drivers/s390/block/dasd_ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   4  *                  Horst Hummel <Horst.Hummel@de.ibm.com>
   5  *                  Carsten Otte <Cotte@de.ibm.com>
   6  *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
   7  * Bugreports.to..: <Linux390@de.ibm.com>
   8  * Copyright IBM Corp. 1999, 2001
   9  *
  10  * i/o controls for the dasd driver.
  11  */
  12
  13 #define KMSG_COMPONENT "dasd"
  14
  15 #include <linux/interrupt.h>
  16 #include <linux/compat.h>
  17 #include <linux/major.h>
  18 #include <linux/fs.h>
  19 #include <linux/blkpg.h>
  20 #include <linux/slab.h>
  21 #include <asm/ccwdev.h>
  22 #include <asm/schid.h>
  23 #include <asm/cmb.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/dasd_mod.h>
  26
  27 /* This is ugly... */
  28 #define PRINTK_HEADER "dasd_ioctl:"
  29
  30 #include "dasd_int.h"
  31
  32
  33 static int
  34 dasd_ioctl_api_version(void __user *argp)
  35 {
  36         int ver = DASD_API_VERSION;
  37         return put_user(ver, (int __user *)argp);
  38 }
  39
  40 /*
  41  * Enable device.
  42  * used by dasdfmt after BIODASDDISABLE to retrigger blocksize detection
  43  */
  44 static int
  45 dasd_ioctl_enable(struct block_device *bdev)
  46 {
  47         struct dasd_device *base;
  48
  49         if (!capable(CAP_SYS_ADMIN))
  50                 return -EACCES;
  51
  52         base = dasd_device_from_gendisk(bdev->bd_disk);
  53         if (!base)
  54                 return -ENODEV;
  55
  56         dasd_enable_device(base);
  57         /* Formatting the dasd device can change the capacity. */
  58         bd_set_nr_sectors(bdev, get_capacity(base->block->gdp));
  59         dasd_put_device(base);
  60         return 0;
  61 }
  62
  63 /*
  64  * Disable device.
  65  * Used by dasdfmt. Disable I/O operations but allow ioctls.
  66  */
  67 static int
  68 dasd_ioctl_disable(struct block_device *bdev)
  69 {
  70         struct dasd_device *base;
  71
  72         if (!capable(CAP_SYS_ADMIN))
  73                 return -EACCES;
  74
  75         base = dasd_device_from_gendisk(bdev->bd_disk);
  76         if (!base)
  77                 return -ENODEV;
  78         /*
  79          * Man this is sick. We don't do a real disable but only downgrade
  80          * the device to DASD_STATE_BASIC. The reason is that dasdfmt uses
  81          * BIODASDDISABLE to disable accesses to the device via the block
  82          * device layer but it still wants to do i/o on the device by
  83          * using the BIODASDFMT ioctl. Therefore the correct state for the
  84          * device is DASD_STATE_BASIC that allows to do basic i/o.
  85          */
  86         dasd_set_target_state(base, DASD_STATE_BASIC);
  87         /*
  88          * Set i_size to zero, since read, write, etc. check against this
  89          * value.
  90          */
  91         bd_set_nr_sectors(bdev, 0);
  92         dasd_put_device(base);
  93         return 0;
  94 }
  95
  96 /*
  97  * Quiesce device.
  98  */
  99 static int dasd_ioctl_quiesce(struct dasd_block *block)
 100 {
 101         unsigned long flags;
 102         struct dasd_device *base;
 103
 104         base = block->base;
 105         if (!capable (CAP_SYS_ADMIN))
 106                 return -EACCES;
 107
 108         pr_info("%s: The DASD has been put in the quiesce "
 109                 "state\n", dev_name(&base->cdev->dev));
 110         spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
 111         dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
 112         spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags);
 113         return 0;
 114 }
 115
 116
 117 /*
 118  * Resume device.
 119  */
 120 static int dasd_ioctl_resume(struct dasd_block *block)
 121 {
 122         unsigned long flags;
 123         struct dasd_device *base;
 124
 125         base = block->base;
 126         if (!capable (CAP_SYS_ADMIN))
 127                 return -EACCES;
 128
 129         pr_info("%s: I/O operations have been resumed "
 130                 "on the DASD\n", dev_name(&base->cdev->dev));
 131         spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
 132         dasd_device_remove_stop_bits(base, DASD_STOPPED_QUIESCE);
 133         spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags);
 134
 135         dasd_schedule_block_bh(block);
 136         return 0;
 137 }
 138
 139 /*
 140  * Abort all failfast I/O on a device.
 141  */
 142 static int dasd_ioctl_abortio(struct dasd_block *block)
 143 {
 144         unsigned long flags;
 145         struct dasd_device *base;
 146         struct dasd_ccw_req *cqr, *n;
 147
 148         base = block->base;
 149         if (!capable(CAP_SYS_ADMIN))
 150                 return -EACCES;
 151
 152         if (test_and_set_bit(DASD_FLAG_ABORTALL, &base->flags))
 153                 return 0;
 154         DBF_DEV_EVENT(DBF_NOTICE, base, "%s", "abortall flag set");
 155
 156         spin_lock_irqsave(&block->request_queue_lock, flags);
 157         spin_lock(&block->queue_lock);
 158         list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
 159                 if (test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
 160                     cqr->callback_data &&
 161                     cqr->callback_data != DASD_SLEEPON_START_TAG &&
 162                     cqr->callback_data != DASD_SLEEPON_END_TAG) {
 163                         spin_unlock(&block->queue_lock);
 164                         blk_abort_request(cqr->callback_data);
 165                         spin_lock(&block->queue_lock);
 166                 }
 167         }
 168         spin_unlock(&block->queue_lock);
 169         spin_unlock_irqrestore(&block->request_queue_lock, flags);
 170
 171         dasd_schedule_block_bh(block);
 172         return 0;
 173 }
 174
 175 /*
 176  * Allow I/O on a device
 177  */
 178 static int dasd_ioctl_allowio(struct dasd_block *block)
 179 {
 180         struct dasd_device *base;
 181
 182         base = block->base;
 183         if (!capable(CAP_SYS_ADMIN))
 184                 return -EACCES;
 185
 186         if (test_and_clear_bit(DASD_FLAG_ABORTALL, &base->flags))
 187                 DBF_DEV_EVENT(DBF_NOTICE, base, "%s", "abortall flag unset");
 188
 189         return 0;
 190 }
 191
 192 /*
 193  * performs formatting of _device_ according to _fdata_
 194  * Note: The discipline's format_function is assumed to deliver formatting
 195  * commands to format multiple units of the device. In terms of the ECKD
 196  * devices this means CCWs are generated to format multiple tracks.
 197  */
 198 static int
 199 dasd_format(struct dasd_block *block, struct format_data_t *fdata)
 200 {
 201         struct dasd_device *base;
 202         int rc;
 203
 204         base = block->base;
 205         if (base->discipline->format_device == NULL)
 206                 return -EPERM;
 207
 208         if (base->state != DASD_STATE_BASIC) {
 209                 pr_warn("%s: The DASD cannot be formatted while it is enabled\n",
 210                         dev_name(&base->cdev->dev));
 211                 return -EBUSY;
 212         }
 213
 214         DBF_DEV_EVENT(DBF_NOTICE, base,
 215                       "formatting units %u to %u (%u B blocks) flags %u",
 216                       fdata->start_unit,
 217                       fdata->stop_unit, fdata->blksize, fdata->intensity);
 218
 219         /* Since dasdfmt keeps the device open after it was disabled,
 220          * there still exists an inode for this device.
 221          * We must update i_blkbits, otherwise we might get errors when
 222          * enabling the device later.
 223          */
 224         if (fdata->start_unit == 0) {
 225                 struct block_device *bdev = bdget_disk(block->gdp, 0);
 226                 bdev->bd_inode->i_blkbits = blksize_bits(fdata->blksize);
 227                 bdput(bdev);
 228         }
 229
 230         rc = base->discipline->format_device(base, fdata, 1);
 231         if (rc == -EAGAIN)
 232                 rc = base->discipline->format_device(base, fdata, 0);
 233
 234         return rc;
 235 }
 236
 237 static int dasd_check_format(struct dasd_block *block,
 238                              struct format_check_t *cdata)
 239 {
 240         struct dasd_device *base;
 241         int rc;
 242
 243         base = block->base;
 244         if (!base->discipline->check_device_format)
 245                 return -ENOTTY;
 246
 247         rc = base->discipline->check_device_format(base, cdata, 1);
 248         if (rc == -EAGAIN)
 249                 rc = base->discipline->check_device_format(base, cdata, 0);
 250
 251         return rc;
 252 }
 253
 254 /*
 255  * Format device.
 256  */
 257 static int
 258 dasd_ioctl_format(struct block_device *bdev, void __user *argp)
 259 {
 260         struct dasd_device *base;
 261         struct format_data_t fdata;
 262         int rc;
 263
 264         if (!capable(CAP_SYS_ADMIN))
 265                 return -EACCES;
 266         if (!argp)
 267                 return -EINVAL;
 268         base = dasd_device_from_gendisk(bdev->bd_disk);
 269         if (!base)
 270                 return -ENODEV;
 271         if (base->features & DASD_FEATURE_READONLY ||
 272             test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
 273                 dasd_put_device(base);
 274                 return -EROFS;
 275         }
 276         if (copy_from_user(&fdata, argp, sizeof(struct format_data_t))) {
 277                 dasd_put_device(base);
 278                 return -EFAULT;
 279         }
 280         if (bdev_is_partition(bdev)) {
 281                 pr_warn("%s: The specified DASD is a partition and cannot be formatted\n",
 282                         dev_name(&base->cdev->dev));
 283                 dasd_put_device(base);
 284                 return -EINVAL;
 285         }
 286         rc = dasd_format(base->block, &fdata);
 287         dasd_put_device(base);
 288
 289         return rc;
 290 }
 291
 292 /*
 293  * Check device format
 294  */
 295 static int dasd_ioctl_check_format(struct block_device *bdev, void __user *argp)
 296 {
 297         struct format_check_t cdata;
 298         struct dasd_device *base;
 299         int rc = 0;
 300
 301         if (!argp)
 302                 return -EINVAL;
 303
 304         base = dasd_device_from_gendisk(bdev->bd_disk);
 305         if (!base)
 306                 return -ENODEV;
 307         if (bdev_is_partition(bdev)) {
 308                 pr_warn("%s: The specified DASD is a partition and cannot be checked\n",
 309                         dev_name(&base->cdev->dev));
 310                 rc = -EINVAL;
 311                 goto out_err;
 312         }
 313
 314         if (copy_from_user(&cdata, argp, sizeof(cdata))) {
 315                 rc = -EFAULT;
 316                 goto out_err;
 317         }
 318
 319         rc = dasd_check_format(base->block, &cdata);
 320         if (rc)
 321                 goto out_err;
 322
 323         if (copy_to_user(argp, &cdata, sizeof(cdata)))
 324                 rc = -EFAULT;
 325
 326 out_err:
 327         dasd_put_device(base);
 328
 329         return rc;
 330 }
 331
 332 static int dasd_release_space(struct dasd_device *device,
 333                               struct format_data_t *rdata)
 334 {
 335         if (!device->discipline->is_ese && !device->discipline->is_ese(device))
 336                 return -ENOTSUPP;
 337         if (!device->discipline->release_space)
 338                 return -ENOTSUPP;
 339
 340         return device->discipline->release_space(device, rdata);
 341 }
 342
 343 /*
 344  * Release allocated space
 345  */
 346 static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp)
 347 {
 348         struct format_data_t rdata;
 349         struct dasd_device *base;
 350         int rc = 0;
 351
 352         if (!capable(CAP_SYS_ADMIN))
 353                 return -EACCES;
 354         if (!argp)
 355                 return -EINVAL;
 356
 357         base = dasd_device_from_gendisk(bdev->bd_disk);
 358         if (!base)
 359                 return -ENODEV;
 360         if (base->features & DASD_FEATURE_READONLY ||
 361             test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
 362                 rc = -EROFS;
 363                 goto out_err;
 364         }
 365         if (bdev_is_partition(bdev)) {
 366                 pr_warn("%s: The specified DASD is a partition and tracks cannot be released\n",
 367                         dev_name(&base->cdev->dev));
 368                 rc = -EINVAL;
 369                 goto out_err;
 370         }
 371
 372         if (copy_from_user(&rdata, argp, sizeof(rdata))) {
 373                 rc = -EFAULT;
 374                 goto out_err;
 375         }
 376
 377         rc = dasd_release_space(base, &rdata);
 378
 379 out_err:
 380         dasd_put_device(base);
 381
 382         return rc;
 383 }
 384
 385 #ifdef CONFIG_DASD_PROFILE
 386 /*
 387  * Reset device profile information
 388  */
 389 static int dasd_ioctl_reset_profile(struct dasd_block *block)
 390 {
 391         dasd_profile_reset(&block->profile);
 392         return 0;
 393 }
 394
 395 /*
 396  * Return device profile information
 397  */
 398 static int dasd_ioctl_read_profile(struct dasd_block *block, void __user *argp)
 399 {
 400         struct dasd_profile_info_t *data;
 401         int rc = 0;
 402
 403         data = kmalloc(sizeof(*data), GFP_KERNEL);
 404         if (!data)
 405                 return -ENOMEM;
 406
 407         spin_lock_bh(&block->profile.lock);
 408         if (block->profile.data) {
 409                 data->dasd_io_reqs = block->profile.data->dasd_io_reqs;
 410                 data->dasd_io_sects = block->profile.data->dasd_io_sects;
 411                 memcpy(data->dasd_io_secs, block->profile.data->dasd_io_secs,
 412                        sizeof(data->dasd_io_secs));
 413                 memcpy(data->dasd_io_times, block->profile.data->dasd_io_times,
 414                        sizeof(data->dasd_io_times));
 415                 memcpy(data->dasd_io_timps, block->profile.data->dasd_io_timps,
 416                        sizeof(data->dasd_io_timps));
 417                 memcpy(data->dasd_io_time1, block->profile.data->dasd_io_time1,
 418                        sizeof(data->dasd_io_time1));
 419                 memcpy(data->dasd_io_time2, block->profile.data->dasd_io_time2,
 420                        sizeof(data->dasd_io_time2));
 421                 memcpy(data->dasd_io_time2ps,
 422                        block->profile.data->dasd_io_time2ps,
 423                        sizeof(data->dasd_io_time2ps));
 424                 memcpy(data->dasd_io_time3, block->profile.data->dasd_io_time3,
 425                        sizeof(data->dasd_io_time3));
 426                 memcpy(data->dasd_io_nr_req,
 427                        block->profile.data->dasd_io_nr_req,
 428                        sizeof(data->dasd_io_nr_req));
 429                 spin_unlock_bh(&block->profile.lock);
 430         } else {
 431                 spin_unlock_bh(&block->profile.lock);
 432                 rc = -EIO;
 433                 goto out;
 434         }
 435         if (copy_to_user(argp, data, sizeof(*data)))
 436                 rc = -EFAULT;
 437 out:
 438         kfree(data);
 439         return rc;
 440 }
 441 #else
 442 static int dasd_ioctl_reset_profile(struct dasd_block *block)
 443 {
 444         return -ENOTTY;
 445 }
 446
 447 static int dasd_ioctl_read_profile(struct dasd_block *block, void __user *argp)
 448 {
 449         return -ENOTTY;
 450 }
 451 #endif
 452
 453 /*
 454  * Return dasd information. Used for BIODASDINFO and BIODASDINFO2.
 455  */
 456 static int __dasd_ioctl_information(struct dasd_block *block,
 457                 struct dasd_information2_t *dasd_info)
 458 {
 459         struct subchannel_id sch_id;
 460         struct ccw_dev_id dev_id;
 461         struct dasd_device *base;
 462         struct ccw_device *cdev;
 463         struct list_head *l;
 464         unsigned long flags;
 465         int rc;
 466
 467         base = block->base;
 468         if (!base->discipline || !base->discipline->fill_info)
 469                 return -EINVAL;
 470
 471         rc = base->discipline->fill_info(base, dasd_info);
 472         if (rc)
 473                 return rc;
 474
 475         cdev = base->cdev;
 476         ccw_device_get_id(cdev, &dev_id);
 477         ccw_device_get_schid(cdev, &sch_id);
 478
 479         dasd_info->devno = dev_id.devno;
 480         dasd_info->schid = sch_id.sch_no;
 481         dasd_info->cu_type = cdev->id.cu_type;
 482         dasd_info->cu_model = cdev->id.cu_model;
 483         dasd_info->dev_type = cdev->id.dev_type;
 484         dasd_info->dev_model = cdev->id.dev_model;
 485         dasd_info->status = base->state;
 486         /*
 487          * The open_count is increased for every opener, that includes
 488          * the blkdev_get in dasd_scan_partitions.
 489          * This must be hidden from user-space.
 490          */
 491         dasd_info->open_count = atomic_read(&block->open_count);
 492         if (!block->bdev)
 493                 dasd_info->open_count++;
 494
 495         /*
 496          * check if device is really formatted
 497          * LDL / CDL was returned by 'fill_info'
 498          */
 499         if ((base->state < DASD_STATE_READY) ||
 500             (dasd_check_blocksize(block->bp_block)))
 501                 dasd_info->format = DASD_FORMAT_NONE;
 502
 503         dasd_info->features |=
 504                 ((base->features & DASD_FEATURE_READONLY) != 0);
 505
 506         memcpy(dasd_info->type, base->discipline->name, 4);
 507
 508         spin_lock_irqsave(&block->queue_lock, flags);
 509         list_for_each(l, &base->ccw_queue)
 510                 dasd_info->chanq_len++;
 511         spin_unlock_irqrestore(&block->queue_lock, flags);
 512         return 0;
 513 }
 514
 515 static int dasd_ioctl_information(struct dasd_block *block, void __user *argp,
 516                 size_t copy_size)
 517 {
 518         struct dasd_information2_t *dasd_info;
 519         int error;
 520
 521         dasd_info = kzalloc(sizeof(*dasd_info), GFP_KERNEL);
 522         if (!dasd_info)
 523                 return -ENOMEM;
 524
 525         error = __dasd_ioctl_information(block, dasd_info);
 526         if (!error && copy_to_user(argp, dasd_info, copy_size))
 527                 error = -EFAULT;
 528         kfree(dasd_info);
 529         return error;
 530 }
 531
 532 /*
 533  * Set read only
 534  */
 535 static int
 536 dasd_ioctl_set_ro(struct block_device *bdev, void __user *argp)
 537 {
 538         struct dasd_device *base;
 539         int intval, rc;
 540
 541         if (!capable(CAP_SYS_ADMIN))
 542                 return -EACCES;
 543         if (bdev_is_partition(bdev))
 544                 // ro setting is not allowed for partitions
 545                 return -EINVAL;
 546         if (get_user(intval, (int __user *)argp))
 547                 return -EFAULT;
 548         base = dasd_device_from_gendisk(bdev->bd_disk);
 549         if (!base)
 550                 return -ENODEV;
 551         if (!intval && test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
 552                 dasd_put_device(base);
 553                 return -EROFS;
 554         }
 555         set_disk_ro(bdev->bd_disk, intval);
 556         rc = dasd_set_feature(base->cdev, DASD_FEATURE_READONLY, intval);
 557         dasd_put_device(base);
 558         return rc;
 559 }
 560
 561 static int dasd_ioctl_readall_cmb(struct dasd_block *block, unsigned int cmd,
 562                                   struct cmbdata __user *argp)
 563 {
 564         size_t size = _IOC_SIZE(cmd);
 565         struct cmbdata data;
 566         int ret;
 567
 568         ret = cmf_readall(block->base->cdev, &data);
 569         if (!ret && copy_to_user(argp, &data, min(size, sizeof(*argp))))
 570                 return -EFAULT;
 571         return ret;
 572 }
 573
 574 int dasd_ioctl(struct block_device *bdev, fmode_t mode,
 575                unsigned int cmd, unsigned long arg)
 576 {
 577         struct dasd_block *block;
 578         struct dasd_device *base;
 579         void __user *argp;
 580         int rc;
 581
 582         if (is_compat_task())
 583                 argp = compat_ptr(arg);
 584         else
 585                 argp = (void __user *)arg;
 586
 587         if ((_IOC_DIR(cmd) != _IOC_NONE) && !arg) {
 588                 PRINT_DEBUG("empty data ptr");
 589                 return -EINVAL;
 590         }
 591
 592         base = dasd_device_from_gendisk(bdev->bd_disk);
 593         if (!base)
 594                 return -ENODEV;
 595         block = base->block;
 596         rc = 0;
 597         switch (cmd) {
 598         case BIODASDDISABLE:
 599                 rc = dasd_ioctl_disable(bdev);
 600                 break;
 601         case BIODASDENABLE:
 602                 rc = dasd_ioctl_enable(bdev);
 603                 break;
 604         case BIODASDQUIESCE:
 605                 rc = dasd_ioctl_quiesce(block);
 606                 break;
 607         case BIODASDRESUME:
 608                 rc = dasd_ioctl_resume(block);
 609                 break;
 610         case BIODASDABORTIO:
 611                 rc = dasd_ioctl_abortio(block);
 612                 break;
 613         case BIODASDALLOWIO:
 614                 rc = dasd_ioctl_allowio(block);
 615                 break;
 616         case BIODASDFMT:
 617                 rc = dasd_ioctl_format(bdev, argp);
 618                 break;
 619         case BIODASDCHECKFMT:
 620                 rc = dasd_ioctl_check_format(bdev, argp);
 621                 break;
 622         case BIODASDINFO:
 623                 rc = dasd_ioctl_information(block, argp,
 624                                 sizeof(struct dasd_information_t));
 625                 break;
 626         case BIODASDINFO2:
 627                 rc = dasd_ioctl_information(block, argp,
 628                                 sizeof(struct dasd_information2_t));
 629                 break;
 630         case BIODASDPRRD:
 631                 rc = dasd_ioctl_read_profile(block, argp);
 632                 break;
 633         case BIODASDPRRST:
 634                 rc = dasd_ioctl_reset_profile(block);
 635                 break;
 636         case BLKROSET:
 637                 rc = dasd_ioctl_set_ro(bdev, argp);
 638                 break;
 639         case DASDAPIVER:
 640                 rc = dasd_ioctl_api_version(argp);
 641                 break;
 642         case BIODASDCMFENABLE:
 643                 rc = enable_cmf(base->cdev);
 644                 break;
 645         case BIODASDCMFDISABLE:
 646                 rc = disable_cmf(base->cdev);
 647                 break;
 648         case BIODASDREADALLCMB:
 649                 rc = dasd_ioctl_readall_cmb(block, cmd, argp);
 650                 break;
 651         case BIODASDRAS:
 652                 rc = dasd_ioctl_release_space(bdev, argp);
 653                 break;
 654         default:
 655                 /* if the discipline has an ioctl method try it. */
 656                 rc = -ENOTTY;
 657                 if (base->discipline->ioctl)
 658                         rc = base->discipline->ioctl(block, cmd, argp);
 659         }
 660         dasd_put_device(base);
 661         return rc;
 662 }
 663
 664
 665 /**
 666  * dasd_biodasdinfo() - fill out the dasd information structure
 667  * @disk [in]: pointer to gendisk structure that references a DASD
 668  * @info [out]: pointer to the dasd_information2_t structure
 669  *
 670  * Provide access to DASD specific information.
 671  * The gendisk structure is checked if it belongs to the DASD driver by
 672  * comparing the gendisk->fops pointer.
 673  * If it does not belong to the DASD driver -EINVAL is returned.
 674  * Otherwise the provided dasd_information2_t structure is filled out.
 675  *
 676  * Returns:
 677  *   %0 on success and a negative error value on failure.
 678  */
 679 int dasd_biodasdinfo(struct gendisk *disk, struct dasd_information2_t *info)
 680 {
 681         struct dasd_device *base;
 682         int error;
 683
 684         if (disk->fops != &dasd_device_operations)
 685                 return -EINVAL;
 686
 687         base = dasd_device_from_gendisk(disk);
 688         if (!base)
 689                 return -ENODEV;
 690         error = __dasd_ioctl_information(base->block, info);
 691         dasd_put_device(base);
 692         return error;
 693 }
 694 /* export that symbol_get in partition detection is possible */
 695 EXPORT_SYMBOL_GPL(dasd_biodasdinfo);