Root/drivers/base/core.c

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
174ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
175              const char *buf, size_t size)
176{
177    struct dev_ext_attribute *ea = to_ext_attr(attr);
178
179    if (strtobool(buf, ea->var) < 0)
180        return -EINVAL;
181
182    return size;
183}
184EXPORT_SYMBOL_GPL(device_store_bool);
185
186ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
187             char *buf)
188{
189    struct dev_ext_attribute *ea = to_ext_attr(attr);
190
191    return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
192}
193EXPORT_SYMBOL_GPL(device_show_bool);
194
195/**
196 * device_release - free device structure.
197 * @kobj: device's kobject.
198 *
199 * This is called once the reference count for the object
200 * reaches 0. We forward the call to the device's release
201 * method, which should handle actually freeing the structure.
202 */
203static void device_release(struct kobject *kobj)
204{
205    struct device *dev = kobj_to_dev(kobj);
206    struct device_private *p = dev->p;
207
208    /*
209     * Some platform devices are driven without driver attached
210     * and managed resources may have been acquired. Make sure
211     * all resources are released.
212     *
213     * Drivers still can add resources into device after device
214     * is deleted but alive, so release devres here to avoid
215     * possible memory leak.
216     */
217    devres_release_all(dev);
218
219    if (dev->release)
220        dev->release(dev);
221    else if (dev->type && dev->type->release)
222        dev->type->release(dev);
223    else if (dev->class && dev->class->dev_release)
224        dev->class->dev_release(dev);
225    else
226        WARN(1, KERN_ERR "Device '%s' does not have a release() "
227            "function, it is broken and must be fixed.\n",
228            dev_name(dev));
229    kfree(p);
230}
231
232static const void *device_namespace(struct kobject *kobj)
233{
234    struct device *dev = kobj_to_dev(kobj);
235    const void *ns = NULL;
236
237    if (dev->class && dev->class->ns_type)
238        ns = dev->class->namespace(dev);
239
240    return ns;
241}
242
243static struct kobj_type device_ktype = {
244    .release = device_release,
245    .sysfs_ops = &dev_sysfs_ops,
246    .namespace = device_namespace,
247};
248
249
250static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
251{
252    struct kobj_type *ktype = get_ktype(kobj);
253
254    if (ktype == &device_ktype) {
255        struct device *dev = kobj_to_dev(kobj);
256        if (dev->bus)
257            return 1;
258        if (dev->class)
259            return 1;
260    }
261    return 0;
262}
263
264static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
265{
266    struct device *dev = kobj_to_dev(kobj);
267
268    if (dev->bus)
269        return dev->bus->name;
270    if (dev->class)
271        return dev->class->name;
272    return NULL;
273}
274
275static int dev_uevent(struct kset *kset, struct kobject *kobj,
276              struct kobj_uevent_env *env)
277{
278    struct device *dev = kobj_to_dev(kobj);
279    int retval = 0;
280
281    /* add device node properties if present */
282    if (MAJOR(dev->devt)) {
283        const char *tmp;
284        const char *name;
285        umode_t mode = 0;
286
287        add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
288        add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
289        name = device_get_devnode(dev, &mode, &tmp);
290        if (name) {
291            add_uevent_var(env, "DEVNAME=%s", name);
292            kfree(tmp);
293            if (mode)
294                add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
295        }
296    }
297
298    if (dev->type && dev->type->name)
299        add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
300
301    if (dev->driver)
302        add_uevent_var(env, "DRIVER=%s", dev->driver->name);
303
304    /* Add common DT information about the device */
305    of_device_uevent(dev, env);
306
307    /* have the bus specific function add its stuff */
308    if (dev->bus && dev->bus->uevent) {
309        retval = dev->bus->uevent(dev, env);
310        if (retval)
311            pr_debug("device: '%s': %s: bus uevent() returned %d\n",
312                 dev_name(dev), __func__, retval);
313    }
314
315    /* have the class specific function add its stuff */
316    if (dev->class && dev->class->dev_uevent) {
317        retval = dev->class->dev_uevent(dev, env);
318        if (retval)
319            pr_debug("device: '%s': %s: class uevent() "
320                 "returned %d\n", dev_name(dev),
321                 __func__, retval);
322    }
323
324    /* have the device type specific function add its stuff */
325    if (dev->type && dev->type->uevent) {
326        retval = dev->type->uevent(dev, env);
327        if (retval)
328            pr_debug("device: '%s': %s: dev_type uevent() "
329                 "returned %d\n", dev_name(dev),
330                 __func__, retval);
331    }
332
333    return retval;
334}
335
336static const struct kset_uevent_ops device_uevent_ops = {
337    .filter = dev_uevent_filter,
338    .name = dev_uevent_name,
339    .uevent = dev_uevent,
340};
341
342static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
343               char *buf)
344{
345    struct kobject *top_kobj;
346    struct kset *kset;
347    struct kobj_uevent_env *env = NULL;
348    int i;
349    size_t count = 0;
350    int retval;
351
352    /* search the kset, the device belongs to */
353    top_kobj = &dev->kobj;
354    while (!top_kobj->kset && top_kobj->parent)
355        top_kobj = top_kobj->parent;
356    if (!top_kobj->kset)
357        goto out;
358
359    kset = top_kobj->kset;
360    if (!kset->uevent_ops || !kset->uevent_ops->uevent)
361        goto out;
362
363    /* respect filter */
364    if (kset->uevent_ops && kset->uevent_ops->filter)
365        if (!kset->uevent_ops->filter(kset, &dev->kobj))
366            goto out;
367
368    env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
369    if (!env)
370        return -ENOMEM;
371
372    /* let the kset specific function add its keys */
373    retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
374    if (retval)
375        goto out;
376
377    /* copy keys to file */
378    for (i = 0; i < env->envp_idx; i++)
379        count += sprintf(&buf[count], "%s\n", env->envp[i]);
380out:
381    kfree(env);
382    return count;
383}
384
385static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
386                const char *buf, size_t count)
387{
388    enum kobject_action action;
389
390    if (kobject_action_type(buf, count, &action) == 0)
391        kobject_uevent(&dev->kobj, action);
392    else
393        dev_err(dev, "uevent: unknown action-string\n");
394    return count;
395}
396
397static struct device_attribute uevent_attr =
398    __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
399
400static int device_add_attributes(struct device *dev,
401                 struct device_attribute *attrs)
402{
403    int error = 0;
404    int i;
405
406    if (attrs) {
407        for (i = 0; attr_name(attrs[i]); i++) {
408            error = device_create_file(dev, &attrs[i]);
409            if (error)
410                break;
411        }
412        if (error)
413            while (--i >= 0)
414                device_remove_file(dev, &attrs[i]);
415    }
416    return error;
417}
418
419static void device_remove_attributes(struct device *dev,
420                     struct device_attribute *attrs)
421{
422    int i;
423
424    if (attrs)
425        for (i = 0; attr_name(attrs[i]); i++)
426            device_remove_file(dev, &attrs[i]);
427}
428
429static int device_add_bin_attributes(struct device *dev,
430                     struct bin_attribute *attrs)
431{
432    int error = 0;
433    int i;
434
435    if (attrs) {
436        for (i = 0; attr_name(attrs[i]); i++) {
437            error = device_create_bin_file(dev, &attrs[i]);
438            if (error)
439                break;
440        }
441        if (error)
442            while (--i >= 0)
443                device_remove_bin_file(dev, &attrs[i]);
444    }
445    return error;
446}
447
448static void device_remove_bin_attributes(struct device *dev,
449                     struct bin_attribute *attrs)
450{
451    int i;
452
453    if (attrs)
454        for (i = 0; attr_name(attrs[i]); i++)
455            device_remove_bin_file(dev, &attrs[i]);
456}
457
458static int device_add_groups(struct device *dev,
459                 const struct attribute_group **groups)
460{
461    int error = 0;
462    int i;
463
464    if (groups) {
465        for (i = 0; groups[i]; i++) {
466            error = sysfs_create_group(&dev->kobj, groups[i]);
467            if (error) {
468                while (--i >= 0)
469                    sysfs_remove_group(&dev->kobj,
470                               groups[i]);
471                break;
472            }
473        }
474    }
475    return error;
476}
477
478static void device_remove_groups(struct device *dev,
479                 const struct attribute_group **groups)
480{
481    int i;
482
483    if (groups)
484        for (i = 0; groups[i]; i++)
485            sysfs_remove_group(&dev->kobj, groups[i]);
486}
487
488static int device_add_attrs(struct device *dev)
489{
490    struct class *class = dev->class;
491    const struct device_type *type = dev->type;
492    int error;
493
494    if (class) {
495        error = device_add_attributes(dev, class->dev_attrs);
496        if (error)
497            return error;
498        error = device_add_bin_attributes(dev, class->dev_bin_attrs);
499        if (error)
500            goto err_remove_class_attrs;
501    }
502
503    if (type) {
504        error = device_add_groups(dev, type->groups);
505        if (error)
506            goto err_remove_class_bin_attrs;
507    }
508
509    error = device_add_groups(dev, dev->groups);
510    if (error)
511        goto err_remove_type_groups;
512
513    return 0;
514
515 err_remove_type_groups:
516    if (type)
517        device_remove_groups(dev, type->groups);
518 err_remove_class_bin_attrs:
519    if (class)
520        device_remove_bin_attributes(dev, class->dev_bin_attrs);
521 err_remove_class_attrs:
522    if (class)
523        device_remove_attributes(dev, class->dev_attrs);
524
525    return error;
526}
527
528static void device_remove_attrs(struct device *dev)
529{
530    struct class *class = dev->class;
531    const struct device_type *type = dev->type;
532
533    device_remove_groups(dev, dev->groups);
534
535    if (type)
536        device_remove_groups(dev, type->groups);
537
538    if (class) {
539        device_remove_attributes(dev, class->dev_attrs);
540        device_remove_bin_attributes(dev, class->dev_bin_attrs);
541    }
542}
543
544
545static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
546            char *buf)
547{
548    return print_dev_t(buf, dev->devt);
549}
550
551static struct device_attribute devt_attr =
552    __ATTR(dev, S_IRUGO, show_dev, NULL);
553
554/* /sys/devices/ */
555struct kset *devices_kset;
556
557/**
558 * device_create_file - create sysfs attribute file for device.
559 * @dev: device.
560 * @attr: device attribute descriptor.
561 */
562int device_create_file(struct device *dev,
563               const struct device_attribute *attr)
564{
565    int error = 0;
566    if (dev)
567        error = sysfs_create_file(&dev->kobj, &attr->attr);
568    return error;
569}
570
571/**
572 * device_remove_file - remove sysfs attribute file.
573 * @dev: device.
574 * @attr: device attribute descriptor.
575 */
576void device_remove_file(struct device *dev,
577            const struct device_attribute *attr)
578{
579    if (dev)
580        sysfs_remove_file(&dev->kobj, &attr->attr);
581}
582
583/**
584 * device_create_bin_file - create sysfs binary attribute file for device.
585 * @dev: device.
586 * @attr: device binary attribute descriptor.
587 */
588int device_create_bin_file(struct device *dev,
589               const struct bin_attribute *attr)
590{
591    int error = -EINVAL;
592    if (dev)
593        error = sysfs_create_bin_file(&dev->kobj, attr);
594    return error;
595}
596EXPORT_SYMBOL_GPL(device_create_bin_file);
597
598/**
599 * device_remove_bin_file - remove sysfs binary attribute file
600 * @dev: device.
601 * @attr: device binary attribute descriptor.
602 */
603void device_remove_bin_file(struct device *dev,
604                const struct bin_attribute *attr)
605{
606    if (dev)
607        sysfs_remove_bin_file(&dev->kobj, attr);
608}
609EXPORT_SYMBOL_GPL(device_remove_bin_file);
610
611/**
612 * device_schedule_callback_owner - helper to schedule a callback for a device
613 * @dev: device.
614 * @func: callback function to invoke later.
615 * @owner: module owning the callback routine
616 *
617 * Attribute methods must not unregister themselves or their parent device
618 * (which would amount to the same thing). Attempts to do so will deadlock,
619 * since unregistration is mutually exclusive with driver callbacks.
620 *
621 * Instead methods can call this routine, which will attempt to allocate
622 * and schedule a workqueue request to call back @func with @dev as its
623 * argument in the workqueue's process context. @dev will be pinned until
624 * @func returns.
625 *
626 * This routine is usually called via the inline device_schedule_callback(),
627 * which automatically sets @owner to THIS_MODULE.
628 *
629 * Returns 0 if the request was submitted, -ENOMEM if storage could not
630 * be allocated, -ENODEV if a reference to @owner isn't available.
631 *
632 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
633 * underlying sysfs routine (since it is intended for use by attribute
634 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
635 */
636int device_schedule_callback_owner(struct device *dev,
637        void (*func)(struct device *), struct module *owner)
638{
639    return sysfs_schedule_callback(&dev->kobj,
640            (void (*)(void *)) func, dev, owner);
641}
642EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
643
644static void klist_children_get(struct klist_node *n)
645{
646    struct device_private *p = to_device_private_parent(n);
647    struct device *dev = p->device;
648
649    get_device(dev);
650}
651
652static void klist_children_put(struct klist_node *n)
653{
654    struct device_private *p = to_device_private_parent(n);
655    struct device *dev = p->device;
656
657    put_device(dev);
658}
659
660/**
661 * device_initialize - init device structure.
662 * @dev: device.
663 *
664 * This prepares the device for use by other layers by initializing
665 * its fields.
666 * It is the first half of device_register(), if called by
667 * that function, though it can also be called separately, so one
668 * may use @dev's fields. In particular, get_device()/put_device()
669 * may be used for reference counting of @dev after calling this
670 * function.
671 *
672 * All fields in @dev must be initialized by the caller to 0, except
673 * for those explicitly set to some other value. The simplest
674 * approach is to use kzalloc() to allocate the structure containing
675 * @dev.
676 *
677 * NOTE: Use put_device() to give up your reference instead of freeing
678 * @dev directly once you have called this function.
679 */
680void device_initialize(struct device *dev)
681{
682    dev->kobj.kset = devices_kset;
683    kobject_init(&dev->kobj, &device_ktype);
684    INIT_LIST_HEAD(&dev->dma_pools);
685    mutex_init(&dev->mutex);
686    lockdep_set_novalidate_class(&dev->mutex);
687    spin_lock_init(&dev->devres_lock);
688    INIT_LIST_HEAD(&dev->devres_head);
689    device_pm_init(dev);
690    set_dev_node(dev, -1);
691}
692
693static struct kobject *virtual_device_parent(struct device *dev)
694{
695    static struct kobject *virtual_dir = NULL;
696
697    if (!virtual_dir)
698        virtual_dir = kobject_create_and_add("virtual",
699                             &devices_kset->kobj);
700
701    return virtual_dir;
702}
703
704struct class_dir {
705    struct kobject kobj;
706    struct class *class;
707};
708
709#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
710
711static void class_dir_release(struct kobject *kobj)
712{
713    struct class_dir *dir = to_class_dir(kobj);
714    kfree(dir);
715}
716
717static const
718struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
719{
720    struct class_dir *dir = to_class_dir(kobj);
721    return dir->class->ns_type;
722}
723
724static struct kobj_type class_dir_ktype = {
725    .release = class_dir_release,
726    .sysfs_ops = &kobj_sysfs_ops,
727    .child_ns_type = class_dir_child_ns_type
728};
729
730static struct kobject *
731class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
732{
733    struct class_dir *dir;
734    int retval;
735
736    dir = kzalloc(sizeof(*dir), GFP_KERNEL);
737    if (!dir)
738        return NULL;
739
740    dir->class = class;
741    kobject_init(&dir->kobj, &class_dir_ktype);
742
743    dir->kobj.kset = &class->p->glue_dirs;
744
745    retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
746    if (retval < 0) {
747        kobject_put(&dir->kobj);
748        return NULL;
749    }
750    return &dir->kobj;
751}
752
753
754static struct kobject *get_device_parent(struct device *dev,
755                     struct device *parent)
756{
757    if (dev->class) {
758        static DEFINE_MUTEX(gdp_mutex);
759        struct kobject *kobj = NULL;
760        struct kobject *parent_kobj;
761        struct kobject *k;
762
763#ifdef CONFIG_BLOCK
764        /* block disks show up in /sys/block */
765        if (sysfs_deprecated && dev->class == &block_class) {
766            if (parent && parent->class == &block_class)
767                return &parent->kobj;
768            return &block_class.p->subsys.kobj;
769        }
770#endif
771
772        /*
773         * If we have no parent, we live in "virtual".
774         * Class-devices with a non class-device as parent, live
775         * in a "glue" directory to prevent namespace collisions.
776         */
777        if (parent == NULL)
778            parent_kobj = virtual_device_parent(dev);
779        else if (parent->class && !dev->class->ns_type)
780            return &parent->kobj;
781        else
782            parent_kobj = &parent->kobj;
783
784        mutex_lock(&gdp_mutex);
785
786        /* find our class-directory at the parent and reference it */
787        spin_lock(&dev->class->p->glue_dirs.list_lock);
788        list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
789            if (k->parent == parent_kobj) {
790                kobj = kobject_get(k);
791                break;
792            }
793        spin_unlock(&dev->class->p->glue_dirs.list_lock);
794        if (kobj) {
795            mutex_unlock(&gdp_mutex);
796            return kobj;
797        }
798
799        /* or create a new class-directory at the parent device */
800        k = class_dir_create_and_add(dev->class, parent_kobj);
801        /* do not emit an uevent for this simple "glue" directory */
802        mutex_unlock(&gdp_mutex);
803        return k;
804    }
805
806    /* subsystems can specify a default root directory for their devices */
807    if (!parent && dev->bus && dev->bus->dev_root)
808        return &dev->bus->dev_root->kobj;
809
810    if (parent)
811        return &parent->kobj;
812    return NULL;
813}
814
815static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
816{
817    /* see if we live in a "glue" directory */
818    if (!glue_dir || !dev->class ||
819        glue_dir->kset != &dev->class->p->glue_dirs)
820        return;
821
822    kobject_put(glue_dir);
823}
824
825static void cleanup_device_parent(struct device *dev)
826{
827    cleanup_glue_dir(dev, dev->kobj.parent);
828}
829
830static int device_add_class_symlinks(struct device *dev)
831{
832    int error;
833
834    if (!dev->class)
835        return 0;
836
837    error = sysfs_create_link(&dev->kobj,
838                  &dev->class->p->subsys.kobj,
839                  "subsystem");
840    if (error)
841        goto out;
842
843    if (dev->parent && device_is_not_partition(dev)) {
844        error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
845                      "device");
846        if (error)
847            goto out_subsys;
848    }
849
850#ifdef CONFIG_BLOCK
851    /* /sys/block has directories and does not need symlinks */
852    if (sysfs_deprecated && dev->class == &block_class)
853        return 0;
854#endif
855
856    /* link in the class directory pointing to the device */
857    error = sysfs_create_link(&dev->class->p->subsys.kobj,
858                  &dev->kobj, dev_name(dev));
859    if (error)
860        goto out_device;
861
862    return 0;
863
864out_device:
865    sysfs_remove_link(&dev->kobj, "device");
866
867out_subsys:
868    sysfs_remove_link(&dev->kobj, "subsystem");
869out:
870    return error;
871}
872
873static void device_remove_class_symlinks(struct device *dev)
874{
875    if (!dev->class)
876        return;
877
878    if (dev->parent && device_is_not_partition(dev))
879        sysfs_remove_link(&dev->kobj, "device");
880    sysfs_remove_link(&dev->kobj, "subsystem");
881#ifdef CONFIG_BLOCK
882    if (sysfs_deprecated && dev->class == &block_class)
883        return;
884#endif
885    sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
886}
887
888/**
889 * dev_set_name - set a device name
890 * @dev: device
891 * @fmt: format string for the device's name
892 */
893int dev_set_name(struct device *dev, const char *fmt, ...)
894{
895    va_list vargs;
896    int err;
897
898    va_start(vargs, fmt);
899    err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
900    va_end(vargs);
901    return err;
902}
903EXPORT_SYMBOL_GPL(dev_set_name);
904
905/**
906 * device_to_dev_kobj - select a /sys/dev/ directory for the device
907 * @dev: device
908 *
909 * By default we select char/ for new entries. Setting class->dev_obj
910 * to NULL prevents an entry from being created. class->dev_kobj must
911 * be set (or cleared) before any devices are registered to the class
912 * otherwise device_create_sys_dev_entry() and
913 * device_remove_sys_dev_entry() will disagree about the presence of
914 * the link.
915 */
916static struct kobject *device_to_dev_kobj(struct device *dev)
917{
918    struct kobject *kobj;
919
920    if (dev->class)
921        kobj = dev->class->dev_kobj;
922    else
923        kobj = sysfs_dev_char_kobj;
924
925    return kobj;
926}
927
928static int device_create_sys_dev_entry(struct device *dev)
929{
930    struct kobject *kobj = device_to_dev_kobj(dev);
931    int error = 0;
932    char devt_str[15];
933
934    if (kobj) {
935        format_dev_t(devt_str, dev->devt);
936        error = sysfs_create_link(kobj, &dev->kobj, devt_str);
937    }
938
939    return error;
940}
941
942static void device_remove_sys_dev_entry(struct device *dev)
943{
944    struct kobject *kobj = device_to_dev_kobj(dev);
945    char devt_str[15];
946
947    if (kobj) {
948        format_dev_t(devt_str, dev->devt);
949        sysfs_remove_link(kobj, devt_str);
950    }
951}
952
953int device_private_init(struct device *dev)
954{
955    dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
956    if (!dev->p)
957        return -ENOMEM;
958    dev->p->device = dev;
959    klist_init(&dev->p->klist_children, klist_children_get,
960           klist_children_put);
961    INIT_LIST_HEAD(&dev->p->deferred_probe);
962    return 0;
963}
964
965/**
966 * device_add - add device to device hierarchy.
967 * @dev: device.
968 *
969 * This is part 2 of device_register(), though may be called
970 * separately _iff_ device_initialize() has been called separately.
971 *
972 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
973 * to the global and sibling lists for the device, then
974 * adds it to the other relevant subsystems of the driver model.
975 *
976 * Do not call this routine or device_register() more than once for
977 * any device structure. The driver model core is not designed to work
978 * with devices that get unregistered and then spring back to life.
979 * (Among other things, it's very hard to guarantee that all references
980 * to the previous incarnation of @dev have been dropped.) Allocate
981 * and register a fresh new struct device instead.
982 *
983 * NOTE: _Never_ directly free @dev after calling this function, even
984 * if it returned an error! Always use put_device() to give up your
985 * reference instead.
986 */
987int device_add(struct device *dev)
988{
989    struct device *parent = NULL;
990    struct kobject *kobj;
991    struct class_interface *class_intf;
992    int error = -EINVAL;
993
994    dev = get_device(dev);
995    if (!dev)
996        goto done;
997
998    if (!dev->p) {
999        error = device_private_init(dev);
1000        if (error)
1001            goto done;
1002    }
1003
1004    /*
1005     * for statically allocated devices, which should all be converted
1006     * some day, we need to initialize the name. We prevent reading back
1007     * the name, and force the use of dev_name()
1008     */
1009    if (dev->init_name) {
1010        dev_set_name(dev, "%s", dev->init_name);
1011        dev->init_name = NULL;
1012    }
1013
1014    /* subsystems can specify simple device enumeration */
1015    if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
1016        dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
1017
1018    if (!dev_name(dev)) {
1019        error = -EINVAL;
1020        goto name_error;
1021    }
1022
1023    pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1024
1025    parent = get_device(dev->parent);
1026    kobj = get_device_parent(dev, parent);
1027    if (kobj)
1028        dev->kobj.parent = kobj;
1029
1030    /* use parent numa_node */
1031    if (parent)
1032        set_dev_node(dev, dev_to_node(parent));
1033
1034    /* first, register with generic layer. */
1035    /* we require the name to be set before, and pass NULL */
1036    error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1037    if (error)
1038        goto Error;
1039
1040    /* notify platform of device entry */
1041    if (platform_notify)
1042        platform_notify(dev);
1043
1044    error = device_create_file(dev, &uevent_attr);
1045    if (error)
1046        goto attrError;
1047
1048    if (MAJOR(dev->devt)) {
1049        error = device_create_file(dev, &devt_attr);
1050        if (error)
1051            goto ueventattrError;
1052
1053        error = device_create_sys_dev_entry(dev);
1054        if (error)
1055            goto devtattrError;
1056
1057        devtmpfs_create_node(dev);
1058    }
1059
1060    error = device_add_class_symlinks(dev);
1061    if (error)
1062        goto SymlinkError;
1063    error = device_add_attrs(dev);
1064    if (error)
1065        goto AttrsError;
1066    error = bus_add_device(dev);
1067    if (error)
1068        goto BusError;
1069    error = dpm_sysfs_add(dev);
1070    if (error)
1071        goto DPMError;
1072    device_pm_add(dev);
1073
1074    /* Notify clients of device addition. This call must come
1075     * after dpm_sysfs_add() and before kobject_uevent().
1076     */
1077    if (dev->bus)
1078        blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1079                         BUS_NOTIFY_ADD_DEVICE, dev);
1080
1081    kobject_uevent(&dev->kobj, KOBJ_ADD);
1082    bus_probe_device(dev);
1083    if (parent)
1084        klist_add_tail(&dev->p->knode_parent,
1085                   &parent->p->klist_children);
1086
1087    if (dev->class) {
1088        mutex_lock(&dev->class->p->mutex);
1089        /* tie the class to the device */
1090        klist_add_tail(&dev->knode_class,
1091                   &dev->class->p->klist_devices);
1092
1093        /* notify any interfaces that the device is here */
1094        list_for_each_entry(class_intf,
1095                    &dev->class->p->interfaces, node)
1096            if (class_intf->add_dev)
1097                class_intf->add_dev(dev, class_intf);
1098        mutex_unlock(&dev->class->p->mutex);
1099    }
1100done:
1101    put_device(dev);
1102    return error;
1103 DPMError:
1104    bus_remove_device(dev);
1105 BusError:
1106    device_remove_attrs(dev);
1107 AttrsError:
1108    device_remove_class_symlinks(dev);
1109 SymlinkError:
1110    if (MAJOR(dev->devt))
1111        devtmpfs_delete_node(dev);
1112    if (MAJOR(dev->devt))
1113        device_remove_sys_dev_entry(dev);
1114 devtattrError:
1115    if (MAJOR(dev->devt))
1116        device_remove_file(dev, &devt_attr);
1117 ueventattrError:
1118    device_remove_file(dev, &uevent_attr);
1119 attrError:
1120    kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1121    kobject_del(&dev->kobj);
1122 Error:
1123    cleanup_device_parent(dev);
1124    if (parent)
1125        put_device(parent);
1126name_error:
1127    kfree(dev->p);
1128    dev->p = NULL;
1129    goto done;
1130}
1131
1132/**
1133 * device_register - register a device with the system.
1134 * @dev: pointer to the device structure
1135 *
1136 * This happens in two clean steps - initialize the device
1137 * and add it to the system. The two steps can be called
1138 * separately, but this is the easiest and most common.
1139 * I.e. you should only call the two helpers separately if
1140 * have a clearly defined need to use and refcount the device
1141 * before it is added to the hierarchy.
1142 *
1143 * For more information, see the kerneldoc for device_initialize()
1144 * and device_add().
1145 *
1146 * NOTE: _Never_ directly free @dev after calling this function, even
1147 * if it returned an error! Always use put_device() to give up the
1148 * reference initialized in this function instead.
1149 */
1150int device_register(struct device *dev)
1151{
1152    device_initialize(dev);
1153    return device_add(dev);
1154}
1155
1156/**
1157 * get_device - increment reference count for device.
1158 * @dev: device.
1159 *
1160 * This simply forwards the call to kobject_get(), though
1161 * we do take care to provide for the case that we get a NULL
1162 * pointer passed in.
1163 */
1164struct device *get_device(struct device *dev)
1165{
1166    return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1167}
1168
1169/**
1170 * put_device - decrement reference count.
1171 * @dev: device in question.
1172 */
1173void put_device(struct device *dev)
1174{
1175    /* might_sleep(); */
1176    if (dev)
1177        kobject_put(&dev->kobj);
1178}
1179
1180/**
1181 * device_del - delete device from system.
1182 * @dev: device.
1183 *
1184 * This is the first part of the device unregistration
1185 * sequence. This removes the device from the lists we control
1186 * from here, has it removed from the other driver model
1187 * subsystems it was added to in device_add(), and removes it
1188 * from the kobject hierarchy.
1189 *
1190 * NOTE: this should be called manually _iff_ device_add() was
1191 * also called manually.
1192 */
1193void device_del(struct device *dev)
1194{
1195    struct device *parent = dev->parent;
1196    struct class_interface *class_intf;
1197
1198    /* Notify clients of device removal. This call must come
1199     * before dpm_sysfs_remove().
1200     */
1201    if (dev->bus)
1202        blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1203                         BUS_NOTIFY_DEL_DEVICE, dev);
1204    dpm_sysfs_remove(dev);
1205    if (parent)
1206        klist_del(&dev->p->knode_parent);
1207    if (MAJOR(dev->devt)) {
1208        devtmpfs_delete_node(dev);
1209        device_remove_sys_dev_entry(dev);
1210        device_remove_file(dev, &devt_attr);
1211    }
1212    if (dev->class) {
1213        device_remove_class_symlinks(dev);
1214
1215        mutex_lock(&dev->class->p->mutex);
1216        /* notify any interfaces that the device is now gone */
1217        list_for_each_entry(class_intf,
1218                    &dev->class->p->interfaces, node)
1219            if (class_intf->remove_dev)
1220                class_intf->remove_dev(dev, class_intf);
1221        /* remove the device from the class list */
1222        klist_del(&dev->knode_class);
1223        mutex_unlock(&dev->class->p->mutex);
1224    }
1225    device_remove_file(dev, &uevent_attr);
1226    device_remove_attrs(dev);
1227    bus_remove_device(dev);
1228    device_pm_remove(dev);
1229    driver_deferred_probe_del(dev);
1230
1231    /* Notify the platform of the removal, in case they
1232     * need to do anything...
1233     */
1234    if (platform_notify_remove)
1235        platform_notify_remove(dev);
1236    kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1237    cleanup_device_parent(dev);
1238    kobject_del(&dev->kobj);
1239    put_device(parent);
1240}
1241
1242/**
1243 * device_unregister - unregister device from system.
1244 * @dev: device going away.
1245 *
1246 * We do this in two parts, like we do device_register(). First,
1247 * we remove it from all the subsystems with device_del(), then
1248 * we decrement the reference count via put_device(). If that
1249 * is the final reference count, the device will be cleaned up
1250 * via device_release() above. Otherwise, the structure will
1251 * stick around until the final reference to the device is dropped.
1252 */
1253void device_unregister(struct device *dev)
1254{
1255    pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1256    device_del(dev);
1257    put_device(dev);
1258}
1259
1260static struct device *next_device(struct klist_iter *i)
1261{
1262    struct klist_node *n = klist_next(i);
1263    struct device *dev = NULL;
1264    struct device_private *p;
1265
1266    if (n) {
1267        p = to_device_private_parent(n);
1268        dev = p->device;
1269    }
1270    return dev;
1271}
1272
1273/**
1274 * device_get_devnode - path of device node file
1275 * @dev: device
1276 * @mode: returned file access mode
1277 * @tmp: possibly allocated string
1278 *
1279 * Return the relative path of a possible device node.
1280 * Non-default names may need to allocate a memory to compose
1281 * a name. This memory is returned in tmp and needs to be
1282 * freed by the caller.
1283 */
1284const char *device_get_devnode(struct device *dev,
1285                   umode_t *mode, const char **tmp)
1286{
1287    char *s;
1288
1289    *tmp = NULL;
1290
1291    /* the device type may provide a specific name */
1292    if (dev->type && dev->type->devnode)
1293        *tmp = dev->type->devnode(dev, mode);
1294    if (*tmp)
1295        return *tmp;
1296
1297    /* the class may provide a specific name */
1298    if (dev->class && dev->class->devnode)
1299        *tmp = dev->class->devnode(dev, mode);
1300    if (*tmp)
1301        return *tmp;
1302
1303    /* return name without allocation, tmp == NULL */
1304    if (strchr(dev_name(dev), '!') == NULL)
1305        return dev_name(dev);
1306
1307    /* replace '!' in the name with '/' */
1308    *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1309    if (!*tmp)
1310        return NULL;
1311    while ((s = strchr(*tmp, '!')))
1312        s[0] = '/';
1313    return *tmp;
1314}
1315
1316/**
1317 * device_for_each_child - device child iterator.
1318 * @parent: parent struct device.
1319 * @data: data for the callback.
1320 * @fn: function to be called for each device.
1321 *
1322 * Iterate over @parent's child devices, and call @fn for each,
1323 * passing it @data.
1324 *
1325 * We check the return of @fn each time. If it returns anything
1326 * other than 0, we break out and return that value.
1327 */
1328int device_for_each_child(struct device *parent, void *data,
1329              int (*fn)(struct device *dev, void *data))
1330{
1331    struct klist_iter i;
1332    struct device *child;
1333    int error = 0;
1334
1335    if (!parent->p)
1336        return 0;
1337
1338    klist_iter_init(&parent->p->klist_children, &i);
1339    while ((child = next_device(&i)) && !error)
1340        error = fn(child, data);
1341    klist_iter_exit(&i);
1342    return error;
1343}
1344
1345/**
1346 * device_find_child - device iterator for locating a particular device.
1347 * @parent: parent struct device
1348 * @data: Data to pass to match function
1349 * @match: Callback function to check device
1350 *
1351 * This is similar to the device_for_each_child() function above, but it
1352 * returns a reference to a device that is 'found' for later use, as
1353 * determined by the @match callback.
1354 *
1355 * The callback should return 0 if the device doesn't match and non-zero
1356 * if it does. If the callback returns non-zero and a reference to the
1357 * current device can be obtained, this function will return to the caller
1358 * and not iterate over any more devices.
1359 */
1360struct device *device_find_child(struct device *parent, void *data,
1361                 int (*match)(struct device *dev, void *data))
1362{
1363    struct klist_iter i;
1364    struct device *child;
1365
1366    if (!parent)
1367        return NULL;
1368
1369    klist_iter_init(&parent->p->klist_children, &i);
1370    while ((child = next_device(&i)))
1371        if (match(child, data) && get_device(child))
1372            break;
1373    klist_iter_exit(&i);
1374    return child;
1375}
1376
1377int __init devices_init(void)
1378{
1379    devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1380    if (!devices_kset)
1381        return -ENOMEM;
1382    dev_kobj = kobject_create_and_add("dev", NULL);
1383    if (!dev_kobj)
1384        goto dev_kobj_err;
1385    sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1386    if (!sysfs_dev_block_kobj)
1387        goto block_kobj_err;
1388    sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1389    if (!sysfs_dev_char_kobj)
1390        goto char_kobj_err;
1391
1392    return 0;
1393
1394 char_kobj_err:
1395    kobject_put(sysfs_dev_block_kobj);
1396 block_kobj_err:
1397    kobject_put(dev_kobj);
1398 dev_kobj_err:
1399    kset_unregister(devices_kset);
1400    return -ENOMEM;
1401}
1402
1403EXPORT_SYMBOL_GPL(device_for_each_child);
1404EXPORT_SYMBOL_GPL(device_find_child);
1405
1406EXPORT_SYMBOL_GPL(device_initialize);
1407EXPORT_SYMBOL_GPL(device_add);
1408EXPORT_SYMBOL_GPL(device_register);
1409
1410EXPORT_SYMBOL_GPL(device_del);
1411EXPORT_SYMBOL_GPL(device_unregister);
1412EXPORT_SYMBOL_GPL(get_device);
1413EXPORT_SYMBOL_GPL(put_device);
1414
1415EXPORT_SYMBOL_GPL(device_create_file);
1416EXPORT_SYMBOL_GPL(device_remove_file);
1417
1418struct root_device {
1419    struct device dev;
1420    struct module *owner;
1421};
1422
1423static inline struct root_device *to_root_device(struct device *d)
1424{
1425    return container_of(d, struct root_device, dev);
1426}
1427
1428static void root_device_release(struct device *dev)
1429{
1430    kfree(to_root_device(dev));
1431}
1432
1433/**
1434 * __root_device_register - allocate and register a root device
1435 * @name: root device name
1436 * @owner: owner module of the root device, usually THIS_MODULE
1437 *
1438 * This function allocates a root device and registers it
1439 * using device_register(). In order to free the returned
1440 * device, use root_device_unregister().
1441 *
1442 * Root devices are dummy devices which allow other devices
1443 * to be grouped under /sys/devices. Use this function to
1444 * allocate a root device and then use it as the parent of
1445 * any device which should appear under /sys/devices/{name}
1446 *
1447 * The /sys/devices/{name} directory will also contain a
1448 * 'module' symlink which points to the @owner directory
1449 * in sysfs.
1450 *
1451 * Returns &struct device pointer on success, or ERR_PTR() on error.
1452 *
1453 * Note: You probably want to use root_device_register().
1454 */
1455struct device *__root_device_register(const char *name, struct module *owner)
1456{
1457    struct root_device *root;
1458    int err = -ENOMEM;
1459
1460    root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1461    if (!root)
1462        return ERR_PTR(err);
1463
1464    err = dev_set_name(&root->dev, "%s", name);
1465    if (err) {
1466        kfree(root);
1467        return ERR_PTR(err);
1468    }
1469
1470    root->dev.release = root_device_release;
1471
1472    err = device_register(&root->dev);
1473    if (err) {
1474        put_device(&root->dev);
1475        return ERR_PTR(err);
1476    }
1477
1478#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
1479    if (owner) {
1480        struct module_kobject *mk = &owner->mkobj;
1481
1482        err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1483        if (err) {
1484            device_unregister(&root->dev);
1485            return ERR_PTR(err);
1486        }
1487        root->owner = owner;
1488    }
1489#endif
1490
1491    return &root->dev;
1492}
1493EXPORT_SYMBOL_GPL(__root_device_register);
1494
1495/**
1496 * root_device_unregister - unregister and free a root device
1497 * @dev: device going away
1498 *
1499 * This function unregisters and cleans up a device that was created by
1500 * root_device_register().
1501 */
1502void root_device_unregister(struct device *dev)
1503{
1504    struct root_device *root = to_root_device(dev);
1505
1506    if (root->owner)
1507        sysfs_remove_link(&root->dev.kobj, "module");
1508
1509    device_unregister(dev);
1510}
1511EXPORT_SYMBOL_GPL(root_device_unregister);
1512
1513
1514static void device_create_release(struct device *dev)
1515{
1516    pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1517    kfree(dev);
1518}
1519
1520/**
1521 * device_create_vargs - creates a device and registers it with sysfs
1522 * @class: pointer to the struct class that this device should be registered to
1523 * @parent: pointer to the parent struct device of this new device, if any
1524 * @devt: the dev_t for the char device to be added
1525 * @drvdata: the data to be added to the device for callbacks
1526 * @fmt: string for the device's name
1527 * @args: va_list for the device's name
1528 *
1529 * This function can be used by char device classes. A struct device
1530 * will be created in sysfs, registered to the specified class.
1531 *
1532 * A "dev" file will be created, showing the dev_t for the device, if
1533 * the dev_t is not 0,0.
1534 * If a pointer to a parent struct device is passed in, the newly created
1535 * struct device will be a child of that device in sysfs.
1536 * The pointer to the struct device will be returned from the call.
1537 * Any further sysfs files that might be required can be created using this
1538 * pointer.
1539 *
1540 * Returns &struct device pointer on success, or ERR_PTR() on error.
1541 *
1542 * Note: the struct class passed to this function must have previously
1543 * been created with a call to class_create().
1544 */
1545struct device *device_create_vargs(struct class *class, struct device *parent,
1546                   dev_t devt, void *drvdata, const char *fmt,
1547                   va_list args)
1548{
1549    struct device *dev = NULL;
1550    int retval = -ENODEV;
1551
1552    if (class == NULL || IS_ERR(class))
1553        goto error;
1554
1555    dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1556    if (!dev) {
1557        retval = -ENOMEM;
1558        goto error;
1559    }
1560
1561    dev->devt = devt;
1562    dev->class = class;
1563    dev->parent = parent;
1564    dev->release = device_create_release;
1565    dev_set_drvdata(dev, drvdata);
1566
1567    retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1568    if (retval)
1569        goto error;
1570
1571    retval = device_register(dev);
1572    if (retval)
1573        goto error;
1574
1575    return dev;
1576
1577error:
1578    put_device(dev);
1579    return ERR_PTR(retval);
1580}
1581EXPORT_SYMBOL_GPL(device_create_vargs);
1582
1583/**
1584 * device_create - creates a device and registers it with sysfs
1585 * @class: pointer to the struct class that this device should be registered to
1586 * @parent: pointer to the parent struct device of this new device, if any
1587 * @devt: the dev_t for the char device to be added
1588 * @drvdata: the data to be added to the device for callbacks
1589 * @fmt: string for the device's name
1590 *
1591 * This function can be used by char device classes. A struct device
1592 * will be created in sysfs, registered to the specified class.
1593 *
1594 * A "dev" file will be created, showing the dev_t for the device, if
1595 * the dev_t is not 0,0.
1596 * If a pointer to a parent struct device is passed in, the newly created
1597 * struct device will be a child of that device in sysfs.
1598 * The pointer to the struct device will be returned from the call.
1599 * Any further sysfs files that might be required can be created using this
1600 * pointer.
1601 *
1602 * Returns &struct device pointer on success, or ERR_PTR() on error.
1603 *
1604 * Note: the struct class passed to this function must have previously
1605 * been created with a call to class_create().
1606 */
1607struct device *device_create(struct class *class, struct device *parent,
1608                 dev_t devt, void *drvdata, const char *fmt, ...)
1609{
1610    va_list vargs;
1611    struct device *dev;
1612
1613    va_start(vargs, fmt);
1614    dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1615    va_end(vargs);
1616    return dev;
1617}
1618EXPORT_SYMBOL_GPL(device_create);
1619
1620static int __match_devt(struct device *dev, const void *data)
1621{
1622    const dev_t *devt = data;
1623
1624    return dev->devt == *devt;
1625}
1626
1627/**
1628 * device_destroy - removes a device that was created with device_create()
1629 * @class: pointer to the struct class that this device was registered with
1630 * @devt: the dev_t of the device that was previously registered
1631 *
1632 * This call unregisters and cleans up a device that was created with a
1633 * call to device_create().
1634 */
1635void device_destroy(struct class *class, dev_t devt)
1636{
1637    struct device *dev;
1638
1639    dev = class_find_device(class, NULL, &devt, __match_devt);
1640    if (dev) {
1641        put_device(dev);
1642        device_unregister(dev);
1643    }
1644}
1645EXPORT_SYMBOL_GPL(device_destroy);
1646
1647/**
1648 * device_rename - renames a device
1649 * @dev: the pointer to the struct device to be renamed
1650 * @new_name: the new name of the device
1651 *
1652 * It is the responsibility of the caller to provide mutual
1653 * exclusion between two different calls of device_rename
1654 * on the same device to ensure that new_name is valid and
1655 * won't conflict with other devices.
1656 *
1657 * Note: Don't call this function. Currently, the networking layer calls this
1658 * function, but that will change. The following text from Kay Sievers offers
1659 * some insight:
1660 *
1661 * Renaming devices is racy at many levels, symlinks and other stuff are not
1662 * replaced atomically, and you get a "move" uevent, but it's not easy to
1663 * connect the event to the old and new device. Device nodes are not renamed at
1664 * all, there isn't even support for that in the kernel now.
1665 *
1666 * In the meantime, during renaming, your target name might be taken by another
1667 * driver, creating conflicts. Or the old name is taken directly after you
1668 * renamed it -- then you get events for the same DEVPATH, before you even see
1669 * the "move" event. It's just a mess, and nothing new should ever rely on
1670 * kernel device renaming. Besides that, it's not even implemented now for
1671 * other things than (driver-core wise very simple) network devices.
1672 *
1673 * We are currently about to change network renaming in udev to completely
1674 * disallow renaming of devices in the same namespace as the kernel uses,
1675 * because we can't solve the problems properly, that arise with swapping names
1676 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1677 * be allowed to some other name than eth[0-9]*, for the aforementioned
1678 * reasons.
1679 *
1680 * Make up a "real" name in the driver before you register anything, or add
1681 * some other attributes for userspace to find the device, or use udev to add
1682 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1683 * don't even want to get into that and try to implement the missing pieces in
1684 * the core. We really have other pieces to fix in the driver core mess. :)
1685 */
1686int device_rename(struct device *dev, const char *new_name)
1687{
1688    char *old_device_name = NULL;
1689    int error;
1690
1691    dev = get_device(dev);
1692    if (!dev)
1693        return -EINVAL;
1694
1695    pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1696         __func__, new_name);
1697
1698    old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1699    if (!old_device_name) {
1700        error = -ENOMEM;
1701        goto out;
1702    }
1703
1704    if (dev->class) {
1705        error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1706            &dev->kobj, old_device_name, new_name);
1707        if (error)
1708            goto out;
1709    }
1710
1711    error = kobject_rename(&dev->kobj, new_name);
1712    if (error)
1713        goto out;
1714
1715out:
1716    put_device(dev);
1717
1718    kfree(old_device_name);
1719
1720    return error;
1721}
1722EXPORT_SYMBOL_GPL(device_rename);
1723
1724static int device_move_class_links(struct device *dev,
1725                   struct device *old_parent,
1726                   struct device *new_parent)
1727{
1728    int error = 0;
1729
1730    if (old_parent)
1731        sysfs_remove_link(&dev->kobj, "device");
1732    if (new_parent)
1733        error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1734                      "device");
1735    return error;
1736}
1737
1738/**
1739 * device_move - moves a device to a new parent
1740 * @dev: the pointer to the struct device to be moved
1741 * @new_parent: the new parent of the device (can by NULL)
1742 * @dpm_order: how to reorder the dpm_list
1743 */
1744int device_move(struct device *dev, struct device *new_parent,
1745        enum dpm_order dpm_order)
1746{
1747    int error;
1748    struct device *old_parent;
1749    struct kobject *new_parent_kobj;
1750
1751    dev = get_device(dev);
1752    if (!dev)
1753        return -EINVAL;
1754
1755    device_pm_lock();
1756    new_parent = get_device(new_parent);
1757    new_parent_kobj = get_device_parent(dev, new_parent);
1758
1759    pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1760         __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1761    error = kobject_move(&dev->kobj, new_parent_kobj);
1762    if (error) {
1763        cleanup_glue_dir(dev, new_parent_kobj);
1764        put_device(new_parent);
1765        goto out;
1766    }
1767    old_parent = dev->parent;
1768    dev->parent = new_parent;
1769    if (old_parent)
1770        klist_remove(&dev->p->knode_parent);
1771    if (new_parent) {
1772        klist_add_tail(&dev->p->knode_parent,
1773                   &new_parent->p->klist_children);
1774        set_dev_node(dev, dev_to_node(new_parent));
1775    }
1776
1777    if (dev->class) {
1778        error = device_move_class_links(dev, old_parent, new_parent);
1779        if (error) {
1780            /* We ignore errors on cleanup since we're hosed anyway... */
1781            device_move_class_links(dev, new_parent, old_parent);
1782            if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1783                if (new_parent)
1784                    klist_remove(&dev->p->knode_parent);
1785                dev->parent = old_parent;
1786                if (old_parent) {
1787                    klist_add_tail(&dev->p->knode_parent,
1788                               &old_parent->p->klist_children);
1789                    set_dev_node(dev, dev_to_node(old_parent));
1790                }
1791            }
1792            cleanup_glue_dir(dev, new_parent_kobj);
1793            put_device(new_parent);
1794            goto out;
1795        }
1796    }
1797    switch (dpm_order) {
1798    case DPM_ORDER_NONE:
1799        break;
1800    case DPM_ORDER_DEV_AFTER_PARENT:
1801        device_pm_move_after(dev, new_parent);
1802        break;
1803    case DPM_ORDER_PARENT_BEFORE_DEV:
1804        device_pm_move_before(new_parent, dev);
1805        break;
1806    case DPM_ORDER_DEV_LAST:
1807        device_pm_move_last(dev);
1808        break;
1809    }
1810
1811    put_device(old_parent);
1812out:
1813    device_pm_unlock();
1814    put_device(dev);
1815    return error;
1816}
1817EXPORT_SYMBOL_GPL(device_move);
1818
1819/**
1820 * device_shutdown - call ->shutdown() on each device to shutdown.
1821 */
1822void device_shutdown(void)
1823{
1824    struct device *dev;
1825
1826    spin_lock(&devices_kset->list_lock);
1827    /*
1828     * Walk the devices list backward, shutting down each in turn.
1829     * Beware that device unplug events may also start pulling
1830     * devices offline, even as the system is shutting down.
1831     */
1832    while (!list_empty(&devices_kset->list)) {
1833        dev = list_entry(devices_kset->list.prev, struct device,
1834                kobj.entry);
1835
1836        /*
1837         * hold reference count of device's parent to
1838         * prevent it from being freed because parent's
1839         * lock is to be held
1840         */
1841        get_device(dev->parent);
1842        get_device(dev);
1843        /*
1844         * Make sure the device is off the kset list, in the
1845         * event that dev->*->shutdown() doesn't remove it.
1846         */
1847        list_del_init(&dev->kobj.entry);
1848        spin_unlock(&devices_kset->list_lock);
1849
1850        /* hold lock to avoid race with probe/release */
1851        if (dev->parent)
1852            device_lock(dev->parent);
1853        device_lock(dev);
1854
1855        /* Don't allow any more runtime suspends */
1856        pm_runtime_get_noresume(dev);
1857        pm_runtime_barrier(dev);
1858
1859        if (dev->bus && dev->bus->shutdown) {
1860            if (initcall_debug)
1861                dev_info(dev, "shutdown\n");
1862            dev->bus->shutdown(dev);
1863        } else if (dev->driver && dev->driver->shutdown) {
1864            if (initcall_debug)
1865                dev_info(dev, "shutdown\n");
1866            dev->driver->shutdown(dev);
1867        }
1868
1869        device_unlock(dev);
1870        if (dev->parent)
1871            device_unlock(dev->parent);
1872
1873        put_device(dev);
1874        put_device(dev->parent);
1875
1876        spin_lock(&devices_kset->list_lock);
1877    }
1878    spin_unlock(&devices_kset->list_lock);
1879    async_synchronize_full();
1880}
1881
1882/*
1883 * Device logging functions
1884 */
1885
1886#ifdef CONFIG_PRINTK
1887static int
1888create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
1889{
1890    const char *subsys;
1891    size_t pos = 0;
1892
1893    if (dev->class)
1894        subsys = dev->class->name;
1895    else if (dev->bus)
1896        subsys = dev->bus->name;
1897    else
1898        return 0;
1899
1900    pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
1901
1902    /*
1903     * Add device identifier DEVICE=:
1904     * b12:8 block dev_t
1905     * c127:3 char dev_t
1906     * n8 netdev ifindex
1907     * +sound:card0 subsystem:devname
1908     */
1909    if (MAJOR(dev->devt)) {
1910        char c;
1911
1912        if (strcmp(subsys, "block") == 0)
1913            c = 'b';
1914        else
1915            c = 'c';
1916        pos++;
1917        pos += snprintf(hdr + pos, hdrlen - pos,
1918                "DEVICE=%c%u:%u",
1919                c, MAJOR(dev->devt), MINOR(dev->devt));
1920    } else if (strcmp(subsys, "net") == 0) {
1921        struct net_device *net = to_net_dev(dev);
1922
1923        pos++;
1924        pos += snprintf(hdr + pos, hdrlen - pos,
1925                "DEVICE=n%u", net->ifindex);
1926    } else {
1927        pos++;
1928        pos += snprintf(hdr + pos, hdrlen - pos,
1929                "DEVICE=+%s:%s", subsys, dev_name(dev));
1930    }
1931
1932    return pos;
1933}
1934EXPORT_SYMBOL(create_syslog_header);
1935
1936int dev_vprintk_emit(int level, const struct device *dev,
1937             const char *fmt, va_list args)
1938{
1939    char hdr[128];
1940    size_t hdrlen;
1941
1942    hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
1943
1944    return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
1945}
1946EXPORT_SYMBOL(dev_vprintk_emit);
1947
1948int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
1949{
1950    va_list args;
1951    int r;
1952
1953    va_start(args, fmt);
1954
1955    r = dev_vprintk_emit(level, dev, fmt, args);
1956
1957    va_end(args);
1958
1959    return r;
1960}
1961EXPORT_SYMBOL(dev_printk_emit);
1962
1963static int __dev_printk(const char *level, const struct device *dev,
1964            struct va_format *vaf)
1965{
1966    if (!dev)
1967        return printk("%s(NULL device *): %pV", level, vaf);
1968
1969    return dev_printk_emit(level[1] - '0', dev,
1970                   "%s %s: %pV",
1971                   dev_driver_string(dev), dev_name(dev), vaf);
1972}
1973
1974int dev_printk(const char *level, const struct device *dev,
1975           const char *fmt, ...)
1976{
1977    struct va_format vaf;
1978    va_list args;
1979    int r;
1980
1981    va_start(args, fmt);
1982
1983    vaf.fmt = fmt;
1984    vaf.va = &args;
1985
1986    r = __dev_printk(level, dev, &vaf);
1987
1988    va_end(args);
1989
1990    return r;
1991}
1992EXPORT_SYMBOL(dev_printk);
1993
1994#define define_dev_printk_level(func, kern_level) \
1995int func(const struct device *dev, const char *fmt, ...) \
1996{ \
1997    struct va_format vaf; \
1998    va_list args; \
1999    int r; \
2000                                \
2001    va_start(args, fmt); \
2002                                \
2003    vaf.fmt = fmt; \
2004    vaf.va = &args; \
2005                                \
2006    r = __dev_printk(kern_level, dev, &vaf); \
2007                                \
2008    va_end(args); \
2009                                \
2010    return r; \
2011} \
2012EXPORT_SYMBOL(func);
2013
2014define_dev_printk_level(dev_emerg, KERN_EMERG);
2015define_dev_printk_level(dev_alert, KERN_ALERT);
2016define_dev_printk_level(dev_crit, KERN_CRIT);
2017define_dev_printk_level(dev_err, KERN_ERR);
2018define_dev_printk_level(dev_warn, KERN_WARNING);
2019define_dev_printk_level(dev_notice, KERN_NOTICE);
2020define_dev_printk_level(_dev_info, KERN_INFO);
2021
2022#endif
2023

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