summaryrefslogtreecommitdiffstats
path: root/drivers/s390/block/dasd_devmap.c
blob: 8d41f3ed38d7bbce3d87994526d66daee844b246 (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
/*
 * File...........: linux/drivers/s390/block/dasd_devmap.c
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 *		    Horst Hummel <Horst.Hummel@de.ibm.com>
 *		    Carsten Otte <Cotte@de.ibm.com>
 *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
 *
 * Device mapping and dasd= parameter parsing functions. All devmap
 * functions may not be called from interrupt context. In particular
 * dasd_get_device is a no-no from interrupt context.
 *
 */

#define KMSG_COMPONENT "dasd"

#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <asm/debug.h>
#include <asm/uaccess.h>
#include <asm/ipl.h>

/* This is ugly... */
#define PRINTK_HEADER "dasd_devmap:"
#define DASD_BUS_ID_SIZE 20

#include "dasd_int.h"

struct kmem_cache *dasd_page_cache;
EXPORT_SYMBOL_GPL(dasd_page_cache);

/*
 * dasd_devmap_t is used to store the features and the relation
 * between device number and device index. To find a dasd_devmap_t
 * that corresponds to a device number of a device index each
 * dasd_devmap_t is added to two linked lists, one to search by
 * the device number and one to search by the device index. As
 * soon as big minor numbers are available the device index list
 * can be removed since the device number will then be identical
 * to the device index.
 */
struct dasd_devmap {
	struct list_head list;
	char bus_id[DASD_BUS_ID_SIZE];
        unsigned int devindex;
        unsigned short features;
	struct dasd_device *device;
};

/*
 * Parameter parsing functions for dasd= parameter. The syntax is:
 *   <devno>		: (0x)?[0-9a-fA-F]+
 *   <busid>		: [0-0a-f]\.[0-9a-f]\.(0x)?[0-9a-fA-F]+
 *   <feature>		: ro
 *   <feature_list>	: \(<feature>(:<feature>)*\)
 *   <devno-range>	: <devno>(-<devno>)?<feature_list>?
 *   <busid-range>	: <busid>(-<busid>)?<feature_list>?
 *   <devices>		: <devno-range>|<busid-range>
 *   <dasd_module>	: dasd_diag_mod|dasd_eckd_mod|dasd_fba_mod
 *
 *   <dasd>		: autodetect|probeonly|<devices>(,<devices>)*
 */

int dasd_probeonly =  0;	/* is true, when probeonly mode is active */
int dasd_autodetect = 0;	/* is true, when autodetection is active */
int dasd_nopav = 0;		/* is true, when PAV is disabled */
EXPORT_SYMBOL_GPL(dasd_nopav);
int dasd_nofcx;			/* disable High Performance Ficon */
EXPORT_SYMBOL_GPL(dasd_nofcx);

/*
 * char *dasd[] is intended to hold the ranges supplied by the dasd= statement
 * it is named 'dasd' to directly be filled by insmod with the comma separated
 * strings when running as a module.
 */
static char *dasd[256];
module_param_array(dasd, charp, NULL, 0);

/*
 * Single spinlock to protect devmap and servermap structures and lists.
 */
static DEFINE_SPINLOCK(dasd_devmap_lock);

/*
 * Hash lists for devmap structures.
 */
static struct list_head dasd_hashlists[256];
int dasd_max_devindex;

static struct dasd_devmap *dasd_add_busid(const char *, int);

static inline int
dasd_hash_busid(const char *bus_id)
{
	int hash, i;

	hash = 0;
	for (i = 0; (i < DASD_BUS_ID_SIZE) && *bus_id; i++, bus_id++)
		hash += *bus_id;
	return hash & 0xff;
}

#ifndef MODULE
/*
 * The parameter parsing functions for builtin-drivers are called
 * before kmalloc works. Store the pointers to the parameters strings
 * into dasd[] for later processing.
 */
static int __init
dasd_call_setup(char *str)
{
	static int count = 0;

	if (count < 256)
		dasd[count++] = str;
	return 1;
}

__setup ("dasd=", dasd_call_setup);
#endif	/* #ifndef MODULE */

#define	DASD_IPLDEV	"ipldev"

/*
 * Read a device busid/devno from a string.
 */
static int

dasd_busid(char **str, int *id0, int *id1, int *devno)
{
	int val, old_style;

	/* Interpret ipldev busid */
	if (strncmp(DASD_IPLDEV, *str, strlen(DASD_IPLDEV)) == 0) {
		if (ipl_info.type != IPL_TYPE_CCW) {
			pr_err("The IPL device is not a CCW device\n");
			return -EINVAL;
		}
		*id0 = 0;
		*id1 = ipl_info.data.ccw.dev_id.ssid;
		*devno = ipl_info.data.ccw.dev_id.devno;
		*str += strlen(DASD_IPLDEV);

		return 0;
	}
	/* check for leading '0x' */
	old_style = 0;
	if ((*str)[0] == '0' && (*str)[1] == 'x') {
		*str += 2;
		old_style = 1;
	}
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (old_style || (*str)[0] != '.') {
		*id0 = *id1 = 0;
		if (val < 0 || val > 0xffff)
			return -EINVAL;
		*devno = val;
		return 0;
	}
	/* New style x.y.z busid */
	if (val < 0 || val > 0xff)
		return -EINVAL;
	*id0 = val;
	(*str)++;
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (val < 0 || val > 0xff || (*str)++[0] != '.')
		return -EINVAL;
	*id1 = val;
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (val < 0 || val > 0xffff)
		return -EINVAL;
	*devno = val;
	return 0;
}

/*
 * Read colon separated list of dasd features. Currently there is
 * only one: "ro" for read-only devices. The default feature set
 * is empty (value 0).
 */
static int
dasd_feature_list(char *str, char **endp)
{
	int features, len, rc;

	rc = 0;
	if (*str != '(') {
		*endp = str;
		return DASD_FEATURE_DEFAULT;
	}
	str++;
	features = 0;

	while (1) {
		for (len = 0;
		     str[len] && str[len] != ':' && str[len] != ')'; len++);
		if (len == 2 && !strncmp(str, "ro", 2))
			features |= DASD_FEATURE_READONLY;
		else if (len == 4 && !strncmp(str, "diag", 4))
			features |= DASD_FEATURE_USEDIAG;
		else if (len == 6 && !strncmp(str, "erplog", 6))
			features |= DASD_FEATURE_ERPLOG;
		else if (len == 8 && !strncmp(str, "failfast", 8))
			features |= DASD_FEATURE_FAILFAST;
		else {
			pr_warning("%*s is not a supported device option\n",
				   len, str);
			rc = -EINVAL;
		}
		str += len;
		if (*str != ':')
			break;
		str++;
	}
	if (*str != ')') {
		pr_warning("A closing parenthesis ')' is missing in the "
			   "dasd= parameter\n");
		rc = -EINVAL;
	} else
		str++;
	*endp = str;
	if (rc != 0)
		return rc;
	return features;
}

/*
 * Try to match the first element on the comma separated parse string
 * with one of the known keywords. If a keyword is found, take the approprate
 * action and return a pointer to the residual string. If the first element
 * could not be matched to any keyword then return an error code.
 */
static char *
dasd_parse_keyword( char *parsestring ) {

	char *nextcomma, *residual_str;
	int length;

	nextcomma = strchr(parsestring,',');
	if (nextcomma) {
		length = nextcomma - parsestring;
		residual_str = nextcomma + 1;
	} else {
		length = strlen(parsestring);
		residual_str = parsestring + length;
        }
	if (strncmp("autodetect", parsestring, length) == 0) {
		dasd_autodetect = 1;
		pr_info("The autodetection mode has been activated\n");
                return residual_str;
        }
	if (strncmp("probeonly", parsestring, length) == 0) {
		dasd_probeonly = 1;
		pr_info("The probeonly mode has been activated\n");
                return residual_str;
        }
	if (strncmp("nopav", parsestring, length) == 0) {
		if (MACHINE_IS_VM)
			pr_info("'nopav' is not supported on z/VM\n");
		else {
			dasd_nopav = 1;
			pr_info("PAV support has be deactivated\n");
		}
		return residual_str;
	}
	if (strncmp("nofcx", parsestring, length) == 0) {
		dasd_nofcx = 1;
		pr_info("High Performance FICON support has been "
			"deactivated\n");
		return residual_str;
	}
	if (strncmp("fixedbuffers", parsestring, length) == 0) {
		if (dasd_page_cache)
			return residual_str;
		dasd_page_cache =
			kmem_cache_create("dasd_page_cache", PAGE_SIZE,
					  PAGE_SIZE, SLAB_CACHE_DMA,
					  NULL);
		if (!dasd_page_cache)
			DBF_EVENT(DBF_WARNING, "%s", "Failed to create slab, "
				"fixed buffer mode disabled.");
		else
			DBF_EVENT(DBF_INFO, "%s",
				 "turning on fixed buffer mode");
                return residual_str;
        }
	return ERR_PTR(-EINVAL);
}

/*
 * Try to interprete the first element on the comma separated parse string
 * as a device number or a range of devices. If the interpretation is
 * successfull, create the matching dasd_devmap entries and return a pointer
 * to the residual string.
 * If interpretation fails or in case of an error, return an error code.
 */
static char *
dasd_parse_range( char *parsestring ) {

	struct dasd_devmap *devmap;
	int from, from_id0, from_id1;
	int to, to_id0, to_id1;
	int features, rc;
	char bus_id[DASD_BUS_ID_SIZE+1], *str;

	str = parsestring;
	rc = dasd_busid(&str, &from_id0, &from_id1, &from);
	if (rc == 0) {
		to = from;
		to_id0 = from_id0;
		to_id1 = from_id1;
		if (*str == '-') {
			str++;
			rc = dasd_busid(&str, &to_id0, &to_id1, &to);
		}
	}
	if (rc == 0 &&
	    (from_id0 != to_id0 || from_id1 != to_id1 || from > to))
		rc = -EINVAL;
	if (rc) {
		pr_err("%s is not a valid device range\n", parsestring);
		return ERR_PTR(rc);
	}
	features = dasd_feature_list(str, &str);
	if (features < 0)
		return ERR_PTR(-EINVAL);
	/* each device in dasd= parameter should be set initially online */
	features |= DASD_FEATURE_INITIAL_ONLINE;
	while (from <= to) {
		sprintf(bus_id, "%01x.%01x.%04x",
			from_id0, from_id1, from++);
		devmap = dasd_add_busid(bus_id, features);
		if (IS_ERR(devmap))
			return (char *)devmap;
	}
	if (*str == ',')
		return str + 1;
	if (*str == '\0')
		return str;
	pr_warning("The dasd= parameter value %s has an invalid ending\n",
		   str);
	return ERR_PTR(-EINVAL);
}

static char *
dasd_parse_next_element( char *parsestring ) {
	char * residual_str;
	residual_str = dasd_parse_keyword(parsestring);
	if (!IS_ERR(residual_str))
		return residual_str;
	residual_str = dasd_parse_range(parsestring);
	return residual_str;
}

/*
 * Parse parameters stored in dasd[]
 * The 'dasd=...' parameter allows to specify a comma separated list of
 * keywords and device ranges. When the dasd driver is build into the kernel,
 * the complete list will be stored as one element of the dasd[] array.
 * When the dasd driver is build as a module, then the list is broken into
 * it's elements and each dasd[] entry contains one element.
 */
int
dasd_parse(void)
{
	int rc, i;
	char *parsestring;

	rc = 0;
	for (i = 0; i < 256; i++) {
		if (dasd[i] == NULL)
			break;
		parsestring = dasd[i];
		/* loop over the comma separated list in the parsestring */
		while (*parsestring) {
			parsestring = dasd_parse_next_element(parsestring);
			if(IS_ERR(parsestring)) {
				rc = PTR_ERR(parsestring);
				break;
			}
		}
		if (rc) {
			DBF_EVENT(DBF_ALERT, "%s", "invalid range found");
			break;
		}
	}
	return rc;
}

/*
 * Add a devmap for the device specified by busid. It is possible that
 * the devmap already exists (dasd= parameter). The order of the devices
 * added through this function will define the kdevs for the individual
 * devices.
 */
static struct dasd_devmap *
dasd_add_busid(const char *bus_id, int features)
{
	struct dasd_devmap *devmap, *new, *tmp;
	int hash;

	new = (struct dasd_devmap *)
		kzalloc(sizeof(struct dasd_devmap), GFP_KERNEL);
	if (!new)
		return ERR_PTR(-ENOMEM);
	spin_lock(&dasd_devmap_lock);
	devmap = NULL;
	hash = dasd_hash_busid(bus_id);
	list_for_each_entry(tmp, &dasd_hashlists[hash], list)
		if (strncmp(tmp->bus_id, bus_id, DASD_BUS_ID_SIZE) == 0) {
			devmap = tmp;
			break;
		}
	if (!devmap) {
		/* This bus_id is new. */
		new->devindex = dasd_max_devindex++;
		strncpy(new->bus_id, bus_id, DASD_BUS_ID_SIZE);
		new->features = features;
		new->device = NULL;
		list_add(&new->list, &dasd_hashlists[hash]);
		devmap = new;
		new = NULL;
	}
	spin_unlock(&dasd_devmap_lock);
	kfree(new);
	return devmap;
}

/*
 * Find devmap for device with given bus_id.
 */
static struct dasd_devmap *
dasd_find_busid(const char *bus_id)
{
	struct dasd_devmap *devmap, *tmp;
	int hash;

	spin_lock(&dasd_devmap_lock);
	devmap = ERR_PTR(-ENODEV);
	hash = dasd_hash_busid(bus_id);
	list_for_each_entry(tmp, &dasd_hashlists[hash], list) {
		if (strncmp(tmp->bus_id, bus_id, DASD_BUS_ID_SIZE) == 0) {
			devmap = tmp;
			break;
		}
	}
	spin_unlock(&dasd_devmap_lock);
	return devmap;
}

/*
 * Check if busid has been added to the list of dasd ranges.
 */
int
dasd_busid_known(const char *bus_id)
{
	return IS_ERR(dasd_find_busid(bus_id)) ? -ENOENT : 0;
}

/*
 * Forget all about the device numbers added so far.
 * This may only be called at module unload or system shutdown.
 */
static void
dasd_forget_ranges(void)
{
	struct dasd_devmap *devmap, *n;
	int i;

	spin_lock(&dasd_devmap_lock);
	for (i = 0; i < 256; i++) {
		list_for_each_entry_safe(devmap, n, &dasd_hashlists[i], list) {
			BUG_ON(devmap->device != NULL);
			list_del(&devmap->list);
			kfree(devmap);
		}
	}
	spin_unlock(&dasd_devmap_lock);
}

/*
 * Find the device struct by its device index.
 */
struct dasd_device *
dasd_device_from_devindex(int devindex)
{
	struct dasd_devmap *devmap, *tmp;
	struct dasd_device *device;
	int i;

	spin_lock(&dasd_devmap_lock);
	devmap = NULL;
	for (i = 0; (i < 256) && !devmap; i++)
		list_for_each_entry(tmp, &dasd_hashlists[i], list)
			if (tmp->devindex == devindex) {
				/* Found the devmap for the device. */
				devmap = tmp;
				break;
			}
	if (devmap && devmap->device) {
		device = devmap->device;
		dasd_get_device(device);
	} else
		device = ERR_PTR(-ENODEV);
	spin_unlock(&dasd_devmap_lock);
	return device;
}

/*
 * Return devmap for cdev. If no devmap exists yet, create one and
 * connect it to the cdev.
 */
static struct dasd_devmap *
dasd_devmap_from_cdev(struct ccw_device *cdev)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(dev_name(&cdev->dev));
	if (IS_ERR(devmap))
		devmap = dasd_add_busid(dev_name(&cdev->dev),
					DASD_FEATURE_DEFAULT);
	return devmap;
}

/*
 * Create a dasd device structure for cdev.
 */
struct dasd_device *
dasd_create_device(struct ccw_device *cdev)
{
	struct dasd_devmap *devmap;
	struct dasd_device *device;
	unsigned long flags;
	int rc;

	devmap = dasd_devmap_from_cdev(cdev);
	if (IS_ERR(devmap))
		return (void *) devmap;

	device = dasd_alloc_device();
	if (IS_ERR(device))
		return device;
	atomic_set(&device->ref_count, 3);

	spin_lock(&dasd_devmap_lock);
	if (!devmap->device) {
		devmap->device = device;
		device->devindex = devmap->devindex;
		device->features = devmap->features;
		get_device(&cdev->dev);
		device->cdev = cdev;
		rc = 0;
	} else
		/* Someone else was faster. */
		rc = -EBUSY;
	spin_unlock(&dasd_devmap_lock);

	if (rc) {
		dasd_free_device(device);
		return ERR_PTR(rc);
	}

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	dev_set_drvdata(&cdev->dev, device);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	return device;
}

/*
 * Wait queue for dasd_delete_device waits.
 */
static DECLARE_WAIT_QUEUE_HEAD(dasd_delete_wq);

/*
 * Remove a dasd device structure. The passed referenced
 * is destroyed.
 */
void
dasd_delete_device(struct dasd_device *device)
{
	struct ccw_device *cdev;
	struct dasd_devmap *devmap;
	unsigned long flags;

	/* First remove device pointer from devmap. */
	devmap = dasd_find_busid(dev_name(&device->cdev->dev));
	BUG_ON(IS_ERR(devmap));
	spin_lock(&dasd_devmap_lock);
	if (devmap->device != device) {
		spin_unlock(&dasd_devmap_lock);
		dasd_put_device(device);
		return;
	}
	devmap->device = NULL;
	spin_unlock(&dasd_devmap_lock);

	/* Disconnect dasd_device structure from ccw_device structure. */
	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
	dev_set_drvdata(&device->cdev->dev, NULL);
	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);

	/*
	 * Drop ref_count by 3, one for the devmap reference, one for
	 * the cdev reference and one for the passed reference.
	 */
	atomic_sub(3, &device->ref_count);

	/* Wait for reference counter to drop to zero. */
	wait_event(dasd_delete_wq, atomic_read(&device->ref_count) == 0);

	/* Disconnect dasd_device structure from ccw_device structure. */
	cdev = device->cdev;
	device->cdev = NULL;

	/* Put ccw_device structure. */
	put_device(&cdev->dev);

	/* Now the device structure can be freed. */
	dasd_free_device(device);
}

/*
 * Reference counter dropped to zero. Wake up waiter
 * in dasd_delete_device.
 */
void
dasd_put_device_wake(struct dasd_device *device)
{
	wake_up(&dasd_delete_wq);
}

/*
 * Return dasd_device structure associated with cdev.
 * This function needs to be called with the ccw device
 * lock held. It can be used from interrupt context.
 */
struct dasd_device *
dasd_device_from_cdev_locked(struct ccw_device *cdev)
{
	struct dasd_device *device = dev_get_drvdata(&cdev->dev);

	if (!device)
		return ERR_PTR(-ENODEV);
	dasd_get_device(device);
	return device;
}

/*
 * Return dasd_device structure associated with cdev.
 */
struct dasd_device *
dasd_device_from_cdev(struct ccw_device *cdev)
{
	struct dasd_device *device;
	unsigned long flags;

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	device = dasd_device_from_cdev_locked(cdev);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
	return device;
}

/*
 * SECTION: files in sysfs
 */

/*
 * failfast controls the behaviour, if no path is available
 */
static ssize_t dasd_ff_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct dasd_devmap *devmap;
	int ff_flag;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		ff_flag = (devmap->features & DASD_FEATURE_FAILFAST) != 0;
	else
		ff_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_FAILFAST) != 0;
	return snprintf(buf, PAGE_SIZE, ff_flag ? "1\n" : "0\n");
}

static ssize_t dasd_ff_store(struct device *dev, struct device_attribute *attr,
	      const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	int val;
	char *endp;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	val = simple_strtoul(buf, &endp, 0);
	if (((endp + 1) < (buf + count)) || (val > 1))
		return -EINVAL;

	spin_lock(&dasd_devmap_lock);
	if (val)
		devmap->features |= DASD_FEATURE_FAILFAST;
	else
		devmap->features &= ~DASD_FEATURE_FAILFAST;
	if (devmap->device)
		devmap->device->features = devmap->features;
	spin_unlock(&dasd_devmap_lock);
	return count;
}

static DEVICE_ATTR(failfast, 0644, dasd_ff_show, dasd_ff_store);

/*
 * readonly controls the readonly status of a dasd
 */
static ssize_t
dasd_ro_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int ro_flag;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		ro_flag = (devmap->features & DASD_FEATURE_READONLY) != 0;
	else
		ro_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_READONLY) != 0;
	return snprintf(buf, PAGE_SIZE, ro_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_ro_store(struct device *dev, struct device_attribute *attr,
	      const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	struct dasd_device *device;
	int val;
	char *endp;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	val = simple_strtoul(buf, &endp, 0);
	if (((endp + 1) < (buf + count)) || (val > 1))
		return -EINVAL;

	spin_lock(&dasd_devmap_lock);
	if (val)
		devmap->features |= DASD_FEATURE_READONLY;
	else
		devmap->features &= ~DASD_FEATURE_READONLY;
	device = devmap->device;
	if (device) {
		device->features = devmap->features;
		val = val || test_bit(DASD_FLAG_DEVICE_RO, &device->flags);
	}
	spin_unlock(&dasd_devmap_lock);
	if (device && device->block && device->block->gdp)
		set_disk_ro(device->block->gdp, val);
	return count;
}

static DEVICE_ATTR(readonly, 0644, dasd_ro_show, dasd_ro_store);
/*
 * erplog controls the logging of ERP related data
 * (e.g. failing channel programs).
 */
static ssize_t
dasd_erplog_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int erplog;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		erplog = (devmap->features & DASD_FEATURE_ERPLOG) != 0;
	else
		erplog = (DASD_FEATURE_DEFAULT & DASD_FEATURE_ERPLOG) != 0;
	return snprintf(buf, PAGE_SIZE, erplog ? "1\n" : "0\n");
}

static ssize_t
dasd_erplog_store(struct device *dev, struct device_attribute *attr,
	      const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	int val;
	char *endp;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	val = simple_strtoul(buf, &endp, 0);
	if (((endp + 1) < (buf + count)) || (val > 1))
		return -EINVAL;

	spin_lock(&dasd_devmap_lock);
	if (val)
		devmap->features |= DASD_FEATURE_ERPLOG;
	else
		devmap->features &= ~DASD_FEATURE_ERPLOG;
	if (devmap->device)
		devmap->device->features = devmap->features;
	spin_unlock(&dasd_devmap_lock);
	return count;
}

static DEVICE_ATTR(erplog, 0644, dasd_erplog_show, dasd_erplog_store);

/*
 * use_diag controls whether the driver should use diag rather than ssch
 * to talk to the device
 */
static ssize_t
dasd_use_diag_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int use_diag;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		use_diag = (devmap->features & DASD_FEATURE_USEDIAG) != 0;
	else
		use_diag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USEDIAG) != 0;
	return sprintf(buf, use_diag ? "1\n" : "0\n");
}

static ssize_t
dasd_use_diag_store(struct device *dev, struct device_attribute *attr,
		    const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	ssize_t rc;
	int val;
	char *endp;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	val = simple_strtoul(buf, &endp, 0);
	if (((endp + 1) < (buf + count)) || (val > 1))
		return -EINVAL;

	spin_lock(&dasd_devmap_lock);
	/* Changing diag discipline flag is only allowed in offline state. */
	rc = count;
	if (!devmap->device) {
		if (val)
			devmap->features |= DASD_FEATURE_USEDIAG;
		else
			devmap->features &= ~DASD_FEATURE_USEDIAG;
	} else
		rc = -EPERM;
	spin_unlock(&dasd_devmap_lock);
	return rc;
}

static DEVICE_ATTR(use_diag, 0644, dasd_use_diag_show, dasd_use_diag_store);

static ssize_t
dasd_discipline_show(struct device *dev, struct device_attribute *attr,
		     char *buf)
{
	struct dasd_device *device;
	ssize_t len;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		goto out;
	else if (!device->discipline) {
		dasd_put_device(device);
		goto out;
	} else {
		len = snprintf(buf, PAGE_SIZE, "%s\n",
			       device->discipline->name);
		dasd_put_device(device);
		return len;
	}
out:
	len = snprintf(buf, PAGE_SIZE, "none\n");
	return len;
}

static DEVICE_ATTR(discipline, 0444, dasd_discipline_show, NULL);

static ssize_t
dasd_device_status_show(struct device *dev, struct device_attribute *attr,
		     char *buf)
{
	struct dasd_device *device;
	ssize_t len;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (!IS_ERR(device)) {
		switch (device->state) {
		case DASD_STATE_NEW:
			len = snprintf(buf, PAGE_SIZE, "new\n");
			break;
		case DASD_STATE_KNOWN:
			len = snprintf(buf, PAGE_SIZE, "detected\n");
			break;
		case DASD_STATE_BASIC:
			len = snprintf(buf, PAGE_SIZE, "basic\n");
			break;
		case DASD_STATE_UNFMT:
			len = snprintf(buf, PAGE_SIZE, "unformatted\n");
			break;
		case DASD_STATE_READY:
			len = snprintf(buf, PAGE_SIZE, "ready\n");
			break;
		case DASD_STATE_ONLINE:
			len = snprintf(buf, PAGE_SIZE, "online\n");
			break;
		default:
			len = snprintf(buf, PAGE_SIZE, "no stat\n");
			break;
		}
		dasd_put_device(device);
	} else
		len = snprintf(buf, PAGE_SIZE, "unknown\n");
	return len;
}

static DEVICE_ATTR(status, 0444, dasd_device_status_show, NULL);

static ssize_t dasd_alias_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct dasd_device *device;
	struct dasd_uid uid;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return sprintf(buf, "0\n");

	if (device->discipline && device->discipline->get_uid &&
	    !device->discipline->get_uid(device, &uid)) {
		if (uid.type == UA_BASE_PAV_ALIAS ||
		    uid.type == UA_HYPER_PAV_ALIAS) {
			dasd_put_device(device);
			return sprintf(buf, "1\n");
		}
	}
	dasd_put_device(device);

	return sprintf(buf, "0\n");
}

static DEVICE_ATTR(alias, 0444, dasd_alias_show, NULL);

static ssize_t dasd_vendor_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct dasd_device *device;
	struct dasd_uid uid;
	char *vendor;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	vendor = "";
	if (IS_ERR(device))
		return snprintf(buf, PAGE_SIZE, "%s\n", vendor);

	if (device->discipline && device->discipline->get_uid &&
	    !device->discipline->get_uid(device, &uid))
			vendor = uid.vendor;

	dasd_put_device(device);

	return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
}

static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);

#define UID_STRLEN ( /* vendor */ 3 + 1 + /* serial    */ 14 + 1 +\
		     /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1 +\
		     /* vduit */ 32 + 1)

static ssize_t
dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_device *device;
	struct dasd_uid uid;
	char uid_string[UID_STRLEN];
	char ua_string[3];

	device = dasd_device_from_cdev(to_ccwdev(dev));
	uid_string[0] = 0;
	if (IS_ERR(device))
		return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);

	if (device->discipline && device->discipline->get_uid &&
	    !device->discipline->get_uid(device, &uid)) {
		switch (uid.type) {
		case UA_BASE_DEVICE:
			snprintf(ua_string, sizeof(ua_string), "%02x",
				 uid.real_unit_addr);
			break;
		case UA_BASE_PAV_ALIAS:
			snprintf(ua_string, sizeof(ua_string), "%02x",
				 uid.base_unit_addr);
			break;
		case UA_HYPER_PAV_ALIAS:
			snprintf(ua_string, sizeof(ua_string), "xx");
			break;
		default:
			/* should not happen, treat like base device */
			snprintf(ua_string, sizeof(ua_string), "%02x",
				 uid.real_unit_addr);
			break;
		}

		if (strlen(uid.vduit) > 0)
			snprintf(uid_string, sizeof(uid_string),
				 "%s.%s.%04x.%s.%s",
				 uid.vendor, uid.serial, uid.ssid, ua_string,
				 uid.vduit);
		else
			snprintf(uid_string, sizeof(uid_string),
				 "%s.%s.%04x.%s",
				 uid.vendor, uid.serial, uid.ssid, ua_string);
	}
	dasd_put_device(device);

	return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
}
static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);

/*
 * extended error-reporting
 */
static ssize_t
dasd_eer_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int eer_flag;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap) && devmap->device)
		eer_flag = dasd_eer_enabled(devmap->device);
	else
		eer_flag = 0;
	return snprintf(buf, PAGE_SIZE, eer_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_eer_store(struct device *dev, struct device_attribute *attr,
	       const char *buf, size_t count)
{
	struct dasd_devmap *devmap;
	int val, rc;
	char *endp;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);
	if (!devmap->device)
		return -ENODEV;

	val = simple_strtoul(buf, &endp, 0);
	if (((endp + 1) < (buf + count)) || (val > 1))
		return -EINVAL;

	if (val) {
		rc = dasd_eer_enable(devmap->device);
		if (rc)
			return rc;
	} else
		dasd_eer_disable(devmap->device);
	return count;
}

static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);

/*
 * expiration time for default requests
 */
static ssize_t
dasd_expires_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct dasd_device *device;
	int len;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return -ENODEV;
	len = snprintf(buf, PAGE_SIZE, "%lu\n", device->default_expires);
	dasd_put_device(device);
	return len;
}

static ssize_t
dasd_expires_store(struct device *dev, struct device_attribute *attr,
	       const char *buf, size_t count)
{
	struct dasd_device *device;
	unsigned long val;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return -ENODEV;

	if ((strict_strtoul(buf, 10, &val) != 0) ||
	    (val > DASD_EXPIRES_MAX) || val == 0) {
		dasd_put_device(device);
		return -EINVAL;
	}

	if (val)
		device->default_expires = val;

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(expires, 0644, dasd_expires_show, dasd_expires_store);

static struct attribute * dasd_attrs[] = {
	&dev_attr_readonly.attr,
	&dev_attr_discipline.attr,
	&dev_attr_status.attr,
	&dev_attr_alias.attr,
	&dev_attr_vendor.attr,
	&dev_attr_uid.attr,
	&dev_attr_use_diag.attr,
	&dev_attr_eer_enabled.attr,
	&dev_attr_erplog.attr,
	&dev_attr_failfast.attr,
	&dev_attr_expires.attr,
	NULL,
};

static struct attribute_group dasd_attr_group = {
	.attrs = dasd_attrs,
};

/*
 * Return value of the specified feature.
 */
int
dasd_get_feature(struct ccw_device *cdev, int feature)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(dev_name(&cdev->dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	return ((devmap->features & feature) != 0);
}

/*
 * Set / reset given feature.
 * Flag indicates wether to set (!=0) or the reset (=0) the feature.
 */
int
dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
{
	struct dasd_devmap *devmap;

	devmap = dasd_find_busid(dev_name(&cdev->dev));
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	spin_lock(&dasd_devmap_lock);
	if (flag)
		devmap->features |= feature;
	else
		devmap->features &= ~feature;
	if (devmap->device)
		devmap->device->features = devmap->features;
	spin_unlock(&dasd_devmap_lock);
	return 0;
}


int
dasd_add_sysfs_files(struct ccw_device *cdev)
{
	return sysfs_create_group(&cdev->dev.kobj, &dasd_attr_group);
}

void
dasd_remove_sysfs_files(struct ccw_device *cdev)
{
	sysfs_remove_group(&cdev->dev.kobj, &dasd_attr_group);
}


int
dasd_devmap_init(void)
{
	int i;

	/* Initialize devmap structures. */
	dasd_max_devindex = 0;
	for (i = 0; i < 256; i++)
		INIT_LIST_HEAD(&dasd_hashlists[i]);
	return 0;
}

void
dasd_devmap_exit(void)
{
	dasd_forget_ranges();
}