xref: /linux/drivers/base/core.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
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
35 long sysfs_deprecated = 1;
36 #else
37 long sysfs_deprecated = 0;
38 #endif
39 static __init int sysfs_deprecated_setup(char *arg)
40 {
41 	return strict_strtol(arg, 10, &sysfs_deprecated);
42 }
43 early_param("sysfs.deprecated", sysfs_deprecated_setup);
44 #endif
45 
46 int (*platform_notify)(struct device *dev) = NULL;
47 int (*platform_notify_remove)(struct device *dev) = NULL;
48 static struct kobject *dev_kobj;
49 struct kobject *sysfs_dev_char_kobj;
50 struct kobject *sysfs_dev_block_kobj;
51 
52 #ifdef CONFIG_BLOCK
53 static inline int device_is_not_partition(struct device *dev)
54 {
55 	return !(dev->type == &part_type);
56 }
57 #else
58 static 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  */
73 const 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 }
86 EXPORT_SYMBOL(dev_driver_string);
87 
88 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
89 
90 static 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 
106 static 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 
118 static 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 
125 ssize_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 }
138 EXPORT_SYMBOL_GPL(device_store_ulong);
139 
140 ssize_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 }
147 EXPORT_SYMBOL_GPL(device_show_ulong);
148 
149 ssize_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 }
162 EXPORT_SYMBOL_GPL(device_store_int);
163 
164 ssize_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 }
172 EXPORT_SYMBOL_GPL(device_show_int);
173 
174 ssize_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 }
184 EXPORT_SYMBOL_GPL(device_store_bool);
185 
186 ssize_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 }
193 EXPORT_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  */
203 static 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 
232 static 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 
243 static struct kobj_type device_ktype = {
244 	.release	= device_release,
245 	.sysfs_ops	= &dev_sysfs_ops,
246 	.namespace	= device_namespace,
247 };
248 
249 
250 static 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 
264 static 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 
275 static 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 
336 static const struct kset_uevent_ops device_uevent_ops = {
337 	.filter =	dev_uevent_filter,
338 	.name =		dev_uevent_name,
339 	.uevent =	dev_uevent,
340 };
341 
342 static 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]);
380 out:
381 	kfree(env);
382 	return count;
383 }
384 
385 static 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 
397 static struct device_attribute uevent_attr =
398 	__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
399 
400 static 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 
419 static 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 
429 static 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 
448 static 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 
458 static 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 
478 static 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 
488 static 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 
528 static 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 
545 static 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 
551 static struct device_attribute devt_attr =
552 	__ATTR(dev, S_IRUGO, show_dev, NULL);
553 
554 /* /sys/devices/ */
555 struct kset *devices_kset;
556 
557 /**
558  * device_create_file - create sysfs attribute file for device.
559  * @dev: device.
560  * @attr: device attribute descriptor.
561  */
562 int 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  */
576 void 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  */
588 int 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 }
596 EXPORT_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  */
603 void 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 }
609 EXPORT_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  */
636 int 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 }
642 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
643 
644 static 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 
652 static 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  */
680 void 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 
693 static 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 
704 struct 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 
711 static void class_dir_release(struct kobject *kobj)
712 {
713 	struct class_dir *dir = to_class_dir(kobj);
714 	kfree(dir);
715 }
716 
717 static const
718 struct 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 
724 static 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 
730 static struct kobject *
731 class_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 
754 static 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 
815 static 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 
825 static void cleanup_device_parent(struct device *dev)
826 {
827 	cleanup_glue_dir(dev, dev->kobj.parent);
828 }
829 
830 static 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 
864 out_device:
865 	sysfs_remove_link(&dev->kobj, "device");
866 
867 out_subsys:
868 	sysfs_remove_link(&dev->kobj, "subsystem");
869 out:
870 	return error;
871 }
872 
873 static 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  */
893 int 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 }
903 EXPORT_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  */
916 static 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 
928 static 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 
942 static 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 
953 int 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  */
987 int 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 	}
1100 done:
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);
1126 name_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  */
1150 int 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  */
1164 struct 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  */
1173 void 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  */
1193 void 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  */
1253 void 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 
1260 static 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  */
1284 const 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  */
1328 int 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  */
1360 struct 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 
1377 int __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 
1403 EXPORT_SYMBOL_GPL(device_for_each_child);
1404 EXPORT_SYMBOL_GPL(device_find_child);
1405 
1406 EXPORT_SYMBOL_GPL(device_initialize);
1407 EXPORT_SYMBOL_GPL(device_add);
1408 EXPORT_SYMBOL_GPL(device_register);
1409 
1410 EXPORT_SYMBOL_GPL(device_del);
1411 EXPORT_SYMBOL_GPL(device_unregister);
1412 EXPORT_SYMBOL_GPL(get_device);
1413 EXPORT_SYMBOL_GPL(put_device);
1414 
1415 EXPORT_SYMBOL_GPL(device_create_file);
1416 EXPORT_SYMBOL_GPL(device_remove_file);
1417 
1418 struct root_device {
1419 	struct device dev;
1420 	struct module *owner;
1421 };
1422 
1423 static inline struct root_device *to_root_device(struct device *d)
1424 {
1425 	return container_of(d, struct root_device, dev);
1426 }
1427 
1428 static 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  */
1455 struct 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 }
1493 EXPORT_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  */
1502 void 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 }
1511 EXPORT_SYMBOL_GPL(root_device_unregister);
1512 
1513 
1514 static 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  */
1545 struct 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 
1577 error:
1578 	put_device(dev);
1579 	return ERR_PTR(retval);
1580 }
1581 EXPORT_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  */
1607 struct 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 }
1618 EXPORT_SYMBOL_GPL(device_create);
1619 
1620 static int __match_devt(struct device *dev, void *data)
1621 {
1622 	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  */
1635 void 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 }
1645 EXPORT_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  */
1686 int device_rename(struct device *dev, const char *new_name)
1687 {
1688 	char *old_class_name = NULL;
1689 	char *new_class_name = NULL;
1690 	char *old_device_name = NULL;
1691 	int error;
1692 
1693 	dev = get_device(dev);
1694 	if (!dev)
1695 		return -EINVAL;
1696 
1697 	pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1698 		 __func__, new_name);
1699 
1700 	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1701 	if (!old_device_name) {
1702 		error = -ENOMEM;
1703 		goto out;
1704 	}
1705 
1706 	if (dev->class) {
1707 		error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1708 			&dev->kobj, old_device_name, new_name);
1709 		if (error)
1710 			goto out;
1711 	}
1712 
1713 	error = kobject_rename(&dev->kobj, new_name);
1714 	if (error)
1715 		goto out;
1716 
1717 out:
1718 	put_device(dev);
1719 
1720 	kfree(new_class_name);
1721 	kfree(old_class_name);
1722 	kfree(old_device_name);
1723 
1724 	return error;
1725 }
1726 EXPORT_SYMBOL_GPL(device_rename);
1727 
1728 static int device_move_class_links(struct device *dev,
1729 				   struct device *old_parent,
1730 				   struct device *new_parent)
1731 {
1732 	int error = 0;
1733 
1734 	if (old_parent)
1735 		sysfs_remove_link(&dev->kobj, "device");
1736 	if (new_parent)
1737 		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1738 					  "device");
1739 	return error;
1740 }
1741 
1742 /**
1743  * device_move - moves a device to a new parent
1744  * @dev: the pointer to the struct device to be moved
1745  * @new_parent: the new parent of the device (can by NULL)
1746  * @dpm_order: how to reorder the dpm_list
1747  */
1748 int device_move(struct device *dev, struct device *new_parent,
1749 		enum dpm_order dpm_order)
1750 {
1751 	int error;
1752 	struct device *old_parent;
1753 	struct kobject *new_parent_kobj;
1754 
1755 	dev = get_device(dev);
1756 	if (!dev)
1757 		return -EINVAL;
1758 
1759 	device_pm_lock();
1760 	new_parent = get_device(new_parent);
1761 	new_parent_kobj = get_device_parent(dev, new_parent);
1762 
1763 	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1764 		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1765 	error = kobject_move(&dev->kobj, new_parent_kobj);
1766 	if (error) {
1767 		cleanup_glue_dir(dev, new_parent_kobj);
1768 		put_device(new_parent);
1769 		goto out;
1770 	}
1771 	old_parent = dev->parent;
1772 	dev->parent = new_parent;
1773 	if (old_parent)
1774 		klist_remove(&dev->p->knode_parent);
1775 	if (new_parent) {
1776 		klist_add_tail(&dev->p->knode_parent,
1777 			       &new_parent->p->klist_children);
1778 		set_dev_node(dev, dev_to_node(new_parent));
1779 	}
1780 
1781 	if (dev->class) {
1782 		error = device_move_class_links(dev, old_parent, new_parent);
1783 		if (error) {
1784 			/* We ignore errors on cleanup since we're hosed anyway... */
1785 			device_move_class_links(dev, new_parent, old_parent);
1786 			if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1787 				if (new_parent)
1788 					klist_remove(&dev->p->knode_parent);
1789 				dev->parent = old_parent;
1790 				if (old_parent) {
1791 					klist_add_tail(&dev->p->knode_parent,
1792 						       &old_parent->p->klist_children);
1793 					set_dev_node(dev, dev_to_node(old_parent));
1794 				}
1795 			}
1796 			cleanup_glue_dir(dev, new_parent_kobj);
1797 			put_device(new_parent);
1798 			goto out;
1799 		}
1800 	}
1801 	switch (dpm_order) {
1802 	case DPM_ORDER_NONE:
1803 		break;
1804 	case DPM_ORDER_DEV_AFTER_PARENT:
1805 		device_pm_move_after(dev, new_parent);
1806 		break;
1807 	case DPM_ORDER_PARENT_BEFORE_DEV:
1808 		device_pm_move_before(new_parent, dev);
1809 		break;
1810 	case DPM_ORDER_DEV_LAST:
1811 		device_pm_move_last(dev);
1812 		break;
1813 	}
1814 
1815 	put_device(old_parent);
1816 out:
1817 	device_pm_unlock();
1818 	put_device(dev);
1819 	return error;
1820 }
1821 EXPORT_SYMBOL_GPL(device_move);
1822 
1823 /**
1824  * device_shutdown - call ->shutdown() on each device to shutdown.
1825  */
1826 void device_shutdown(void)
1827 {
1828 	struct device *dev;
1829 
1830 	spin_lock(&devices_kset->list_lock);
1831 	/*
1832 	 * Walk the devices list backward, shutting down each in turn.
1833 	 * Beware that device unplug events may also start pulling
1834 	 * devices offline, even as the system is shutting down.
1835 	 */
1836 	while (!list_empty(&devices_kset->list)) {
1837 		dev = list_entry(devices_kset->list.prev, struct device,
1838 				kobj.entry);
1839 
1840 		/*
1841 		 * hold reference count of device's parent to
1842 		 * prevent it from being freed because parent's
1843 		 * lock is to be held
1844 		 */
1845 		get_device(dev->parent);
1846 		get_device(dev);
1847 		/*
1848 		 * Make sure the device is off the kset list, in the
1849 		 * event that dev->*->shutdown() doesn't remove it.
1850 		 */
1851 		list_del_init(&dev->kobj.entry);
1852 		spin_unlock(&devices_kset->list_lock);
1853 
1854 		/* hold lock to avoid race with probe/release */
1855 		if (dev->parent)
1856 			device_lock(dev->parent);
1857 		device_lock(dev);
1858 
1859 		/* Don't allow any more runtime suspends */
1860 		pm_runtime_get_noresume(dev);
1861 		pm_runtime_barrier(dev);
1862 
1863 		if (dev->bus && dev->bus->shutdown) {
1864 			if (initcall_debug)
1865 				dev_info(dev, "shutdown\n");
1866 			dev->bus->shutdown(dev);
1867 		} else if (dev->driver && dev->driver->shutdown) {
1868 			if (initcall_debug)
1869 				dev_info(dev, "shutdown\n");
1870 			dev->driver->shutdown(dev);
1871 		}
1872 
1873 		device_unlock(dev);
1874 		if (dev->parent)
1875 			device_unlock(dev->parent);
1876 
1877 		put_device(dev);
1878 		put_device(dev->parent);
1879 
1880 		spin_lock(&devices_kset->list_lock);
1881 	}
1882 	spin_unlock(&devices_kset->list_lock);
1883 	async_synchronize_full();
1884 }
1885 
1886 /*
1887  * Device logging functions
1888  */
1889 
1890 #ifdef CONFIG_PRINTK
1891 static int
1892 create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
1893 {
1894 	const char *subsys;
1895 	size_t pos = 0;
1896 
1897 	if (dev->class)
1898 		subsys = dev->class->name;
1899 	else if (dev->bus)
1900 		subsys = dev->bus->name;
1901 	else
1902 		return 0;
1903 
1904 	pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
1905 
1906 	/*
1907 	 * Add device identifier DEVICE=:
1908 	 *   b12:8         block dev_t
1909 	 *   c127:3        char dev_t
1910 	 *   n8            netdev ifindex
1911 	 *   +sound:card0  subsystem:devname
1912 	 */
1913 	if (MAJOR(dev->devt)) {
1914 		char c;
1915 
1916 		if (strcmp(subsys, "block") == 0)
1917 			c = 'b';
1918 		else
1919 			c = 'c';
1920 		pos++;
1921 		pos += snprintf(hdr + pos, hdrlen - pos,
1922 				"DEVICE=%c%u:%u",
1923 				c, MAJOR(dev->devt), MINOR(dev->devt));
1924 	} else if (strcmp(subsys, "net") == 0) {
1925 		struct net_device *net = to_net_dev(dev);
1926 
1927 		pos++;
1928 		pos += snprintf(hdr + pos, hdrlen - pos,
1929 				"DEVICE=n%u", net->ifindex);
1930 	} else {
1931 		pos++;
1932 		pos += snprintf(hdr + pos, hdrlen - pos,
1933 				"DEVICE=+%s:%s", subsys, dev_name(dev));
1934 	}
1935 
1936 	return pos;
1937 }
1938 EXPORT_SYMBOL(create_syslog_header);
1939 
1940 int dev_vprintk_emit(int level, const struct device *dev,
1941 		     const char *fmt, va_list args)
1942 {
1943 	char hdr[128];
1944 	size_t hdrlen;
1945 
1946 	hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
1947 
1948 	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
1949 }
1950 EXPORT_SYMBOL(dev_vprintk_emit);
1951 
1952 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
1953 {
1954 	va_list args;
1955 	int r;
1956 
1957 	va_start(args, fmt);
1958 
1959 	r = dev_vprintk_emit(level, dev, fmt, args);
1960 
1961 	va_end(args);
1962 
1963 	return r;
1964 }
1965 EXPORT_SYMBOL(dev_printk_emit);
1966 
1967 static int __dev_printk(const char *level, const struct device *dev,
1968 			struct va_format *vaf)
1969 {
1970 	if (!dev)
1971 		return printk("%s(NULL device *): %pV", level, vaf);
1972 
1973 	return dev_printk_emit(level[1] - '0', dev,
1974 			       "%s %s: %pV",
1975 			       dev_driver_string(dev), dev_name(dev), vaf);
1976 }
1977 
1978 int dev_printk(const char *level, const struct device *dev,
1979 	       const char *fmt, ...)
1980 {
1981 	struct va_format vaf;
1982 	va_list args;
1983 	int r;
1984 
1985 	va_start(args, fmt);
1986 
1987 	vaf.fmt = fmt;
1988 	vaf.va = &args;
1989 
1990 	r = __dev_printk(level, dev, &vaf);
1991 
1992 	va_end(args);
1993 
1994 	return r;
1995 }
1996 EXPORT_SYMBOL(dev_printk);
1997 
1998 #define define_dev_printk_level(func, kern_level)		\
1999 int func(const struct device *dev, const char *fmt, ...)	\
2000 {								\
2001 	struct va_format vaf;					\
2002 	va_list args;						\
2003 	int r;							\
2004 								\
2005 	va_start(args, fmt);					\
2006 								\
2007 	vaf.fmt = fmt;						\
2008 	vaf.va = &args;						\
2009 								\
2010 	r = __dev_printk(kern_level, dev, &vaf);		\
2011 								\
2012 	va_end(args);						\
2013 								\
2014 	return r;						\
2015 }								\
2016 EXPORT_SYMBOL(func);
2017 
2018 define_dev_printk_level(dev_emerg, KERN_EMERG);
2019 define_dev_printk_level(dev_alert, KERN_ALERT);
2020 define_dev_printk_level(dev_crit, KERN_CRIT);
2021 define_dev_printk_level(dev_err, KERN_ERR);
2022 define_dev_printk_level(dev_warn, KERN_WARNING);
2023 define_dev_printk_level(dev_notice, KERN_NOTICE);
2024 define_dev_printk_level(_dev_info, KERN_INFO);
2025 
2026 #endif
2027