aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/scsi/scsi_debug.c
blob: e1168860045cb3522324fd66aae6c5e88da0bd8c (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
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
/*
 *  linux/kernel/scsi_debug.c
 * vvvvvvvvvvvvvvvvvvvvvvv Original vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
 *  Copyright (C) 1992  Eric Youngdale
 *  Simulate a host adapter with 2 disks attached.  Do a lot of checking
 *  to make sure that we are not getting blocks mixed up, and PANIC if
 *  anything out of the ordinary is seen.
 * ^^^^^^^^^^^^^^^^^^^^^^^ Original ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 *
 *  This version is more generic, simulating a variable number of disk
 *  (or disk like devices) sharing a common amount of RAM
 *
 *
 *  For documentation see http://www.torque.net/sg/sdebug26.html
 *
 *   D. Gilbert (dpg) work for Magneto-Optical device test [20010421]
 *   dpg: work for devfs large number of disks [20010809]
 *        forked for lk 2.5 series [20011216, 20020101]
 *        use vmalloc() more inquiry+mode_sense [20020302]
 *        add timers for delayed responses [20020721]
 *   Patrick Mansfield <patmans@us.ibm.com> max_luns+scsi_level [20021031]
 *   Mike Anderson <andmike@us.ibm.com> sysfs work [20021118]
 *   dpg: change style of boot options to "scsi_debug.num_tgts=2" and
 *        module options to "modprobe scsi_debug num_tgts=2" [20021221]
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/genhd.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>

#include <linux/blkdev.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
#include <scsi/scsicam.h>

#include <linux/stat.h>

#include "scsi_logging.h"
#include "scsi_debug.h"

#define SCSI_DEBUG_VERSION "1.75"
static const char * scsi_debug_version_date = "20050113";

/* Additional Sense Code (ASC) used */
#define NO_ADDED_SENSE 0x0
#define UNRECOVERED_READ_ERR 0x11
#define INVALID_OPCODE 0x20
#define ADDR_OUT_OF_RANGE 0x21
#define INVALID_FIELD_IN_CDB 0x24
#define POWERON_RESET 0x29
#define SAVING_PARAMS_UNSUP 0x39
#define THRESHHOLD_EXCEEDED 0x5d

#define SDEBUG_TAGGED_QUEUING 0 /* 0 | MSG_SIMPLE_TAG | MSG_ORDERED_TAG */

/* Default values for driver parameters */
#define DEF_NUM_HOST   1
#define DEF_NUM_TGTS   1
#define DEF_MAX_LUNS   1
/* With these defaults, this driver will make 1 host with 1 target
 * (id 0) containing 1 logical unit (lun 0). That is 1 device.
 */
#define DEF_DELAY   1
#define DEF_DEV_SIZE_MB   8
#define DEF_EVERY_NTH   0
#define DEF_NUM_PARTS   0
#define DEF_OPTS   0
#define DEF_SCSI_LEVEL   5    /* INQUIRY, byte2 [5->SPC-3] */
#define DEF_PTYPE   0
#define DEF_D_SENSE   0

/* bit mask values for scsi_debug_opts */
#define SCSI_DEBUG_OPT_NOISE   1
#define SCSI_DEBUG_OPT_MEDIUM_ERR   2
#define SCSI_DEBUG_OPT_TIMEOUT   4
#define SCSI_DEBUG_OPT_RECOVERED_ERR   8
/* When "every_nth" > 0 then modulo "every_nth" commands:
 *   - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
 *   - a RECOVERED_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_RECOVERED_ERR is set.
 *
 * When "every_nth" < 0 then after "- every_nth" commands:
 *   - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
 *   - a RECOVERED_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_RECOVERED_ERR is set.
 * This will continue until some other action occurs (e.g. the user
 * writing a new value (other than -1 or 1) to every_nth via sysfs).
 */

/* when 1==SCSI_DEBUG_OPT_MEDIUM_ERR, a medium error is simulated at this
 * sector on read commands: */
#define OPT_MEDIUM_ERR_ADDR   0x1234 /* that's sector 4660 in decimal */

/* If REPORT LUNS has luns >= 256 it can choose "flat space" (value 1)
 * or "peripheral device" addressing (value 0) */
#define SAM2_LUN_ADDRESS_METHOD 0

static int scsi_debug_add_host = DEF_NUM_HOST;
static int scsi_debug_delay = DEF_DELAY;
static int scsi_debug_dev_size_mb = DEF_DEV_SIZE_MB;
static int scsi_debug_every_nth = DEF_EVERY_NTH;
static int scsi_debug_max_luns = DEF_MAX_LUNS;
static int scsi_debug_num_parts = DEF_NUM_PARTS;
static int scsi_debug_num_tgts = DEF_NUM_TGTS; /* targets per host */
static int scsi_debug_opts = DEF_OPTS;
static int scsi_debug_scsi_level = DEF_SCSI_LEVEL;
static int scsi_debug_ptype = DEF_PTYPE; /* SCSI peripheral type (0==disk) */
static int scsi_debug_dsense = DEF_D_SENSE;

static int scsi_debug_cmnd_count = 0;

#define DEV_READONLY(TGT)      (0)
#define DEV_REMOVEABLE(TGT)    (0)

static unsigned long sdebug_store_size;	/* in bytes */
static sector_t sdebug_capacity;	/* in sectors */

/* old BIOS stuff, kernel may get rid of them but some mode sense pages
   may still need them */
static int sdebug_heads;		/* heads per disk */
static int sdebug_cylinders_per;	/* cylinders per surface */
static int sdebug_sectors_per;		/* sectors per cylinder */

/* default sector size is 512 bytes, 2**9 bytes */
#define POW2_SECT_SIZE 9
#define SECT_SIZE (1 << POW2_SECT_SIZE)
#define SECT_SIZE_PER(TGT) SECT_SIZE

#define SDEBUG_MAX_PARTS 4

#define SDEBUG_SENSE_LEN 32

struct sdebug_dev_info {
	struct list_head dev_list;
	unsigned char sense_buff[SDEBUG_SENSE_LEN];	/* weak nexus */
	unsigned int channel;
	unsigned int target;
	unsigned int lun;
	struct sdebug_host_info *sdbg_host;
	char reset;
	char used;
};

struct sdebug_host_info {
	struct list_head host_list;
	struct Scsi_Host *shost;
	struct device dev;
	struct list_head dev_info_list;
};

#define to_sdebug_host(d)	\
	container_of(d, struct sdebug_host_info, dev)

static LIST_HEAD(sdebug_host_list);
static DEFINE_SPINLOCK(sdebug_host_list_lock);

typedef void (* done_funct_t) (struct scsi_cmnd *);

struct sdebug_queued_cmd {
	int in_use;
	struct timer_list cmnd_timer;
	done_funct_t done_funct;
	struct scsi_cmnd * a_cmnd;
	int scsi_result;
};
static struct sdebug_queued_cmd queued_arr[SCSI_DEBUG_CANQUEUE];

static struct scsi_host_template sdebug_driver_template = {
	.proc_info =		scsi_debug_proc_info,
	.name =			"SCSI DEBUG",
	.info =			scsi_debug_info,
	.slave_alloc =		scsi_debug_slave_alloc,
	.slave_configure =	scsi_debug_slave_configure,
	.slave_destroy =	scsi_debug_slave_destroy,
	.ioctl =		scsi_debug_ioctl,
	.queuecommand =		scsi_debug_queuecommand,
	.eh_abort_handler =	scsi_debug_abort,
	.eh_bus_reset_handler = scsi_debug_bus_reset,
	.eh_device_reset_handler = scsi_debug_device_reset,
	.eh_host_reset_handler = scsi_debug_host_reset,
	.bios_param =		scsi_debug_biosparam,
	.can_queue =		SCSI_DEBUG_CANQUEUE,
	.this_id =		7,
	.sg_tablesize =		64,
	.cmd_per_lun =		3,
	.max_sectors =		4096,
	.unchecked_isa_dma = 	0,
	.use_clustering = 	DISABLE_CLUSTERING,
	.module =		THIS_MODULE,
};

static unsigned char * fake_storep;	/* ramdisk storage */

static int num_aborts = 0;
static int num_dev_resets = 0;
static int num_bus_resets = 0;
static int num_host_resets = 0;

static DEFINE_SPINLOCK(queued_arr_lock);
static DEFINE_RWLOCK(atomic_rw);

static char sdebug_proc_name[] = "scsi_debug";

static int sdebug_driver_probe(struct device *);
static int sdebug_driver_remove(struct device *);
static struct bus_type pseudo_lld_bus;

static struct device_driver sdebug_driverfs_driver = {
	.name 		= sdebug_proc_name,
	.bus		= &pseudo_lld_bus,
};

static const int check_condition_result =
		(DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;

/* function declarations */
static int resp_inquiry(struct scsi_cmnd * SCpnt, int target,
			struct sdebug_dev_info * devip);
static int resp_requests(struct scsi_cmnd * SCpnt,
			 struct sdebug_dev_info * devip);
static int resp_readcap(struct scsi_cmnd * SCpnt,
			struct sdebug_dev_info * devip);
static int resp_mode_sense(struct scsi_cmnd * SCpnt, int target,
			   struct sdebug_dev_info * devip);
static int resp_read(struct scsi_cmnd * SCpnt, int upper_blk, int block,
		     int num, struct sdebug_dev_info * devip);
static int resp_write(struct scsi_cmnd * SCpnt, int upper_blk, int block,
		      int num, struct sdebug_dev_info * devip);
static int resp_report_luns(struct scsi_cmnd * SCpnt,
			    struct sdebug_dev_info * devip);
static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                                int arr_len);
static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                               int max_arr_len);
static void timer_intr_handler(unsigned long);
static struct sdebug_dev_info * devInfoReg(struct scsi_device * sdev);
static void mk_sense_buffer(struct sdebug_dev_info * devip, int key,
			    int asc, int asq);
static int check_reset(struct scsi_cmnd * SCpnt,
		       struct sdebug_dev_info * devip);
static int schedule_resp(struct scsi_cmnd * cmnd,
			 struct sdebug_dev_info * devip,
			 done_funct_t done, int scsi_result, int delta_jiff);
static void __init sdebug_build_parts(unsigned char * ramp);
static void __init init_all_queued(void);
static void stop_all_queued(void);
static int stop_queued_cmnd(struct scsi_cmnd * cmnd);
static int inquiry_evpd_83(unsigned char * arr, int dev_id_num,
                           const char * dev_id_str, int dev_id_str_len);
static void do_create_driverfs_files(void);
static void do_remove_driverfs_files(void);

static int sdebug_add_adapter(void);
static void sdebug_remove_adapter(void);
static void sdebug_max_tgts_luns(void);

static struct device pseudo_primary;
static struct bus_type pseudo_lld_bus;


static
int scsi_debug_queuecommand(struct scsi_cmnd * SCpnt, done_funct_t done)
{
	unsigned char *cmd = (unsigned char *) SCpnt->cmnd;
	int block, upper_blk, num, k;
	int errsts = 0;
	int target = scmd_id(SCpnt);
	struct sdebug_dev_info * devip = NULL;
	int inj_recovered = 0;

	if (done == NULL)
		return 0;	/* assume mid level reprocessing command */

	if ((SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) && cmd) {
		printk(KERN_INFO "scsi_debug: cmd ");
		for (k = 0, num = SCpnt->cmd_len; k < num; ++k)
			printk("%02x ", (int)cmd[k]);
		printk("\n");
	}
        if(target == sdebug_driver_template.this_id) {
		printk(KERN_INFO "scsi_debug: initiator's id used as "
		       "target!\n");
		return schedule_resp(SCpnt, NULL, done,
				     DID_NO_CONNECT << 16, 0);
        }

	if (SCpnt->device->lun >= scsi_debug_max_luns)
		return schedule_resp(SCpnt, NULL, done,
				     DID_NO_CONNECT << 16, 0);
	devip = devInfoReg(SCpnt->device);
	if (NULL == devip)
		return schedule_resp(SCpnt, NULL, done,
				     DID_NO_CONNECT << 16, 0);

        if ((scsi_debug_every_nth != 0) &&
            (++scsi_debug_cmnd_count >= abs(scsi_debug_every_nth))) {
                scsi_debug_cmnd_count = 0;
		if (scsi_debug_every_nth < -1)
			scsi_debug_every_nth = -1;
		if (SCSI_DEBUG_OPT_TIMEOUT & scsi_debug_opts)
			return 0; /* ignore command causing timeout */
		else if (SCSI_DEBUG_OPT_RECOVERED_ERR & scsi_debug_opts)
			inj_recovered = 1; /* to reads and writes below */
        }

	switch (*cmd) {
	case INQUIRY:     /* mandatory, ignore unit attention */
		errsts = resp_inquiry(SCpnt, target, devip);
		break;
	case REQUEST_SENSE:	/* mandatory, ignore unit attention */
		errsts = resp_requests(SCpnt, devip);
		break;
	case REZERO_UNIT:	/* actually this is REWIND for SSC */
	case START_STOP:
		errsts = check_reset(SCpnt, devip);
		break;
	case ALLOW_MEDIUM_REMOVAL:
		if ((errsts = check_reset(SCpnt, devip)))
			break;
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			printk(KERN_INFO "scsi_debug: Medium removal %s\n",
			        cmd[4] ? "inhibited" : "enabled");
		break;
	case SEND_DIAGNOSTIC:     /* mandatory */
		errsts = check_reset(SCpnt, devip);
		break;
	case TEST_UNIT_READY:     /* mandatory */
		errsts = check_reset(SCpnt, devip);
		break;
        case RESERVE:
		errsts = check_reset(SCpnt, devip);
                break;
        case RESERVE_10:
		errsts = check_reset(SCpnt, devip);
                break;
        case RELEASE:
		errsts = check_reset(SCpnt, devip);
                break;
        case RELEASE_10:
		errsts = check_reset(SCpnt, devip);
                break;
	case READ_CAPACITY:
		errsts = resp_readcap(SCpnt, devip);
		break;
	case READ_16:
	case READ_12:
	case READ_10:
	case READ_6:
		if ((errsts = check_reset(SCpnt, devip)))
			break;
		upper_blk = 0;
		if ((*cmd) == READ_16) {
			upper_blk = cmd[5] + (cmd[4] << 8) +
				    (cmd[3] << 16) + (cmd[2] << 24);
			block = cmd[9] + (cmd[8] << 8) +
				(cmd[7] << 16) + (cmd[6] << 24);
			num = cmd[13] + (cmd[12] << 8) +
				(cmd[11] << 16) + (cmd[10] << 24);
		} else if ((*cmd) == READ_12) {
			block = cmd[5] + (cmd[4] << 8) +
				(cmd[3] << 16) + (cmd[2] << 24);
			num = cmd[9] + (cmd[8] << 8) +
				(cmd[7] << 16) + (cmd[6] << 24);
		} else if ((*cmd) == READ_10) {
			block = cmd[5] + (cmd[4] << 8) +
				(cmd[3] << 16) + (cmd[2] << 24);
			num = cmd[8] + (cmd[7] << 8);
		} else {
			block = cmd[3] + (cmd[2] << 8) +
				((cmd[1] & 0x1f) << 16);
			num = cmd[4];
		}
		errsts = resp_read(SCpnt, upper_blk, block, num, devip);
		if (inj_recovered && (0 == errsts)) {
			mk_sense_buffer(devip, RECOVERED_ERROR,
					THRESHHOLD_EXCEEDED, 0);
			errsts = check_condition_result;
		}
		break;
	case REPORT_LUNS:	/* mandatory, ignore unit attention */
		errsts = resp_report_luns(SCpnt, devip);
		break;
	case VERIFY:		/* 10 byte SBC-2 command */
		errsts = check_reset(SCpnt, devip);
		break;
	case WRITE_16:
	case WRITE_12:
	case WRITE_10:
	case WRITE_6:
		if ((errsts = check_reset(SCpnt, devip)))
			break;
		upper_blk = 0;
		if ((*cmd) == WRITE_16) {
			upper_blk = cmd[5] + (cmd[4] << 8) +
				    (cmd[3] << 16) + (cmd[2] << 24);
			block = cmd[9] + (cmd[8] << 8) +
				(cmd[7] << 16) + (cmd[6] << 24);
			num = cmd[13] + (cmd[12] << 8) +
				(cmd[11] << 16) + (cmd[10] << 24);
		} else if ((*cmd) == WRITE_12) {
			block = cmd[5] + (cmd[4] << 8) +
				(cmd[3] << 16) + (cmd[2] << 24);
			num = cmd[9] + (cmd[8] << 8) +
				(cmd[7] << 16) + (cmd[6] << 24);
		} else if ((*cmd) == WRITE_10) {
			block = cmd[5] + (cmd[4] << 8) +
				(cmd[3] << 16) + (cmd[2] << 24);
			num = cmd[8] + (cmd[7] << 8);
		} else {
			block = cmd[3] + (cmd[2] << 8) +
				((cmd[1] & 0x1f) << 16);
			num = cmd[4];
		}
		errsts = resp_write(SCpnt, upper_blk, block, num, devip);
		if (inj_recovered && (0 == errsts)) {
			mk_sense_buffer(devip, RECOVERED_ERROR,
					THRESHHOLD_EXCEEDED, 0);
			errsts = check_condition_result;
		}
		break;
	case MODE_SENSE:
	case MODE_SENSE_10:
		errsts = resp_mode_sense(SCpnt, target, devip);
		break;
	case SYNCHRONIZE_CACHE:
		errsts = check_reset(SCpnt, devip);
		break;
	default:
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			printk(KERN_INFO "scsi_debug: Opcode: 0x%x not "
			       "supported\n", *cmd);
		if ((errsts = check_reset(SCpnt, devip)))
			break;	/* Unit attention takes precedence */
		mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_OPCODE, 0);
		errsts = check_condition_result;
		break;
	}
	return schedule_resp(SCpnt, devip, done, errsts, scsi_debug_delay);
}

static int scsi_debug_ioctl(struct scsi_device *dev, int cmd, void __user *arg)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) {
		printk(KERN_INFO "scsi_debug: ioctl: cmd=0x%x\n", cmd);
	}
	return -EINVAL;
	/* return -ENOTTY; // correct return but upsets fdisk */
}

static int check_reset(struct scsi_cmnd * SCpnt, struct sdebug_dev_info * devip)
{
	if (devip->reset) {
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			printk(KERN_INFO "scsi_debug: Reporting Unit "
			       "attention: power on reset\n");
		devip->reset = 0;
		mk_sense_buffer(devip, UNIT_ATTENTION, POWERON_RESET, 0);
		return check_condition_result;
	}
	return 0;
}

/* Returns 0 if ok else (DID_ERROR << 16). Sets scp->resid . */
static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
				int arr_len)
{
	int k, req_len, act_len, len, active;
	void * kaddr;
	void * kaddr_off;
	struct scatterlist * sgpnt;

	if (0 == scp->request_bufflen)
		return 0;
	if (NULL == scp->request_buffer)
		return (DID_ERROR << 16);
	if (! ((scp->sc_data_direction == DMA_BIDIRECTIONAL) ||
	      (scp->sc_data_direction == DMA_FROM_DEVICE)))
		return (DID_ERROR << 16);
	if (0 == scp->use_sg) {
		req_len = scp->request_bufflen;
		act_len = (req_len < arr_len) ? req_len : arr_len;
		memcpy(scp->request_buffer, arr, act_len);
		scp->resid = req_len - act_len;
		return 0;
	}
	sgpnt = (struct scatterlist *)scp->request_buffer;
	active = 1;
	for (k = 0, req_len = 0, act_len = 0; k < scp->use_sg; ++k, ++sgpnt) {
		if (active) {
			kaddr = (unsigned char *)
				kmap_atomic(sgpnt->page, KM_USER0);
			if (NULL == kaddr)
				return (DID_ERROR << 16);
			kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
			len = sgpnt->length;
			if ((req_len + len) > arr_len) {
				active = 0;
				len = arr_len - req_len;
			}
			memcpy(kaddr_off, arr + req_len, len);
			kunmap_atomic(kaddr, KM_USER0);
			act_len += len;
		}
		req_len += sgpnt->length;
	}
	scp->resid = req_len - act_len;
	return 0;
}

/* Returns number of bytes fetched into 'arr' or -1 if error. */
static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
			       int max_arr_len)
{
	int k, req_len, len, fin;
	void * kaddr;
	void * kaddr_off;
	struct scatterlist * sgpnt;

	if (0 == scp->request_bufflen)
		return 0;
	if (NULL == scp->request_buffer)
		return -1;
	if (! ((scp->sc_data_direction == DMA_BIDIRECTIONAL) ||
	      (scp->sc_data_direction == DMA_TO_DEVICE)))
		return -1;
	if (0 == scp->use_sg) {
		req_len = scp->request_bufflen;
		len = (req_len < max_arr_len) ? req_len : max_arr_len;
		memcpy(arr, scp->request_buffer, len);
		return len;
	}
	sgpnt = (struct scatterlist *)scp->request_buffer;
	for (k = 0, req_len = 0, fin = 0; k < scp->use_sg; ++k, ++sgpnt) {
		kaddr = (unsigned char *)kmap_atomic(sgpnt->page, KM_USER0);
		if (NULL == kaddr)
			return -1;
		kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
		len = sgpnt->length;
		if ((req_len + len) > max_arr_len) {
			len = max_arr_len - req_len;
			fin = 1;
		}
		memcpy(arr + req_len, kaddr_off, len);
		kunmap_atomic(kaddr, KM_USER0);
		if (fin)
			return req_len + len;
		req_len += sgpnt->length;
	}
	return req_len;
}


static const char * inq_vendor_id = "Linux   ";
static const char * inq_product_id = "scsi_debug      ";
static const char * inq_product_rev = "0004";

static int inquiry_evpd_83(unsigned char * arr, int dev_id_num,
			   const char * dev_id_str, int dev_id_str_len)
{
	int num;

	/* Two identification descriptors: */
	/* T10 vendor identifier field format (faked) */
	arr[0] = 0x2;	/* ASCII */
	arr[1] = 0x1;
	arr[2] = 0x0;
	memcpy(&arr[4], inq_vendor_id, 8);
	memcpy(&arr[12], inq_product_id, 16);
	memcpy(&arr[28], dev_id_str, dev_id_str_len);
	num = 8 + 16 + dev_id_str_len;
	arr[3] = num;
	num += 4;
	/* NAA IEEE registered identifier (faked) */
	arr[num] = 0x1;	/* binary */
	arr[num + 1] = 0x3;
	arr[num + 2] = 0x0;
	arr[num + 3] = 0x8;
	arr[num + 4] = 0x51;	/* ieee company id=0x123456 (faked) */
	arr[num + 5] = 0x23;
	arr[num + 6] = 0x45;
	arr[num + 7] = 0x60;
	arr[num + 8] = (dev_id_num >> 24);
	arr[num + 9] = (dev_id_num >> 16) & 0xff;
	arr[num + 10] = (dev_id_num >> 8) & 0xff;
	arr[num + 11] = dev_id_num & 0xff;
	return num + 12;
}


#define SDEBUG_LONG_INQ_SZ 96
#define SDEBUG_MAX_INQ_ARR_SZ 128

static int resp_inquiry(struct scsi_cmnd * scp, int target,
			struct sdebug_dev_info * devip)
{
	unsigned char pq_pdt;
	unsigned char arr[SDEBUG_MAX_INQ_ARR_SZ];
	unsigned char *cmd = (unsigned char *)scp->cmnd;
	int alloc_len;

	alloc_len = (cmd[3] << 8) + cmd[4];
	memset(arr, 0, SDEBUG_MAX_INQ_ARR_SZ);
	pq_pdt = (scsi_debug_ptype & 0x1f);
	arr[0] = pq_pdt;
	if (0x2 & cmd[1]) {  /* CMDDT bit set */
		mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	} else if (0x1 & cmd[1]) {  /* EVPD bit set */
		int dev_id_num, len;
		char dev_id_str[6];
		
		dev_id_num = ((devip->sdbg_host->shost->host_no + 1) * 2000) +
			     (devip->target * 1000) + devip->lun;
		len = scnprintf(dev_id_str, 6, "%d", dev_id_num);
		if (0 == cmd[2]) { /* supported vital product data pages */
			arr[3] = 3;
			arr[4] = 0x0; /* this page */
			arr[5] = 0x80; /* unit serial number */
			arr[6] = 0x83; /* device identification */
		} else if (0x80 == cmd[2]) { /* unit serial number */
			arr[1] = 0x80;
			arr[3] = len;
			memcpy(&arr[4], dev_id_str, len);
		} else if (0x83 == cmd[2]) { /* device identification */
			arr[1] = 0x83;
			arr[3] = inquiry_evpd_83(&arr[4], dev_id_num,
						 dev_id_str, len);
		} else {
			/* Illegal request, invalid field in cdb */
			mk_sense_buffer(devip, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			return check_condition_result;
		}
		return fill_from_dev_buffer(scp, arr,
			    min(alloc_len, SDEBUG_MAX_INQ_ARR_SZ));
	}
	/* drops through here for a standard inquiry */
	arr[1] = DEV_REMOVEABLE(target) ? 0x80 : 0;	/* Removable disk */
	arr[2] = scsi_debug_scsi_level;
	arr[3] = 2;    /* response_data_format==2 */
	arr[4] = SDEBUG_LONG_INQ_SZ - 5;
	arr[6] = 0x1; /* claim: ADDR16 */
	/* arr[6] |= 0x40; ... claim: EncServ (enclosure services) */
	arr[7] = 0x3a; /* claim: WBUS16, SYNC, LINKED + CMDQUE */
	memcpy(&arr[8], inq_vendor_id, 8);
	memcpy(&arr[16], inq_product_id, 16);
	memcpy(&arr[32], inq_product_rev, 4);
	/* version descriptors (2 bytes each) follow */
	arr[58] = 0x0; arr[59] = 0x40; /* SAM-2 */
	arr[60] = 0x3; arr[61] = 0x0;  /* SPC-3 */
	if (scsi_debug_ptype == 0) {
		arr[62] = 0x1; arr[63] = 0x80; /* SBC */
	} else if (scsi_debug_ptype == 1) {
		arr[62] = 0x2; arr[63] = 0x00; /* SSC */
	}
	return fill_from_dev_buffer(scp, arr,
			    min(alloc_len, SDEBUG_LONG_INQ_SZ));
}

static int resp_requests(struct scsi_cmnd * scp,
			 struct sdebug_dev_info * devip)
{
	unsigned char * sbuff;
	unsigned char *cmd = (unsigned char *)scp->cmnd;
	unsigned char arr[SDEBUG_SENSE_LEN];
	int len = 18;

	memset(arr, 0, SDEBUG_SENSE_LEN);
	if (devip->reset == 1)
		mk_sense_buffer(devip, 0, NO_ADDED_SENSE, 0);
	sbuff = devip->sense_buff;
	if ((cmd[1] & 1) && (! scsi_debug_dsense)) {
		/* DESC bit set and sense_buff in fixed format */
		arr[0] = 0x72;
		arr[1] = sbuff[2];     /* sense key */
		arr[2] = sbuff[12];    /* asc */
		arr[3] = sbuff[13];    /* ascq */
		len = 8;
	} else
		memcpy(arr, sbuff, SDEBUG_SENSE_LEN);
	mk_sense_buffer(devip, 0, NO_ADDED_SENSE, 0);
	return fill_from_dev_buffer(scp, arr, len);
}

#define SDEBUG_READCAP_ARR_SZ 8
static int resp_readcap(struct scsi_cmnd * scp,
			struct sdebug_dev_info * devip)
{
	unsigned char arr[SDEBUG_READCAP_ARR_SZ];
	unsigned long capac;
	int errsts;

	if ((errsts = check_reset(scp, devip)))
		return errsts;
	memset(arr, 0, SDEBUG_READCAP_ARR_SZ);
	capac = (unsigned long)sdebug_capacity - 1;
	arr[0] = (capac >> 24);
	arr[1] = (capac >> 16) & 0xff;
	arr[2] = (capac >> 8) & 0xff;
	arr[3] = capac & 0xff;
	arr[6] = (SECT_SIZE_PER(target) >> 8) & 0xff;
	arr[7] = SECT_SIZE_PER(target) & 0xff;
	return fill_from_dev_buffer(scp, arr, SDEBUG_READCAP_ARR_SZ);
}

/* <<Following mode page info copied from ST318451LW>> */

static int resp_err_recov_pg(unsigned char * p, int pcontrol, int target)
{	/* Read-Write Error Recovery page for mode_sense */
	unsigned char err_recov_pg[] = {0x1, 0xa, 0xc0, 11, 240, 0, 0, 0,
					5, 0, 0xff, 0xff};

	memcpy(p, err_recov_pg, sizeof(err_recov_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(err_recov_pg) - 2);
	return sizeof(err_recov_pg);
}

static int resp_disconnect_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Disconnect-Reconnect page for mode_sense */
	unsigned char disconnect_pg[] = {0x2, 0xe, 128, 128, 0, 10, 0, 0,
					 0, 0, 0, 0, 0, 0, 0, 0};

	memcpy(p, disconnect_pg, sizeof(disconnect_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(disconnect_pg) - 2);
	return sizeof(disconnect_pg);
}

static int resp_format_pg(unsigned char * p, int pcontrol, int target)
{       /* Format device page for mode_sense */
        unsigned char format_pg[] = {0x3, 0x16, 0, 0, 0, 0, 0, 0,
                                     0, 0, 0, 0, 0, 0, 0, 0,
                                     0, 0, 0, 0, 0x40, 0, 0, 0};

        memcpy(p, format_pg, sizeof(format_pg));
        p[10] = (sdebug_sectors_per >> 8) & 0xff;
        p[11] = sdebug_sectors_per & 0xff;
        p[12] = (SECT_SIZE >> 8) & 0xff;
        p[13] = SECT_SIZE & 0xff;
        if (DEV_REMOVEABLE(target))
                p[20] |= 0x20; /* should agree with INQUIRY */
        if (1 == pcontrol)
                memset(p + 2, 0, sizeof(format_pg) - 2);
        return sizeof(format_pg);
}

static int resp_caching_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Caching page for mode_sense */
	unsigned char caching_pg[] = {0x8, 18, 0x14, 0, 0xff, 0xff, 0, 0,
		0xff, 0xff, 0xff, 0xff, 0x80, 0x14, 0, 0,     0, 0, 0, 0};

	memcpy(p, caching_pg, sizeof(caching_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(caching_pg) - 2);
	return sizeof(caching_pg);
}

static int resp_ctrl_m_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Control mode page for mode_sense */
	unsigned char ctrl_m_pg[] = {0xa, 10, 2, 0, 0, 0, 0, 0,
				     0, 0, 0x2, 0x4b};

	if (scsi_debug_dsense)
		ctrl_m_pg[2] |= 0x4;
	memcpy(p, ctrl_m_pg, sizeof(ctrl_m_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(ctrl_m_pg) - 2);
	return sizeof(ctrl_m_pg);
}

static int resp_iec_m_pg(unsigned char * p, int pcontrol, int target)
{	/* Informational Exceptions control mode page for mode_sense */
	unsigned char iec_m_pg[] = {0x1c, 0xa, 0x08, 0, 0, 0, 0, 0,
				    0, 0, 0x0, 0x0};
	memcpy(p, iec_m_pg, sizeof(iec_m_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(iec_m_pg) - 2);
	return sizeof(iec_m_pg);
}

#define SDEBUG_MAX_MSENSE_SZ 256

static int resp_mode_sense(struct scsi_cmnd * scp, int target,
			   struct sdebug_dev_info * devip)
{
	unsigned char dbd;
	int pcontrol, pcode, subpcode;
	unsigned char dev_spec;
	int alloc_len, msense_6, offset, len, errsts;
	unsigned char * ap;
	unsigned char arr[SDEBUG_MAX_MSENSE_SZ];
	unsigned char *cmd = (unsigned char *)scp->cmnd;

	if ((errsts = check_reset(scp, devip)))
		return errsts;
	dbd = cmd[1] & 0x8;
	pcontrol = (cmd[2] & 0xc0) >> 6;
	pcode = cmd[2] & 0x3f;
	subpcode = cmd[3];
	msense_6 = (MODE_SENSE == cmd[0]);
	alloc_len = msense_6 ? cmd[4] : ((cmd[7] << 8) | cmd[8]);
	memset(arr, 0, SDEBUG_MAX_MSENSE_SZ);
	if (0x3 == pcontrol) {  /* Saving values not supported */
		mk_sense_buffer(devip, ILLEGAL_REQUEST, SAVING_PARAMS_UNSUP,
			       	0);
		return check_condition_result;
	}
	dev_spec = DEV_READONLY(target) ? 0x80 : 0x0;
	if (msense_6) {
		arr[2] = dev_spec;
		offset = 4;
	} else {
		arr[3] = dev_spec;
		offset = 8;
	}
	ap = arr + offset;

	if (0 != subpcode) { /* TODO: Control Extension page */
		mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	switch (pcode) {
	case 0x1:	/* Read-Write error recovery page, direct access */
		len = resp_err_recov_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x2:	/* Disconnect-Reconnect page, all devices */
		len = resp_disconnect_pg(ap, pcontrol, target);
		offset += len;
		break;
        case 0x3:       /* Format device page, direct access */
                len = resp_format_pg(ap, pcontrol, target);
                offset += len;
                break;
	case 0x8:	/* Caching page, direct access */
		len = resp_caching_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0xa:	/* Control Mode page, all devices */
		len = resp_ctrl_m_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x1c:	/* Informational Exceptions Mode page, all devices */
		len = resp_iec_m_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x3f:	/* Read all Mode pages */
		len = resp_err_recov_pg(ap, pcontrol, target);
		len += resp_disconnect_pg(ap + len, pcontrol, target);
		len += resp_format_pg(ap + len, pcontrol, target);
		len += resp_caching_pg(ap + len, pcontrol, target);
		len += resp_ctrl_m_pg(ap + len, pcontrol, target);
		len += resp_iec_m_pg(ap + len, pcontrol, target);
		offset += len;
		break;
	default:
		mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	if (msense_6)
		arr[0] = offset - 1;
	else {
		arr[0] = ((offset - 2) >> 8) & 0xff;
		arr[1] = (offset - 2) & 0xff;
	}
	return fill_from_dev_buffer(scp, arr, min(alloc_len, offset));
}

static int resp_read(struct scsi_cmnd * SCpnt, int upper_blk, int block,
		     int num, struct sdebug_dev_info * devip)
{
	unsigned long iflags;
	int ret;

	if (upper_blk || (block + num > sdebug_capacity)) {
		mk_sense_buffer(devip, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE,
				0);
		return check_condition_result;
	}
	if ((SCSI_DEBUG_OPT_MEDIUM_ERR & scsi_debug_opts) &&
	    (block <= OPT_MEDIUM_ERR_ADDR) &&
	    ((block + num) > OPT_MEDIUM_ERR_ADDR)) {
		mk_sense_buffer(devip, MEDIUM_ERROR, UNRECOVERED_READ_ERR,
				0);
		/* claim unrecoverable read error */
		return check_condition_result;
	}
	read_lock_irqsave(&atomic_rw, iflags);
	ret = fill_from_dev_buffer(SCpnt, fake_storep + (block * SECT_SIZE),
			   	   num * SECT_SIZE);
	read_unlock_irqrestore(&atomic_rw, iflags);
	return ret;
}

static int resp_write(struct scsi_cmnd * SCpnt, int upper_blk, int block,
		      int num, struct sdebug_dev_info * devip)
{
	unsigned long iflags;
	int res;

	if (upper_blk || (block + num > sdebug_capacity)) {
		mk_sense_buffer(devip, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE,
			       	0);
		return check_condition_result;
	}

	write_lock_irqsave(&atomic_rw, iflags);
	res = fetch_to_dev_buffer(SCpnt, fake_storep + (block * SECT_SIZE),
			   	  num * SECT_SIZE);
	write_unlock_irqrestore(&atomic_rw, iflags);
	if (-1 == res)
		return (DID_ERROR << 16);
	else if ((res < (num * SECT_SIZE)) &&
		 (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
		printk(KERN_INFO "scsi_debug: write: cdb indicated=%d, "
		       " IO sent=%d bytes\n", num * SECT_SIZE, res);
	return 0;
}

#define SDEBUG_RLUN_ARR_SZ 128

static int resp_report_luns(struct scsi_cmnd * scp,
			    struct sdebug_dev_info * devip)
{
	unsigned int alloc_len;
	int lun_cnt, i, upper;
	unsigned char *cmd = (unsigned char *)scp->cmnd;
	int select_report = (int)cmd[2];
	struct scsi_lun *one_lun;
	unsigned char arr[SDEBUG_RLUN_ARR_SZ];

	alloc_len = cmd[9] + (cmd[8] << 8) + (cmd[7] << 16) + (cmd[6] << 24);
	if ((alloc_len < 16) || (select_report > 2)) {
		mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	/* can produce response with up to 16k luns (lun 0 to lun 16383) */
	memset(arr, 0, SDEBUG_RLUN_ARR_SZ);
	lun_cnt = scsi_debug_max_luns;
	arr[2] = ((sizeof(struct scsi_lun) * lun_cnt) >> 8) & 0xff;
	arr[3] = (sizeof(struct scsi_lun) * lun_cnt) & 0xff;
	lun_cnt = min((int)((SDEBUG_RLUN_ARR_SZ - 8) /
			    sizeof(struct scsi_lun)), lun_cnt);
	one_lun = (struct scsi_lun *) &arr[8];
	for (i = 0; i < lun_cnt; i++) {
		upper = (i >> 8) & 0x3f;
		if (upper)
			one_lun[i].scsi_lun[0] =
			    (upper | (SAM2_LUN_ADDRESS_METHOD << 6));
		one_lun[i].scsi_lun[1] = i & 0xff;
	}
	return fill_from_dev_buffer(scp, arr,
				    min((int)alloc_len, SDEBUG_RLUN_ARR_SZ));
}

/* When timer goes off this function is called. */
static void timer_intr_handler(unsigned long indx)
{
	struct sdebug_queued_cmd * sqcp;
	unsigned long iflags;

	if (indx >= SCSI_DEBUG_CANQUEUE) {
		printk(KERN_ERR "scsi_debug:timer_intr_handler: indx too "
		       "large\n");
		return;
	}
	spin_lock_irqsave(&queued_arr_lock, iflags);
	sqcp = &queued_arr[(int)indx];
	if (! sqcp->in_use) {
		printk(KERN_ERR "scsi_debug:timer_intr_handler: Unexpected "
		       "interrupt\n");
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		return;
	}
	sqcp->in_use = 0;
	if (sqcp->done_funct) {
		sqcp->a_cmnd->result = sqcp->scsi_result;
		sqcp->done_funct(sqcp->a_cmnd); /* callback to mid level */
	}
	sqcp->done_funct = NULL;
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

static int scsi_debug_slave_alloc(struct scsi_device * sdp)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp, "scsi_debug: slave_alloc\n");
	return 0;
}

static int scsi_debug_slave_configure(struct scsi_device * sdp)
{
	struct sdebug_dev_info * devip;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp, "scsi_debug: slave_configure\n");
	if (sdp->host->max_cmd_len != SCSI_DEBUG_MAX_CMD_LEN)
		sdp->host->max_cmd_len = SCSI_DEBUG_MAX_CMD_LEN;
	devip = devInfoReg(sdp);
	sdp->hostdata = devip;
	if (sdp->host->cmd_per_lun)
		scsi_adjust_queue_depth(sdp, SDEBUG_TAGGED_QUEUING,
					sdp->host->cmd_per_lun);
	return 0;
}

static void scsi_debug_slave_destroy(struct scsi_device * sdp)
{
	struct sdebug_dev_info * devip =
				(struct sdebug_dev_info *)sdp->hostdata;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp, "scsi_debug: slave_destroy\n");
	if (devip) {
		/* make this slot avaliable for re-use */
		devip->used = 0;
		sdp->hostdata = NULL;
	}
}

static struct sdebug_dev_info * devInfoReg(struct scsi_device * sdev)
{
	struct sdebug_host_info * sdbg_host;
	struct sdebug_dev_info * open_devip = NULL;
	struct sdebug_dev_info * devip =
			(struct sdebug_dev_info *)sdev->hostdata;

	if (devip)
		return devip;
	sdbg_host = *(struct sdebug_host_info **) sdev->host->hostdata;
        if(! sdbg_host) {
                printk(KERN_ERR "Host info NULL\n");
		return NULL;
        }
	list_for_each_entry(devip, &sdbg_host->dev_info_list, dev_list) {
		if ((devip->used) && (devip->channel == sdev->channel) &&
                    (devip->target == sdev->id) &&
                    (devip->lun == sdev->lun))
                        return devip;
		else {
			if ((!devip->used) && (!open_devip))
				open_devip = devip;
		}
	}
	if (NULL == open_devip) { /* try and make a new one */
		open_devip = kzalloc(sizeof(*open_devip),GFP_KERNEL);
		if (NULL == open_devip) {
			printk(KERN_ERR "%s: out of memory at line %d\n",
				__FUNCTION__, __LINE__);
			return NULL;
		}
		open_devip->sdbg_host = sdbg_host;
		list_add_tail(&open_devip->dev_list,
		&sdbg_host->dev_info_list);
	}
        if (open_devip) {
		open_devip->channel = sdev->channel;
		open_devip->target = sdev->id;
		open_devip->lun = sdev->lun;
		open_devip->sdbg_host = sdbg_host;
		open_devip->reset = 1;
		open_devip->used = 1;
		memset(open_devip->sense_buff, 0, SDEBUG_SENSE_LEN);
		if (scsi_debug_dsense)
			open_devip->sense_buff[0] = 0x72;
		else {
			open_devip->sense_buff[0] = 0x70;
			open_devip->sense_buff[7] = 0xa;
		}
		return open_devip;
        }
        return NULL;
}

static void mk_sense_buffer(struct sdebug_dev_info * devip, int key,
			    int asc, int asq)
{
	unsigned char * sbuff;

	sbuff = devip->sense_buff;
	memset(sbuff, 0, SDEBUG_SENSE_LEN);
	if (scsi_debug_dsense) {
		sbuff[0] = 0x72;  /* descriptor, current */
		sbuff[1] = key;
		sbuff[2] = asc;
		sbuff[3] = asq;
	} else {
		sbuff[0] = 0x70;  /* fixed, current */
		sbuff[2] = key;
		sbuff[7] = 0xa;	  /* implies 18 byte sense buffer */
		sbuff[12] = asc;
		sbuff[13] = asq;
	}
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug:    [sense_key,asc,ascq]: "
		      "[0x%x,0x%x,0x%x]\n", key, asc, asq);
}

static int scsi_debug_abort(struct scsi_cmnd * SCpnt)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: abort\n");
	++num_aborts;
	stop_queued_cmnd(SCpnt);
	return SUCCESS;
}

static int scsi_debug_biosparam(struct scsi_device *sdev,
		struct block_device * bdev, sector_t capacity, int *info)
{
	int res;
	unsigned char *buf;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: biosparam\n");
	buf = scsi_bios_ptable(bdev);
	if (buf) {
		res = scsi_partsize(buf, capacity,
				    &info[2], &info[0], &info[1]);
		kfree(buf);
		if (! res)
			return res;
	}
	info[0] = sdebug_heads;
	info[1] = sdebug_sectors_per;
	info[2] = sdebug_cylinders_per;
	return 0;
}

static int scsi_debug_device_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_dev_info * devip;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: device_reset\n");
	++num_dev_resets;
	if (SCpnt) {
		devip = devInfoReg(SCpnt->device);
		if (devip)
			devip->reset = 1;
	}
	return SUCCESS;
}

static int scsi_debug_bus_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_host_info *sdbg_host;
        struct sdebug_dev_info * dev_info;
        struct scsi_device * sdp;
        struct Scsi_Host * hp;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: bus_reset\n");
	++num_bus_resets;
	if (SCpnt && ((sdp = SCpnt->device)) && ((hp = sdp->host))) {
		sdbg_host = *(struct sdebug_host_info **) hp->hostdata;
		if (sdbg_host) {
			list_for_each_entry(dev_info,
                                            &sdbg_host->dev_info_list,
                                            dev_list)
				dev_info->reset = 1;
		}
	}
	return SUCCESS;
}

static int scsi_debug_host_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_host_info * sdbg_host;
        struct sdebug_dev_info * dev_info;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: host_reset\n");
	++num_host_resets;
        spin_lock(&sdebug_host_list_lock);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                list_for_each_entry(dev_info, &sdbg_host->dev_info_list,
                                    dev_list)
                        dev_info->reset = 1;
        }
        spin_unlock(&sdebug_host_list_lock);
	stop_all_queued();
	return SUCCESS;
}

/* Returns 1 if found 'cmnd' and deleted its timer. else returns 0 */
static int stop_queued_cmnd(struct scsi_cmnd * cmnd)
{
	unsigned long iflags;
	int k;
	struct sdebug_queued_cmd * sqcp;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
		sqcp = &queued_arr[k];
		if (sqcp->in_use && (cmnd == sqcp->a_cmnd)) {
			del_timer_sync(&sqcp->cmnd_timer);
			sqcp->in_use = 0;
			sqcp->a_cmnd = NULL;
			break;
		}
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	return (k < SCSI_DEBUG_CANQUEUE) ? 1 : 0;
}

/* Deletes (stops) timers of all queued commands */
static void stop_all_queued(void)
{
	unsigned long iflags;
	int k;
	struct sdebug_queued_cmd * sqcp;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
		sqcp = &queued_arr[k];
		if (sqcp->in_use && sqcp->a_cmnd) {
			del_timer_sync(&sqcp->cmnd_timer);
			sqcp->in_use = 0;
			sqcp->a_cmnd = NULL;
		}
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

/* Initializes timers in queued array */
static void __init init_all_queued(void)
{
	unsigned long iflags;
	int k;
	struct sdebug_queued_cmd * sqcp;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
		sqcp = &queued_arr[k];
		init_timer(&sqcp->cmnd_timer);
		sqcp->in_use = 0;
		sqcp->a_cmnd = NULL;
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

static void __init sdebug_build_parts(unsigned char * ramp)
{
	struct partition * pp;
	int starts[SDEBUG_MAX_PARTS + 2];
	int sectors_per_part, num_sectors, k;
	int heads_by_sects, start_sec, end_sec;

	/* assume partition table already zeroed */
	if ((scsi_debug_num_parts < 1) || (sdebug_store_size < 1048576))
		return;
	if (scsi_debug_num_parts > SDEBUG_MAX_PARTS) {
		scsi_debug_num_parts = SDEBUG_MAX_PARTS;
		printk(KERN_WARNING "scsi_debug:build_parts: reducing "
				    "partitions to %d\n", SDEBUG_MAX_PARTS);
	}
	num_sectors = (int)(sdebug_store_size / SECT_SIZE);
	sectors_per_part = (num_sectors - sdebug_sectors_per)
			   / scsi_debug_num_parts;
	heads_by_sects = sdebug_heads * sdebug_sectors_per;
        starts[0] = sdebug_sectors_per;
	for (k = 1; k < scsi_debug_num_parts; ++k)
		starts[k] = ((k * sectors_per_part) / heads_by_sects)
			    * heads_by_sects;
	starts[scsi_debug_num_parts] = num_sectors;
	starts[scsi_debug_num_parts + 1] = 0;

	ramp[510] = 0x55;	/* magic partition markings */
	ramp[511] = 0xAA;
	pp = (struct partition *)(ramp + 0x1be);
	for (k = 0; starts[k + 1]; ++k, ++pp) {
		start_sec = starts[k];
		end_sec = starts[k + 1] - 1;
		pp->boot_ind = 0;

		pp->cyl = start_sec / heads_by_sects;
		pp->head = (start_sec - (pp->cyl * heads_by_sects))
			   / sdebug_sectors_per;
		pp->sector = (start_sec % sdebug_sectors_per) + 1;

		pp->end_cyl = end_sec / heads_by_sects;
		pp->end_head = (end_sec - (pp->end_cyl * heads_by_sects))
			       / sdebug_sectors_per;
		pp->end_sector = (end_sec % sdebug_sectors_per) + 1;

		pp->start_sect = start_sec;
		pp->nr_sects = end_sec - start_sec + 1;
		pp->sys_ind = 0x83;	/* plain Linux partition */
	}
}

static int schedule_resp(struct scsi_cmnd * cmnd,
			 struct sdebug_dev_info * devip,
			 done_funct_t done, int scsi_result, int delta_jiff)
{
	if ((SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) && cmnd) {
		if (scsi_result) {
			struct scsi_device * sdp = cmnd->device;

			sdev_printk(KERN_INFO, sdp,
				"non-zero result=0x%x\n",
			       	scsi_result);
		}
	}
	if (cmnd && devip) {
		/* simulate autosense by this driver */
		if (SAM_STAT_CHECK_CONDITION == (scsi_result & 0xff))
			memcpy(cmnd->sense_buffer, devip->sense_buff,
			       (SCSI_SENSE_BUFFERSIZE > SDEBUG_SENSE_LEN) ?
			       SDEBUG_SENSE_LEN : SCSI_SENSE_BUFFERSIZE);
	}
	if (delta_jiff <= 0) {
		if (cmnd)
			cmnd->result = scsi_result;
		if (done)
			done(cmnd);
		return 0;
	} else {
		unsigned long iflags;
		int k;
		struct sdebug_queued_cmd * sqcp = NULL;

		spin_lock_irqsave(&queued_arr_lock, iflags);
		for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
			sqcp = &queued_arr[k];
			if (! sqcp->in_use)
				break;
		}
		if (k >= SCSI_DEBUG_CANQUEUE) {
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
			printk(KERN_WARNING "scsi_debug: can_queue exceeded\n");
			return 1;	/* report busy to mid level */
		}
		sqcp->in_use = 1;
		sqcp->a_cmnd = cmnd;
		sqcp->scsi_result = scsi_result;
		sqcp->done_funct = done;
		sqcp->cmnd_timer.function = timer_intr_handler;
		sqcp->cmnd_timer.data = k;
		sqcp->cmnd_timer.expires = jiffies + delta_jiff;
		add_timer(&sqcp->cmnd_timer);
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		if (cmnd)
			cmnd->result = 0;
		return 0;
	}
}

/* Set 'perm' (4th argument) to 0 to disable module_param's definition
 * of sysfs parameters (which module_param doesn't yet support).
 * Sysfs parameters defined explicitly below.
 */
module_param_named(add_host, scsi_debug_add_host, int, 0); /* perm=0644 */
module_param_named(delay, scsi_debug_delay, int, 0); /* perm=0644 */
module_param_named(dev_size_mb, scsi_debug_dev_size_mb, int, 0);
module_param_named(dsense, scsi_debug_dsense, int, 0);
module_param_named(every_nth, scsi_debug_every_nth, int, 0);
module_param_named(max_luns, scsi_debug_max_luns, int, 0);
module_param_named(num_parts, scsi_debug_num_parts, int, 0);
module_param_named(num_tgts, scsi_debug_num_tgts, int, 0);
module_param_named(opts, scsi_debug_opts, int, 0); /* perm=0644 */
module_param_named(ptype, scsi_debug_ptype, int, 0);
module_param_named(scsi_level, scsi_debug_scsi_level, int, 0);

MODULE_AUTHOR("Eric Youngdale + Douglas Gilbert");
MODULE_DESCRIPTION("SCSI debug adapter driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(SCSI_DEBUG_VERSION);

MODULE_PARM_DESC(add_host, "0..127 hosts allowed(def=1)");
MODULE_PARM_DESC(delay, "# of jiffies to delay response(def=1)");
MODULE_PARM_DESC(dev_size_mb, "size in MB of ram shared by devs");
MODULE_PARM_DESC(dsense, "use descriptor sense format(def: fixed)");
MODULE_PARM_DESC(every_nth, "timeout every nth command(def=100)");
MODULE_PARM_DESC(max_luns, "number of SCSI LUNs per target to simulate");
MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");
MODULE_PARM_DESC(num_tgts, "number of SCSI targets per host to simulate");
MODULE_PARM_DESC(opts, "1->noise, 2->medium_error, 4->...");
MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");
MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=5[SPC-3])");


static char sdebug_info[256];

static const char * scsi_debug_info(struct Scsi_Host * shp)
{
	sprintf(sdebug_info, "scsi_debug, version %s [%s], "
		"dev_size_mb=%d, opts=0x%x", SCSI_DEBUG_VERSION,
		scsi_debug_version_date, scsi_debug_dev_size_mb,
		scsi_debug_opts);
	return sdebug_info;
}

/* scsi_debug_proc_info
 * Used if the driver currently has no own support for /proc/scsi
 */
static int scsi_debug_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset,
				int length, int inout)
{
	int len, pos, begin;
	int orig_length;

	orig_length = length;

	if (inout == 1) {
		char arr[16];
		int minLen = length > 15 ? 15 : length;

		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
			return -EACCES;
		memcpy(arr, buffer, minLen);
		arr[minLen] = '\0';
		if (1 != sscanf(arr, "%d", &pos))
			return -EINVAL;
		scsi_debug_opts = pos;
		if (scsi_debug_every_nth != 0)
                        scsi_debug_cmnd_count = 0;
		return length;
	}
	begin = 0;
	pos = len = sprintf(buffer, "scsi_debug adapter driver, version "
	    "%s [%s]\n"
	    "num_tgts=%d, shared (ram) size=%d MB, opts=0x%x, "
	    "every_nth=%d(curr:%d)\n"
	    "delay=%d, max_luns=%d, scsi_level=%d\n"
	    "sector_size=%d bytes, cylinders=%d, heads=%d, sectors=%d\n"
	    "number of aborts=%d, device_reset=%d, bus_resets=%d, "
	    "host_resets=%d\n",
	    SCSI_DEBUG_VERSION, scsi_debug_version_date, scsi_debug_num_tgts,
	    scsi_debug_dev_size_mb, scsi_debug_opts, scsi_debug_every_nth,
	    scsi_debug_cmnd_count, scsi_debug_delay,
	    scsi_debug_max_luns, scsi_debug_scsi_level,
	    SECT_SIZE, sdebug_cylinders_per, sdebug_heads, sdebug_sectors_per,
	    num_aborts, num_dev_resets, num_bus_resets, num_host_resets);
	if (pos < offset) {
		len = 0;
		begin = pos;
	}
	*start = buffer + (offset - begin);	/* Start of wanted data */
	len -= (offset - begin);
	if (len > length)
		len = length;
	return len;
}

static ssize_t sdebug_delay_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_delay);
}

static ssize_t sdebug_delay_store(struct device_driver * ddp,
				  const char * buf, size_t count)
{
        int delay;
	char work[20];

        if (1 == sscanf(buf, "%10s", work)) {
		if ((1 == sscanf(work, "%d", &delay)) && (delay >= 0)) {
			scsi_debug_delay = delay;
			return count;
		}
	}
	return -EINVAL;
}
DRIVER_ATTR(delay, S_IRUGO | S_IWUSR, sdebug_delay_show,
	    sdebug_delay_store);

static ssize_t sdebug_opts_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "0x%x\n", scsi_debug_opts);
}

static ssize_t sdebug_opts_store(struct device_driver * ddp,
				 const char * buf, size_t count)
{
        int opts;
	char work[20];

        if (1 == sscanf(buf, "%10s", work)) {
		if (0 == strnicmp(work,"0x", 2)) {
			if (1 == sscanf(&work[2], "%x", &opts))
				goto opts_done;
		} else {
			if (1 == sscanf(work, "%d", &opts))
				goto opts_done;
		}
	}
	return -EINVAL;
opts_done:
	scsi_debug_opts = opts;
	scsi_debug_cmnd_count = 0;
	return count;
}
DRIVER_ATTR(opts, S_IRUGO | S_IWUSR, sdebug_opts_show,
	    sdebug_opts_store);

static ssize_t sdebug_ptype_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_ptype);
}
static ssize_t sdebug_ptype_store(struct device_driver * ddp,
				  const char * buf, size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_ptype = n;
		return count;
	}
	return -EINVAL;
}
DRIVER_ATTR(ptype, S_IRUGO | S_IWUSR, sdebug_ptype_show, sdebug_ptype_store);

static ssize_t sdebug_dsense_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dsense);
}
static ssize_t sdebug_dsense_store(struct device_driver * ddp,
				  const char * buf, size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_dsense = n;
		return count;
	}
	return -EINVAL;
}
DRIVER_ATTR(dsense, S_IRUGO | S_IWUSR, sdebug_dsense_show,
	    sdebug_dsense_store);

static ssize_t sdebug_num_tgts_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_num_tgts);
}
static ssize_t sdebug_num_tgts_store(struct device_driver * ddp,
				     const char * buf, size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_num_tgts = n;
		sdebug_max_tgts_luns();
		return count;
	}
	return -EINVAL;
}
DRIVER_ATTR(num_tgts, S_IRUGO | S_IWUSR, sdebug_num_tgts_show,
	    sdebug_num_tgts_store);

static ssize_t sdebug_dev_size_mb_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dev_size_mb);
}
DRIVER_ATTR(dev_size_mb, S_IRUGO, sdebug_dev_size_mb_show, NULL);

static ssize_t sdebug_num_parts_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_num_parts);
}
DRIVER_ATTR(num_parts, S_IRUGO, sdebug_num_parts_show, NULL);

static ssize_t sdebug_every_nth_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_every_nth);
}
static ssize_t sdebug_every_nth_store(struct device_driver * ddp,
				      const char * buf, size_t count)
{
        int nth;

	if ((count > 0) && (1 == sscanf(buf, "%d", &nth))) {
		scsi_debug_every_nth = nth;
		scsi_debug_cmnd_count = 0;
		return count;
	}
	return -EINVAL;
}
DRIVER_ATTR(every_nth, S_IRUGO | S_IWUSR, sdebug_every_nth_show,
	    sdebug_every_nth_store);

static ssize_t sdebug_max_luns_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_max_luns);
}
static ssize_t sdebug_max_luns_store(struct device_driver * ddp,
				     const char * buf, size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_max_luns = n;
		sdebug_max_tgts_luns();
		return count;
	}
	return -EINVAL;
}
DRIVER_ATTR(max_luns, S_IRUGO | S_IWUSR, sdebug_max_luns_show,
	    sdebug_max_luns_store);

static ssize_t sdebug_scsi_level_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_scsi_level);
}
DRIVER_ATTR(scsi_level, S_IRUGO, sdebug_scsi_level_show, NULL);

static ssize_t sdebug_add_host_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_add_host);
}

static ssize_t sdebug_add_host_store(struct device_driver * ddp,
				     const char * buf, size_t count)
{
        int delta_hosts;
	char work[20];

        if (1 != sscanf(buf, "%10s", work))
		return -EINVAL;
	{	/* temporary hack around sscanf() problem with -ve nums */
		int neg = 0;

		if ('-' == *work)
			neg = 1;
		if (1 != sscanf(work + neg, "%d", &delta_hosts))
			return -EINVAL;
		if (neg)
			delta_hosts = -delta_hosts;
	}
	if (delta_hosts > 0) {
		do {
			sdebug_add_adapter();
		} while (--delta_hosts);
	} else if (delta_hosts < 0) {
		do {
			sdebug_remove_adapter();
		} while (++delta_hosts);
	}
	return count;
}
DRIVER_ATTR(add_host, S_IRUGO | S_IWUSR, sdebug_add_host_show, 
	    sdebug_add_host_store);

static void do_create_driverfs_files(void)
{
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_add_host);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_delay);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_dev_size_mb);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_dsense);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_every_nth);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_max_luns);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_num_parts);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_ptype);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_opts);
	driver_create_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
}

static void do_remove_driverfs_files(void)
{
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_opts);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_ptype);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_parts);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_max_luns);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_every_nth);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dsense);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dev_size_mb);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_delay);
	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_add_host);
}

static int __init scsi_debug_init(void)
{
	unsigned long sz;
	int host_to_add;
	int k;

	if (scsi_debug_dev_size_mb < 1)
		scsi_debug_dev_size_mb = 1;  /* force minimum 1 MB ramdisk */
	sdebug_store_size = (unsigned long)scsi_debug_dev_size_mb * 1048576;
	sdebug_capacity = sdebug_store_size / SECT_SIZE;

	/* play around with geometry, don't waste too much on track 0 */
	sdebug_heads = 8;
	sdebug_sectors_per = 32;
	if (scsi_debug_dev_size_mb >= 16)
		sdebug_heads = 32;
	else if (scsi_debug_dev_size_mb >= 256)
		sdebug_heads = 64;
	sdebug_cylinders_per = (unsigned long)sdebug_capacity /
			       (sdebug_sectors_per * sdebug_heads);
	if (sdebug_cylinders_per >= 1024) {
		/* other LLDs do this; implies >= 1GB ram disk ... */
		sdebug_heads = 255;
		sdebug_sectors_per = 63;
		sdebug_cylinders_per = (unsigned long)sdebug_capacity /
			       (sdebug_sectors_per * sdebug_heads);
	}

	sz = sdebug_store_size;
	fake_storep = vmalloc(sz);
	if (NULL == fake_storep) {
		printk(KERN_ERR "scsi_debug_init: out of memory, 1\n");
		return -ENOMEM;
	}
	memset(fake_storep, 0, sz);
	if (scsi_debug_num_parts > 0)
		sdebug_build_parts(fake_storep);

	init_all_queued();

	device_register(&pseudo_primary);
	bus_register(&pseudo_lld_bus);
	driver_register(&sdebug_driverfs_driver);
	do_create_driverfs_files();

	sdebug_driver_template.proc_name = (char *)sdebug_proc_name;

	host_to_add = scsi_debug_add_host;
        scsi_debug_add_host = 0;

        for (k = 0; k < host_to_add; k++) {
                if (sdebug_add_adapter()) {
                        printk(KERN_ERR "scsi_debug_init: "
                               "sdebug_add_adapter failed k=%d\n", k);
                        break;
                }
        }

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) {
		printk(KERN_INFO "scsi_debug_init: built %d host(s)\n",
		       scsi_debug_add_host);
	}
	return 0;
}

static void __exit scsi_debug_exit(void)
{
	int k = scsi_debug_add_host;

	stop_all_queued();
	for (; k; k--)
		sdebug_remove_adapter();
	do_remove_driverfs_files();
	driver_unregister(&sdebug_driverfs_driver);
	bus_unregister(&pseudo_lld_bus);
	device_unregister(&pseudo_primary);

	vfree(fake_storep);
}

device_initcall(scsi_debug_init);
module_exit(scsi_debug_exit);

static void pseudo_0_release(struct device * dev)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: pseudo_0_release() called\n");
}

static struct device pseudo_primary = {
	.bus_id		= "pseudo_0",
	.release	= pseudo_0_release,
};

static int pseudo_lld_bus_match(struct device *dev,
                          struct device_driver *dev_driver)
{
        return 1;
}

static struct bus_type pseudo_lld_bus = {
        .name = "pseudo",
        .match = pseudo_lld_bus_match,
	.probe = sdebug_driver_probe,
	.remove = sdebug_driver_remove,
};

static void sdebug_release_adapter(struct device * dev)
{
        struct sdebug_host_info *sdbg_host;

	sdbg_host = to_sdebug_host(dev);
        kfree(sdbg_host);
}

static int sdebug_add_adapter(void)
{
	int k, devs_per_host;
        int error = 0;
        struct sdebug_host_info *sdbg_host;
        struct sdebug_dev_info *sdbg_devinfo;
        struct list_head *lh, *lh_sf;

        sdbg_host = kzalloc(sizeof(*sdbg_host), GFP_KERNEL);

        if (NULL == sdbg_host) {
                printk(KERN_ERR "%s: out of memory at line %d\n",
                       __FUNCTION__, __LINE__);
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&sdbg_host->dev_info_list);

	devs_per_host = scsi_debug_num_tgts * scsi_debug_max_luns;
        for (k = 0; k < devs_per_host; k++) {
                sdbg_devinfo = kzalloc(sizeof(*sdbg_devinfo), GFP_KERNEL);
                if (NULL == sdbg_devinfo) {
                        printk(KERN_ERR "%s: out of memory at line %d\n",
                               __FUNCTION__, __LINE__);
                        error = -ENOMEM;
			goto clean;
                }
                sdbg_devinfo->sdbg_host = sdbg_host;
                list_add_tail(&sdbg_devinfo->dev_list,
                              &sdbg_host->dev_info_list);
        }

        spin_lock(&sdebug_host_list_lock);
        list_add_tail(&sdbg_host->host_list, &sdebug_host_list);
        spin_unlock(&sdebug_host_list_lock);

        sdbg_host->dev.bus = &pseudo_lld_bus;
        sdbg_host->dev.parent = &pseudo_primary;
        sdbg_host->dev.release = &sdebug_release_adapter;
        sprintf(sdbg_host->dev.bus_id, "adapter%d", scsi_debug_add_host);

        error = device_register(&sdbg_host->dev);

        if (error)
		goto clean;

	++scsi_debug_add_host;
        return error;

clean:
	list_for_each_safe(lh, lh_sf, &sdbg_host->dev_info_list) {
		sdbg_devinfo = list_entry(lh, struct sdebug_dev_info,
					  dev_list);
		list_del(&sdbg_devinfo->dev_list);
		kfree(sdbg_devinfo);
	}

	kfree(sdbg_host);
        return error;
}

static void sdebug_remove_adapter(void)
{
        struct sdebug_host_info * sdbg_host = NULL;

        spin_lock(&sdebug_host_list_lock);
        if (!list_empty(&sdebug_host_list)) {
                sdbg_host = list_entry(sdebug_host_list.prev,
                                       struct sdebug_host_info, host_list);
		list_del(&sdbg_host->host_list);
	}
        spin_unlock(&sdebug_host_list_lock);

	if (!sdbg_host)
		return;

        device_unregister(&sdbg_host->dev);
        --scsi_debug_add_host;
}

static int sdebug_driver_probe(struct device * dev)
{
        int error = 0;
        struct sdebug_host_info *sdbg_host;
        struct Scsi_Host *hpnt;

	sdbg_host = to_sdebug_host(dev);

        hpnt = scsi_host_alloc(&sdebug_driver_template, sizeof(sdbg_host));
        if (NULL == hpnt) {
                printk(KERN_ERR "%s: scsi_register failed\n", __FUNCTION__);
                error = -ENODEV;
		return error;
        }

        sdbg_host->shost = hpnt;
	*((struct sdebug_host_info **)hpnt->hostdata) = sdbg_host;
	if ((hpnt->this_id >= 0) && (scsi_debug_num_tgts > hpnt->this_id))
		hpnt->max_id = scsi_debug_num_tgts + 1;
	else
		hpnt->max_id = scsi_debug_num_tgts;
	hpnt->max_lun = scsi_debug_max_luns;

        error = scsi_add_host(hpnt, &sdbg_host->dev);
        if (error) {
                printk(KERN_ERR "%s: scsi_add_host failed\n", __FUNCTION__);
                error = -ENODEV;
		scsi_host_put(hpnt);
        } else
		scsi_scan_host(hpnt);


        return error;
}

static int sdebug_driver_remove(struct device * dev)
{
        struct list_head *lh, *lh_sf;
        struct sdebug_host_info *sdbg_host;
        struct sdebug_dev_info *sdbg_devinfo;

	sdbg_host = to_sdebug_host(dev);

	if (!sdbg_host) {
		printk(KERN_ERR "%s: Unable to locate host info\n",
		       __FUNCTION__);
		return -ENODEV;
	}

        scsi_remove_host(sdbg_host->shost);

        list_for_each_safe(lh, lh_sf, &sdbg_host->dev_info_list) {
                sdbg_devinfo = list_entry(lh, struct sdebug_dev_info,
                                          dev_list);
                list_del(&sdbg_devinfo->dev_list);
                kfree(sdbg_devinfo);
        }

        scsi_host_put(sdbg_host->shost);
        return 0;
}

static void sdebug_max_tgts_luns(void)
{
	struct sdebug_host_info * sdbg_host;
	struct Scsi_Host *hpnt;

	spin_lock(&sdebug_host_list_lock);
	list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
		hpnt = sdbg_host->shost;
		if ((hpnt->this_id >= 0) &&
		    (scsi_debug_num_tgts > hpnt->this_id))
			hpnt->max_id = scsi_debug_num_tgts + 1;
		else
			hpnt->max_id = scsi_debug_num_tgts;
		hpnt->max_lun = scsi_debug_max_luns;
	}
	spin_unlock(&sdebug_host_list_lock);
}