git.oblomov.eu Git - linux-2.6/blob - drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  bus driver for ccwgroup
   3  *
   4  *  Copyright IBM Corp. 2002, 2009
   5  *
   6  *  Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *             Cornelia Huck (cornelia.huck@de.ibm.com)
   8  */
   9 #include <linux/module.h>
  10 #include <linux/errno.h>
  11 #include <linux/slab.h>
  12 #include <linux/list.h>
  13 #include <linux/device.h>
  14 #include <linux/init.h>
  15 #include <linux/ctype.h>
  16 #include <linux/dcache.h>
  17
  18 #include <asm/ccwdev.h>
  19 #include <asm/ccwgroup.h>
  20
  21 #define CCW_BUS_ID_SIZE         20
  22
  23 /* In Linux 2.4, we had a channel device layer called "chandev"
  24  * that did all sorts of obscure stuff for networking devices.
  25  * This is another driver that serves as a replacement for just
  26  * one of its functions, namely the translation of single subchannels
  27  * to devices that use multiple subchannels.
  28  */
  29
  30 /* a device matches a driver if all its slave devices match the same
  31  * entry of the driver */
  32 static int
  33 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
  34 {
  35         struct ccwgroup_device *gdev;
  36         struct ccwgroup_driver *gdrv;
  37
  38         gdev = to_ccwgroupdev(dev);
  39         gdrv = to_ccwgroupdrv(drv);
  40
  41         if (gdev->creator_id == gdrv->driver_id)
  42                 return 1;
  43
  44         return 0;
  45 }
  46 static int
  47 ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
  48 {
  49         /* TODO */
  50         return 0;
  51 }
  52
  53 static struct bus_type ccwgroup_bus_type;
  54
  55 static void
  56 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  57 {
  58         int i;
  59         char str[8];
  60
  61         for (i = 0; i < gdev->count; i++) {
  62                 sprintf(str, "cdev%d", i);
  63                 sysfs_remove_link(&gdev->dev.kobj, str);
  64                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  65         }
  66
  67 }
  68
  69 /*
  70  * Provide an 'ungroup' attribute so the user can remove group devices no
  71  * longer needed or accidentially created. Saves memory :)
  72  */
  73 static void ccwgroup_ungroup_callback(struct device *dev)
  74 {
  75         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
  76
  77         mutex_lock(&gdev->reg_mutex);
  78         if (device_is_registered(&gdev->dev)) {
  79                 __ccwgroup_remove_symlinks(gdev);
  80                 device_unregister(dev);
  81         }
  82         mutex_unlock(&gdev->reg_mutex);
  83 }
  84
  85 static ssize_t
  86 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  87 {
  88         struct ccwgroup_device *gdev;
  89         int rc;
  90
  91         gdev = to_ccwgroupdev(dev);
  92
  93         /* Prevent concurrent online/offline processing and ungrouping. */
  94         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  95                 return -EAGAIN;
  96         if (gdev->state != CCWGROUP_OFFLINE) {
  97                 rc = -EINVAL;
  98                 goto out;
  99         }
 100         /* Note that we cannot unregister the device from one of its
 101          * attribute methods, so we have to use this roundabout approach.
 102          */
 103         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
 104 out:
 105         if (rc) {
 106                 if (rc != -EAGAIN)
 107                         /* Release onoff "lock" when ungrouping failed. */
 108                         atomic_set(&gdev->onoff, 0);
 109                 return rc;
 110         }
 111         return count;
 112 }
 113
 114 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 115
 116 static void
 117 ccwgroup_release (struct device *dev)
 118 {
 119         struct ccwgroup_device *gdev;
 120         int i;
 121
 122         gdev = to_ccwgroupdev(dev);
 123
 124         for (i = 0; i < gdev->count; i++) {
 125                 if (gdev->cdev[i]) {
 126                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 127                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 128                         put_device(&gdev->cdev[i]->dev);
 129                 }
 130         }
 131         kfree(gdev);
 132 }
 133
 134 static int
 135 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 136 {
 137         char str[8];
 138         int i, rc;
 139
 140         for (i = 0; i < gdev->count; i++) {
 141                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 142                                        "group_device");
 143                 if (rc) {
 144                         for (--i; i >= 0; i--)
 145                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 146                                                   "group_device");
 147                         return rc;
 148                 }
 149         }
 150         for (i = 0; i < gdev->count; i++) {
 151                 sprintf(str, "cdev%d", i);
 152                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 153                                        str);
 154                 if (rc) {
 155                         for (--i; i >= 0; i--) {
 156                                 sprintf(str, "cdev%d", i);
 157                                 sysfs_remove_link(&gdev->dev.kobj, str);
 158                         }
 159                         for (i = 0; i < gdev->count; i++)
 160                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 161                                                   "group_device");
 162                         return rc;
 163                 }
 164         }
 165         return 0;
 166 }
 167
 168 static int __get_next_bus_id(const char **buf, char *bus_id)
 169 {
 170         int rc, len;
 171         char *start, *end;
 172
 173         start = (char *)*buf;
 174         end = strchr(start, ',');
 175         if (!end) {
 176                 /* Last entry. Strip trailing newline, if applicable. */
 177                 end = strchr(start, '\n');
 178                 if (end)
 179                         *end = '\0';
 180                 len = strlen(start) + 1;
 181         } else {
 182                 len = end - start + 1;
 183                 end++;
 184         }
 185         if (len < CCW_BUS_ID_SIZE) {
 186                 strlcpy(bus_id, start, len);
 187                 rc = 0;
 188         } else
 189                 rc = -EINVAL;
 190         *buf = end;
 191         return rc;
 192 }
 193
 194 static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
 195 {
 196         int cssid, ssid, devno;
 197
 198         /* Must be of form %x.%x.%04x */
 199         if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 200                 return 0;
 201         return 1;
 202 }
 203
 204 /**
 205  * ccwgroup_create_from_string() - create and register a ccw group device
 206  * @root: parent device for the new device
 207  * @creator_id: identifier of creating driver
 208  * @cdrv: ccw driver of slave devices
 209  * @num_devices: number of slave devices
 210  * @buf: buffer containing comma separated bus ids of slave devices
 211  *
 212  * Create and register a new ccw group device as a child of @root. Slave
 213  * devices are obtained from the list of bus ids given in @buf and must all
 214  * belong to @cdrv.
 215  * Returns:
 216  *  %0 on success and an error code on failure.
 217  * Context:
 218  *  non-atomic
 219  */
 220 int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
 221                                 struct ccw_driver *cdrv, int num_devices,
 222                                 const char *buf)
 223 {
 224         struct ccwgroup_device *gdev;
 225         int rc, i;
 226         char tmp_bus_id[CCW_BUS_ID_SIZE];
 227         const char *curr_buf;
 228
 229         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 230                        GFP_KERNEL);
 231         if (!gdev)
 232                 return -ENOMEM;
 233
 234         atomic_set(&gdev->onoff, 0);
 235         mutex_init(&gdev->reg_mutex);
 236         mutex_lock(&gdev->reg_mutex);
 237         gdev->creator_id = creator_id;
 238         gdev->count = num_devices;
 239         gdev->dev.bus = &ccwgroup_bus_type;
 240         gdev->dev.parent = root;
 241         gdev->dev.release = ccwgroup_release;
 242         device_initialize(&gdev->dev);
 243
 244         curr_buf = buf;
 245         for (i = 0; i < num_devices && curr_buf; i++) {
 246                 rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
 247                 if (rc != 0)
 248                         goto error;
 249                 if (!__is_valid_bus_id(tmp_bus_id)) {
 250                         rc = -EINVAL;
 251                         goto error;
 252                 }
 253                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
 254                 /*
 255                  * All devices have to be of the same type in
 256                  * order to be grouped.
 257                  */
 258                 if (!gdev->cdev[i]
 259                     || gdev->cdev[i]->id.driver_info !=
 260                     gdev->cdev[0]->id.driver_info) {
 261                         rc = -EINVAL;
 262                         goto error;
 263                 }
 264                 /* Don't allow a device to belong to more than one group. */
 265                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 266                         rc = -EINVAL;
 267                         goto error;
 268                 }
 269                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 270         }
 271         /* Check for sufficient number of bus ids. */
 272         if (i < num_devices && !curr_buf) {
 273                 rc = -EINVAL;
 274                 goto error;
 275         }
 276         /* Check for trailing stuff. */
 277         if (i == num_devices && strlen(curr_buf) > 0) {
 278                 rc = -EINVAL;
 279                 goto error;
 280         }
 281
 282         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 283
 284         rc = device_add(&gdev->dev);
 285         if (rc)
 286                 goto error;
 287         get_device(&gdev->dev);
 288         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 289
 290         if (rc) {
 291                 device_unregister(&gdev->dev);
 292                 goto error;
 293         }
 294
 295         rc = __ccwgroup_create_symlinks(gdev);
 296         if (!rc) {
 297                 mutex_unlock(&gdev->reg_mutex);
 298                 put_device(&gdev->dev);
 299                 return 0;
 300         }
 301         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 302         device_unregister(&gdev->dev);
 303 error:
 304         for (i = 0; i < num_devices; i++)
 305                 if (gdev->cdev[i]) {
 306                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 307                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 308                         put_device(&gdev->cdev[i]->dev);
 309                         gdev->cdev[i] = NULL;
 310                 }
 311         mutex_unlock(&gdev->reg_mutex);
 312         put_device(&gdev->dev);
 313         return rc;
 314 }
 315 EXPORT_SYMBOL(ccwgroup_create_from_string);
 316
 317 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 318                              void *data);
 319
 320 static struct notifier_block ccwgroup_nb = {
 321         .notifier_call = ccwgroup_notifier
 322 };
 323
 324 static int __init init_ccwgroup(void)
 325 {
 326         int ret;
 327
 328         ret = bus_register(&ccwgroup_bus_type);
 329         if (ret)
 330                 return ret;
 331
 332         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 333         if (ret)
 334                 bus_unregister(&ccwgroup_bus_type);
 335
 336         return ret;
 337 }
 338
 339 static void __exit cleanup_ccwgroup(void)
 340 {
 341         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 342         bus_unregister(&ccwgroup_bus_type);
 343 }
 344
 345 module_init(init_ccwgroup);
 346 module_exit(cleanup_ccwgroup);
 347
 348 /************************** driver stuff ******************************/
 349
 350 static int
 351 ccwgroup_set_online(struct ccwgroup_device *gdev)
 352 {
 353         struct ccwgroup_driver *gdrv;
 354         int ret;
 355
 356         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 357                 return -EAGAIN;
 358         if (gdev->state == CCWGROUP_ONLINE) {
 359                 ret = 0;
 360                 goto out;
 361         }
 362         if (!gdev->dev.driver) {
 363                 ret = -EINVAL;
 364                 goto out;
 365         }
 366         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 367         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 368                 goto out;
 369
 370         gdev->state = CCWGROUP_ONLINE;
 371  out:
 372         atomic_set(&gdev->onoff, 0);
 373         return ret;
 374 }
 375
 376 static int
 377 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 378 {
 379         struct ccwgroup_driver *gdrv;
 380         int ret;
 381
 382         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 383                 return -EAGAIN;
 384         if (gdev->state == CCWGROUP_OFFLINE) {
 385                 ret = 0;
 386                 goto out;
 387         }
 388         if (!gdev->dev.driver) {
 389                 ret = -EINVAL;
 390                 goto out;
 391         }
 392         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 393         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 394                 goto out;
 395
 396         gdev->state = CCWGROUP_OFFLINE;
 397  out:
 398         atomic_set(&gdev->onoff, 0);
 399         return ret;
 400 }
 401
 402 static ssize_t
 403 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 404 {
 405         struct ccwgroup_device *gdev;
 406         struct ccwgroup_driver *gdrv;
 407         unsigned long value;
 408         int ret;
 409
 410         if (!dev->driver)
 411                 return -ENODEV;
 412
 413         gdev = to_ccwgroupdev(dev);
 414         gdrv = to_ccwgroupdrv(dev->driver);
 415
 416         if (!try_module_get(gdrv->owner))
 417                 return -EINVAL;
 418
 419         ret = strict_strtoul(buf, 0, &value);
 420         if (ret)
 421                 goto out;
 422
 423         if (value == 1)
 424                 ret = ccwgroup_set_online(gdev);
 425         else if (value == 0)
 426                 ret = ccwgroup_set_offline(gdev);
 427         else
 428                 ret = -EINVAL;
 429 out:
 430         module_put(gdrv->owner);
 431         return (ret == 0) ? count : ret;
 432 }
 433
 434 static ssize_t
 435 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 436 {
 437         int online;
 438
 439         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 440
 441         return sprintf(buf, online ? "1\n" : "0\n");
 442 }
 443
 444 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 445
 446 static int
 447 ccwgroup_probe (struct device *dev)
 448 {
 449         struct ccwgroup_device *gdev;
 450         struct ccwgroup_driver *gdrv;
 451
 452         int ret;
 453
 454         gdev = to_ccwgroupdev(dev);
 455         gdrv = to_ccwgroupdrv(dev->driver);
 456
 457         if ((ret = device_create_file(dev, &dev_attr_online)))
 458                 return ret;
 459
 460         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 461         if (ret)
 462                 device_remove_file(dev, &dev_attr_online);
 463
 464         return ret;
 465 }
 466
 467 static int
 468 ccwgroup_remove (struct device *dev)
 469 {
 470         struct ccwgroup_device *gdev;
 471         struct ccwgroup_driver *gdrv;
 472
 473         device_remove_file(dev, &dev_attr_online);
 474         device_remove_file(dev, &dev_attr_ungroup);
 475
 476         if (!dev->driver)
 477                 return 0;
 478
 479         gdev = to_ccwgroupdev(dev);
 480         gdrv = to_ccwgroupdrv(dev->driver);
 481
 482         if (gdrv->remove)
 483                 gdrv->remove(gdev);
 484
 485         return 0;
 486 }
 487
 488 static void ccwgroup_shutdown(struct device *dev)
 489 {
 490         struct ccwgroup_device *gdev;
 491         struct ccwgroup_driver *gdrv;
 492
 493         if (!dev->driver)
 494                 return;
 495
 496         gdev = to_ccwgroupdev(dev);
 497         gdrv = to_ccwgroupdrv(dev->driver);
 498
 499         if (gdrv->shutdown)
 500                 gdrv->shutdown(gdev);
 501 }
 502
 503 static int ccwgroup_pm_prepare(struct device *dev)
 504 {
 505         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 506         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 507
 508         /* Fail while device is being set online/offline. */
 509         if (atomic_read(&gdev->onoff))
 510                 return -EAGAIN;
 511
 512         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 513                 return 0;
 514
 515         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 516 }
 517
 518 static void ccwgroup_pm_complete(struct device *dev)
 519 {
 520         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 521         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 522
 523         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 524                 return;
 525
 526         if (gdrv->complete)
 527                 gdrv->complete(gdev);
 528 }
 529
 530 static int ccwgroup_pm_freeze(struct device *dev)
 531 {
 532         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 533         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 534
 535         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 536                 return 0;
 537
 538         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 539 }
 540
 541 static int ccwgroup_pm_thaw(struct device *dev)
 542 {
 543         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 544         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 545
 546         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 547                 return 0;
 548
 549         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 550 }
 551
 552 static int ccwgroup_pm_restore(struct device *dev)
 553 {
 554         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 555         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 556
 557         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 558                 return 0;
 559
 560         return gdrv->restore ? gdrv->restore(gdev) : 0;
 561 }
 562
 563 static struct dev_pm_ops ccwgroup_pm_ops = {
 564         .prepare = ccwgroup_pm_prepare,
 565         .complete = ccwgroup_pm_complete,
 566         .freeze = ccwgroup_pm_freeze,
 567         .thaw = ccwgroup_pm_thaw,
 568         .restore = ccwgroup_pm_restore,
 569 };
 570
 571 static struct bus_type ccwgroup_bus_type = {
 572         .name   = "ccwgroup",
 573         .match  = ccwgroup_bus_match,
 574         .uevent = ccwgroup_uevent,
 575         .probe  = ccwgroup_probe,
 576         .remove = ccwgroup_remove,
 577         .shutdown = ccwgroup_shutdown,
 578         .pm = &ccwgroup_pm_ops,
 579 };
 580
 581
 582 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 583                              void *data)
 584 {
 585         struct device *dev = data;
 586
 587         if (action == BUS_NOTIFY_UNBIND_DRIVER)
 588                 device_schedule_callback(dev, ccwgroup_ungroup_callback);
 589
 590         return NOTIFY_OK;
 591 }
 592
 593
 594 /**
 595  * ccwgroup_driver_register() - register a ccw group driver
 596  * @cdriver: driver to be registered
 597  *
 598  * This function is mainly a wrapper around driver_register().
 599  */
 600 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 601 {
 602         /* register our new driver with the core */
 603         cdriver->driver.bus = &ccwgroup_bus_type;
 604         cdriver->driver.name = cdriver->name;
 605         cdriver->driver.owner = cdriver->owner;
 606
 607         return driver_register(&cdriver->driver);
 608 }
 609
 610 static int
 611 __ccwgroup_match_all(struct device *dev, void *data)
 612 {
 613         return 1;
 614 }
 615
 616 /**
 617  * ccwgroup_driver_unregister() - deregister a ccw group driver
 618  * @cdriver: driver to be deregistered
 619  *
 620  * This function is mainly a wrapper around driver_unregister().
 621  */
 622 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 623 {
 624         struct device *dev;
 625
 626         /* We don't want ccwgroup devices to live longer than their driver. */
 627         get_driver(&cdriver->driver);
 628         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 629                                          __ccwgroup_match_all))) {
 630                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 631
 632                 mutex_lock(&gdev->reg_mutex);
 633                 __ccwgroup_remove_symlinks(gdev);
 634                 device_unregister(dev);
 635                 mutex_unlock(&gdev->reg_mutex);
 636                 put_device(dev);
 637         }
 638         put_driver(&cdriver->driver);
 639         driver_unregister(&cdriver->driver);
 640 }
 641
 642 /**
 643  * ccwgroup_probe_ccwdev() - probe function for slave devices
 644  * @cdev: ccw device to be probed
 645  *
 646  * This is a dummy probe function for ccw devices that are slave devices in
 647  * a ccw group device.
 648  * Returns:
 649  *  always %0
 650  */
 651 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 652 {
 653         return 0;
 654 }
 655
 656 static struct ccwgroup_device *
 657 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 658 {
 659         struct ccwgroup_device *gdev;
 660
 661         gdev = dev_get_drvdata(&cdev->dev);
 662         if (gdev) {
 663                 if (get_device(&gdev->dev)) {
 664                         mutex_lock(&gdev->reg_mutex);
 665                         if (device_is_registered(&gdev->dev))
 666                                 return gdev;
 667                         mutex_unlock(&gdev->reg_mutex);
 668                         put_device(&gdev->dev);
 669                 }
 670                 return NULL;
 671         }
 672         return NULL;
 673 }
 674
 675 /**
 676  * ccwgroup_remove_ccwdev() - remove function for slave devices
 677  * @cdev: ccw device to be removed
 678  *
 679  * This is a remove function for ccw devices that are slave devices in a ccw
 680  * group device. It sets the ccw device offline and also deregisters the
 681  * embedding ccw group device.
 682  */
 683 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 684 {
 685         struct ccwgroup_device *gdev;
 686
 687         /* Ignore offlining errors, device is gone anyway. */
 688         ccw_device_set_offline(cdev);
 689         /* If one of its devices is gone, the whole group is done for. */
 690         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 691         if (gdev) {
 692                 __ccwgroup_remove_symlinks(gdev);
 693                 device_unregister(&gdev->dev);
 694                 mutex_unlock(&gdev->reg_mutex);
 695                 put_device(&gdev->dev);
 696         }
 697 }
 698
 699 MODULE_LICENSE("GPL");
 700 EXPORT_SYMBOL(ccwgroup_driver_register);
 701 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 702 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 703 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);