summaryrefslogtreecommitdiff
path: root/drivers/s390/block/dasd_ioctl.c
blob: 61b9675e2a675e9dc1ec69101d8a4bc368d461c8 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * 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>
 * Copyright IBM Corp. 1999, 2001
 *
 * i/o controls for the dasd driver.
 */

#define KMSG_COMPONENT "dasd"

#include <linux/interrupt.h>
#include <linux/compat.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/blkpg.h>
#include <linux/slab.h>
#include <asm/ccwdev.h>
#include <asm/schid.h>
#include <asm/cmb.h>
#include <linux/uaccess.h>
#include <linux/dasd_mod.h>

/* This is ugly... */
#define PRINTK_HEADER "dasd_ioctl:"

#include "dasd_int.h"


static int
dasd_ioctl_api_version(void __user *argp)
{
	int ver = DASD_API_VERSION;
	return put_user(ver, (int __user *)argp);
}

/*
 * Enable device.
 * used by dasdfmt after BIODASDDISABLE to retrigger blocksize detection
 */
static int
dasd_ioctl_enable(struct block_device *bdev)
{
	struct dasd_device *base;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;

	dasd_enable_device(base);
	dasd_put_device(base);
	return 0;
}

/*
 * Disable device.
 * Used by dasdfmt. Disable I/O operations but allow ioctls.
 */
static int
dasd_ioctl_disable(struct block_device *bdev)
{
	struct dasd_device *base;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	/*
	 * Man this is sick. We don't do a real disable but only downgrade
	 * the device to DASD_STATE_BASIC. The reason is that dasdfmt uses
	 * BIODASDDISABLE to disable accesses to the device via the block
	 * device layer but it still wants to do i/o on the device by
	 * using the BIODASDFMT ioctl. Therefore the correct state for the
	 * device is DASD_STATE_BASIC that allows to do basic i/o.
	 */
	dasd_set_target_state(base, DASD_STATE_BASIC);
	/*
	 * Set i_size to zero, since read, write, etc. check against this
	 * value.
	 */
	set_capacity(bdev->bd_disk, 0);
	dasd_put_device(base);
	return 0;
}

/*
 * Quiesce device.
 */
static int dasd_ioctl_quiesce(struct dasd_block *block)
{
	unsigned long flags;
	struct dasd_device *base;

	base = block->base;
	if (!capable (CAP_SYS_ADMIN))
		return -EACCES;

	pr_info("%s: The DASD has been put in the quiesce "
		"state\n", dev_name(&base->cdev->dev));
	spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
	dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
	spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags);
	return 0;
}


/*
 * Resume device.
 */
static int dasd_ioctl_resume(struct dasd_block *block)
{
	unsigned long flags;
	struct dasd_device *base;

	base = block->base;
	if (!capable (CAP_SYS_ADMIN))
		return -EACCES;

	pr_info("%s: I/O operations have been resumed "
		"on the DASD\n", dev_name(&base->cdev->dev));
	spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
	dasd_device_remove_stop_bits(base, DASD_STOPPED_QUIESCE);
	spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags);

	dasd_schedule_block_bh(block);
	dasd_schedule_device_bh(base);
	return 0;
}

/*
 * Abort all failfast I/O on a device.
 */
static int dasd_ioctl_abortio(struct dasd_block *block)
{
	unsigned long flags;
	struct dasd_device *base;
	struct dasd_ccw_req *cqr, *n;

	base = block->base;
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (test_and_set_bit(DASD_FLAG_ABORTALL, &base->flags))
		return 0;
	DBF_DEV_EVENT(DBF_NOTICE, base, "%s", "abortall flag set");

	spin_lock_irqsave(&block->request_queue_lock, flags);
	spin_lock(&block->queue_lock);
	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
		if (test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
		    cqr->callback_data &&
		    cqr->callback_data != DASD_SLEEPON_START_TAG &&
		    cqr->callback_data != DASD_SLEEPON_END_TAG) {
			spin_unlock(&block->queue_lock);
			blk_abort_request(cqr->callback_data);
			spin_lock(&block->queue_lock);
		}
	}
	spin_unlock(&block->queue_lock);
	spin_unlock_irqrestore(&block->request_queue_lock, flags);

	dasd_schedule_block_bh(block);
	return 0;
}

/*
 * Allow I/O on a device
 */
static int dasd_ioctl_allowio(struct dasd_block *block)
{
	struct dasd_device *base;

	base = block->base;
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (test_and_clear_bit(DASD_FLAG_ABORTALL, &base->flags))
		DBF_DEV_EVENT(DBF_NOTICE, base, "%s", "abortall flag unset");

	return 0;
}

/*
 * performs formatting of _device_ according to _fdata_
 * Note: The discipline's format_function is assumed to deliver formatting
 * commands to format multiple units of the device. In terms of the ECKD
 * devices this means CCWs are generated to format multiple tracks.
 */
static int
dasd_format(struct dasd_block *block, struct format_data_t *fdata)
{
	struct dasd_device *base;
	int rc;

	base = block->base;
	if (base->discipline->format_device == NULL)
		return -EPERM;

	if (base->state != DASD_STATE_BASIC) {
		pr_warn("%s: The DASD cannot be formatted while it is enabled\n",
			dev_name(&base->cdev->dev));
		return -EBUSY;
	}

	DBF_DEV_EVENT(DBF_NOTICE, base,
		      "formatting units %u to %u (%u B blocks) flags %u",
		      fdata->start_unit,
		      fdata->stop_unit, fdata->blksize, fdata->intensity);

	/* Since dasdfmt keeps the device open after it was disabled,
	 * there still exists an inode for this device.
	 * We must update i_blkbits, otherwise we might get errors when
	 * enabling the device later.
	 */
	if (fdata->start_unit == 0) {
		block->gdp->part0->bd_inode->i_blkbits =
			blksize_bits(fdata->blksize);
	}

	rc = base->discipline->format_device(base, fdata, 1);
	if (rc == -EAGAIN)
		rc = base->discipline->format_device(base, fdata, 0);

	return rc;
}

static int dasd_check_format(struct dasd_block *block,
			     struct format_check_t *cdata)
{
	struct dasd_device *base;
	int rc;

	base = block->base;
	if (!base->discipline->check_device_format)
		return -ENOTTY;

	rc = base->discipline->check_device_format(base, cdata, 1);
	if (rc == -EAGAIN)
		rc = base->discipline->check_device_format(base, cdata, 0);

	return rc;
}

/*
 * Format device.
 */
static int
dasd_ioctl_format(struct block_device *bdev, void __user *argp)
{
	struct dasd_device *base;
	struct format_data_t fdata;
	int rc;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
	if (!argp)
		return -EINVAL;
	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	if (base->features & DASD_FEATURE_READONLY ||
	    test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
		dasd_put_device(base);
		return -EROFS;
	}
	if (copy_from_user(&fdata, argp, sizeof(struct format_data_t))) {
		dasd_put_device(base);
		return -EFAULT;
	}
	if (bdev_is_partition(bdev)) {
		pr_warn("%s: The specified DASD is a partition and cannot be formatted\n",
			dev_name(&base->cdev->dev));
		dasd_put_device(base);
		return -EINVAL;
	}
	rc = dasd_format(base->block, &fdata);
	dasd_put_device(base);

	return rc;
}

/*
 * Check device format
 */
static int dasd_ioctl_check_format(struct block_device *bdev, void __user *argp)
{
	struct format_check_t cdata;
	struct dasd_device *base;
	int rc = 0;

	if (!argp)
		return -EINVAL;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	if (bdev_is_partition(bdev)) {
		pr_warn("%s: The specified DASD is a partition and cannot be checked\n",
			dev_name(&base->cdev->dev));
		rc = -EINVAL;
		goto out_err;
	}

	if (copy_from_user(&cdata, argp, sizeof(cdata))) {
		rc = -EFAULT;
		goto out_err;
	}

	rc = dasd_check_format(base->block, &cdata);
	if (rc)
		goto out_err;

	if (copy_to_user(argp, &cdata, sizeof(cdata)))
		rc = -EFAULT;

out_err:
	dasd_put_device(base);

	return rc;
}

static int dasd_release_space(struct dasd_device *device,
			      struct format_data_t *rdata)
{
	if (!device->discipline->is_ese && !device->discipline->is_ese(device))
		return -ENOTSUPP;
	if (!device->discipline->release_space)
		return -ENOTSUPP;

	return device->discipline->release_space(device, rdata);
}

/*
 * Release allocated space
 */
static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp)
{
	struct format_data_t rdata;
	struct dasd_device *base;
	int rc = 0;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
	if (!argp)
		return -EINVAL;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	if (base->features & DASD_FEATURE_READONLY ||
	    test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
		rc = -EROFS;
		goto out_err;
	}
	if (bdev_is_partition(bdev)) {
		pr_warn("%s: The specified DASD is a partition and tracks cannot be released\n",
			dev_name(&base->cdev->dev));
		rc = -EINVAL;
		goto out_err;
	}

	if (copy_from_user(&rdata, argp, sizeof(rdata))) {
		rc = -EFAULT;
		goto out_err;
	}

	rc = dasd_release_space(base, &rdata);

out_err:
	dasd_put_device(base);

	return rc;
}

/*
 * Swap driver iternal copy relation.
 */
static int
dasd_ioctl_copy_pair_swap(struct block_device *bdev, void __user *argp)
{
	struct dasd_copypair_swap_data_t data;
	struct dasd_device *device;
	int rc;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	device = dasd_device_from_gendisk(bdev->bd_disk);
	if (!device)
		return -ENODEV;

	if (copy_from_user(&data, argp, sizeof(struct dasd_copypair_swap_data_t))) {
		dasd_put_device(device);
		return -EFAULT;
	}
	if (memchr_inv(data.reserved, 0, sizeof(data.reserved))) {
		pr_warn("%s: Invalid swap data specified\n",
			dev_name(&device->cdev->dev));
		dasd_put_device(device);
		return DASD_COPYPAIRSWAP_INVALID;
	}
	if (bdev_is_partition(bdev)) {
		pr_warn("%s: The specified DASD is a partition and cannot be swapped\n",
			dev_name(&device->cdev->dev));
		dasd_put_device(device);
		return DASD_COPYPAIRSWAP_INVALID;
	}
	if (!device->copy) {
		pr_warn("%s: The specified DASD has no copy pair set up\n",
			dev_name(&device->cdev->dev));
		dasd_put_device(device);
		return -ENODEV;
	}
	if (!device->discipline->copy_pair_swap) {
		dasd_put_device(device);
		return -EOPNOTSUPP;
	}
	rc = device->discipline->copy_pair_swap(device, data.primary,
						data.secondary);
	dasd_put_device(device);

	return rc;
}

#ifdef CONFIG_DASD_PROFILE
/*
 * Reset device profile information
 */
static int dasd_ioctl_reset_profile(struct dasd_block *block)
{
	dasd_profile_reset(&block->profile);
	return 0;
}

/*
 * Return device profile information
 */
static int dasd_ioctl_read_profile(struct dasd_block *block, void __user *argp)
{
	struct dasd_profile_info_t *data;
	int rc = 0;

	data = kmalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	spin_lock_bh(&block->profile.lock);
	if (block->profile.data) {
		data->dasd_io_reqs = block->profile.data->dasd_io_reqs;
		data->dasd_io_sects = block->profile.data->dasd_io_sects;
		memcpy(data->dasd_io_secs, block->profile.data->dasd_io_secs,
		       sizeof(data->dasd_io_secs));
		memcpy(data->dasd_io_times, block->profile.data->dasd_io_times,
		       sizeof(data->dasd_io_times));
		memcpy(data->dasd_io_timps, block->profile.data->dasd_io_timps,
		       sizeof(data->dasd_io_timps));
		memcpy(data->dasd_io_time1, block->profile.data->dasd_io_time1,
		       sizeof(data->dasd_io_time1));
		memcpy(data->dasd_io_time2, block->profile.data->dasd_io_time2,
		       sizeof(data->dasd_io_time2));
		memcpy(data->dasd_io_time2ps,
		       block->profile.data->dasd_io_time2ps,
		       sizeof(data->dasd_io_time2ps));
		memcpy(data->dasd_io_time3, block->profile.data->dasd_io_time3,
		       sizeof(data->dasd_io_time3));
		memcpy(data->dasd_io_nr_req,
		       block->profile.data->dasd_io_nr_req,
		       sizeof(data->dasd_io_nr_req));
		spin_unlock_bh(&block->profile.lock);
	} else {
		spin_unlock_bh(&block->profile.lock);
		rc = -EIO;
		goto out;
	}
	if (copy_to_user(argp, data, sizeof(*data)))
		rc = -EFAULT;
out:
	kfree(data);
	return rc;
}
#else
static int dasd_ioctl_reset_profile(struct dasd_block *block)
{
	return -ENOTTY;
}

static int dasd_ioctl_read_profile(struct dasd_block *block, void __user *argp)
{
	return -ENOTTY;
}
#endif

/*
 * Return dasd information. Used for BIODASDINFO and BIODASDINFO2.
 */
static int __dasd_ioctl_information(struct dasd_block *block,
		struct dasd_information2_t *dasd_info)
{
	struct subchannel_id sch_id;
	struct ccw_dev_id dev_id;
	struct dasd_device *base;
	struct ccw_device *cdev;
	struct list_head *l;
	unsigned long flags;
	int rc;

	base = block->base;
	if (!base->discipline || !base->discipline->fill_info)
		return -EINVAL;

	rc = base->discipline->fill_info(base, dasd_info);
	if (rc)
		return rc;

	cdev = base->cdev;
	ccw_device_get_id(cdev, &dev_id);
	ccw_device_get_schid(cdev, &sch_id);

	dasd_info->devno = dev_id.devno;
	dasd_info->schid = sch_id.sch_no;
	dasd_info->cu_type = cdev->id.cu_type;
	dasd_info->cu_model = cdev->id.cu_model;
	dasd_info->dev_type = cdev->id.dev_type;
	dasd_info->dev_model = cdev->id.dev_model;
	dasd_info->status = base->state;
	/*
	 * The open_count is increased for every opener, that includes
	 * the blkdev_get in dasd_scan_partitions.
	 * This must be hidden from user-space.
	 */
	dasd_info->open_count = atomic_read(&block->open_count);
	if (!block->bdev_handle)
		dasd_info->open_count++;

	/*
	 * check if device is really formatted
	 * LDL / CDL was returned by 'fill_info'
	 */
	if ((base->state < DASD_STATE_READY) ||
	    (dasd_check_blocksize(block->bp_block)))
		dasd_info->format = DASD_FORMAT_NONE;

	dasd_info->features |=
		((base->features & DASD_FEATURE_READONLY) != 0);

	memcpy(dasd_info->type, base->discipline->name, 4);

	spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
	list_for_each(l, &base->ccw_queue)
		dasd_info->chanq_len++;
	spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags);
	return 0;
}

static int dasd_ioctl_information(struct dasd_block *block, void __user *argp,
		size_t copy_size)
{
	struct dasd_information2_t *dasd_info;
	int error;

	dasd_info = kzalloc(sizeof(*dasd_info), GFP_KERNEL);
	if (!dasd_info)
		return -ENOMEM;

	error = __dasd_ioctl_information(block, dasd_info);
	if (!error && copy_to_user(argp, dasd_info, copy_size))
		error = -EFAULT;
	kfree(dasd_info);
	return error;
}

/*
 * Set read only
 */
int dasd_set_read_only(struct block_device *bdev, bool ro)
{
	struct dasd_device *base;
	int rc;

	/* do not manipulate hardware state for partitions */
	if (bdev_is_partition(bdev))
		return 0;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	if (!ro && test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
		rc = -EROFS;
	else
		rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, ro);
	dasd_put_device(base);
	return rc;
}

static int dasd_ioctl_readall_cmb(struct dasd_block *block, unsigned int cmd,
				  struct cmbdata __user *argp)
{
	size_t size = _IOC_SIZE(cmd);
	struct cmbdata data;
	int ret;

	ret = cmf_readall(block->base->cdev, &data);
	if (!ret && copy_to_user(argp, &data, min(size, sizeof(*argp))))
		return -EFAULT;
	return ret;
}

int dasd_ioctl(struct block_device *bdev, blk_mode_t mode,
	       unsigned int cmd, unsigned long arg)
{
	struct dasd_block *block;
	struct dasd_device *base;
	void __user *argp;
	int rc;

	if (is_compat_task())
		argp = compat_ptr(arg);
	else
		argp = (void __user *)arg;

	if ((_IOC_DIR(cmd) != _IOC_NONE) && !arg)
		return -EINVAL;

	base = dasd_device_from_gendisk(bdev->bd_disk);
	if (!base)
		return -ENODEV;
	block = base->block;
	rc = 0;
	switch (cmd) {
	case BIODASDDISABLE:
		rc = dasd_ioctl_disable(bdev);
		break;
	case BIODASDENABLE:
		rc = dasd_ioctl_enable(bdev);
		break;
	case BIODASDQUIESCE:
		rc = dasd_ioctl_quiesce(block);
		break;
	case BIODASDRESUME:
		rc = dasd_ioctl_resume(block);
		break;
	case BIODASDABORTIO:
		rc = dasd_ioctl_abortio(block);
		break;
	case BIODASDALLOWIO:
		rc = dasd_ioctl_allowio(block);
		break;
	case BIODASDFMT:
		rc = dasd_ioctl_format(bdev, argp);
		break;
	case BIODASDCHECKFMT:
		rc = dasd_ioctl_check_format(bdev, argp);
		break;
	case BIODASDINFO:
		rc = dasd_ioctl_information(block, argp,
				sizeof(struct dasd_information_t));
		break;
	case BIODASDINFO2:
		rc = dasd_ioctl_information(block, argp,
				sizeof(struct dasd_information2_t));
		break;
	case BIODASDPRRD:
		rc = dasd_ioctl_read_profile(block, argp);
		break;
	case BIODASDPRRST:
		rc = dasd_ioctl_reset_profile(block);
		break;
	case DASDAPIVER:
		rc = dasd_ioctl_api_version(argp);
		break;
	case BIODASDCMFENABLE:
		rc = enable_cmf(base->cdev);
		break;
	case BIODASDCMFDISABLE:
		rc = disable_cmf(base->cdev);
		break;
	case BIODASDREADALLCMB:
		rc = dasd_ioctl_readall_cmb(block, cmd, argp);
		break;
	case BIODASDRAS:
		rc = dasd_ioctl_release_space(bdev, argp);
		break;
	case BIODASDCOPYPAIRSWAP:
		rc = dasd_ioctl_copy_pair_swap(bdev, argp);
		break;
	default:
		/* if the discipline has an ioctl method try it. */
		rc = -ENOTTY;
		if (base->discipline->ioctl)
			rc = base->discipline->ioctl(block, cmd, argp);
	}
	dasd_put_device(base);
	return rc;
}


/**
 * dasd_biodasdinfo() - fill out the dasd information structure
 * @disk: [in] pointer to gendisk structure that references a DASD
 * @info: [out] pointer to the dasd_information2_t structure
 *
 * Provide access to DASD specific information.
 * The gendisk structure is checked if it belongs to the DASD driver by
 * comparing the gendisk->fops pointer.
 * If it does not belong to the DASD driver -EINVAL is returned.
 * Otherwise the provided dasd_information2_t structure is filled out.
 *
 * Returns:
 *   %0 on success and a negative error value on failure.
 */
int dasd_biodasdinfo(struct gendisk *disk, struct dasd_information2_t *info)
{
	struct dasd_device *base;
	int error;

	if (disk->fops != &dasd_device_operations)
		return -EINVAL;

	base = dasd_device_from_gendisk(disk);
	if (!base)
		return -ENODEV;
	error = __dasd_ioctl_information(base->block, info);
	dasd_put_device(base);
	return error;
}
/* export that symbol_get in partition detection is possible */
EXPORT_SYMBOL_GPL(dasd_biodasdinfo);