linux/drivers/base/core.c
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   1/*
   2 * drivers/base/core.c - core driver model code (device registration, etc)
   3 *
   4 * Copyright (c) 2002-3 Patrick Mochel
   5 * Copyright (c) 2002-3 Open Source Development Labs
   6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
   7 * Copyright (c) 2006 Novell, Inc.
   8 *
   9 * This file is released under the GPLv2
  10 *
  11 */
  12
  13#include <linux/device.h>
  14#include <linux/err.h>
  15#include <linux/init.h>
  16#include <linux/module.h>
  17#include <linux/slab.h>
  18#include <linux/string.h>
  19#include <linux/kdev_t.h>
  20#include <linux/notifier.h>
  21#include <linux/of.h>
  22#include <linux/of_device.h>
  23#include <linux/genhd.h>
  24#include <linux/kallsyms.h>
  25#include <linux/mutex.h>
  26#include <linux/async.h>
  27#include <linux/pm_runtime.h>
  28#include <linux/netdevice.h>
  29
  30#include "base.h"
  31#include "power/power.h"
  32
  33#ifdef CONFIG_SYSFS_DEPRECATED
  34#ifdef CONFIG_SYSFS_DEPRECATED_V2
  35long sysfs_deprecated = 1;
  36#else
  37long sysfs_deprecated = 0;
  38#endif
  39static __init int sysfs_deprecated_setup(char *arg)
  40{
  41        return strict_strtol(arg, 10, &sysfs_deprecated);
  42}
  43early_param("sysfs.deprecated", sysfs_deprecated_setup);
  44#endif
  45
  46int (*platform_notify)(struct device *dev) = NULL;
  47int (*platform_notify_remove)(struct device *dev) = NULL;
  48static struct kobject *dev_kobj;
  49struct kobject *sysfs_dev_char_kobj;
  50struct kobject *sysfs_dev_block_kobj;
  51
  52#ifdef CONFIG_BLOCK
  53static inline int device_is_not_partition(struct device *dev)
  54{
  55        return !(dev->type == &part_type);
  56}
  57#else
  58static inline int device_is_not_partition(struct device *dev)
  59{
  60        return 1;
  61}
  62#endif
  63
  64/**
  65 * dev_driver_string - Return a device's driver name, if at all possible
  66 * @dev: struct device to get the name of
  67 *
  68 * Will return the device's driver's name if it is bound to a device.  If
  69 * the device is not bound to a driver, it will return the name of the bus
  70 * it is attached to.  If it is not attached to a bus either, an empty
  71 * string will be returned.
  72 */
  73const char *dev_driver_string(const struct device *dev)
  74{
  75        struct device_driver *drv;
  76
  77        /* dev->driver can change to NULL underneath us because of unbinding,
  78         * so be careful about accessing it.  dev->bus and dev->class should
  79         * never change once they are set, so they don't need special care.
  80         */
  81        drv = ACCESS_ONCE(dev->driver);
  82        return drv ? drv->name :
  83                        (dev->bus ? dev->bus->name :
  84                        (dev->class ? dev->class->name : ""));
  85}
  86EXPORT_SYMBOL(dev_driver_string);
  87
  88#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
  89
  90static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
  91                             char *buf)
  92{
  93        struct device_attribute *dev_attr = to_dev_attr(attr);
  94        struct device *dev = kobj_to_dev(kobj);
  95        ssize_t ret = -EIO;
  96
  97        if (dev_attr->show)
  98                ret = dev_attr->show(dev, dev_attr, buf);
  99        if (ret >= (ssize_t)PAGE_SIZE) {
 100                print_symbol("dev_attr_show: %s returned bad count\n",
 101                                (unsigned long)dev_attr->show);
 102        }
 103        return ret;
 104}
 105
 106static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
 107                              const char *buf, size_t count)
 108{
 109        struct device_attribute *dev_attr = to_dev_attr(attr);
 110        struct device *dev = kobj_to_dev(kobj);
 111        ssize_t ret = -EIO;
 112
 113        if (dev_attr->store)
 114                ret = dev_attr->store(dev, dev_attr, buf, count);
 115        return ret;
 116}
 117
 118static const struct sysfs_ops dev_sysfs_ops = {
 119        .show   = dev_attr_show,
 120        .store  = dev_attr_store,
 121};
 122
 123#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
 124
 125ssize_t device_store_ulong(struct device *dev,
 126                           struct device_attribute *attr,
 127                           const char *buf, size_t size)
 128{
 129        struct dev_ext_attribute *ea = to_ext_attr(attr);
 130        char *end;
 131        unsigned long new = simple_strtoul(buf, &end, 0);
 132        if (end == buf)
 133                return -EINVAL;
 134        *(unsigned long *)(ea->var) = new;
 135        /* Always return full write size even if we didn't consume all */
 136        return size;
 137}
 138EXPORT_SYMBOL_GPL(device_store_ulong);
 139
 140ssize_t device_show_ulong(struct device *dev,
 141                          struct device_attribute *attr,
 142                          char *buf)
 143{
 144        struct dev_ext_attribute *ea = to_ext_attr(attr);
 145        return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
 146}
 147EXPORT_SYMBOL_GPL(device_show_ulong);
 148
 149ssize_t device_store_int(struct device *dev,
 150                         struct device_attribute *attr,
 151                         const char *buf, size_t size)
 152{
 153        struct dev_ext_attribute *ea = to_ext_attr(attr);
 154        char *end;
 155        long new = simple_strtol(buf, &end, 0);
 156        if (end == buf || new > INT_MAX || new < INT_MIN)
 157                return -EINVAL;
 158        *(int *)(ea->var) = new;
 159        /* Always return full write size even if we didn't consume all */
 160        return size;
 161}
 162EXPORT_SYMBOL_GPL(device_store_int);
 163
 164ssize_t device_show_int(struct device *dev,
 165                        struct device_attribute *attr,
 166                        char *buf)
 167{
 168        struct dev_ext_attribute *ea = to_ext_attr(attr);
 169
 170        return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
 171}
 172EXPORT_SYMBOL_GPL(device_show_int);
 173
 174/**
 175 *      device_release - free device structure.
 176 *      @kobj:  device's kobject.
 177 *
 178 *      This is called once the reference count for the object
 179 *      reaches 0. We forward the call to the device's release
 180 *      method, which should handle actually freeing the structure.
 181 */
 182static void device_release(struct kobject *kobj)
 183{
 184        struct device *dev = kobj_to_dev(kobj);
 185        struct device_private *p = dev->p;
 186
 187        if (dev->release)
 188                dev->release(dev);
 189        else if (dev->type && dev->type->release)
 190                dev->type->release(dev);
 191        else if (dev->class && dev->class->dev_release)
 192                dev->class->dev_release(dev);
 193        else
 194                WARN(1, KERN_ERR "Device '%s' does not have a release() "
 195                        "function, it is broken and must be fixed.\n",
 196                        dev_name(dev));
 197        kfree(p);
 198}
 199
 200static const void *device_namespace(struct kobject *kobj)
 201{
 202        struct device *dev = kobj_to_dev(kobj);
 203        const void *ns = NULL;
 204
 205        if (dev->class && dev->class->ns_type)
 206                ns = dev->class->namespace(dev);
 207
 208        return ns;
 209}
 210
 211static struct kobj_type device_ktype = {
 212        .release        = device_release,
 213        .sysfs_ops      = &dev_sysfs_ops,
 214        .namespace      = device_namespace,
 215};
 216
 217
 218static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
 219{
 220        struct kobj_type *ktype = get_ktype(kobj);
 221
 222        if (ktype == &device_ktype) {
 223                struct device *dev = kobj_to_dev(kobj);
 224                if (dev->bus)
 225                        return 1;
 226                if (dev->class)
 227                        return 1;
 228        }
 229        return 0;
 230}
 231
 232static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
 233{
 234        struct device *dev = kobj_to_dev(kobj);
 235
 236        if (dev->bus)
 237                return dev->bus->name;
 238        if (dev->class)
 239                return dev->class->name;
 240        return NULL;
 241}
 242
 243static int dev_uevent(struct kset *kset, struct kobject *kobj,
 244                      struct kobj_uevent_env *env)
 245{
 246        struct device *dev = kobj_to_dev(kobj);
 247        int retval = 0;
 248
 249        /* add device node properties if present */
 250        if (MAJOR(dev->devt)) {
 251                const char *tmp;
 252                const char *name;
 253                umode_t mode = 0;
 254
 255                add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
 256                add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
 257                name = device_get_devnode(dev, &mode, &tmp);
 258                if (name) {
 259                        add_uevent_var(env, "DEVNAME=%s", name);
 260                        kfree(tmp);
 261                        if (mode)
 262                                add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
 263                }
 264        }
 265
 266        if (dev->type && dev->type->name)
 267                add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
 268
 269        if (dev->driver)
 270                add_uevent_var(env, "DRIVER=%s", dev->driver->name);
 271
 272        /* Add common DT information about the device */
 273        of_device_uevent(dev, env);
 274
 275        /* have the bus specific function add its stuff */
 276        if (dev->bus && dev->bus->uevent) {
 277                retval = dev->bus->uevent(dev, env);
 278                if (retval)
 279                        pr_debug("device: '%s': %s: bus uevent() returned %d\n",
 280                                 dev_name(dev), __func__, retval);
 281        }
 282
 283        /* have the class specific function add its stuff */
 284        if (dev->class && dev->class->dev_uevent) {
 285                retval = dev->class->dev_uevent(dev, env);
 286                if (retval)
 287                        pr_debug("device: '%s': %s: class uevent() "
 288                                 "returned %d\n", dev_name(dev),
 289                                 __func__, retval);
 290        }
 291
 292        /* have the device type specific function add its stuff */
 293        if (dev->type && dev->type->uevent) {
 294                retval = dev->type->uevent(dev, env);
 295                if (retval)
 296                        pr_debug("device: '%s': %s: dev_type uevent() "
 297                                 "returned %d\n", dev_name(dev),
 298                                 __func__, retval);
 299        }
 300
 301        return retval;
 302}
 303
 304static const struct kset_uevent_ops device_uevent_ops = {
 305        .filter =       dev_uevent_filter,
 306        .name =         dev_uevent_name,
 307        .uevent =       dev_uevent,
 308};
 309
 310static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
 311                           char *buf)
 312{
 313        struct kobject *top_kobj;
 314        struct kset *kset;
 315        struct kobj_uevent_env *env = NULL;
 316        int i;
 317        size_t count = 0;
 318        int retval;
 319
 320        /* search the kset, the device belongs to */
 321        top_kobj = &dev->kobj;
 322        while (!top_kobj->kset && top_kobj->parent)
 323                top_kobj = top_kobj->parent;
 324        if (!top_kobj->kset)
 325                goto out;
 326
 327        kset = top_kobj->kset;
 328        if (!kset->uevent_ops || !kset->uevent_ops->uevent)
 329                goto out;
 330
 331        /* respect filter */
 332        if (kset->uevent_ops && kset->uevent_ops->filter)
 333                if (!kset->uevent_ops->filter(kset, &dev->kobj))
 334                        goto out;
 335
 336        env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
 337        if (!env)
 338                return -ENOMEM;
 339
 340        /* let the kset specific function add its keys */
 341        retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
 342        if (retval)
 343                goto out;
 344
 345        /* copy keys to file */
 346        for (i = 0; i < env->envp_idx; i++)
 347                count += sprintf(&buf[count], "%s\n", env->envp[i]);
 348out:
 349        kfree(env);
 350        return count;
 351}
 352
 353static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
 354                            const char *buf, size_t count)
 355{
 356        enum kobject_action action;
 357
 358        if (kobject_action_type(buf, count, &action) == 0)
 359                kobject_uevent(&dev->kobj, action);
 360        else
 361                dev_err(dev, "uevent: unknown action-string\n");
 362        return count;
 363}
 364
 365static struct device_attribute uevent_attr =
 366        __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
 367
 368static int device_add_attributes(struct device *dev,
 369                                 struct device_attribute *attrs)
 370{
 371        int error = 0;
 372        int i;
 373
 374        if (attrs) {
 375                for (i = 0; attr_name(attrs[i]); i++) {
 376                        error = device_create_file(dev, &attrs[i]);
 377                        if (error)
 378                                break;
 379                }
 380                if (error)
 381                        while (--i >= 0)
 382                                device_remove_file(dev, &attrs[i]);
 383        }
 384        return error;
 385}
 386
 387static void device_remove_attributes(struct device *dev,
 388                                     struct device_attribute *attrs)
 389{
 390        int i;
 391
 392        if (attrs)
 393                for (i = 0; attr_name(attrs[i]); i++)
 394                        device_remove_file(dev, &attrs[i]);
 395}
 396
 397static int device_add_bin_attributes(struct device *dev,
 398                                     struct bin_attribute *attrs)
 399{
 400        int error = 0;
 401        int i;
 402
 403        if (attrs) {
 404                for (i = 0; attr_name(attrs[i]); i++) {
 405                        error = device_create_bin_file(dev, &attrs[i]);
 406                        if (error)
 407                                break;
 408                }
 409                if (error)
 410                        while (--i >= 0)
 411                                device_remove_bin_file(dev, &attrs[i]);
 412        }
 413        return error;
 414}
 415
 416static void device_remove_bin_attributes(struct device *dev,
 417                                         struct bin_attribute *attrs)
 418{
 419        int i;
 420
 421        if (attrs)
 422                for (i = 0; attr_name(attrs[i]); i++)
 423                        device_remove_bin_file(dev, &attrs[i]);
 424}
 425
 426static int device_add_groups(struct device *dev,
 427                             const struct attribute_group **groups)
 428{
 429        int error = 0;
 430        int i;
 431
 432        if (groups) {
 433                for (i = 0; groups[i]; i++) {
 434                        error = sysfs_create_group(&dev->kobj, groups[i]);
 435                        if (error) {
 436                                while (--i >= 0)
 437                                        sysfs_remove_group(&dev->kobj,
 438                                                           groups[i]);
 439                                break;
 440                        }
 441                }
 442        }
 443        return error;
 444}
 445
 446static void device_remove_groups(struct device *dev,
 447                                 const struct attribute_group **groups)
 448{
 449        int i;
 450
 451        if (groups)
 452                for (i = 0; groups[i]; i++)
 453                        sysfs_remove_group(&dev->kobj, groups[i]);
 454}
 455
 456static int device_add_attrs(struct device *dev)
 457{
 458        struct class *class = dev->class;
 459        const struct device_type *type = dev->type;
 460        int error;
 461
 462        if (class) {
 463                error = device_add_attributes(dev, class->dev_attrs);
 464                if (error)
 465                        return error;
 466                error = device_add_bin_attributes(dev, class->dev_bin_attrs);
 467                if (error)
 468                        goto err_remove_class_attrs;
 469        }
 470
 471        if (type) {
 472                error = device_add_groups(dev, type->groups);
 473                if (error)
 474                        goto err_remove_class_bin_attrs;
 475        }
 476
 477        error = device_add_groups(dev, dev->groups);
 478        if (error)
 479                goto err_remove_type_groups;
 480
 481        return 0;
 482
 483 err_remove_type_groups:
 484        if (type)
 485                device_remove_groups(dev, type->groups);
 486 err_remove_class_bin_attrs:
 487        if (class)
 488                device_remove_bin_attributes(dev, class->dev_bin_attrs);
 489 err_remove_class_attrs:
 490        if (class)
 491                device_remove_attributes(dev, class->dev_attrs);
 492
 493        return error;
 494}
 495
 496static void device_remove_attrs(struct device *dev)
 497{
 498        struct class *class = dev->class;
 499        const struct device_type *type = dev->type;
 500
 501        device_remove_groups(dev, dev->groups);
 502
 503        if (type)
 504                device_remove_groups(dev, type->groups);
 505
 506        if (class) {
 507                device_remove_attributes(dev, class->dev_attrs);
 508                device_remove_bin_attributes(dev, class->dev_bin_attrs);
 509        }
 510}
 511
 512
 513static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
 514                        char *buf)
 515{
 516        return print_dev_t(buf, dev->devt);
 517}
 518
 519static struct device_attribute devt_attr =
 520        __ATTR(dev, S_IRUGO, show_dev, NULL);
 521
 522/* /sys/devices/ */
 523struct kset *devices_kset;
 524
 525/**
 526 * device_create_file - create sysfs attribute file for device.
 527 * @dev: device.
 528 * @attr: device attribute descriptor.
 529 */
 530int device_create_file(struct device *dev,
 531                       const struct device_attribute *attr)
 532{
 533        int error = 0;
 534        if (dev)
 535                error = sysfs_create_file(&dev->kobj, &attr->attr);
 536        return error;
 537}
 538
 539/**
 540 * device_remove_file - remove sysfs attribute file.
 541 * @dev: device.
 542 * @attr: device attribute descriptor.
 543 */
 544void device_remove_file(struct device *dev,
 545                        const struct device_attribute *attr)
 546{
 547        if (dev)
 548                sysfs_remove_file(&dev->kobj, &attr->attr);
 549}
 550
 551/**
 552 * device_create_bin_file - create sysfs binary attribute file for device.
 553 * @dev: device.
 554 * @attr: device binary attribute descriptor.
 555 */
 556int device_create_bin_file(struct device *dev,
 557                           const struct bin_attribute *attr)
 558{
 559        int error = -EINVAL;
 560        if (dev)
 561                error = sysfs_create_bin_file(&dev->kobj, attr);
 562        return error;
 563}
 564EXPORT_SYMBOL_GPL(device_create_bin_file);
 565
 566/**
 567 * device_remove_bin_file - remove sysfs binary attribute file
 568 * @dev: device.
 569 * @attr: device binary attribute descriptor.
 570 */
 571void device_remove_bin_file(struct device *dev,
 572                            const struct bin_attribute *attr)
 573{
 574        if (dev)
 575                sysfs_remove_bin_file(&dev->kobj, attr);
 576}
 577EXPORT_SYMBOL_GPL(device_remove_bin_file);
 578
 579/**
 580 * device_schedule_callback_owner - helper to schedule a callback for a device
 581 * @dev: device.
 582 * @func: callback function to invoke later.
 583 * @owner: module owning the callback routine
 584 *
 585 * Attribute methods must not unregister themselves or their parent device
 586 * (which would amount to the same thing).  Attempts to do so will deadlock,
 587 * since unregistration is mutually exclusive with driver callbacks.
 588 *
 589 * Instead methods can call this routine, which will attempt to allocate
 590 * and schedule a workqueue request to call back @func with @dev as its
 591 * argument in the workqueue's process context.  @dev will be pinned until
 592 * @func returns.
 593 *
 594 * This routine is usually called via the inline device_schedule_callback(),
 595 * which automatically sets @owner to THIS_MODULE.
 596 *
 597 * Returns 0 if the request was submitted, -ENOMEM if storage could not
 598 * be allocated, -ENODEV if a reference to @owner isn't available.
 599 *
 600 * NOTE: This routine won't work if CONFIG_SYSFS isn't set!  It uses an
 601 * underlying sysfs routine (since it is intended for use by attribute
 602 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
 603 */
 604int device_schedule_callback_owner(struct device *dev,
 605                void (*func)(struct device *), struct module *owner)
 606{
 607        return sysfs_schedule_callback(&dev->kobj,
 608                        (void (*)(void *)) func, dev, owner);
 609}
 610EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
 611
 612static void klist_children_get(struct klist_node *n)
 613{
 614        struct device_private *p = to_device_private_parent(n);
 615        struct device *dev = p->device;
 616
 617        get_device(dev);
 618}
 619
 620static void klist_children_put(struct klist_node *n)
 621{
 622        struct device_private *p = to_device_private_parent(n);
 623        struct device *dev = p->device;
 624
 625        put_device(dev);
 626}
 627
 628/**
 629 * device_initialize - init device structure.
 630 * @dev: device.
 631 *
 632 * This prepares the device for use by other layers by initializing
 633 * its fields.
 634 * It is the first half of device_register(), if called by
 635 * that function, though it can also be called separately, so one
 636 * may use @dev's fields. In particular, get_device()/put_device()
 637 * may be used for reference counting of @dev after calling this
 638 * function.
 639 *
 640 * All fields in @dev must be initialized by the caller to 0, except
 641 * for those explicitly set to some other value.  The simplest
 642 * approach is to use kzalloc() to allocate the structure containing
 643 * @dev.
 644 *
 645 * NOTE: Use put_device() to give up your reference instead of freeing
 646 * @dev directly once you have called this function.
 647 */
 648void device_initialize(struct device *dev)
 649{
 650        dev->kobj.kset = devices_kset;
 651        kobject_init(&dev->kobj, &device_ktype);
 652        INIT_LIST_HEAD(&dev->dma_pools);
 653        mutex_init(&dev->mutex);
 654        lockdep_set_novalidate_class(&dev->mutex);
 655        spin_lock_init(&dev->devres_lock);
 656        INIT_LIST_HEAD(&dev->devres_head);
 657        device_pm_init(dev);
 658        set_dev_node(dev, -1);
 659}
 660
 661static struct kobject *virtual_device_parent(struct device *dev)
 662{
 663        static struct kobject *virtual_dir = NULL;
 664
 665        if (!virtual_dir)
 666                virtual_dir = kobject_create_and_add("virtual",
 667                                                     &devices_kset->kobj);
 668
 669        return virtual_dir;
 670}
 671
 672struct class_dir {
 673        struct kobject kobj;
 674        struct class *class;
 675};
 676
 677#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
 678
 679static void class_dir_release(struct kobject *kobj)
 680{
 681        struct class_dir *dir = to_class_dir(kobj);
 682        kfree(dir);
 683}
 684
 685static const
 686struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
 687{
 688        struct class_dir *dir = to_class_dir(kobj);
 689        return dir->class->ns_type;
 690}
 691
 692static struct kobj_type class_dir_ktype = {
 693        .release        = class_dir_release,
 694        .sysfs_ops      = &kobj_sysfs_ops,
 695        .child_ns_type  = class_dir_child_ns_type
 696};
 697
 698static struct kobject *
 699class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
 700{
 701        struct class_dir *dir;
 702        int retval;
 703
 704        dir = kzalloc(sizeof(*dir), GFP_KERNEL);
 705        if (!dir)
 706                return NULL;
 707
 708        dir->class = class;
 709        kobject_init(&dir->kobj, &class_dir_ktype);
 710
 711        dir->kobj.kset = &class->p->glue_dirs;
 712
 713        retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
 714        if (retval < 0) {
 715                kobject_put(&dir->kobj);
 716                return NULL;
 717        }
 718        return &dir->kobj;
 719}
 720
 721
 722static struct kobject *get_device_parent(struct device *dev,
 723                                         struct device *parent)
 724{
 725        if (dev->class) {
 726                static DEFINE_MUTEX(gdp_mutex);
 727                struct kobject *kobj = NULL;
 728                struct kobject *parent_kobj;
 729                struct kobject *k;
 730
 731#ifdef CONFIG_BLOCK
 732                /* block disks show up in /sys/block */
 733                if (sysfs_deprecated && dev->class == &block_class) {
 734                        if (parent && parent->class == &block_class)
 735                                return &parent->kobj;
 736                        return &block_class.p->subsys.kobj;
 737                }
 738#endif
 739
 740                /*
 741                 * If we have no parent, we live in "virtual".
 742                 * Class-devices with a non class-device as parent, live
 743                 * in a "glue" directory to prevent namespace collisions.
 744                 */
 745                if (parent == NULL)
 746                        parent_kobj = virtual_device_parent(dev);
 747                else if (parent->class && !dev->class->ns_type)
 748                        return &parent->kobj;
 749                else
 750                        parent_kobj = &parent->kobj;
 751
 752                mutex_lock(&gdp_mutex);
 753
 754                /* find our class-directory at the parent and reference it */
 755                spin_lock(&dev->class->p->glue_dirs.list_lock);
 756                list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
 757                        if (k->parent == parent_kobj) {
 758                                kobj = kobject_get(k);
 759                                break;
 760                        }
 761                spin_unlock(&dev->class->p->glue_dirs.list_lock);
 762                if (kobj) {
 763                        mutex_unlock(&gdp_mutex);
 764                        return kobj;
 765                }
 766
 767                /* or create a new class-directory at the parent device */
 768                k = class_dir_create_and_add(dev->class, parent_kobj);
 769                /* do not emit an uevent for this simple "glue" directory */
 770                mutex_unlock(&gdp_mutex);
 771                return k;
 772        }
 773
 774        /* subsystems can specify a default root directory for their devices */
 775        if (!parent && dev->bus && dev->bus->dev_root)
 776                return &dev->bus->dev_root->kobj;
 777
 778        if (parent)
 779                return &parent->kobj;
 780        return NULL;
 781}
 782
 783static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
 784{
 785        /* see if we live in a "glue" directory */
 786        if (!glue_dir || !dev->class ||
 787            glue_dir->kset != &dev->class->p->glue_dirs)
 788                return;
 789
 790        kobject_put(glue_dir);
 791}
 792
 793static void cleanup_device_parent(struct device *dev)
 794{
 795        cleanup_glue_dir(dev, dev->kobj.parent);
 796}
 797
 798static int device_add_class_symlinks(struct device *dev)
 799{
 800        int error;
 801
 802        if (!dev->class)
 803                return 0;
 804
 805        error = sysfs_create_link(&dev->kobj,
 806                                  &dev->class->p->subsys.kobj,
 807                                  "subsystem");
 808        if (error)
 809                goto out;
 810
 811        if (dev->parent && device_is_not_partition(dev)) {
 812                error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
 813                                          "device");
 814                if (error)
 815                        goto out_subsys;
 816        }
 817
 818#ifdef CONFIG_BLOCK
 819        /* /sys/block has directories and does not need symlinks */
 820        if (sysfs_deprecated && dev->class == &block_class)
 821                return 0;
 822#endif
 823
 824        /* link in the class directory pointing to the device */
 825        error = sysfs_create_link(&dev->class->p->subsys.kobj,
 826                                  &dev->kobj, dev_name(dev));
 827        if (error)
 828                goto out_device;
 829
 830        return 0;
 831
 832out_device:
 833        sysfs_remove_link(&dev->kobj, "device");
 834
 835out_subsys:
 836        sysfs_remove_link(&dev->kobj, "subsystem");
 837out:
 838        return error;
 839}
 840
 841static void device_remove_class_symlinks(struct device *dev)
 842{
 843        if (!dev->class)
 844                return;
 845
 846        if (dev->parent && device_is_not_partition(dev))
 847                sysfs_remove_link(&dev->kobj, "device");
 848        sysfs_remove_link(&dev->kobj, "subsystem");
 849#ifdef CONFIG_BLOCK
 850        if (sysfs_deprecated && dev->class == &block_class)
 851                return;
 852#endif
 853        sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
 854}
 855
 856/**
 857 * dev_set_name - set a device name
 858 * @dev: device
 859 * @fmt: format string for the device's name
 860 */
 861int dev_set_name(struct device *dev, const char *fmt, ...)
 862{
 863        va_list vargs;
 864        int err;
 865
 866        va_start(vargs, fmt);
 867        err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
 868        va_end(vargs);
 869        return err;
 870}
 871EXPORT_SYMBOL_GPL(dev_set_name);
 872
 873/**
 874 * device_to_dev_kobj - select a /sys/dev/ directory for the device
 875 * @dev: device
 876 *
 877 * By default we select char/ for new entries.  Setting class->dev_obj
 878 * to NULL prevents an entry from being created.  class->dev_kobj must
 879 * be set (or cleared) before any devices are registered to the class
 880 * otherwise device_create_sys_dev_entry() and
 881 * device_remove_sys_dev_entry() will disagree about the presence of
 882 * the link.
 883 */
 884static struct kobject *device_to_dev_kobj(struct device *dev)
 885{
 886        struct kobject *kobj;
 887
 888        if (dev->class)
 889                kobj = dev->class->dev_kobj;
 890        else
 891                kobj = sysfs_dev_char_kobj;
 892
 893        return kobj;
 894}
 895
 896static int device_create_sys_dev_entry(struct device *dev)
 897{
 898        struct kobject *kobj = device_to_dev_kobj(dev);
 899        int error = 0;
 900        char devt_str[15];
 901
 902        if (kobj) {
 903                format_dev_t(devt_str, dev->devt);
 904                error = sysfs_create_link(kobj, &dev->kobj, devt_str);
 905        }
 906
 907        return error;
 908}
 909
 910static void device_remove_sys_dev_entry(struct device *dev)
 911{
 912        struct kobject *kobj = device_to_dev_kobj(dev);
 913        char devt_str[15];
 914
 915        if (kobj) {
 916                format_dev_t(devt_str, dev->devt);
 917                sysfs_remove_link(kobj, devt_str);
 918        }
 919}
 920
 921int device_private_init(struct device *dev)
 922{
 923        dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
 924        if (!dev->p)
 925                return -ENOMEM;
 926        dev->p->device = dev;
 927        klist_init(&dev->p->klist_children, klist_children_get,
 928                   klist_children_put);
 929        INIT_LIST_HEAD(&dev->p->deferred_probe);
 930        return 0;
 931}
 932
 933/**
 934 * device_add - add device to device hierarchy.
 935 * @dev: device.
 936 *
 937 * This is part 2 of device_register(), though may be called
 938 * separately _iff_ device_initialize() has been called separately.
 939 *
 940 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
 941 * to the global and sibling lists for the device, then
 942 * adds it to the other relevant subsystems of the driver model.
 943 *
 944 * Do not call this routine or device_register() more than once for
 945 * any device structure.  The driver model core is not designed to work
 946 * with devices that get unregistered and then spring back to life.
 947 * (Among other things, it's very hard to guarantee that all references
 948 * to the previous incarnation of @dev have been dropped.)  Allocate
 949 * and register a fresh new struct device instead.
 950 *
 951 * NOTE: _Never_ directly free @dev after calling this function, even
 952 * if it returned an error! Always use put_device() to give up your
 953 * reference instead.
 954 */
 955int device_add(struct device *dev)
 956{
 957        struct device *parent = NULL;
 958        struct kobject *kobj;
 959        struct class_interface *class_intf;
 960        int error = -EINVAL;
 961
 962        dev = get_device(dev);
 963        if (!dev)
 964                goto done;
 965
 966        if (!dev->p) {
 967                error = device_private_init(dev);
 968                if (error)
 969                        goto done;
 970        }
 971
 972        /*
 973         * for statically allocated devices, which should all be converted
 974         * some day, we need to initialize the name. We prevent reading back
 975         * the name, and force the use of dev_name()
 976         */
 977        if (dev->init_name) {
 978                dev_set_name(dev, "%s", dev->init_name);
 979                dev->init_name = NULL;
 980        }
 981
 982        /* subsystems can specify simple device enumeration */
 983        if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
 984                dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
 985
 986        if (!dev_name(dev)) {
 987                error = -EINVAL;
 988                goto name_error;
 989        }
 990
 991        pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
 992
 993        parent = get_device(dev->parent);
 994        kobj = get_device_parent(dev, parent);
 995        if (kobj)
 996                dev->kobj.parent = kobj;
 997
 998        /* use parent numa_node */
 999        if (parent)
1000                set_dev_node(dev, dev_to_node(parent));
1001
1002        /* first, register with generic layer. */
1003        /* we require the name to be set before, and pass NULL */
1004        error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1005        if (error)
1006                goto Error;
1007
1008        /* notify platform of device entry */
1009        if (platform_notify)
1010                platform_notify(dev);
1011
1012        error = device_create_file(dev, &uevent_attr);
1013        if (error)
1014                goto attrError;
1015
1016        if (MAJOR(dev->devt)) {
1017                error = device_create_file(dev, &devt_attr);
1018                if (error)
1019                        goto ueventattrError;
1020
1021                error = device_create_sys_dev_entry(dev);
1022                if (error)
1023                        goto devtattrError;
1024
1025                devtmpfs_create_node(dev);
1026        }
1027
1028        error = device_add_class_symlinks(dev);
1029        if (error)
1030                goto SymlinkError;
1031        error = device_add_attrs(dev);
1032        if (error)
1033                goto AttrsError;
1034        error = bus_add_device(dev);
1035        if (error)
1036                goto BusError;
1037        error = dpm_sysfs_add(dev);
1038        if (error)
1039                goto DPMError;
1040        device_pm_add(dev);
1041
1042        /* Notify clients of device addition.  This call must come
1043         * after dpm_sysfs_add() and before kobject_uevent().
1044         */
1045        if (dev->bus)
1046                blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1047                                             BUS_NOTIFY_ADD_DEVICE, dev);
1048
1049        kobject_uevent(&dev->kobj, KOBJ_ADD);
1050        bus_probe_device(dev);
1051        if (parent)
1052                klist_add_tail(&dev->p->knode_parent,
1053                               &parent->p->klist_children);
1054
1055        if (dev->class) {
1056                mutex_lock(&dev->class->p->mutex);
1057                /* tie the class to the device */
1058                klist_add_tail(&dev->knode_class,
1059                               &dev->class->p->klist_devices);
1060
1061                /* notify any interfaces that the device is here */
1062                list_for_each_entry(class_intf,
1063                                    &dev->class->p->interfaces, node)
1064                        if (class_intf->add_dev)
1065                                class_intf->add_dev(dev, class_intf);
1066                mutex_unlock(&dev->class->p->mutex);
1067        }
1068done:
1069        put_device(dev);
1070        return error;
1071 DPMError:
1072        bus_remove_device(dev);
1073 BusError:
1074        device_remove_attrs(dev);
1075 AttrsError:
1076        device_remove_class_symlinks(dev);
1077 SymlinkError:
1078        if (MAJOR(dev->devt))
1079                devtmpfs_delete_node(dev);
1080        if (MAJOR(dev->devt))
1081                device_remove_sys_dev_entry(dev);
1082 devtattrError:
1083        if (MAJOR(dev->devt))
1084                device_remove_file(dev, &devt_attr);
1085 ueventattrError:
1086        device_remove_file(dev, &uevent_attr);
1087 attrError:
1088        kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1089        kobject_del(&dev->kobj);
1090 Error:
1091        cleanup_device_parent(dev);
1092        if (parent)
1093                put_device(parent);
1094name_error:
1095        kfree(dev->p);
1096        dev->p = NULL;
1097        goto done;
1098}
1099
1100/**
1101 * device_register - register a device with the system.
1102 * @dev: pointer to the device structure
1103 *
1104 * This happens in two clean steps - initialize the device
1105 * and add it to the system. The two steps can be called
1106 * separately, but this is the easiest and most common.
1107 * I.e. you should only call the two helpers separately if
1108 * have a clearly defined need to use and refcount the device
1109 * before it is added to the hierarchy.
1110 *
1111 * For more information, see the kerneldoc for device_initialize()
1112 * and device_add().
1113 *
1114 * NOTE: _Never_ directly free @dev after calling this function, even
1115 * if it returned an error! Always use put_device() to give up the
1116 * reference initialized in this function instead.
1117 */
1118int device_register(struct device *dev)
1119{
1120        device_initialize(dev);
1121        return device_add(dev);
1122}
1123
1124/**
1125 * get_device - increment reference count for device.
1126 * @dev: device.
1127 *
1128 * This simply forwards the call to kobject_get(), though
1129 * we do take care to provide for the case that we get a NULL
1130 * pointer passed in.
1131 */
1132struct device *get_device(struct device *dev)
1133{
1134        return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1135}
1136
1137/**
1138 * put_device - decrement reference count.
1139 * @dev: device in question.
1140 */
1141void put_device(struct device *dev)
1142{
1143        /* might_sleep(); */
1144        if (dev)
1145                kobject_put(&dev->kobj);
1146}
1147
1148/**
1149 * device_del - delete device from system.
1150 * @dev: device.
1151 *
1152 * This is the first part of the device unregistration
1153 * sequence. This removes the device from the lists we control
1154 * from here, has it removed from the other driver model
1155 * subsystems it was added to in device_add(), and removes it
1156 * from the kobject hierarchy.
1157 *
1158 * NOTE: this should be called manually _iff_ device_add() was
1159 * also called manually.
1160 */
1161void device_del(struct device *dev)
1162{
1163        struct device *parent = dev->parent;
1164        struct class_interface *class_intf;
1165
1166        /* Notify clients of device removal.  This call must come
1167         * before dpm_sysfs_remove().
1168         */
1169        if (dev->bus)
1170                blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1171                                             BUS_NOTIFY_DEL_DEVICE, dev);
1172        device_pm_remove(dev);
1173        dpm_sysfs_remove(dev);
1174        if (parent)
1175                klist_del(&dev->p->knode_parent);
1176        if (MAJOR(dev->devt)) {
1177                devtmpfs_delete_node(dev);
1178                device_remove_sys_dev_entry(dev);
1179                device_remove_file(dev, &devt_attr);
1180        }
1181        if (dev->class) {
1182                device_remove_class_symlinks(dev);
1183
1184                mutex_lock(&dev->class->p->mutex);
1185                /* notify any interfaces that the device is now gone */
1186                list_for_each_entry(class_intf,
1187                                    &dev->class->p->interfaces, node)
1188                        if (class_intf->remove_dev)
1189                                class_intf->remove_dev(dev, class_intf);
1190                /* remove the device from the class list */
1191                klist_del(&dev->knode_class);
1192                mutex_unlock(&dev->class->p->mutex);
1193        }
1194        device_remove_file(dev, &uevent_attr);
1195        device_remove_attrs(dev);
1196        bus_remove_device(dev);
1197        driver_deferred_probe_del(dev);
1198
1199        /*
1200         * Some platform devices are driven without driver attached
1201         * and managed resources may have been acquired.  Make sure
1202         * all resources are released.
1203         */
1204        devres_release_all(dev);
1205
1206        /* Notify the platform of the removal, in case they
1207         * need to do anything...
1208         */
1209        if (platform_notify_remove)
1210                platform_notify_remove(dev);
1211        kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1212        cleanup_device_parent(dev);
1213        kobject_del(&dev->kobj);
1214        put_device(parent);
1215}
1216
1217/**
1218 * device_unregister - unregister device from system.
1219 * @dev: device going away.
1220 *
1221 * We do this in two parts, like we do device_register(). First,
1222 * we remove it from all the subsystems with device_del(), then
1223 * we decrement the reference count via put_device(). If that
1224 * is the final reference count, the device will be cleaned up
1225 * via device_release() above. Otherwise, the structure will
1226 * stick around until the final reference to the device is dropped.
1227 */
1228void device_unregister(struct device *dev)
1229{
1230        pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1231        device_del(dev);
1232        put_device(dev);
1233}
1234
1235static struct device *next_device(struct klist_iter *i)
1236{
1237        struct klist_node *n = klist_next(i);
1238        struct device *dev = NULL;
1239        struct device_private *p;
1240
1241        if (n) {
1242                p = to_device_private_parent(n);
1243                dev = p->device;
1244        }
1245        return dev;
1246}
1247
1248/**
1249 * device_get_devnode - path of device node file
1250 * @dev: device
1251 * @mode: returned file access mode
1252 * @tmp: possibly allocated string
1253 *
1254 * Return the relative path of a possible device node.
1255 * Non-default names may need to allocate a memory to compose
1256 * a name. This memory is returned in tmp and needs to be
1257 * freed by the caller.
1258 */
1259const char *device_get_devnode(struct device *dev,
1260                               umode_t *mode, const char **tmp)
1261{
1262        char *s;
1263
1264        *tmp = NULL;
1265
1266        /* the device type may provide a specific name */
1267        if (dev->type && dev->type->devnode)
1268                *tmp = dev->type->devnode(dev, mode);
1269        if (*tmp)
1270                return *tmp;
1271
1272        /* the class may provide a specific name */
1273        if (dev->class && dev->class->devnode)
1274                *tmp = dev->class->devnode(dev, mode);
1275        if (*tmp)
1276                return *tmp;
1277
1278        /* return name without allocation, tmp == NULL */
1279        if (strchr(dev_name(dev), '!') == NULL)
1280                return dev_name(dev);
1281
1282        /* replace '!' in the name with '/' */
1283        *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1284        if (!*tmp)
1285                return NULL;
1286        while ((s = strchr(*tmp, '!')))
1287                s[0] = '/';
1288        return *tmp;
1289}
1290
1291/**
1292 * device_for_each_child - device child iterator.
1293 * @parent: parent struct device.
1294 * @data: data for the callback.
1295 * @fn: function to be called for each device.
1296 *
1297 * Iterate over @parent's child devices, and call @fn for each,
1298 * passing it @data.
1299 *
1300 * We check the return of @fn each time. If it returns anything
1301 * other than 0, we break out and return that value.
1302 */
1303int device_for_each_child(struct device *parent, void *data,
1304                          int (*fn)(struct device *dev, void *data))
1305{
1306        struct klist_iter i;
1307        struct device *child;
1308        int error = 0;
1309
1310        if (!parent->p)
1311                return 0;
1312
1313        klist_iter_init(&parent->p->klist_children, &i);
1314        while ((child = next_device(&i)) && !error)
1315                error = fn(child, data);
1316        klist_iter_exit(&i);
1317        return error;
1318}
1319
1320/**
1321 * device_find_child - device iterator for locating a particular device.
1322 * @parent: parent struct device
1323 * @data: Data to pass to match function
1324 * @match: Callback function to check device
1325 *
1326 * This is similar to the device_for_each_child() function above, but it
1327 * returns a reference to a device that is 'found' for later use, as
1328 * determined by the @match callback.
1329 *
1330 * The callback should return 0 if the device doesn't match and non-zero
1331 * if it does.  If the callback returns non-zero and a reference to the
1332 * current device can be obtained, this function will return to the caller
1333 * and not iterate over any more devices.
1334 */
1335struct device *device_find_child(struct device *parent, void *data,
1336                                 int (*match)(struct device *dev, void *data))
1337{
1338        struct klist_iter i;
1339        struct device *child;
1340
1341        if (!parent)
1342                return NULL;
1343
1344        klist_iter_init(&parent->p->klist_children, &i);
1345        while ((child = next_device(&i)))
1346                if (match(child, data) && get_device(child))
1347                        break;
1348        klist_iter_exit(&i);
1349        return child;
1350}
1351
1352int __init devices_init(void)
1353{
1354        devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1355        if (!devices_kset)
1356                return -ENOMEM;
1357        dev_kobj = kobject_create_and_add("dev", NULL);
1358        if (!dev_kobj)
1359                goto dev_kobj_err;
1360        sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1361        if (!sysfs_dev_block_kobj)
1362                goto block_kobj_err;
1363        sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1364        if (!sysfs_dev_char_kobj)
1365                goto char_kobj_err;
1366
1367        return 0;
1368
1369 char_kobj_err:
1370        kobject_put(sysfs_dev_block_kobj);
1371 block_kobj_err:
1372        kobject_put(dev_kobj);
1373 dev_kobj_err:
1374        kset_unregister(devices_kset);
1375        return -ENOMEM;
1376}
1377
1378EXPORT_SYMBOL_GPL(device_for_each_child);
1379EXPORT_SYMBOL_GPL(device_find_child);
1380
1381EXPORT_SYMBOL_GPL(device_initialize);
1382EXPORT_SYMBOL_GPL(device_add);
1383EXPORT_SYMBOL_GPL(device_register);
1384
1385EXPORT_SYMBOL_GPL(device_del);
1386EXPORT_SYMBOL_GPL(device_unregister);
1387EXPORT_SYMBOL_GPL(get_device);
1388EXPORT_SYMBOL_GPL(put_device);
1389
1390EXPORT_SYMBOL_GPL(device_create_file);
1391EXPORT_SYMBOL_GPL(device_remove_file);
1392
1393struct root_device {
1394        struct device dev;
1395        struct module *owner;
1396};
1397
1398inline struct root_device *to_root_device(struct device *d)
1399{
1400        return container_of(d, struct root_device, dev);
1401}
1402
1403static void root_device_release(struct device *dev)
1404{
1405        kfree(to_root_device(dev));
1406}
1407
1408/**
1409 * __root_device_register - allocate and register a root device
1410 * @name: root device name
1411 * @owner: owner module of the root device, usually THIS_MODULE
1412 *
1413 * This function allocates a root device and registers it
1414 * using device_register(). In order to free the returned
1415 * device, use root_device_unregister().
1416 *
1417 * Root devices are dummy devices which allow other devices
1418 * to be grouped under /sys/devices. Use this function to
1419 * allocate a root device and then use it as the parent of
1420 * any device which should appear under /sys/devices/{name}
1421 *
1422 * The /sys/devices/{name} directory will also contain a
1423 * 'module' symlink which points to the @owner directory
1424 * in sysfs.
1425 *
1426 * Returns &struct device pointer on success, or ERR_PTR() on error.
1427 *
1428 * Note: You probably want to use root_device_register().
1429 */
1430struct device *__root_device_register(const char *name, struct module *owner)
1431{
1432        struct root_device *root;
1433        int err = -ENOMEM;
1434
1435        root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1436        if (!root)
1437                return ERR_PTR(err);
1438
1439        err = dev_set_name(&root->dev, "%s", name);
1440        if (err) {
1441                kfree(root);
1442                return ERR_PTR(err);
1443        }
1444
1445        root->dev.release = root_device_release;
1446
1447        err = device_register(&root->dev);
1448        if (err) {
1449                put_device(&root->dev);
1450                return ERR_PTR(err);
1451        }
1452
1453#ifdef CONFIG_MODULES   /* gotta find a "cleaner" way to do this */
1454        if (owner) {
1455                struct module_kobject *mk = &owner->mkobj;
1456
1457                err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1458                if (err) {
1459                        device_unregister(&root->dev);
1460                        return ERR_PTR(err);
1461                }
1462                root->owner = owner;
1463        }
1464#endif
1465
1466        return &root->dev;
1467}
1468EXPORT_SYMBOL_GPL(__root_device_register);
1469
1470/**
1471 * root_device_unregister - unregister and free a root device
1472 * @dev: device going away
1473 *
1474 * This function unregisters and cleans up a device that was created by
1475 * root_device_register().
1476 */
1477void root_device_unregister(struct device *dev)
1478{
1479        struct root_device *root = to_root_device(dev);
1480
1481        if (root->owner)
1482                sysfs_remove_link(&root->dev.kobj, "module");
1483
1484        device_unregister(dev);
1485}
1486EXPORT_SYMBOL_GPL(root_device_unregister);
1487
1488
1489static void device_create_release(struct device *dev)
1490{
1491        pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1492        kfree(dev);
1493}
1494
1495/**
1496 * device_create_vargs - creates a device and registers it with sysfs
1497 * @class: pointer to the struct class that this device should be registered to
1498 * @parent: pointer to the parent struct device of this new device, if any
1499 * @devt: the dev_t for the char device to be added
1500 * @drvdata: the data to be added to the device for callbacks
1501 * @fmt: string for the device's name
1502 * @args: va_list for the device's name
1503 *
1504 * This function can be used by char device classes.  A struct device
1505 * will be created in sysfs, registered to the specified class.
1506 *
1507 * A "dev" file will be created, showing the dev_t for the device, if
1508 * the dev_t is not 0,0.
1509 * If a pointer to a parent struct device is passed in, the newly created
1510 * struct device will be a child of that device in sysfs.
1511 * The pointer to the struct device will be returned from the call.
1512 * Any further sysfs files that might be required can be created using this
1513 * pointer.
1514 *
1515 * Returns &struct device pointer on success, or ERR_PTR() on error.
1516 *
1517 * Note: the struct class passed to this function must have previously
1518 * been created with a call to class_create().
1519 */
1520struct device *device_create_vargs(struct class *class, struct device *parent,
1521                                   dev_t devt, void *drvdata, const char *fmt,
1522                                   va_list args)
1523{
1524        struct device *dev = NULL;
1525        int retval = -ENODEV;
1526
1527        if (class == NULL || IS_ERR(class))
1528                goto error;
1529
1530        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1531        if (!dev) {
1532                retval = -ENOMEM;
1533                goto error;
1534        }
1535
1536        dev->devt = devt;
1537        dev->class = class;
1538        dev->parent = parent;
1539        dev->release = device_create_release;
1540        dev_set_drvdata(dev, drvdata);
1541
1542        retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1543        if (retval)
1544                goto error;
1545
1546        retval = device_register(dev);
1547        if (retval)
1548                goto error;
1549
1550        return dev;
1551
1552error:
1553        put_device(dev);
1554        return ERR_PTR(retval);
1555}
1556EXPORT_SYMBOL_GPL(device_create_vargs);
1557
1558/**
1559 * device_create - creates a device and registers it with sysfs
1560 * @class: pointer to the struct class that this device should be registered to
1561 * @parent: pointer to the parent struct device of this new device, if any
1562 * @devt: the dev_t for the char device to be added
1563 * @drvdata: the data to be added to the device for callbacks
1564 * @fmt: string for the device's name
1565 *
1566 * This function can be used by char device classes.  A struct device
1567 * will be created in sysfs, registered to the specified class.
1568 *
1569 * A "dev" file will be created, showing the dev_t for the device, if
1570 * the dev_t is not 0,0.
1571 * If a pointer to a parent struct device is passed in, the newly created
1572 * struct device will be a child of that device in sysfs.
1573 * The pointer to the struct device will be returned from the call.
1574 * Any further sysfs files that might be required can be created using this
1575 * pointer.
1576 *
1577 * Returns &struct device pointer on success, or ERR_PTR() on error.
1578 *
1579 * Note: the struct class passed to this function must have previously
1580 * been created with a call to class_create().
1581 */
1582struct device *device_create(struct class *class, struct device *parent,
1583                             dev_t devt, void *drvdata, const char *fmt, ...)
1584{
1585        va_list vargs;
1586        struct device *dev;
1587
1588        va_start(vargs, fmt);
1589        dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1590        va_end(vargs);
1591        return dev;
1592}
1593EXPORT_SYMBOL_GPL(device_create);
1594
1595static int __match_devt(struct device *dev, void *data)
1596{
1597        dev_t *devt = data;
1598
1599        return dev->devt == *devt;
1600}
1601
1602/**
1603 * device_destroy - removes a device that was created with device_create()
1604 * @class: pointer to the struct class that this device was registered with
1605 * @devt: the dev_t of the device that was previously registered
1606 *
1607 * This call unregisters and cleans up a device that was created with a
1608 * call to device_create().
1609 */
1610void device_destroy(struct class *class, dev_t devt)
1611{
1612        struct device *dev;
1613
1614        dev = class_find_device(class, NULL, &devt, __match_devt);
1615        if (dev) {
1616                put_device(dev);
1617                device_unregister(dev);
1618        }
1619}
1620EXPORT_SYMBOL_GPL(device_destroy);
1621
1622/**
1623 * device_rename - renames a device
1624 * @dev: the pointer to the struct device to be renamed
1625 * @new_name: the new name of the device
1626 *
1627 * It is the responsibility of the caller to provide mutual
1628 * exclusion between two different calls of device_rename
1629 * on the same device to ensure that new_name is valid and
1630 * won't conflict with other devices.
1631 *
1632 * Note: Don't call this function.  Currently, the networking layer calls this
1633 * function, but that will change.  The following text from Kay Sievers offers
1634 * some insight:
1635 *
1636 * Renaming devices is racy at many levels, symlinks and other stuff are not
1637 * replaced atomically, and you get a "move" uevent, but it's not easy to
1638 * connect the event to the old and new device. Device nodes are not renamed at
1639 * all, there isn't even support for that in the kernel now.
1640 *
1641 * In the meantime, during renaming, your target name might be taken by another
1642 * driver, creating conflicts. Or the old name is taken directly after you
1643 * renamed it -- then you get events for the same DEVPATH, before you even see
1644 * the "move" event. It's just a mess, and nothing new should ever rely on
1645 * kernel device renaming. Besides that, it's not even implemented now for
1646 * other things than (driver-core wise very simple) network devices.
1647 *
1648 * We are currently about to change network renaming in udev to completely
1649 * disallow renaming of devices in the same namespace as the kernel uses,
1650 * because we can't solve the problems properly, that arise with swapping names
1651 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1652 * be allowed to some other name than eth[0-9]*, for the aforementioned
1653 * reasons.
1654 *
1655 * Make up a "real" name in the driver before you register anything, or add
1656 * some other attributes for userspace to find the device, or use udev to add
1657 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1658 * don't even want to get into that and try to implement the missing pieces in
1659 * the core. We really have other pieces to fix in the driver core mess. :)
1660 */
1661int device_rename(struct device *dev, const char *new_name)
1662{
1663        char *old_class_name = NULL;
1664        char *new_class_name = NULL;
1665        char *old_device_name = NULL;
1666        int error;
1667
1668        dev = get_device(dev);
1669        if (!dev)
1670                return -EINVAL;
1671
1672        pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1673                 __func__, new_name);
1674
1675        old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1676        if (!old_device_name) {
1677                error = -ENOMEM;
1678                goto out;
1679        }
1680
1681        if (dev->class) {
1682                error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1683                        &dev->kobj, old_device_name, new_name);
1684                if (error)
1685                        goto out;
1686        }
1687
1688        error = kobject_rename(&dev->kobj, new_name);
1689        if (error)
1690                goto out;
1691
1692out:
1693        put_device(dev);
1694
1695        kfree(new_class_name);
1696        kfree(old_class_name);
1697        kfree(old_device_name);
1698
1699        return error;
1700}
1701EXPORT_SYMBOL_GPL(device_rename);
1702
1703static int device_move_class_links(struct device *dev,
1704                                   struct device *old_parent,
1705                                   struct device *new_parent)
1706{
1707        int error = 0;
1708
1709        if (old_parent)
1710                sysfs_remove_link(&dev->kobj, "device");
1711        if (new_parent)
1712                error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1713                                          "device");
1714        return error;
1715}
1716
1717/**
1718 * device_move - moves a device to a new parent
1719 * @dev: the pointer to the struct device to be moved
1720 * @new_parent: the new parent of the device (can by NULL)
1721 * @dpm_order: how to reorder the dpm_list
1722 */
1723int device_move(struct device *dev, struct device *new_parent,
1724                enum dpm_order dpm_order)
1725{
1726        int error;
1727        struct device *old_parent;
1728        struct kobject *new_parent_kobj;
1729
1730        dev = get_device(dev);
1731        if (!dev)
1732                return -EINVAL;
1733
1734        device_pm_lock();
1735        new_parent = get_device(new_parent);
1736        new_parent_kobj = get_device_parent(dev, new_parent);
1737
1738        pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1739                 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1740        error = kobject_move(&dev->kobj, new_parent_kobj);
1741        if (error) {
1742                cleanup_glue_dir(dev, new_parent_kobj);
1743                put_device(new_parent);
1744                goto out;
1745        }
1746        old_parent = dev->parent;
1747        dev->parent = new_parent;
1748        if (old_parent)
1749                klist_remove(&dev->p->knode_parent);
1750        if (new_parent) {
1751                klist_add_tail(&dev->p->knode_parent,
1752                               &new_parent->p->klist_children);
1753                set_dev_node(dev, dev_to_node(new_parent));
1754        }
1755
1756        if (dev->class) {
1757                error = device_move_class_links(dev, old_parent, new_parent);
1758                if (error) {
1759                        /* We ignore errors on cleanup since we're hosed anyway... */
1760                        device_move_class_links(dev, new_parent, old_parent);
1761                        if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1762                                if (new_parent)
1763                                        klist_remove(&dev->p->knode_parent);
1764                                dev->parent = old_parent;
1765                                if (old_parent) {
1766                                        klist_add_tail(&dev->p->knode_parent,
1767                                                       &old_parent->p->klist_children);
1768                                        set_dev_node(dev, dev_to_node(old_parent));
1769                                }
1770                        }
1771                        cleanup_glue_dir(dev, new_parent_kobj);
1772                        put_device(new_parent);
1773                        goto out;
1774                }
1775        }
1776        switch (dpm_order) {
1777        case DPM_ORDER_NONE:
1778                break;
1779        case DPM_ORDER_DEV_AFTER_PARENT:
1780                device_pm_move_after(dev, new_parent);
1781                break;
1782        case DPM_ORDER_PARENT_BEFORE_DEV:
1783                device_pm_move_before(new_parent, dev);
1784                break;
1785        case DPM_ORDER_DEV_LAST:
1786                device_pm_move_last(dev);
1787                break;
1788        }
1789
1790        put_device(old_parent);
1791out:
1792        device_pm_unlock();
1793        put_device(dev);
1794        return error;
1795}
1796EXPORT_SYMBOL_GPL(device_move);
1797
1798/**
1799 * device_shutdown - call ->shutdown() on each device to shutdown.
1800 */
1801void device_shutdown(void)
1802{
1803        struct device *dev;
1804
1805        spin_lock(&devices_kset->list_lock);
1806        /*
1807         * Walk the devices list backward, shutting down each in turn.
1808         * Beware that device unplug events may also start pulling
1809         * devices offline, even as the system is shutting down.
1810         */
1811        while (!list_empty(&devices_kset->list)) {
1812                dev = list_entry(devices_kset->list.prev, struct device,
1813                                kobj.entry);
1814
1815                /*
1816                 * hold reference count of device's parent to
1817                 * prevent it from being freed because parent's
1818                 * lock is to be held
1819                 */
1820                get_device(dev->parent);
1821                get_device(dev);
1822                /*
1823                 * Make sure the device is off the kset list, in the
1824                 * event that dev->*->shutdown() doesn't remove it.
1825                 */
1826                list_del_init(&dev->kobj.entry);
1827                spin_unlock(&devices_kset->list_lock);
1828
1829                /* hold lock to avoid race with probe/release */
1830                if (dev->parent)
1831                        device_lock(dev->parent);
1832                device_lock(dev);
1833
1834                /* Don't allow any more runtime suspends */
1835                pm_runtime_get_noresume(dev);
1836                pm_runtime_barrier(dev);
1837
1838                if (dev->bus && dev->bus->shutdown) {
1839                        dev_dbg(dev, "shutdown\n");
1840                        dev->bus->shutdown(dev);
1841                } else if (dev->driver && dev->driver->shutdown) {
1842                        dev_dbg(dev, "shutdown\n");
1843                        dev->driver->shutdown(dev);
1844                }
1845
1846                device_unlock(dev);
1847                if (dev->parent)
1848                        device_unlock(dev->parent);
1849
1850                put_device(dev);
1851                put_device(dev->parent);
1852
1853                spin_lock(&devices_kset->list_lock);
1854        }
1855        spin_unlock(&devices_kset->list_lock);
1856        async_synchronize_full();
1857}
1858
1859/*
1860 * Device logging functions
1861 */
1862
1863#ifdef CONFIG_PRINTK
1864int __dev_printk(const char *level, const struct device *dev,
1865                 struct va_format *vaf)
1866{
1867        char dict[128];
1868        const char *level_extra = "";
1869        size_t dictlen = 0;
1870        const char *subsys;
1871
1872        if (!dev)
1873                return printk("%s(NULL device *): %pV", level, vaf);
1874
1875        if (dev->class)
1876                subsys = dev->class->name;
1877        else if (dev->bus)
1878                subsys = dev->bus->name;
1879        else
1880                goto skip;
1881
1882        dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
1883                            "SUBSYSTEM=%s", subsys);
1884
1885        /*
1886         * Add device identifier DEVICE=:
1887         *   b12:8         block dev_t
1888         *   c127:3        char dev_t
1889         *   n8            netdev ifindex
1890         *   +sound:card0  subsystem:devname
1891         */
1892        if (MAJOR(dev->devt)) {
1893                char c;
1894
1895                if (strcmp(subsys, "block") == 0)
1896                        c = 'b';
1897                else
1898                        c = 'c';
1899                dictlen++;
1900                dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
1901                                   "DEVICE=%c%u:%u",
1902                                   c, MAJOR(dev->devt), MINOR(dev->devt));
1903        } else if (strcmp(subsys, "net") == 0) {
1904                struct net_device *net = to_net_dev(dev);
1905
1906                dictlen++;
1907                dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
1908                                    "DEVICE=n%u", net->ifindex);
1909        } else {
1910                dictlen++;
1911                dictlen += snprintf(dict + dictlen, sizeof(dict) - dictlen,
1912                                    "DEVICE=+%s:%s", subsys, dev_name(dev));
1913        }
1914skip:
1915        if (level[2])
1916                level_extra = &level[2]; /* skip past KERN_SOH "L" */
1917
1918        return printk_emit(0, level[1] - '0',
1919                           dictlen ? dict : NULL, dictlen,
1920                           "%s %s: %s%pV",
1921                           dev_driver_string(dev), dev_name(dev),
1922                           level_extra, vaf);
1923}
1924EXPORT_SYMBOL(__dev_printk);
1925
1926int dev_printk(const char *level, const struct device *dev,
1927               const char *fmt, ...)
1928{
1929        struct va_format vaf;
1930        va_list args;
1931        int r;
1932
1933        va_start(args, fmt);
1934
1935        vaf.fmt = fmt;
1936        vaf.va = &args;
1937
1938        r = __dev_printk(level, dev, &vaf);
1939        va_end(args);
1940
1941        return r;
1942}
1943EXPORT_SYMBOL(dev_printk);
1944
1945#define define_dev_printk_level(func, kern_level)               \
1946int func(const struct device *dev, const char *fmt, ...)        \
1947{                                                               \
1948        struct va_format vaf;                                   \
1949        va_list args;                                           \
1950        int r;                                                  \
1951                                                                \
1952        va_start(args, fmt);                                    \
1953                                                                \
1954        vaf.fmt = fmt;                                          \
1955        vaf.va = &args;                                         \
1956                                                                \
1957        r = __dev_printk(kern_level, dev, &vaf);                \
1958        va_end(args);                                           \
1959                                                                \
1960        return r;                                               \
1961}                                                               \
1962EXPORT_SYMBOL(func);
1963
1964define_dev_printk_level(dev_emerg, KERN_EMERG);
1965define_dev_printk_level(dev_alert, KERN_ALERT);
1966define_dev_printk_level(dev_crit, KERN_CRIT);
1967define_dev_printk_level(dev_err, KERN_ERR);
1968define_dev_printk_level(dev_warn, KERN_WARNING);
1969define_dev_printk_level(dev_notice, KERN_NOTICE);
1970define_dev_printk_level(_dev_info, KERN_INFO);
1971
1972#endif
1973
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