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                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 127                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 128                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 129                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 130                         put_device(&gdev->cdev[i]->dev);
 131                 }
 132         }
 133         kfree(gdev);
 134 }
 135
 136 static int
 137 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 138 {
 139         char str[8];
 140         int i, rc;
 141
 142         for (i = 0; i < gdev->count; i++) {
 143                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 144                                        "group_device");
 145                 if (rc) {
 146                         for (--i; i >= 0; i--)
 147                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 148                                                   "group_device");
 149                         return rc;
 150                 }
 151         }
 152         for (i = 0; i < gdev->count; i++) {
 153                 sprintf(str, "cdev%d", i);
 154                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 155                                        str);
 156                 if (rc) {
 157                         for (--i; i >= 0; i--) {
 158                                 sprintf(str, "cdev%d", i);
 159                                 sysfs_remove_link(&gdev->dev.kobj, str);
 160                         }
 161                         for (i = 0; i < gdev->count; i++)
 162                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 163                                                   "group_device");
 164                         return rc;
 165                 }
 166         }
 167         return 0;
 168 }
 169
 170 static int __get_next_bus_id(const char **buf, char *bus_id)
 171 {
 172         int rc, len;
 173         char *start, *end;
 174
 175         start = (char *)*buf;
 176         end = strchr(start, ',');
 177         if (!end) {
 178                 /* Last entry. Strip trailing newline, if applicable. */
 179                 end = strchr(start, '\n');
 180                 if (end)
 181                         *end = '\0';
 182                 len = strlen(start) + 1;
 183         } else {
 184                 len = end - start + 1;
 185                 end++;
 186         }
 187         if (len < CCW_BUS_ID_SIZE) {
 188                 strlcpy(bus_id, start, len);
 189                 rc = 0;
 190         } else
 191                 rc = -EINVAL;
 192         *buf = end;
 193         return rc;
 194 }
 195
 196 static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
 197 {
 198         int cssid, ssid, devno;
 199
 200         /* Must be of form %x.%x.%04x */
 201         if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 202                 return 0;
 203         return 1;
 204 }
 205
 206 /**
 207  * ccwgroup_create_from_string() - create and register a ccw group device
 208  * @root: parent device for the new device
 209  * @creator_id: identifier of creating driver
 210  * @cdrv: ccw driver of slave devices
 211  * @num_devices: number of slave devices
 212  * @buf: buffer containing comma separated bus ids of slave devices
 213  *
 214  * Create and register a new ccw group device as a child of @root. Slave
 215  * devices are obtained from the list of bus ids given in @buf and must all
 216  * belong to @cdrv.
 217  * Returns:
 218  *  %0 on success and an error code on failure.
 219  * Context:
 220  *  non-atomic
 221  */
 222 int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
 223                                 struct ccw_driver *cdrv, int num_devices,
 224                                 const char *buf)
 225 {
 226         struct ccwgroup_device *gdev;
 227         int rc, i;
 228         char tmp_bus_id[CCW_BUS_ID_SIZE];
 229         const char *curr_buf;
 230
 231         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 232                        GFP_KERNEL);
 233         if (!gdev)
 234                 return -ENOMEM;
 235
 236         atomic_set(&gdev->onoff, 0);
 237         mutex_init(&gdev->reg_mutex);
 238         mutex_lock(&gdev->reg_mutex);
 239         gdev->creator_id = creator_id;
 240         gdev->count = num_devices;
 241         gdev->dev.bus = &ccwgroup_bus_type;
 242         gdev->dev.parent = root;
 243         gdev->dev.release = ccwgroup_release;
 244         device_initialize(&gdev->dev);
 245
 246         curr_buf = buf;
 247         for (i = 0; i < num_devices && curr_buf; i++) {
 248                 rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
 249                 if (rc != 0)
 250                         goto error;
 251                 if (!__is_valid_bus_id(tmp_bus_id)) {
 252                         rc = -EINVAL;
 253                         goto error;
 254                 }
 255                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
 256                 /*
 257                  * All devices have to be of the same type in
 258                  * order to be grouped.
 259                  */
 260                 if (!gdev->cdev[i]
 261                     || gdev->cdev[i]->id.driver_info !=
 262                     gdev->cdev[0]->id.driver_info) {
 263                         rc = -EINVAL;
 264                         goto error;
 265                 }
 266                 /* Don't allow a device to belong to more than one group. */
 267                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 268                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 269                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 270                         rc = -EINVAL;
 271                         goto error;
 272                 }
 273                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 274                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 275         }
 276         /* Check for sufficient number of bus ids. */
 277         if (i < num_devices && !curr_buf) {
 278                 rc = -EINVAL;
 279                 goto error;
 280         }
 281         /* Check for trailing stuff. */
 282         if (i == num_devices && strlen(curr_buf) > 0) {
 283                 rc = -EINVAL;
 284                 goto error;
 285         }
 286
 287         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 288
 289         rc = device_add(&gdev->dev);
 290         if (rc)
 291                 goto error;
 292         get_device(&gdev->dev);
 293         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 294
 295         if (rc) {
 296                 device_unregister(&gdev->dev);
 297                 goto error;
 298         }
 299
 300         rc = __ccwgroup_create_symlinks(gdev);
 301         if (!rc) {
 302                 mutex_unlock(&gdev->reg_mutex);
 303                 put_device(&gdev->dev);
 304                 return 0;
 305         }
 306         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 307         device_unregister(&gdev->dev);
 308 error:
 309         for (i = 0; i < num_devices; i++)
 310                 if (gdev->cdev[i]) {
 311                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 312                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 313                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 314                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 315                         put_device(&gdev->cdev[i]->dev);
 316                         gdev->cdev[i] = NULL;
 317                 }
 318         mutex_unlock(&gdev->reg_mutex);
 319         put_device(&gdev->dev);
 320         return rc;
 321 }
 322 EXPORT_SYMBOL(ccwgroup_create_from_string);
 323
 324 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 325                              void *data);
 326
 327 static struct notifier_block ccwgroup_nb = {
 328         .notifier_call = ccwgroup_notifier
 329 };
 330
 331 static int __init init_ccwgroup(void)
 332 {
 333         int ret;
 334
 335         ret = bus_register(&ccwgroup_bus_type);
 336         if (ret)
 337                 return ret;
 338
 339         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 340         if (ret)
 341                 bus_unregister(&ccwgroup_bus_type);
 342
 343         return ret;
 344 }
 345
 346 static void __exit cleanup_ccwgroup(void)
 347 {
 348         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 349         bus_unregister(&ccwgroup_bus_type);
 350 }
 351
 352 module_init(init_ccwgroup);
 353 module_exit(cleanup_ccwgroup);
 354
 355 /************************** driver stuff ******************************/
 356
 357 static int
 358 ccwgroup_set_online(struct ccwgroup_device *gdev)
 359 {
 360         struct ccwgroup_driver *gdrv;
 361         int ret;
 362
 363         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 364                 return -EAGAIN;
 365         if (gdev->state == CCWGROUP_ONLINE) {
 366                 ret = 0;
 367                 goto out;
 368         }
 369         if (!gdev->dev.driver) {
 370                 ret = -EINVAL;
 371                 goto out;
 372         }
 373         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 374         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 375                 goto out;
 376
 377         gdev->state = CCWGROUP_ONLINE;
 378  out:
 379         atomic_set(&gdev->onoff, 0);
 380         return ret;
 381 }
 382
 383 static int
 384 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 385 {
 386         struct ccwgroup_driver *gdrv;
 387         int ret;
 388
 389         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 390                 return -EAGAIN;
 391         if (gdev->state == CCWGROUP_OFFLINE) {
 392                 ret = 0;
 393                 goto out;
 394         }
 395         if (!gdev->dev.driver) {
 396                 ret = -EINVAL;
 397                 goto out;
 398         }
 399         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 400         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 401                 goto out;
 402
 403         gdev->state = CCWGROUP_OFFLINE;
 404  out:
 405         atomic_set(&gdev->onoff, 0);
 406         return ret;
 407 }
 408
 409 static ssize_t
 410 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 411 {
 412         struct ccwgroup_device *gdev;
 413         struct ccwgroup_driver *gdrv;
 414         unsigned long value;
 415         int ret;
 416
 417         if (!dev->driver)
 418                 return -ENODEV;
 419
 420         gdev = to_ccwgroupdev(dev);
 421         gdrv = to_ccwgroupdrv(dev->driver);
 422
 423         if (!try_module_get(gdrv->owner))
 424                 return -EINVAL;
 425
 426         ret = strict_strtoul(buf, 0, &value);
 427         if (ret)
 428                 goto out;
 429
 430         if (value == 1)
 431                 ret = ccwgroup_set_online(gdev);
 432         else if (value == 0)
 433                 ret = ccwgroup_set_offline(gdev);
 434         else
 435                 ret = -EINVAL;
 436 out:
 437         module_put(gdrv->owner);
 438         return (ret == 0) ? count : ret;
 439 }
 440
 441 static ssize_t
 442 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 443 {
 444         int online;
 445
 446         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 447
 448         return sprintf(buf, online ? "1\n" : "0\n");
 449 }
 450
 451 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 452
 453 static int
 454 ccwgroup_probe (struct device *dev)
 455 {
 456         struct ccwgroup_device *gdev;
 457         struct ccwgroup_driver *gdrv;
 458
 459         int ret;
 460
 461         gdev = to_ccwgroupdev(dev);
 462         gdrv = to_ccwgroupdrv(dev->driver);
 463
 464         if ((ret = device_create_file(dev, &dev_attr_online)))
 465                 return ret;
 466
 467         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 468         if (ret)
 469                 device_remove_file(dev, &dev_attr_online);
 470
 471         return ret;
 472 }
 473
 474 static int
 475 ccwgroup_remove (struct device *dev)
 476 {
 477         struct ccwgroup_device *gdev;
 478         struct ccwgroup_driver *gdrv;
 479
 480         device_remove_file(dev, &dev_attr_online);
 481         device_remove_file(dev, &dev_attr_ungroup);
 482
 483         if (!dev->driver)
 484                 return 0;
 485
 486         gdev = to_ccwgroupdev(dev);
 487         gdrv = to_ccwgroupdrv(dev->driver);
 488
 489         if (gdrv->remove)
 490                 gdrv->remove(gdev);
 491
 492         return 0;
 493 }
 494
 495 static void ccwgroup_shutdown(struct device *dev)
 496 {
 497         struct ccwgroup_device *gdev;
 498         struct ccwgroup_driver *gdrv;
 499
 500         if (!dev->driver)
 501                 return;
 502
 503         gdev = to_ccwgroupdev(dev);
 504         gdrv = to_ccwgroupdrv(dev->driver);
 505
 506         if (gdrv->shutdown)
 507                 gdrv->shutdown(gdev);
 508 }
 509
 510 static int ccwgroup_pm_prepare(struct device *dev)
 511 {
 512         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 513         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 514
 515         /* Fail while device is being set online/offline. */
 516         if (atomic_read(&gdev->onoff))
 517                 return -EAGAIN;
 518
 519         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 520                 return 0;
 521
 522         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 523 }
 524
 525 static void ccwgroup_pm_complete(struct device *dev)
 526 {
 527         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 528         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 529
 530         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 531                 return;
 532
 533         if (gdrv->complete)
 534                 gdrv->complete(gdev);
 535 }
 536
 537 static int ccwgroup_pm_freeze(struct device *dev)
 538 {
 539         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 540         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 541
 542         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 543                 return 0;
 544
 545         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 546 }
 547
 548 static int ccwgroup_pm_thaw(struct device *dev)
 549 {
 550         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 551         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 552
 553         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 554                 return 0;
 555
 556         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 557 }
 558
 559 static int ccwgroup_pm_restore(struct device *dev)
 560 {
 561         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 562         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 563
 564         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 565                 return 0;
 566
 567         return gdrv->restore ? gdrv->restore(gdev) : 0;
 568 }
 569
 570 static const struct dev_pm_ops ccwgroup_pm_ops = {
 571         .prepare = ccwgroup_pm_prepare,
 572         .complete = ccwgroup_pm_complete,
 573         .freeze = ccwgroup_pm_freeze,
 574         .thaw = ccwgroup_pm_thaw,
 575         .restore = ccwgroup_pm_restore,
 576 };
 577
 578 static struct bus_type ccwgroup_bus_type = {
 579         .name   = "ccwgroup",
 580         .match  = ccwgroup_bus_match,
 581         .uevent = ccwgroup_uevent,
 582         .probe  = ccwgroup_probe,
 583         .remove = ccwgroup_remove,
 584         .shutdown = ccwgroup_shutdown,
 585         .pm = &ccwgroup_pm_ops,
 586 };
 587
 588
 589 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 590                              void *data)
 591 {
 592         struct device *dev = data;
 593
 594         if (action == BUS_NOTIFY_UNBIND_DRIVER)
 595                 device_schedule_callback(dev, ccwgroup_ungroup_callback);
 596
 597         return NOTIFY_OK;
 598 }
 599
 600
 601 /**
 602  * ccwgroup_driver_register() - register a ccw group driver
 603  * @cdriver: driver to be registered
 604  *
 605  * This function is mainly a wrapper around driver_register().
 606  */
 607 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 608 {
 609         /* register our new driver with the core */
 610         cdriver->driver.bus = &ccwgroup_bus_type;
 611         cdriver->driver.name = cdriver->name;
 612         cdriver->driver.owner = cdriver->owner;
 613
 614         return driver_register(&cdriver->driver);
 615 }
 616
 617 static int
 618 __ccwgroup_match_all(struct device *dev, void *data)
 619 {
 620         return 1;
 621 }
 622
 623 /**
 624  * ccwgroup_driver_unregister() - deregister a ccw group driver
 625  * @cdriver: driver to be deregistered
 626  *
 627  * This function is mainly a wrapper around driver_unregister().
 628  */
 629 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 630 {
 631         struct device *dev;
 632
 633         /* We don't want ccwgroup devices to live longer than their driver. */
 634         get_driver(&cdriver->driver);
 635         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 636                                          __ccwgroup_match_all))) {
 637                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 638
 639                 mutex_lock(&gdev->reg_mutex);
 640                 __ccwgroup_remove_symlinks(gdev);
 641                 device_unregister(dev);
 642                 mutex_unlock(&gdev->reg_mutex);
 643                 put_device(dev);
 644         }
 645         put_driver(&cdriver->driver);
 646         driver_unregister(&cdriver->driver);
 647 }
 648
 649 /**
 650  * ccwgroup_probe_ccwdev() - probe function for slave devices
 651  * @cdev: ccw device to be probed
 652  *
 653  * This is a dummy probe function for ccw devices that are slave devices in
 654  * a ccw group device.
 655  * Returns:
 656  *  always %0
 657  */
 658 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 659 {
 660         return 0;
 661 }
 662
 663 static struct ccwgroup_device *
 664 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 665 {
 666         struct ccwgroup_device *gdev;
 667
 668         gdev = dev_get_drvdata(&cdev->dev);
 669         if (gdev) {
 670                 if (get_device(&gdev->dev)) {
 671                         mutex_lock(&gdev->reg_mutex);
 672                         if (device_is_registered(&gdev->dev))
 673                                 return gdev;
 674                         mutex_unlock(&gdev->reg_mutex);
 675                         put_device(&gdev->dev);
 676                 }
 677                 return NULL;
 678         }
 679         return NULL;
 680 }
 681
 682 /**
 683  * ccwgroup_remove_ccwdev() - remove function for slave devices
 684  * @cdev: ccw device to be removed
 685  *
 686  * This is a remove function for ccw devices that are slave devices in a ccw
 687  * group device. It sets the ccw device offline and also deregisters the
 688  * embedding ccw group device.
 689  */
 690 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 691 {
 692         struct ccwgroup_device *gdev;
 693
 694         /* Ignore offlining errors, device is gone anyway. */
 695         ccw_device_set_offline(cdev);
 696         /* If one of its devices is gone, the whole group is done for. */
 697         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 698         if (gdev) {
 699                 __ccwgroup_remove_symlinks(gdev);
 700                 device_unregister(&gdev->dev);
 701                 mutex_unlock(&gdev->reg_mutex);
 702                 put_device(&gdev->dev);
 703         }
 704 }
 705
 706 MODULE_LICENSE("GPL");
 707 EXPORT_SYMBOL(ccwgroup_driver_register);
 708 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 709 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 710 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);