summaryrefslogtreecommitdiff
path: root/drivers/s390/char/tape_core.c
blob: 585618663ba458bb846e8659630a8df778659b6e (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
/*
 *  drivers/s390/char/tape_core.c
 *    basic function of the tape device driver
 *
 *  S390 and zSeries version
 *    Copyright IBM Corp. 2001, 2009
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 *		 Michael Holzheu <holzheu@de.ibm.com>
 *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
 *		 Stefan Bader <shbader@de.ibm.com>
 */

#define KMSG_COMPONENT "tape"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/init.h>	     // for kernel parameters
#include <linux/kmod.h>	     // for requesting modules
#include <linux/spinlock.h>  // for locks
#include <linux/vmalloc.h>
#include <linux/list.h>
#include <linux/slab.h>

#include <asm/types.h>	     // for variable types

#define TAPE_DBF_AREA	tape_core_dbf

#include "tape.h"
#include "tape_std.h"

#define LONG_BUSY_TIMEOUT 180 /* seconds */

static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
static void tape_delayed_next_request(struct work_struct *);
static void tape_long_busy_timeout(unsigned long data);

/*
 * One list to contain all tape devices of all disciplines, so
 * we can assign the devices to minor numbers of the same major
 * The list is protected by the rwlock
 */
static LIST_HEAD(tape_device_list);
static DEFINE_RWLOCK(tape_device_lock);

/*
 * Pointer to debug area.
 */
debug_info_t *TAPE_DBF_AREA = NULL;
EXPORT_SYMBOL(TAPE_DBF_AREA);

/*
 * Printable strings for tape enumerations.
 */
const char *tape_state_verbose[TS_SIZE] =
{
	[TS_UNUSED]   = "UNUSED",
	[TS_IN_USE]   = "IN_USE",
	[TS_BLKUSE]   = "BLKUSE",
	[TS_INIT]     = "INIT  ",
	[TS_NOT_OPER] = "NOT_OP"
};

const char *tape_op_verbose[TO_SIZE] =
{
	[TO_BLOCK] = "BLK",	[TO_BSB] = "BSB",
	[TO_BSF] = "BSF",	[TO_DSE] = "DSE",
	[TO_FSB] = "FSB",	[TO_FSF] = "FSF",
	[TO_LBL] = "LBL",	[TO_NOP] = "NOP",
	[TO_RBA] = "RBA",	[TO_RBI] = "RBI",
	[TO_RFO] = "RFO",	[TO_REW] = "REW",
	[TO_RUN] = "RUN",	[TO_WRI] = "WRI",
	[TO_WTM] = "WTM",	[TO_MSEN] = "MSN",
	[TO_LOAD] = "LOA",	[TO_READ_CONFIG] = "RCF",
	[TO_READ_ATTMSG] = "RAT",
	[TO_DIS] = "DIS",	[TO_ASSIGN] = "ASS",
	[TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
	[TO_CRYPT_OFF] = "COF",	[TO_KEKL_SET] = "KLS",
	[TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
};

static int devid_to_int(struct ccw_dev_id *dev_id)
{
	return dev_id->devno + (dev_id->ssid << 16);
}

/*
 * Some channel attached tape specific attributes.
 *
 * FIXME: In the future the first_minor and blocksize attribute should be
 *        replaced by a link to the cdev tree.
 */
static ssize_t
tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = dev_get_drvdata(dev);
	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
}

static
DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);

static ssize_t
tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = dev_get_drvdata(dev);
	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
}

static
DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);

static ssize_t
tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = dev_get_drvdata(dev);
	return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
		"OFFLINE" : tape_state_verbose[tdev->tape_state]);
}

static
DEVICE_ATTR(state, 0444, tape_state_show, NULL);

static ssize_t
tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;
	ssize_t rc;

	tdev = dev_get_drvdata(dev);
	if (tdev->first_minor < 0)
		return scnprintf(buf, PAGE_SIZE, "N/A\n");

	spin_lock_irq(get_ccwdev_lock(tdev->cdev));
	if (list_empty(&tdev->req_queue))
		rc = scnprintf(buf, PAGE_SIZE, "---\n");
	else {
		struct tape_request *req;

		req = list_entry(tdev->req_queue.next, struct tape_request,
			list);
		rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
	}
	spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
	return rc;
}

static
DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);

static ssize_t
tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct tape_device *tdev;

	tdev = dev_get_drvdata(dev);

	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
}

static
DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);

static struct attribute *tape_attrs[] = {
	&dev_attr_medium_state.attr,
	&dev_attr_first_minor.attr,
	&dev_attr_state.attr,
	&dev_attr_operation.attr,
	&dev_attr_blocksize.attr,
	NULL
};

static struct attribute_group tape_attr_group = {
	.attrs = tape_attrs,
};

/*
 * Tape state functions
 */
void
tape_state_set(struct tape_device *device, enum tape_state newstate)
{
	const char *str;

	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(3, "ts_set err: not oper\n");
		return;
	}
	DBF_EVENT(4, "ts. dev:	%x\n", device->first_minor);
	DBF_EVENT(4, "old ts:\t\n");
	if (device->tape_state < TS_SIZE && device->tape_state >=0 )
		str = tape_state_verbose[device->tape_state];
	else
		str = "UNKNOWN TS";
	DBF_EVENT(4, "%s\n", str);
	DBF_EVENT(4, "new ts:\t\n");
	if (newstate < TS_SIZE && newstate >= 0)
		str = tape_state_verbose[newstate];
	else
		str = "UNKNOWN TS";
	DBF_EVENT(4, "%s\n", str);
	device->tape_state = newstate;
	wake_up(&device->state_change_wq);
}

struct tape_med_state_work_data {
	struct tape_device *device;
	enum tape_medium_state state;
	struct work_struct  work;
};

static void
tape_med_state_work_handler(struct work_struct *work)
{
	static char env_state_loaded[] = "MEDIUM_STATE=LOADED";
	static char env_state_unloaded[] = "MEDIUM_STATE=UNLOADED";
	struct tape_med_state_work_data *p =
		container_of(work, struct tape_med_state_work_data, work);
	struct tape_device *device = p->device;
	char *envp[] = { NULL, NULL };

	switch (p->state) {
	case MS_UNLOADED:
		pr_info("%s: The tape cartridge has been successfully "
			"unloaded\n", dev_name(&device->cdev->dev));
		envp[0] = env_state_unloaded;
		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
		break;
	case MS_LOADED:
		pr_info("%s: A tape cartridge has been mounted\n",
			dev_name(&device->cdev->dev));
		envp[0] = env_state_loaded;
		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
		break;
	default:
		break;
	}
	tape_put_device(device);
	kfree(p);
}

static void
tape_med_state_work(struct tape_device *device, enum tape_medium_state state)
{
	struct tape_med_state_work_data *p;

	p = kzalloc(sizeof(*p), GFP_ATOMIC);
	if (p) {
		INIT_WORK(&p->work, tape_med_state_work_handler);
		p->device = tape_get_device(device);
		p->state = state;
		schedule_work(&p->work);
	}
}

void
tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
{
	enum tape_medium_state oldstate;

	oldstate = device->medium_state;
	if (oldstate == newstate)
		return;
	device->medium_state = newstate;
	switch(newstate){
	case MS_UNLOADED:
		device->tape_generic_status |= GMT_DR_OPEN(~0);
		if (oldstate == MS_LOADED)
			tape_med_state_work(device, MS_UNLOADED);
		break;
	case MS_LOADED:
		device->tape_generic_status &= ~GMT_DR_OPEN(~0);
		if (oldstate == MS_UNLOADED)
			tape_med_state_work(device, MS_LOADED);
		break;
	default:
		break;
	}
	wake_up(&device->state_change_wq);
}

/*
 * Stop running ccw. Has to be called with the device lock held.
 */
static int
__tape_cancel_io(struct tape_device *device, struct tape_request *request)
{
	int retries;
	int rc;

	/* Check if interrupt has already been processed */
	if (request->callback == NULL)
		return 0;

	rc = 0;
	for (retries = 0; retries < 5; retries++) {
		rc = ccw_device_clear(device->cdev, (long) request);

		switch (rc) {
			case 0:
				request->status	= TAPE_REQUEST_DONE;
				return 0;
			case -EBUSY:
				request->status	= TAPE_REQUEST_CANCEL;
				schedule_delayed_work(&device->tape_dnr, 0);
				return 0;
			case -ENODEV:
				DBF_EXCEPTION(2, "device gone, retry\n");
				break;
			case -EIO:
				DBF_EXCEPTION(2, "I/O error, retry\n");
				break;
			default:
				BUG();
		}
	}

	return rc;
}

/*
 * Add device into the sorted list, giving it the first
 * available minor number.
 */
static int
tape_assign_minor(struct tape_device *device)
{
	struct tape_device *tmp;
	int minor;

	minor = 0;
	write_lock(&tape_device_lock);
	list_for_each_entry(tmp, &tape_device_list, node) {
		if (minor < tmp->first_minor)
			break;
		minor += TAPE_MINORS_PER_DEV;
	}
	if (minor >= 256) {
		write_unlock(&tape_device_lock);
		return -ENODEV;
	}
	device->first_minor = minor;
	list_add_tail(&device->node, &tmp->node);
	write_unlock(&tape_device_lock);
	return 0;
}

/* remove device from the list */
static void
tape_remove_minor(struct tape_device *device)
{
	write_lock(&tape_device_lock);
	list_del_init(&device->node);
	device->first_minor = -1;
	write_unlock(&tape_device_lock);
}

/*
 * Set a device online.
 *
 * This function is called by the common I/O layer to move a device from the
 * detected but offline into the online state.
 * If we return an error (RC < 0) the device remains in the offline state. This
 * can happen if the device is assigned somewhere else, for example.
 */
int
tape_generic_online(struct tape_device *device,
		   struct tape_discipline *discipline)
{
	int rc;

	DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);

	if (device->tape_state != TS_INIT) {
		DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
		return -EINVAL;
	}

	init_timer(&device->lb_timeout);
	device->lb_timeout.function = tape_long_busy_timeout;

	/* Let the discipline have a go at the device. */
	device->discipline = discipline;
	if (!try_module_get(discipline->owner)) {
		return -EINVAL;
	}

	rc = discipline->setup_device(device);
	if (rc)
		goto out;
	rc = tape_assign_minor(device);
	if (rc)
		goto out_discipline;

	rc = tapechar_setup_device(device);
	if (rc)
		goto out_minor;

	tape_state_set(device, TS_UNUSED);

	DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);

	return 0;

out_minor:
	tape_remove_minor(device);
out_discipline:
	device->discipline->cleanup_device(device);
	device->discipline = NULL;
out:
	module_put(discipline->owner);
	return rc;
}

static void
tape_cleanup_device(struct tape_device *device)
{
	tapechar_cleanup_device(device);
	device->discipline->cleanup_device(device);
	module_put(device->discipline->owner);
	tape_remove_minor(device);
	tape_med_state_set(device, MS_UNKNOWN);
}

/*
 * Suspend device.
 *
 * Called by the common I/O layer if the drive should be suspended on user
 * request. We refuse to suspend if the device is loaded or in use for the
 * following reason:
 * While the Linux guest is suspended, it might be logged off which causes
 * devices to be detached. Tape devices are automatically rewound and unloaded
 * during DETACH processing (unless the tape device was attached with the
 * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
 * resume the original state of the tape device, since we would need to
 * manually re-load the cartridge which was active at suspend time.
 */
int tape_generic_pm_suspend(struct ccw_device *cdev)
{
	struct tape_device *device;

	device = dev_get_drvdata(&cdev->dev);
	if (!device) {
		return -ENODEV;
	}

	DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
		device->cdev_id, device);

	if (device->medium_state != MS_UNLOADED) {
		pr_err("A cartridge is loaded in tape device %s, "
		       "refusing to suspend\n", dev_name(&cdev->dev));
		return -EBUSY;
	}

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	switch (device->tape_state) {
		case TS_INIT:
		case TS_NOT_OPER:
		case TS_UNUSED:
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			break;
		default:
			pr_err("Tape device %s is busy, refusing to "
			       "suspend\n", dev_name(&cdev->dev));
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			return -EBUSY;
	}

	DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
	return 0;
}

/*
 * Set device offline.
 *
 * Called by the common I/O layer if the drive should set offline on user
 * request. We may prevent this by returning an error.
 * Manual offline is only allowed while the drive is not in use.
 */
int
tape_generic_offline(struct ccw_device *cdev)
{
	struct tape_device *device;

	device = dev_get_drvdata(&cdev->dev);
	if (!device) {
		return -ENODEV;
	}

	DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
		device->cdev_id, device);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	switch (device->tape_state) {
		case TS_INIT:
		case TS_NOT_OPER:
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			break;
		case TS_UNUSED:
			tape_state_set(device, TS_INIT);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);
			break;
		default:
			DBF_EVENT(3, "(%08x): Set offline failed "
				"- drive in use.\n",
				device->cdev_id);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			return -EBUSY;
	}

	DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
	return 0;
}

/*
 * Allocate memory for a new device structure.
 */
static struct tape_device *
tape_alloc_device(void)
{
	struct tape_device *device;

	device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
	if (device == NULL) {
		DBF_EXCEPTION(2, "ti:no mem\n");
		return ERR_PTR(-ENOMEM);
	}
	device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
	if (device->modeset_byte == NULL) {
		DBF_EXCEPTION(2, "ti:no mem\n");
		kfree(device);
		return ERR_PTR(-ENOMEM);
	}
	mutex_init(&device->mutex);
	INIT_LIST_HEAD(&device->req_queue);
	INIT_LIST_HEAD(&device->node);
	init_waitqueue_head(&device->state_change_wq);
	init_waitqueue_head(&device->wait_queue);
	device->tape_state = TS_INIT;
	device->medium_state = MS_UNKNOWN;
	*device->modeset_byte = 0;
	device->first_minor = -1;
	atomic_set(&device->ref_count, 1);
	INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);

	return device;
}

/*
 * Get a reference to an existing device structure. This will automatically
 * increment the reference count.
 */
struct tape_device *
tape_get_device(struct tape_device *device)
{
	int count;

	count = atomic_inc_return(&device->ref_count);
	DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
	return device;
}

/*
 * Decrease the reference counter of a devices structure. If the
 * reference counter reaches zero free the device structure.
 * The function returns a NULL pointer to be used by the caller
 * for clearing reference pointers.
 */
void
tape_put_device(struct tape_device *device)
{
	int count;

	count = atomic_dec_return(&device->ref_count);
	DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
	BUG_ON(count < 0);
	if (count == 0) {
		kfree(device->modeset_byte);
		kfree(device);
	}
}

/*
 * Find tape device by a device index.
 */
struct tape_device *
tape_find_device(int devindex)
{
	struct tape_device *device, *tmp;

	device = ERR_PTR(-ENODEV);
	read_lock(&tape_device_lock);
	list_for_each_entry(tmp, &tape_device_list, node) {
		if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
			device = tape_get_device(tmp);
			break;
		}
	}
	read_unlock(&tape_device_lock);
	return device;
}

/*
 * Driverfs tape probe function.
 */
int
tape_generic_probe(struct ccw_device *cdev)
{
	struct tape_device *device;
	int ret;
	struct ccw_dev_id dev_id;

	device = tape_alloc_device();
	if (IS_ERR(device))
		return -ENODEV;
	ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
				     CCWDEV_DO_MULTIPATH);
	ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
	if (ret) {
		tape_put_device(device);
		return ret;
	}
	dev_set_drvdata(&cdev->dev, device);
	cdev->handler = __tape_do_irq;
	device->cdev = cdev;
	ccw_device_get_id(cdev, &dev_id);
	device->cdev_id = devid_to_int(&dev_id);
	return ret;
}

static void
__tape_discard_requests(struct tape_device *device)
{
	struct tape_request *	request;
	struct list_head *	l, *n;

	list_for_each_safe(l, n, &device->req_queue) {
		request = list_entry(l, struct tape_request, list);
		if (request->status == TAPE_REQUEST_IN_IO)
			request->status = TAPE_REQUEST_DONE;
		list_del(&request->list);

		/* Decrease ref_count for removed request. */
		request->device = NULL;
		tape_put_device(device);
		request->rc = -EIO;
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}
}

/*
 * Driverfs tape remove function.
 *
 * This function is called whenever the common I/O layer detects the device
 * gone. This can happen at any time and we cannot refuse.
 */
void
tape_generic_remove(struct ccw_device *cdev)
{
	struct tape_device *	device;

	device = dev_get_drvdata(&cdev->dev);
	if (!device) {
		return;
	}
	DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	switch (device->tape_state) {
		case TS_INIT:
			tape_state_set(device, TS_NOT_OPER);
		case TS_NOT_OPER:
			/*
			 * Nothing to do.
			 */
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			break;
		case TS_UNUSED:
			/*
			 * Need only to release the device.
			 */
			tape_state_set(device, TS_NOT_OPER);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);
			break;
		default:
			/*
			 * There may be requests on the queue. We will not get
			 * an interrupt for a request that was running. So we
			 * just post them all as I/O errors.
			 */
			DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
				device->cdev_id);
			pr_warning("%s: A tape unit was detached while in "
				   "use\n", dev_name(&device->cdev->dev));
			tape_state_set(device, TS_NOT_OPER);
			__tape_discard_requests(device);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);
	}

	device = dev_get_drvdata(&cdev->dev);
	if (device) {
		sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
		dev_set_drvdata(&cdev->dev, NULL);
		tape_put_device(device);
	}
}

/*
 * Allocate a new tape ccw request
 */
struct tape_request *
tape_alloc_request(int cplength, int datasize)
{
	struct tape_request *request;

	BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);

	DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);

	request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
	if (request == NULL) {
		DBF_EXCEPTION(1, "cqra nomem\n");
		return ERR_PTR(-ENOMEM);
	}
	/* allocate channel program */
	if (cplength > 0) {
		request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
					  GFP_ATOMIC | GFP_DMA);
		if (request->cpaddr == NULL) {
			DBF_EXCEPTION(1, "cqra nomem\n");
			kfree(request);
			return ERR_PTR(-ENOMEM);
		}
	}
	/* alloc small kernel buffer */
	if (datasize > 0) {
		request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
		if (request->cpdata == NULL) {
			DBF_EXCEPTION(1, "cqra nomem\n");
			kfree(request->cpaddr);
			kfree(request);
			return ERR_PTR(-ENOMEM);
		}
	}
	DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
		request->cpdata);

	return request;
}

/*
 * Free tape ccw request
 */
void
tape_free_request (struct tape_request * request)
{
	DBF_LH(6, "Free request %p\n", request);

	if (request->device)
		tape_put_device(request->device);
	kfree(request->cpdata);
	kfree(request->cpaddr);
	kfree(request);
}

static int
__tape_start_io(struct tape_device *device, struct tape_request *request)
{
	int rc;

	rc = ccw_device_start(
		device->cdev,
		request->cpaddr,
		(unsigned long) request,
		0x00,
		request->options
	);
	if (rc == 0) {
		request->status = TAPE_REQUEST_IN_IO;
	} else if (rc == -EBUSY) {
		/* The common I/O subsystem is currently busy. Retry later. */
		request->status = TAPE_REQUEST_QUEUED;
		schedule_delayed_work(&device->tape_dnr, 0);
		rc = 0;
	} else {
		/* Start failed. Remove request and indicate failure. */
		DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
	}
	return rc;
}

static void
__tape_start_next_request(struct tape_device *device)
{
	struct list_head *l, *n;
	struct tape_request *request;
	int rc;

	DBF_LH(6, "__tape_start_next_request(%p)\n", device);
	/*
	 * Try to start each request on request queue until one is
	 * started successful.
	 */
	list_for_each_safe(l, n, &device->req_queue) {
		request = list_entry(l, struct tape_request, list);

		/*
		 * Avoid race condition if bottom-half was triggered more than
		 * once.
		 */
		if (request->status == TAPE_REQUEST_IN_IO)
			return;
		/*
		 * Request has already been stopped. We have to wait until
		 * the request is removed from the queue in the interrupt
		 * handling.
		 */
		if (request->status == TAPE_REQUEST_DONE)
			return;

		/*
		 * We wanted to cancel the request but the common I/O layer
		 * was busy at that time. This can only happen if this
		 * function is called by delayed_next_request.
		 * Otherwise we start the next request on the queue.
		 */
		if (request->status == TAPE_REQUEST_CANCEL) {
			rc = __tape_cancel_io(device, request);
		} else {
			rc = __tape_start_io(device, request);
		}
		if (rc == 0)
			return;

		/* Set ending status. */
		request->rc = rc;
		request->status = TAPE_REQUEST_DONE;

		/* Remove from request queue. */
		list_del(&request->list);

		/* Do callback. */
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}
}

static void
tape_delayed_next_request(struct work_struct *work)
{
	struct tape_device *device =
		container_of(work, struct tape_device, tape_dnr.work);

	DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	__tape_start_next_request(device);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
}

static void tape_long_busy_timeout(unsigned long data)
{
	struct tape_request *request;
	struct tape_device *device;

	device = (struct tape_device *) data;
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	request = list_entry(device->req_queue.next, struct tape_request, list);
	BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
	DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
	__tape_start_next_request(device);
	device->lb_timeout.data = 0UL;
	tape_put_device(device);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
}

static void
__tape_end_request(
	struct tape_device *	device,
	struct tape_request *	request,
	int			rc)
{
	DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
	if (request) {
		request->rc = rc;
		request->status = TAPE_REQUEST_DONE;

		/* Remove from request queue. */
		list_del(&request->list);

		/* Do callback. */
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}

	/* Start next request. */
	if (!list_empty(&device->req_queue))
		__tape_start_next_request(device);
}

/*
 * Write sense data to dbf
 */
void
tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
		    struct irb *irb)
{
	unsigned int *sptr;
	const char* op;

	if (request != NULL)
		op = tape_op_verbose[request->op];
	else
		op = "---";
	DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
		  irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
	DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
	sptr = (unsigned int *) irb->ecw;
	DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
	DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
	DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
	DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
}

/*
 * I/O helper function. Adds the request to the request queue
 * and starts it if the tape is idle. Has to be called with
 * the device lock held.
 */
static int
__tape_start_request(struct tape_device *device, struct tape_request *request)
{
	int rc;

	switch (request->op) {
		case TO_MSEN:
		case TO_ASSIGN:
		case TO_UNASSIGN:
		case TO_READ_ATTMSG:
		case TO_RDC:
			if (device->tape_state == TS_INIT)
				break;
			if (device->tape_state == TS_UNUSED)
				break;
		default:
			if (device->tape_state == TS_BLKUSE)
				break;
			if (device->tape_state != TS_IN_USE)
				return -ENODEV;
	}

	/* Increase use count of device for the added request. */
	request->device = tape_get_device(device);

	if (list_empty(&device->req_queue)) {
		/* No other requests are on the queue. Start this one. */
		rc = __tape_start_io(device, request);
		if (rc)
			return rc;

		DBF_LH(5, "Request %p added for execution.\n", request);
		list_add(&request->list, &device->req_queue);
	} else {
		DBF_LH(5, "Request %p add to queue.\n", request);
		request->status = TAPE_REQUEST_QUEUED;
		list_add_tail(&request->list, &device->req_queue);
	}
	return 0;
}

/*
 * Add the request to the request queue, try to start it if the
 * tape is idle. Return without waiting for end of i/o.
 */
int
tape_do_io_async(struct tape_device *device, struct tape_request *request)
{
	int rc;

	DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Add request to request queue and try to start it. */
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	return rc;
}

/*
 * tape_do_io/__tape_wake_up
 * Add the request to the request queue, try to start it if the
 * tape is idle and wait uninterruptible for its completion.
 */
static void
__tape_wake_up(struct tape_request *request, void *data)
{
	request->callback = NULL;
	wake_up((wait_queue_head_t *) data);
}

int
tape_do_io(struct tape_device *device, struct tape_request *request)
{
	int rc;

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Setup callback */
	request->callback = __tape_wake_up;
	request->callback_data = &device->wait_queue;
	/* Add request to request queue and try to start it. */
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc)
		return rc;
	/* Request added to the queue. Wait for its completion. */
	wait_event(device->wait_queue, (request->callback == NULL));
	/* Get rc from request */
	return request->rc;
}

/*
 * tape_do_io_interruptible/__tape_wake_up_interruptible
 * Add the request to the request queue, try to start it if the
 * tape is idle and wait uninterruptible for its completion.
 */
static void
__tape_wake_up_interruptible(struct tape_request *request, void *data)
{
	request->callback = NULL;
	wake_up_interruptible((wait_queue_head_t *) data);
}

int
tape_do_io_interruptible(struct tape_device *device,
			 struct tape_request *request)
{
	int rc;

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	/* Setup callback */
	request->callback = __tape_wake_up_interruptible;
	request->callback_data = &device->wait_queue;
	rc = __tape_start_request(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc)
		return rc;
	/* Request added to the queue. Wait for its completion. */
	rc = wait_event_interruptible(device->wait_queue,
				      (request->callback == NULL));
	if (rc != -ERESTARTSYS)
		/* Request finished normally. */
		return request->rc;

	/* Interrupted by a signal. We have to stop the current request. */
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	rc = __tape_cancel_io(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	if (rc == 0) {
		/* Wait for the interrupt that acknowledges the halt. */
		do {
			rc = wait_event_interruptible(
				device->wait_queue,
				(request->callback == NULL)
			);
		} while (rc == -ERESTARTSYS);

		DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
		rc = -ERESTARTSYS;
	}
	return rc;
}

/*
 * Stop running ccw.
 */
int
tape_cancel_io(struct tape_device *device, struct tape_request *request)
{
	int rc;

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	rc = __tape_cancel_io(device, request);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	return rc;
}

/*
 * Tape interrupt routine, called from the ccw_device layer
 */
static void
__tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
{
	struct tape_device *device;
	struct tape_request *request;
	int rc;

	device = dev_get_drvdata(&cdev->dev);
	if (device == NULL) {
		return;
	}
	request = (struct tape_request *) intparm;

	DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);

	/* On special conditions irb is an error pointer */
	if (IS_ERR(irb)) {
		/* FIXME: What to do with the request? */
		switch (PTR_ERR(irb)) {
			case -ETIMEDOUT:
				DBF_LH(1, "(%08x): Request timed out\n",
				       device->cdev_id);
			case -EIO:
				__tape_end_request(device, request, -EIO);
				break;
			default:
				DBF_LH(1, "(%08x): Unexpected i/o error %li\n",
				       device->cdev_id,	PTR_ERR(irb));
		}
		return;
	}

	/*
	 * If the condition code is not zero and the start function bit is
	 * still set, this is an deferred error and the last start I/O did
	 * not succeed. At this point the condition that caused the deferred
	 * error might still apply. So we just schedule the request to be
	 * started later.
	 */
	if (irb->scsw.cmd.cc != 0 &&
	    (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
	    (request->status == TAPE_REQUEST_IN_IO)) {
		DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
			device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
		request->status = TAPE_REQUEST_QUEUED;
		schedule_delayed_work(&device->tape_dnr, HZ);
		return;
	}

	/* May be an unsolicited irq */
	if(request != NULL)
		request->rescnt = irb->scsw.cmd.count;
	else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
		 !list_empty(&device->req_queue)) {
		/* Not Ready to Ready after long busy ? */
		struct tape_request *req;
		req = list_entry(device->req_queue.next,
				 struct tape_request, list);
		if (req->status == TAPE_REQUEST_LONG_BUSY) {
			DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
			if (del_timer(&device->lb_timeout)) {
				device->lb_timeout.data = 0UL;
				tape_put_device(device);
				__tape_start_next_request(device);
			}
			return;
		}
	}
	if (irb->scsw.cmd.dstat != 0x0c) {
		/* Set the 'ONLINE' flag depending on sense byte 1 */
		if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
			device->tape_generic_status |= GMT_ONLINE(~0);
		else
			device->tape_generic_status &= ~GMT_ONLINE(~0);

		/*
		 * Any request that does not come back with channel end
		 * and device end is unusual. Log the sense data.
		 */
		DBF_EVENT(3,"-- Tape Interrupthandler --\n");
		tape_dump_sense_dbf(device, request, irb);
	} else {
		/* Upon normal completion the device _is_ online */
		device->tape_generic_status |= GMT_ONLINE(~0);
	}
	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(6, "tape:device is not operational\n");
		return;
	}

	/*
	 * Request that were canceled still come back with an interrupt.
	 * To detect these request the state will be set to TAPE_REQUEST_DONE.
	 */
	if(request != NULL && request->status == TAPE_REQUEST_DONE) {
		__tape_end_request(device, request, -EIO);
		return;
	}

	rc = device->discipline->irq(device, request, irb);
	/*
	 * rc < 0 : request finished unsuccessfully.
	 * rc == TAPE_IO_SUCCESS: request finished successfully.
	 * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
	 * rc == TAPE_IO_RETRY: request finished but needs another go.
	 * rc == TAPE_IO_STOP: request needs to get terminated.
	 */
	switch (rc) {
		case TAPE_IO_SUCCESS:
			/* Upon normal completion the device _is_ online */
			device->tape_generic_status |= GMT_ONLINE(~0);
			__tape_end_request(device, request, rc);
			break;
		case TAPE_IO_PENDING:
			break;
		case TAPE_IO_LONG_BUSY:
			device->lb_timeout.data =
				(unsigned long) tape_get_device(device);
			device->lb_timeout.expires = jiffies +
				LONG_BUSY_TIMEOUT * HZ;
			DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
			add_timer(&device->lb_timeout);
			request->status = TAPE_REQUEST_LONG_BUSY;
			break;
		case TAPE_IO_RETRY:
			rc = __tape_start_io(device, request);
			if (rc)
				__tape_end_request(device, request, rc);
			break;
		case TAPE_IO_STOP:
			rc = __tape_cancel_io(device, request);
			if (rc)
				__tape_end_request(device, request, rc);
			break;
		default:
			if (rc > 0) {
				DBF_EVENT(6, "xunknownrc\n");
				__tape_end_request(device, request, -EIO);
			} else {
				__tape_end_request(device, request, rc);
			}
			break;
	}
}

/*
 * Tape device open function used by tape_char frontend.
 */
int
tape_open(struct tape_device *device)
{
	int rc;

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	if (device->tape_state == TS_NOT_OPER) {
		DBF_EVENT(6, "TAPE:nodev\n");
		rc = -ENODEV;
	} else if (device->tape_state == TS_IN_USE) {
		DBF_EVENT(6, "TAPE:dbusy\n");
		rc = -EBUSY;
	} else if (device->tape_state == TS_BLKUSE) {
		DBF_EVENT(6, "TAPE:dbusy\n");
		rc = -EBUSY;
	} else if (device->discipline != NULL &&
		   !try_module_get(device->discipline->owner)) {
		DBF_EVENT(6, "TAPE:nodisc\n");
		rc = -ENODEV;
	} else {
		tape_state_set(device, TS_IN_USE);
		rc = 0;
	}
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	return rc;
}

/*
 * Tape device release function used by tape_char frontend.
 */
int
tape_release(struct tape_device *device)
{
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	if (device->tape_state == TS_IN_USE)
		tape_state_set(device, TS_UNUSED);
	module_put(device->discipline->owner);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
	return 0;
}

/*
 * Execute a magnetic tape command a number of times.
 */
int
tape_mtop(struct tape_device *device, int mt_op, int mt_count)
{
	tape_mtop_fn fn;
	int rc;

	DBF_EVENT(6, "TAPE:mtio\n");
	DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
	DBF_EVENT(6, "TAPE:arg:	 %x\n", mt_count);

	if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
		return -EINVAL;
	fn = device->discipline->mtop_array[mt_op];
	if (fn == NULL)
		return -EINVAL;

	/* We assume that the backends can handle count up to 500. */
	if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
	    mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
		rc = 0;
		for (; mt_count > 500; mt_count -= 500)
			if ((rc = fn(device, 500)) != 0)
				break;
		if (rc == 0)
			rc = fn(device, mt_count);
	} else
		rc = fn(device, mt_count);
	return rc;

}

/*
 * Tape init function.
 */
static int
tape_init (void)
{
	TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
	debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
#ifdef DBF_LIKE_HELL
	debug_set_level(TAPE_DBF_AREA, 6);
#endif
	DBF_EVENT(3, "tape init\n");
	tape_proc_init();
	tapechar_init ();
	return 0;
}

/*
 * Tape exit function.
 */
static void
tape_exit(void)
{
	DBF_EVENT(6, "tape exit\n");

	/* Get rid of the frontends */
	tapechar_exit();
	tape_proc_cleanup();
	debug_unregister (TAPE_DBF_AREA);
}

MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
	      "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
MODULE_LICENSE("GPL");

module_init(tape_init);
module_exit(tape_exit);

EXPORT_SYMBOL(tape_generic_remove);
EXPORT_SYMBOL(tape_generic_probe);
EXPORT_SYMBOL(tape_generic_online);
EXPORT_SYMBOL(tape_generic_offline);
EXPORT_SYMBOL(tape_generic_pm_suspend);
EXPORT_SYMBOL(tape_put_device);
EXPORT_SYMBOL(tape_get_device);
EXPORT_SYMBOL(tape_state_verbose);
EXPORT_SYMBOL(tape_op_verbose);
EXPORT_SYMBOL(tape_state_set);
EXPORT_SYMBOL(tape_med_state_set);
EXPORT_SYMBOL(tape_alloc_request);
EXPORT_SYMBOL(tape_free_request);
EXPORT_SYMBOL(tape_dump_sense_dbf);
EXPORT_SYMBOL(tape_do_io);
EXPORT_SYMBOL(tape_do_io_async);
EXPORT_SYMBOL(tape_do_io_interruptible);
EXPORT_SYMBOL(tape_cancel_io);
EXPORT_SYMBOL(tape_mtop);