned int node;

	if (nr_online_nodes > 1) {
		/*
		 * Actually have multiple NUMA nodes,
		 * so split pools on NUMA node boundaries
		 */
		return SVC_POOL_PERNODE;
	}

	node = first_online_node;
	if (nr_cpus_node(node) > 2) {
		/*
		 * Non-trivial SMP, or CONFIG_NUMA on
		 * non-NUMA hardware, e.g. with a generic
		 * x86_64 kernel on Xeons.  In this case we
		 * want to divide the pools on cpu boundaries.
		 */
		return SVC_POOL_PERCPU;
	}

	/* default: one global pool */
	return SVC_POOL_GLOBAL;
}

/*
 * Allocate the to_pool[] and pool_to[] arrays.
 * Returns 0 on success or an errno.
 */
static int
svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
{
	m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
	if (!m->to_pool)
		goto fail;
	m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
	if (!m->pool_to)
		goto fail_free;

	return 0;

fail_free:
	kfree(m->to_pool);
	m->to_pool = NULL;
fail:
	return -ENOMEM;
}

/*
 * Initialise the pool map for SVC_POOL_PERCPU mode.
 * Returns number of pools or <0 on error.
 */
static int
svc_pool_map_init_percpu(struct svc_pool_map *m)
{
	unsigned int maxpools = nr_cpu_ids;
	unsigned int pidx = 0;
	unsigned int cpu;
	int err;

	err = svc_pool_map_alloc_arrays(m, maxpools);
	if (err)
		return err;

	for_each_online_cpu(cpu) {
		BUG_ON(pidx >= maxpools);
		m->to_pool[cpu] = pidx;
		m->pool_to[pidx] = cpu;
		pidx++;
	}
	/* cpus brought online later all get mapped to pool0, sorry */

	return pidx;
};


/*
 * Initialise the pool map for SVC_POOL_PERNODE mode.
 * Returns number of pools or <0 on error.
 */
static int
svc_pool_map_init_pernode(struct svc_pool_map *m)
{
	unsigned int maxpools = nr_node_ids;
	unsigned int pidx = 0;
	unsigned int node;
	int err;

	err = svc_pool_map_alloc_arrays(m, maxpools);
	if (err)
		return err;

	for_each_node_with_cpus(node) {
		/* some architectures (e.g. SN2) have cpuless nodes */
		BUG_ON(pidx > maxpools);
		m->to_pool[node] = pidx;
		m->pool_to[pidx] = node;
		pidx++;
	}
	/* nodes brought online later all get mapped to pool0, sorry */

	return pidx;
}


/*
 * Add a reference to the global map of cpus to pools (and
 * vice versa).  Initialise the map if we're the first user.
 * Returns the number of pools.
 */
unsigned int
svc_pool_map_get(void)
{
	struct svc_pool_map *m = &svc_pool_map;
	int npools = -1;

	mutex_lock(&svc_pool_map_mutex);

	if (m->count++) {
		mutex_unlock(&svc_pool_map_mutex);
		return m->npools;
	}

	if (m->mode == SVC_POOL_AUTO)
		m->mode = svc_pool_map_choose_mode();

	switch (m->mode) {
	case SVC_POOL_PERCPU:
		npools = svc_pool_map_init_percpu(m);
		break;
	case SVC_POOL_PERNODE:
		npools = svc_pool_map_init_pernode(m);
		break;
	}

	if (npools < 0) {
		/* default, or memory allocation failure */
		npools = 1;
		m->mode = SVC_POOL_GLOBAL;
	}
	m->npools = npools;

	mutex_unlock(&svc_pool_map_mutex);
	return m->npools;
}
EXPORT_SYMBOL_GPL(svc_pool_map_get);

/*
 * Drop a reference to the global map of cpus to pools.
 * When the last reference is dropped, the map data is
 * freed; this allows the sysadmin to change the pool
 * mode using the pool_mode module option without
 * rebooting or re-loading sunrpc.ko.
 */
void
svc_pool_map_put(void)
{
	struct svc_pool_map *m = &svc_pool_map;

	mutex_lock(&svc_pool_map_mutex);

	if (!--m->count) {
		kfree(m->to_pool);
		m->to_pool = NULL;
		kfree(m->pool_to);
		m->pool_to = NULL;
		m->npools = 0;
	}

	mutex_unlock(&svc_pool_map_mutex);
}
EXPORT_SYMBOL_GPL(svc_pool_map_put);

static int svc_pool_map_get_node(unsigned int pidx)
{
	const struct svc_pool_map *m = &svc_pool_map;

	if (m->count) {
		if (m->mode == SVC_POOL_PERCPU)
			return cpu_to_node(m->pool_to[pidx]);
		if (m->mode == SVC_POOL_PERNODE)
			return m->pool_to[pidx];
	}
	return NUMA_NO_NODE;
}
/*
 * Set the given thread's cpus_allowed mask so that it
 * will only run on cpus in the given pool.
 */
static inline void
svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
{
	struct svc_pool_map *m = &svc_pool_map;
	unsigned int node = m->pool_to[pidx];

	/*
	 * The caller checks for sv_nrpools > 1, which
	 * implies that we've been initialized.
	 */
	WARN_ON_ONCE(m->count == 0);
	if (m->count == 0)
		return;

	switch (m->mode) {
	case SVC_POOL_PERCPU:
	{
		set_cpus_allowed_ptr(task, cpumask_of(node));
		break;
	}
	case SVC_POOL_PERNODE:
	{
		set_cpus_allowed_ptr(task, cpumask_of_node(node));
		break;
	}
	}
}

/*
 * Use the mapping mode to choose a pool for a given CPU.
 * Used when enqueueing an incoming RPC.  Always returns
 * a non-NULL pool pointer.
 */
struct svc_pool *
svc_pool_for_cpu(struct svc_serv *serv, int cpu)
{
	struct svc_pool_map *m = &svc_pool_map;
	unsigned int pidx = 0;

	/*
	 * An uninitialised map happens in a pure client when
	 * lockd is brought up, so silently treat it the
	 * same as SVC_POOL_GLOBAL.
	 */
	if (svc_serv_is_pooled(serv)) {
		switch (m->mode) {
		case SVC_POOL_PERCPU:
			pidx = m->to_pool[cpu];
			break;
		case SVC_POOL_PERNODE:
			pidx = m->to_pool[cpu_to_node(cpu)];
			break;
		}
	}
	return &serv->sv_pools[pidx % serv->sv_nrpools];
}

int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
{
	int err;

	err = rpcb_create_local(net);
	if (err)
		return err;

	/* Remove any stale portmap registrations */
	svc_unregister(serv, net);
	return 0;
}
EXPORT_SYMBOL_GPL(svc_rpcb_setup);

void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
{
	svc_unregister(serv, net);
	rpcb_put_local(net);
}
EXPORT_SYMBOL_GPL(svc_rpcb_cleanup);

static int svc_uses_rpcbind(struct svc_serv *serv)
{
	struct svc_program	*progp;
	unsigned int		i;

	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
		for (i = 0; i < progp->pg_nvers; i++) {
			if (progp->pg_vers[i] == NULL)
				continue;
			if (!progp->pg_vers[i]->vs_hidden)
				return 1;
		}
	}

	return 0;
}

int svc_bind(struct svc_serv *serv, struct net *net)
{
	if (!svc_uses_rpcbind(serv))
		return 0;
	return svc_rpcb_setup(serv, net);
}
EXPORT_SYMBOL_GPL(svc_bind);

#if defined(CONFIG_SUNRPC_BACKCHANNEL)
static void
__svc_init_bc(struct svc_serv *serv)
{
	INIT_LIST_HEAD(&serv->sv_cb_list);
	spin_lock_init(&serv->sv_cb_lock);
	init_waitqueue_head(&serv->sv_cb_waitq);
}
#else
static void
__svc_init_bc(struct svc_serv *serv)
{
}
#endif

/*
 * Create an RPC service
 */
static struct svc_serv *
__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
	     const struct svc_serv_ops *ops)
{
	struct svc_serv	*serv;
	unsigned int vers;
	unsigned int xdrsize;
	unsigned int i;

	if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
		return NULL;
	serv->sv_name      = prog->pg_name;
	serv->sv_program   = prog;
	serv->sv_nrthreads = 1;
	serv->sv_stats     = prog->pg_stats;
	if (bufsize > RPCSVC_MAXPAYLOAD)
		bufsize = RPCSVC_MAXPAYLOAD;
	serv->sv_max_payload = bufsize? bufsize : 4096;
	serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
	serv->sv_ops = ops;
	xdrsize = 0;
	while (prog) {
		prog->pg_lovers = prog->pg_nvers-1;
		for (vers=0; vers<prog->pg_nvers ; vers++)
			if (prog->pg_vers[vers]) {
				prog->pg_hivers = vers;
				if (prog->pg_lovers > vers)
					prog->pg_lovers = vers;
				if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
					xdrsize = prog->pg_vers[vers]->vs_xdrsize;
			}
		prog = prog->pg_next;
	}
	serv->sv_xdrsize   = xdrsize;
	INIT_LIST_HEAD(&serv->sv_tempsocks);
	INIT_LIST_HEAD(&serv->sv_permsocks);
	timer_setup(&serv->sv_temptimer, NULL, 0);
	spin_lock_init(&serv->sv_lock);

	__svc_init_bc(serv);

	serv->sv_nrpools = npools;
	serv->sv_pools =
		kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
			GFP_KERNEL);
	if (!serv->sv_pools) {
		kfree(serv);
		return NULL;
	}

	for (i = 0; i < serv->sv_nrpools; i++) {
		struct svc_pool *pool = &serv->sv_pools[i];

		dprintk("svc: initialising pool %u for %s\n",
				i, serv->sv_name);

		pool->sp_id = i;
		INIT_LIST_HEAD(&pool->sp_sockets);
		INIT_LIST_HEAD(&pool->sp_all_threads);
		spin_lock_init(&pool->sp_lock);
	}

	return serv;
}

struct svc_serv *
svc_create(struct svc_program *prog, unsigned int bufsize,
	   const struct svc_serv_ops *ops)
{
	return __svc_create(prog, bufsize, /*npools*/1, ops);
}
EXPORT_SYMBOL_GPL(svc_create);

struct svc_serv *
svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
		  const struct svc_serv_ops *ops)
{
	struct svc_serv *serv;
	unsigned int npools = svc_pool_map_get();

	serv = __svc_create(prog, bufsize, npools, ops);
	if (!serv)
		goto out_err;
	return serv;
out_err:
	svc_pool_map_put();
	return NULL;
}
EXPORT_SYMBOL_GPL(svc_create_pooled);

void svc_shutdown_net(struct svc_serv *serv, struct net *net)
{
	svc_close_net(serv, net);

	if (serv->sv_ops->svo_shutdown)
		serv->sv_ops->svo_shutdown(serv, net);
}
EXPORT_SYMBOL_GPL(svc_shutdown_net);

/*
 * Destroy an RPC service. Should be called with appropriate locking to
 * protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
 */
void
svc_destroy(struct svc_serv *serv)
{
	dprintk("svc: svc_destroy(%s, %d)\n",
				serv->sv_program->pg_name,
				serv->sv_nrthreads);

	if (serv->sv_nrthreads) {
		if (--(serv->sv_nrthreads) != 0) {
			svc_sock_update_bufs(serv);
			return;
		}
	} else
		printk("svc_destroy: no threads for serv=%p!\n", serv);

	del_timer_sync(&serv->sv_temptimer);

	/*
	 * The last user is gone and thus all sockets have to be destroyed to
	 * the point. Check this.
	 */
	BUG_ON(!list_empty(&serv->sv_permsocks));
	BUG_ON(!list_empty(&serv->sv_tempsocks));

	cache_clean_deferred(serv);

	if (svc_serv_is_pooled(serv))
		svc_pool_map_put();

	kfree(serv->sv_pools);
	kfree(serv);
}
EXPORT_SYMBOL_GPL(svc_destroy);

/*
 * Allocate an RPC server's buffer space.
 * We allocate pages and place them in rq_pages.
 */
static int
svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
{
	unsigned int pages, arghi;

	/* bc_xprt uses fore channel allocated buffers */
	if (svc_is_backchannel(rqstp))
		return 1;

	pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
				       * We assume one is at most one page
				       */
	arghi = 0;
	WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
	if (pages > RPCSVC_MAXPAGES)
		pages = RPCSVC_MAXPAGES;
	while (pages) {
		struct page *p = alloc_pages_node(node, GFP_KERNEL, 0);
		if (!p)
			break;
		rqstp->rq_pages[arghi++] = p;
		pages--;
	}
	return pages == 0;
}

/*
 * Release an RPC server buffer
 */
static void
svc_release_buffer(struct svc_rqst *rqstp)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
		if (rqstp->rq_pages[i])
			put_page(rqstp->rq_pages[i]);
}

struct svc_rqst *
svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
{
	struct svc_rqst	*rqstp;

	rqstp = kzalloc_node(sizeof(*rqstp), GFP_KERNEL, node);
	if (!rqstp)
		return rqstp;

	__set_bit(RQ_BUSY, &rqstp->rq_flags);
	spin_lock_init(&rqstp->rq_lock);
	rqstp->rq_server = serv;
	rqstp->rq_pool = pool;

	rqstp->rq_scratch_page = alloc_pages_node(node, GFP_KERNEL, 0);
	if (!rqstp->rq_scratch_page)
		goto out_enomem;

	rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
	if (!rqstp->rq_argp)
		goto out_enomem;

	rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
	if (!rqstp->rq_resp)
		goto out_enomem;

	if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
		goto out_enomem;

	return rqstp;
out_enomem:
	svc_rqst_free(rqstp);
	return NULL;
}
EXPORT_SYMBOL_GPL(svc_rqst_alloc);

struct svc_rqst *
svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
{
	struct svc_rqst	*rqstp;

	rqstp = svc_rqst_alloc(serv, pool, node);
	if (!rqstp)
		return ERR_PTR(-ENOMEM);

	serv->sv_nrthreads++;
	spin_lock_bh(&pool->sp_lock);
	pool->sp_nrthreads++;
	list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
	spin_unlock_bh(&pool->sp_lock);
	return rqstp;
}
EXPORT_SYMBOL_GPL(svc_prepare_thread);

/*
 * Choose a pool in which to create a new thread, for svc_set_num_threads
 */
static inline struct svc_pool *
choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
	if (pool != NULL)
		return pool;

	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
}

/*
 * Choose a thread to kill, for svc_set_num_threads
 */
static inline struct task_struct *
choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
	unsigned int i;
	struct task_struct *task = NULL;

	if (pool != NULL) {
		spin_lock_bh(&pool->sp_lock);
	} else {
		/* choose a pool in round-robin fashion */
		for (i = 0; i < serv->sv_nrpools; i++) {
			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
			spin_lock_bh(&pool->sp_lock);
			if (!list_empty(&pool->sp_all_threads))
				goto found_pool;
			spin_unlock_bh(&pool->sp_lock);
		}
		return NULL;
	}

found_pool:
	if (!list_empty(&pool->sp_all_threads)) {
		struct svc_rqst *rqstp;

		/*
		 * Remove from the pool->sp_all_threads list
		 * so we don't try to kill it again.
		 */
		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
		set_bit(RQ_VICTIM, &rqstp->rq_flags);
		list_del_rcu(&rqstp->rq_all);
		task = rqstp->rq_task;
	}
	spin_unlock_bh(&pool->sp_lock);

	return task;
}

/* create new threads */
static int
svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	struct svc_rqst	*rqstp;
	struct task_struct *task;
	struct svc_pool *chosen_pool;
	unsigned int state = serv->sv_nrthreads-1;
	int node;

	do {
		nrservs--;
		chosen_pool = choose_pool(serv, pool, &state);

		node = svc_pool_map_get_node(chosen_pool->sp_id);
		rqstp = svc_prepare_thread(serv, chosen_pool, node);
		if (IS_ERR(rqstp))
			return PTR_ERR(rqstp);

		__module_get(serv->sv_ops->svo_module);
		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
					      node, "%s", serv->sv_name);
		if (IS_ERR(task)) {
			module_put(serv->sv_ops->svo_module);
			svc_exit_thread(rqstp);
			return PTR_ERR(task);
		}

		rqstp->rq_task = task;
		if (serv->sv_nrpools > 1)
			svc_pool_map_set_cpumask(task, chosen_pool->sp_id);

		svc_sock_update_bufs(serv);
		wake_up_process(task);
	} while (nrservs > 0);

	return 0;
}


/* destroy old threads */
static int
svc_signal_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	struct task_struct *task;
	unsigned int state = serv->sv_nrthreads-1;

	/* destroy old threads */
	do {
		task = choose_victim(serv, pool, &state);
		if (task == NULL)
			break;
		send_sig(SIGINT, task, 1);
		nrservs++;
	} while (nrservs < 0);

	return 0;
}

/*
 * Create or destroy enough new threads to make the number
 * of threads the given number.  If `pool' is non-NULL, applies
 * only to threads in that pool, otherwise round-robins between
 * all pools.  Caller must ensure that mutual exclusion between this and
 * server startup or shutdown.
 *
 * Destroying threads relies on the service threads filling in
 * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
 * has been created using svc_create_pooled().
 *
 * Based on code that used to be in nfsd_svc() but tweaked
 * to be pool-aware.
 */
int
svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	if (pool == NULL) {
		/* The -1 assumes caller has done a svc_get() */
		nrservs -= (serv->sv_nrthreads-1);
	} else {
		spin_lock_bh(&pool->sp_lock);
		nrservs -= pool->sp_nrthreads;
		spin_unlock_bh(&pool->sp_lock);
	}

	if (nrservs > 0)
		return svc_start_kthreads(serv, pool, nrservs);
	if (nrservs < 0)
		return svc_signal_kthreads(serv, pool, nrservs);
	return 0;
}
EXPORT_SYMBOL_GPL(svc_set_num_threads);

/* destroy old threads */
static int
svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	struct task_struct *task;
	unsigned int state = serv->sv_nrthreads-1;

	/* destroy old threads */
	do {
		task = choose_victim(serv, pool, &state);
		if (task == NULL)
			break;
		kthread_stop(task);
		nrservs++;
	} while (nrservs < 0);
	return 0;
}

int
svc_set_num_threads_sync(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	if (pool == NULL) {
		/* The -1 assumes caller has done a svc_get() */
		nrservs -= (serv->sv_nrthreads-1);
	} else {
		spin_lock_bh(&pool->sp_lock);
		nrservs -= pool->sp_nrthreads;
		spin_unlock_bh(&pool->sp_lock);
	}

	if (nrservs > 0)
		return svc_start_kthreads(serv, pool, nrservs);
	if (nrservs < 0)
		return svc_stop_kthreads(serv, pool, nrservs);
	return 0;
}
EXPORT_SYMBOL_GPL(svc_set_num_threads_sync);

/*
 * Called from a server thread as it's exiting. Caller must hold the "service
 * mutex" for the service.
 */
void
svc_rqst_free(struct svc_rqst *rqstp)
{
	svc_release_buffer(rqstp);
	if (rqstp->rq_scratch_page)
		put_page(rqstp->rq_scratch_page);
	kfree(rqstp->rq_resp);
	kfree(rqstp->rq_argp);
	kfree(rqstp->rq_auth_data);
	kfree_rcu(rqstp, rq_rcu_head);
}
EXPORT_SYMBOL_GPL(svc_rqst_free);

void
svc_exit_thread(struct svc_rqst *rqstp)
{
	struct svc_serv	*serv = rqstp->rq_server;
	struct svc_pool	*pool = rqstp->rq_pool;

	spin_lock_bh(&pool->sp_lock);
	pool->sp_nrthreads--;
	if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
		list_del_rcu(&rqstp->rq_all);
	spin_unlock_bh(&pool->sp_lock);

	svc_rqst_free(rqstp);

	/* Release the server */
	if (serv)
		svc_destroy(serv);
}
EXPORT_SYMBOL_GPL(svc_exit_thread);

/*
 * Register an "inet" protocol family netid with the local
 * rpcbind daemon via an rpcbind v4 SET request.
 *
 * No netconfig infrastructure is available in the kernel, so
 * we map IP_ protocol numbers to netids by hand.
 *
 * Returns zero on success; a negative errno value is returned
 * if any error occurs.
 */
static int __svc_rpcb_register4(struct net *net, const u32 program,
				const u32 version,
				const unsigned short protocol,
				const unsigned short port)
{
	const struct sockaddr_in sin = {
		.sin_family		= AF_INET,
		.sin_addr.s_addr	= htonl(INADDR_ANY),
		.sin_port		= htons(port),
	};
	const char *netid;
	int error;

	switch (protocol) {
	case IPPROTO_UDP:
		netid = RPCBIND_NETID_UDP;
		break;
	case IPPROTO_TCP:
		netid = RPCBIND_NETID_TCP;
		break;
	default:
		return -ENOPROTOOPT;
	}

	error = rpcb_v4_register(net, program, version,
					(const struct sockaddr *)&sin, netid);

	/*
	 * User space didn't support rpcbind v4, so retry this
	 * registration request with the legacy rpcbind v2 protocol.
	 */
	if (error == -EPROTONOSUPPORT)
		error = rpcb_register(net, program, version, protocol, port);

	return error;
}

#if IS_ENABLED(CONFIG_IPV6)
/*
 * Register an "inet6" protocol family netid with the local
 * rpcbind daemon via an rpcbind v4 SET request.
 *
 * No netconfig infrastructure is available in the kernel, so
 * we map IP_ protocol numbers to netids by hand.
 *
 * Returns zero on success; a negative errno value is returned
 * if any error occurs.
 */
static int __svc_rpcb_register6(struct net *net, const u32 program,
				const u32 version,
				const unsigned short protocol,
				const unsigned short port)
{
	const struct sockaddr_in6 sin6 = {
		.sin6_family		= AF_INET6,
		.sin6_addr		= IN6ADDR_ANY_INIT,
		.sin6_port		= htons(port),
	};
	const char *netid;
	int error;

	switch (protocol) {
	case IPPROTO_UDP:
		netid = RPCBIND_NETID_UDP6;
		break;
	case IPPROTO_TCP:
		netid = RPCBIND_NETID_TCP6;
		break;
	default:
		return -ENOPROTOOPT;
	}

	error = rpcb_v4_register(net, program, version,
					(const struct sockaddr *)&sin6, netid);

	/*
	 * User space didn't support rpcbind version 4, so we won't
	 * use a PF_INET6 listener.
	 */
	if (error == -EPROTONOSUPPORT)
		error = -EAFNOSUPPORT;

	return error;
}
#endif	/* IS_ENABLED(CONFIG_IPV6) */

/*
 * Register a kernel RPC service via rpcbind version 4.
 *
 * Returns zero on success; a negative errno value is returned
 * if any error occurs.
 */
static int __svc_register(struct net *net, const char *progname,
			  const u32 program, const u32 version,
			  const int family,
			  const unsigned short protocol,
			  const unsigned short port)
{
	int error = -EAFNOSUPPORT;

	switch (family) {
	case PF_INET:
		error = __svc_rpcb_register4(net, program, version,
						protocol, port);
		break;
#if IS_ENABLED(CONFIG_IPV6)
	case PF_INET6:
		error = __svc_rpcb_register6(net, program, version,
						protocol, port);
#endif
	}

	trace_svc_register(progname, version, protocol, port, family, error);
	return error;
}

int svc_rpcbind_set_version(struct net *net,
			    const struct svc_program *progp,
			    u32 version, int family,
			    unsigned short proto,
			    unsigned short port)
{
	return __svc_register(net, progp->pg_name, progp->pg_prog,
				version, family, proto, port);

}
EXPORT_SYMBOL_GPL(svc_rpcbind_set_version);

int svc_generic_rpcbind_set(struct net *net,
			    const struct svc_program *progp,
			    u32 version, int family,
			    unsigned short proto,
			    unsigned short port)
{
	const struct svc_version *vers = progp->pg_vers[version];
	int error;

	if (vers == NULL)
		return 0;

	if (vers->vs_hidden) {
		trace_svc_noregister(progp->pg_name, version, proto,
				     port, family, 0);
		return 0;
	}

	/*
	 * Don't register a UDP port if we need congestion
	 * control.
	 */
	if (vers->vs_need_cong_ctrl && proto == IPPROTO_UDP)
		return 0;

	error = svc_rpcbind_set_version(net, progp, version,
					family, proto, port);

	return (vers->vs_rpcb_optnl) ? 0 : error;
}
EXPORT_SYMBOL_GPL(svc_generic_rpcbind_set);

/**
 * svc_register - register an RPC service with the local portmapper
 * @serv: svc_serv struct for the service to register
 * @net: net namespace for the service to register
 * @family: protocol family of service's listener socket
 * @proto: transport protocol number to advertise
 * @port: port to advertise
 *
 * Service is registered for any address in the passed-in protocol family
 */
int svc_register(const struct svc_serv *serv, struct net *net,
		 const int family, const unsigned short proto,
		 const unsigned short port)
{
	struct svc_program	*progp;
	unsigned int		i;
	int			error = 0;

	WARN_ON_ONCE(proto == 0 && port == 0);
	if (proto == 0 && port == 0)
		return -EINVAL;

	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
		for (i = 0; i < progp->pg_nvers; i++) {

			error = progp->pg_rpcbind_set(net, progp, i,
					family, proto, port);
			if (error < 0) {
				printk(KERN_WARNING "svc: failed to register "
					"%sv%u RPC service (errno %d).\n",
					progp->pg_name, i, -error);
				break;
			}
		}
	}

	return error;
}

/*
 * If user space is running rpcbind, it should take the v4 UNSET
 * and clear everything for this [program, version].  If user space
 * is running portmap, it will reject the v4 UNSET, but won't have
 * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
 * in this case to clear all existing entries for [program, version].
 */
static void __svc_unregister(struct net *net, const u32 program, const u32 version,
			     const char *progname)
{
	int error;

	error = rpcb_v4_register(net, program, version, NULL, "");

	/*
	 * User space didn't support rpcbind v4, so retry this
	 * request with the legacy rpcbind v2 protocol.
	 */
	if (error == -EPROTONOSUPPORT)
		error = rpcb_register(net, program, version, 0, 0);

	trace_svc_unregister(progname, version, error);
}

/*
 * All netids, bind addresses and ports registered for [program, version]
 * are removed from the local rpcbind database (if the service is not
 * hidden) to make way for a new instance of the service.
 *
 * The result of unregistration is reported via dprintk for those who want
 * verification of the result, but is otherwise not important.
 */
static void svc_unregister(const struct svc_serv *serv, struct net *net)
{
	struct svc_program *progp;
	unsigned long flags;
	unsigned int i;

	clear_thread_flag(TIF_SIGPENDING);

	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
		for (i = 0; i < progp->pg_nvers; i++) {
			if (progp->pg_vers[i] == NULL)
				continue;
			if (progp->pg_vers[i]->vs_hidden)
				continue;
			__svc_unregister(net, progp->pg_prog, i, progp->pg_name);
		}
	}

	spin_lock_irqsave(&current->sighand->siglock, flags);
	recalc_sigpending();
	spin_unlock_irqrestore(&current->sighand->siglock, flags);
}

/*
 * dprintk the given error with the address of the client that caused it.
 */
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
static __printf(2, 3)
void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	char 	buf[RPC_MAX_ADDRBUFLEN];

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	dprintk("svc: %s: %pV", svc_print_addr(rqstp, buf, sizeof(buf)), &vaf);

	va_end(args);
}
#else
static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {}
#endif

__be32
svc_return_autherr(struct svc_rqst *rqstp, __be32 auth_err)
{
	set_bit(RQ_AUTHERR, &rqstp->rq_flags);
	return auth_err;
}
EXPORT_SYMBOL_GPL(svc_return_autherr);

static __be32
svc_get_autherr(struct svc_rqst *rqstp, __be32 *statp)
{
	if (test_and_clear_bit(RQ_AUTHERR, &rqstp->rq_flags))
		return *statp;
	return rpc_auth_ok;
}

static int
svc_generic_dispatch(struct svc_rqst *rqstp, __be32 *statp)
{
	struct kvec *argv = &rqstp->rq_arg.head[0];
	struct kvec *resv = &rqstp->rq_res.head[0];
	const struct svc_procedure *procp = rqstp->rq_procinfo;

	/*
	 * Decode arguments
	 * XXX: why do we ignore the return value?
	 */
	if (procp->pc_decode &&
	    !procp->pc_decode(rqstp, argv->iov_base)) {
		*statp = rpc_garbage_args;
		return 1;
	}

	*statp = procp->pc_func(rqstp);

	if (*statp == rpc_drop_reply ||
	    test_bit(RQ_DROPME, &rqstp->rq_flags))
		return 0;

	if (test_bit(RQ_AUTHERR, &rqstp->rq_flags))
		return 1;

	if (*statp != rpc_success)
		return 1;

	/* Encode reply */
	if (procp->pc_encode &&
	    !procp->pc_encode(rqstp, resv->iov_base + resv->iov_len)) {
		dprintk("svc: failed to encode reply\n");
		/* serv->sv_stats->rpcsystemerr++; */
		*statp = rpc_system_err;
	}
	return 1;
}

__be32
svc_generic_init_request(struct svc_rqst *rqstp,
		const struct svc_program *progp,
		struct svc_process_info *ret)
{
	const struct svc_version *versp = NULL;	/* compiler food */
	const struct svc_procedure *procp = NULL;

	if (rqstp->rq_vers >= progp->pg_nvers )
		goto err_bad_vers;
	versp = progp->pg_vers[rqstp->rq_vers];
	if (!versp)
		goto err_bad_vers;

	/*
	 * Some protocol versions (namely NFSv4) require some form of
	 * congestion control.  (See RFC 7530 section 3.1 paragraph 2)
	 * In other words, UDP is not allowed. We mark those when setting
	 * up the svc_xprt, and verify that here.
	 *
	 * The spec is not very clear about what error should be returned
	 * when someone tries to access a server that is listening on UDP
	 * for lower versions. RPC_PROG_MISMATCH seems to be the closest
	 * fit.
	 */
	if (versp->vs_need_cong_ctrl && rqstp->rq_xprt &&
	    !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
		goto err_bad_vers;

	if (rqstp->rq_proc >= versp->vs_nproc)
		goto err_bad_proc;
	rqstp->rq_procinfo = procp = &versp->vs_proc[rqstp->rq_proc];
	if (!procp)
		goto err_bad_proc;

	/* Initialize storage for argp and resp */
	memset(rqstp->rq_argp, 0, procp->pc_argsize);
	memset(rqstp->rq_resp, 0, procp->pc_ressize);

	/* Bump per-procedure stats counter */
	versp->vs_count[rqstp->rq_proc]++;

	ret->dispatch = versp->vs_dispatch;
	return rpc_success;
err_bad_vers:
	ret->mismatch.lovers = progp->pg_lovers;
	ret->mismatch.hivers = progp->pg_hivers;
	return rpc_prog_mismatch;
err_bad_proc:
	return rpc_proc_unavail;
}
EXPORT_SYMBOL_GPL(svc_generic_init_request);

/*
 * Common routine for processing the RPC request.
 */
static int
svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
{
	struct svc_program	*progp;
	const struct svc_procedure *procp = NULL;
	struct svc_serv		*serv = rqstp->rq_server;
	struct svc_process_info process;
	__be32			*statp;
	u32			prog, vers;
	__be32			auth_stat, rpc_stat;
	int			auth_res;
	__be32			*reply_statp;

	rpc_stat = rpc_success;

	if (argv->iov_len < 6*4)
		goto err_short_len;

	/* Will be turned off by GSS integrity and privacy services */
	set_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
	/* Will be turned off only when NFSv4 Sessions are used */
	set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
	clear_bit(RQ_DROPME, &rqstp->rq_flags);

	svc_putu32(resv, rqstp->rq_xid);

	vers = svc_getnl(argv);

	/* First words of reply: */
	svc_putnl(resv, 1);		/* REPLY */

	if (vers != 2)		/* RPC version number */
		goto err_bad_rpc;

	/* Save position in case we later decide to reject: */
	reply_statp = resv->iov_base + resv->iov_len;

	svc_putnl(resv, 0);		/* ACCEPT */

	rqstp->rq_prog = prog = svc_getnl(argv);	/* program number */
	rqstp->rq_vers = svc_getnl(argv);	/* version number */
	rqstp->rq_proc = svc_getnl(argv);	/* procedure number */

	for (progp = serv->sv_program; progp; progp = progp->pg_next)
		if (prog == progp->pg_prog)
			break;

	/*
	 * Decode auth data, and add verifier to reply buffer.
	 * We do this before anything else in order to get a decent
	 * auth verifier.
	 */
	auth_res = svc_authenticate(rqstp, &auth_stat);
	/* Also give the program a chance to reject this call: */
	if (auth_res == SVC_OK && progp) {
		auth_stat = rpc_autherr_badcred;
		auth_res = progp->pg_authenticate(rqstp);
	}
	if (auth_res != SVC_OK)
		trace_svc_authenticate(rqstp, auth_res, auth_stat);
	switch (auth_res) {
	case SVC_OK:
		break;
	case SVC_GARBAGE:
		goto err_garbage;
	case SVC_SYSERR:
		rpc_stat = rpc_system_err;
		goto err_bad;
	case SVC_DENIED:
		goto err_bad_auth;
	case SVC_CLOSE:
		goto close;
	case SVC_DROP:
		goto dropit;
	case SVC_COMPLETE:
		goto sendit;
	}

	if (progp == NULL)
		goto err_bad_prog;

	rpc_stat = progp->pg_init_request(rqstp, progp, &process);
	switch (rpc_stat) {
	case rpc_success:
		break;
	case rpc_prog_unavail:
		goto err_bad_prog;
	case rpc_prog_mismatch:
		goto err_bad_vers;
	case rpc_proc_unavail:
		goto err_bad_proc;
	}

	procp = rqstp->rq_procinfo;
	/* Should this check go into the dispatcher? */
	if (!procp || !procp->pc_func)
		goto err_bad_proc;

	/* Syntactic check complete */
	serv->sv_stats->rpccnt++;
	trace_svc_process(rqstp, progp->pg_name);

	/* Build the reply header. */
	statp = resv->iov_base +resv->iov_len;
	svc_putnl(resv, RPC_SUCCESS);

	/* un-reserve some of the out-queue now that we have a
	 * better idea of reply size
	 */
	if (procp->pc_xdrressize)
		svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);

	/* Call the function that processes the request. */
	if (!process.dispatch) {
		if (!svc_generic_dispatch(rqstp, statp))
			goto release_dropit;
		if (*statp == rpc_garbage_args)
			goto err_garbage;
		auth_stat = svc_get_autherr(rqstp, statp);
		if (auth_stat != rpc_auth_ok)
			goto err_release_bad_auth;
	} else {
		dprintk("svc: calling dispatcher\n");
		if (!process.dispatch(rqstp, statp))
			goto release_dropit; /* Release reply info */
	}

	/* Check RPC status result */
	if (*statp != rpc_success)
		resv->iov_len = ((void*)statp)  - resv->iov_base + 4;

	/* Release reply info */
	if (procp->pc_release)
		procp->pc_release(rqstp);

	if (procp->pc_encode == NULL)
		goto dropit;

 sendit:
	if (svc_authorise(rqstp))
		goto close_xprt;
	return 1;		/* Caller can now send it */

release_dropit:
	if (procp->pc_release)
		procp->pc_release(rqstp);
 dropit:
	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
	dprintk("svc: svc_process dropit\n");
	return 0;

 close:
	svc_authorise(rqstp);
close_xprt:
	if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
		svc_close_xprt(rqstp->rq_xprt);
	dprintk("svc: svc_process close\n");
	return 0;

err_short_len:
	svc_printk(rqstp, "short len %zd, dropping request\n",
			argv->iov_len);
	goto close_xprt;

err_bad_rpc:
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, 1);	/* REJECT */
	svc_putnl(resv, 0);	/* RPC_MISMATCH */
	svc_putnl(resv, 2);	/* Only RPCv2 supported */
	svc_putnl(resv, 2);
	goto sendit;

err_release_bad_auth:
	if (procp->pc_release)
		procp->pc_release(rqstp);
err_bad_auth:
	dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
	serv->sv_stats->rpcbadauth++;
	/* Restore write pointer to location of accept status: */
	xdr_ressize_check(rqstp, reply_statp);
	svc_putnl(resv, 1);	/* REJECT */
	svc_putnl(resv, 1);	/* AUTH_ERROR */
	svc_putnl(resv, ntohl(auth_stat));	/* status */
	goto sendit;

err_bad_prog:
	dprintk("svc: unknown program %d\n", prog);
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROG_UNAVAIL);
	goto sendit;

err_bad_vers:
	svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
		       rqstp->rq_vers, rqstp->rq_prog, progp->pg_name);

	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROG_MISMATCH);
	svc_putnl(resv, process.mismatch.lovers);
	svc_putnl(resv, process.mismatch.hivers);
	goto sendit;

err_bad_proc:
	svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc);

	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROC_UNAVAIL);
	goto sendit;

err_garbage:
	svc_printk(rqstp, "failed to decode args\n");

	rpc_stat = rpc_garbage_args;
err_bad:
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, ntohl(rpc_stat));
	goto sendit;
}

/*
 * Process the RPC request.
 */
int
svc_process(struct svc_rqst *rqstp)
{
	struct kvec		*argv = &rqstp->rq_arg.head[0];
	struct kvec		*resv = &rqstp->rq_res.head[0];
	struct svc_serv		*serv = rqstp->rq_server;
	u32			dir;

	/*
	 * Setup response xdr_buf.
	 * Initially it has just one page
	 */
	rqstp->rq_next_page = &rqstp->rq_respages[1];
	resv->iov_base = page_address(rqstp->rq_respages[0]);
	resv->iov_len = 0;
	rqstp->rq_res.pages = rqstp->rq_respages + 1;
	rqstp->rq_res.len = 0;
	rqstp->rq_res.page_base = 0;
	rqstp->rq_res.page_len = 0;
	rqstp->rq_res.buflen = PAGE_SIZE;
	rqstp->rq_res.tail[0].iov_base = NULL;
	rqstp->rq_res.tail[0].iov_len = 0;

	dir  = svc_getnl(argv);
	if (dir != 0) {
		/* direction != CALL */
		svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
		serv->sv_stats->rpcbadfmt++;
		goto out_drop;
	}

	/* Returns 1 for send, 0 for drop */
	if (likely(svc_process_common(rqstp, argv, resv)))
		return svc_send(rqstp);

out_drop:
	svc_drop(rqstp);
	return 0;
}
EXPORT_SYMBOL_GPL(svc_process);

#if defined(CONFIG_SUNRPC_BACKCHANNEL)
/*
 * Process a backchannel RPC request that arrived over an existing
 * outbound connection
 */
int
bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
	       struct svc_rqst *rqstp)
{
	struct kvec	*argv = &rqstp->rq_arg.head[0];
	struct kvec	*resv = &rqstp->rq_res.head[0];
	struct rpc_task *task;
	int proc_error;
	int error;

	dprintk("svc: %s(%p)\n", __func__, req);

	/* Build the svc_rqst used by the common processing routine */
	rqstp->rq_xid = req->rq_xid;
	rqstp->rq_prot = req->rq_xprt->prot;
	rqstp->rq_server = serv;
	rqstp->rq_bc_net = req->rq_xprt->xprt_net;

	rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
	memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
	memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
	memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));

	/* Adjust the argument buffer length */
	rqstp->rq_arg.len = req->rq_private_buf.len;
	if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
		rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
		rqstp->rq_arg.page_len = 0;
	} else if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len +
			rqstp->rq_arg.page_len)
		rqstp->rq_arg.page_len = rqstp->rq_arg.len -
			rqstp->rq_arg.head[0].iov_len;
	else
		rqstp->rq_arg.len = rqstp->rq_arg.head[0].iov_len +
			rqstp->rq_arg.page_len;

	/* reset result send buffer "put" position */
	resv->iov_len = 0;

	/*
	 * Skip the next two words because they've already been
	 * processed in the transport
	 */
	svc_getu32(argv);	/* XID */
	svc_getnl(argv);	/* CALLDIR */

	/* Parse and execute the bc call */
	proc_error = svc_process_common(rqstp, argv, resv);

	atomic_dec(&req->rq_xprt->bc_slot_count);
	if (!proc_error) {
		/* Processing error: drop the request */
		xprt_free_bc_request(req);
		error = -EINVAL;
		goto out;
	}
	/* Finally, send the reply synchronously */
	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
	task = rpc_run_bc_task(req);
	if (IS_ERR(task)) {
		error = PTR_ERR(task);
		goto out;
	}

	WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
	error = task->tk_status;
	rpc_put_task(task);

out:
	dprintk("svc: %s(), error=%d\n", __func__, error);
	return error;
}
EXPORT_SYMBOL_GPL(bc_svc_process);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */

/*
 * Return (transport-specific) limit on the rpc payload.
 */
u32 svc_max_payload(const struct svc_rqst *rqstp)
{
	u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;

	if (rqstp->rq_server->sv_max_payload < max)
		max = rqstp->rq_server->sv_max_payload;
	return max;
}
EXPORT_SYMBOL_GPL(svc_max_payload);

/**
 * svc_encode_result_payload - mark a range of bytes as a result payload
 * @rqstp: svc_rqst to operate on
 * @offset: payload's byte offset in rqstp->rq_res
 * @length: size of payload, in bytes
 *
 * Returns zero on success, or a negative errno if a permanent
 * error occurred.
 */
int svc_encode_result_payload(struct svc_rqst *rqstp, unsigned int offset,
			      unsigned int length)
{
	return rqstp->rq_xprt->xpt_ops->xpo_result_payload(rqstp, offset,
							   length);
}
EXPORT_SYMBOL_GPL(svc_encode_result_payload);

/**
 * svc_fill_write_vector - Construct data argument for VFS write call
 * @rqstp: svc_rqst to operate on
 * @pages: list of pages containing data payload
 * @first: buffer containing first section of write payload
 * @total: total number of bytes of write payload
 *
 * Fills in rqstp::rq_vec, and returns the number of elements.
 */
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp, struct page **pages,
				   struct kvec *first, size_t total)
{
	struct kvec *vec = rqstp->rq_vec;
	unsigned int i;

	/* Some types of transport can present the write payload
	 * entirely in rq_arg.pages. In this case, @first is empty.
	 */
	i = 0;
	if (first->iov_len) {
		vec[i].iov_base = first->iov_base;
		vec[i].iov_len = min_t(size_t, total, first->iov_len);
		total -= vec[i].iov_len;
		++i;
	}

	while (total) {
		vec[i].iov_base = page_address(*pages);
		vec[i].iov_len = min_t(size_t, total, PAGE_SIZE);
		total -= vec[i].iov_len;
		++i;
		++pages;
	}

	WARN_ON_ONCE(i > ARRAY_SIZE(rqstp->rq_vec));
	return i;
}
EXPORT_SYMBOL_GPL(svc_fill_write_vector);

/**
 * svc_fill_symlink_pathname - Construct pathname argument for VFS symlink call
 * @rqstp: svc_rqst to operate on
 * @first: buffer containing first section of pathname
 * @p: buffer containing remaining section of pathname
 * @total: total length of the pathname argument
 *
 * The VFS symlink API demands a NUL-terminated pathname in mapped memory.
 * Returns pointer to a NUL-terminated string, or an ERR_PTR. Caller must free
 * the returned string.
 */
char *svc_fill_symlink_pathname(struct svc_rqst *rqstp, struct kvec *first,
				void *p, size_t total)
{
	size_t len, remaining;
	char *result, *dst;

	result = kmalloc(total + 1, GFP_KERNEL);
	if (!result)
		return ERR_PTR(-ESERVERFAULT);

	dst = result;
	remaining = total;

	len = min_t(size_t, total, first->iov_len);
	if (len) {
		memcpy(dst, first->iov_base, len);
		dst += len;
		remaining -= len;
	}

	if (remaining) {
		len = min_t(size_t, remaining, PAGE_SIZE);
		memcpy(dst, p, len);
		dst += len;
	}

	*dst = '\0';

	/* Sanity check: Linux doesn't allow the pathname argument to
	 * contain a NUL byte.
	 */
	if (strlen(result) != total) {
		kfree(result);
		return ERR_PTR(-EINVAL);
	}
	return result;
}
EXPORT_SYMBOL_GPL(svc_fill_symlink_pathname);