/* * class.c - basic device class management * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2003-2004 Greg Kroah-Hartman * Copyright (c) 2003-2004 IBM Corp. * * This file is released under the GPLv2 * */ #include <linux/device.h>#include <linux/module.h>#include <linux/init.h>#include <linux/string.h>#include <linux/kdev_t.h>#include <linux/err.h>#include <linux/slab.h>#include <linux/genhd.h>#include "base.h" #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)#define to_class(obj) container_of(obj, struct class, subsys.kobj) static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,			       char *buf){	struct class_attribute *class_attr = to_class_attr(attr);	struct class *dc = to_class(kobj);	ssize_t ret = -EIO; 	if (class_attr->show)		ret = class_attr->show(dc, buf);	return ret;} static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,				const char *buf, size_t count){	struct class_attribute *class_attr = to_class_attr(attr);	struct class *dc = to_class(kobj);	ssize_t ret = -EIO; 	if (class_attr->store)		ret = class_attr->store(dc, buf, count);	return ret;} static void class_release(struct kobject *kobj){	struct class *class = to_class(kobj); 	pr_debug("class '%s': release.\n", class->name); 	if (class->class_release)		class->class_release(class);	else		pr_debug("class '%s' does not have a release() function, "			 "be careful\n", class->name);} static struct sysfs_ops class_sysfs_ops = {	.show	= class_attr_show,	.store	= class_attr_store,}; static struct kobj_type class_ktype = {	.sysfs_ops	= &class_sysfs_ops,	.release	= class_release,}; /* Hotplug events for classes go to the class_obj subsys */static struct kset *class_kset;  int class_create_file(struct class *cls, const struct class_attribute *attr){	int error;	if (cls)		error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);	else		error = -EINVAL;	return error;} void class_remove_file(struct class *cls, const struct class_attribute *attr){	if (cls)		sysfs_remove_file(&cls->subsys.kobj, &attr->attr);} static struct class *class_get(struct class *cls){	if (cls)		return container_of(kset_get(&cls->subsys),				    struct class, subsys);	return NULL;} static void class_put(struct class *cls){	if (cls)		kset_put(&cls->subsys);} static int add_class_attrs(struct class *cls){	int i;	int error = 0; 	if (cls->class_attrs) {		for (i = 0; attr_name(cls->class_attrs[i]); i++) {			error = class_create_file(cls, &cls->class_attrs[i]);			if (error)				goto error;		}	}done:	return error;error:	while (--i >= 0)		class_remove_file(cls, &cls->class_attrs[i]);	goto done;} static void remove_class_attrs(struct class *cls){	int i; 	if (cls->class_attrs) {		for (i = 0; attr_name(cls->class_attrs[i]); i++)			class_remove_file(cls, &cls->class_attrs[i]);	}} int class_register(struct class *cls){	int error; 	pr_debug("device class '%s': registering\n", cls->name); 	INIT_LIST_HEAD(&cls->devices);	INIT_LIST_HEAD(&cls->interfaces);	kset_init(&cls->class_dirs);	init_MUTEX(&cls->sem);	error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);	if (error)		return error; #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)	/* let the block class directory show up in the root of sysfs */	if (cls != &block_class)		cls->subsys.kobj.kset = class_kset;#else	cls->subsys.kobj.kset = class_kset;#endif	cls->subsys.kobj.ktype = &class_ktype; 	error = kset_register(&cls->subsys);	if (!error) {		error = add_class_attrs(class_get(cls));		class_put(cls);	}	return error;} void class_unregister(struct class *cls){	pr_debug("device class '%s': unregistering\n", cls->name);	remove_class_attrs(cls);	kset_unregister(&cls->subsys);} static void class_create_release(struct class *cls){	pr_debug("%s called for %s\n", __func__, cls->name);	kfree(cls);} /** * class_create - create a struct class structure * @owner: pointer to the module that is to "own" this struct class * @name: pointer to a string for the name of this class. * * This is used to create a struct class pointer that can then be used * in calls to device_create(). * * Note, the pointer created here is to be destroyed when finished by * making a call to class_destroy(). */struct class *class_create(struct module *owner, const char *name){	struct class *cls;	int retval; 	cls = kzalloc(sizeof(*cls), GFP_KERNEL);	if (!cls) {		retval = -ENOMEM;		goto error;	} 	cls->name = name;	cls->owner = owner;	cls->class_release = class_create_release; 	retval = class_register(cls);	if (retval)		goto error; 	return cls; error:	kfree(cls);	return ERR_PTR(retval);} /** * class_destroy - destroys a struct class structure * @cls: pointer to the struct class that is to be destroyed * * Note, the pointer to be destroyed must have been created with a call * to class_create(). */void class_destroy(struct class *cls){	if ((cls == NULL) || (IS_ERR(cls)))		return; 	class_unregister(cls);} #ifdef CONFIG_SYSFS_DEPRECATEDchar *make_class_name(const char *name, struct kobject *kobj){	char *class_name;	int size; 	size = strlen(name) + strlen(kobject_name(kobj)) + 2; 	class_name = kmalloc(size, GFP_KERNEL);	if (!class_name)		return NULL; 	strcpy(class_name, name);	strcat(class_name, ":");	strcat(class_name, kobject_name(kobj));	return class_name;}#endif /** * class_for_each_device - device iterator * @class: the class we're iterating * @data: data for the callback * @fn: function to be called for each device * * Iterate over @class's list of devices, and call @fn for each, * passing it @data. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. * * Note, we hold class->sem in this function, so it can not be * re-acquired in @fn, otherwise it will self-deadlocking. For * example, calls to add or remove class members would be verboten. */int class_for_each_device(struct class *class, void *data,			   int (*fn)(struct device *, void *)){	struct device *dev;	int error = 0; 	if (!class)		return -EINVAL;	down(&class->sem);	list_for_each_entry(dev, &class->devices, node) {		dev = get_device(dev);		if (dev) {			error = fn(dev, data);			put_device(dev);		} else			error = -ENODEV;		if (error)			break;	}	up(&class->sem); 	return error;}EXPORT_SYMBOL_GPL(class_for_each_device); /** * class_find_device - device iterator for locating a particular device * @class: the class we're iterating * @data: data for the match function * @match: function to check device * * This is similar to the class_for_each_dev() function above, but it * returns a reference to a device that is 'found' for later use, as * determined by the @match callback. * * The callback should return 0 if the device doesn't match and non-zero * if it does.  If the callback returns non-zero, this function will * return to the caller and not iterate over any more devices. * * Note, you will need to drop the reference with put_device() after use. * * We hold class->sem in this function, so it can not be * re-acquired in @match, otherwise it will self-deadlocking. For * example, calls to add or remove class members would be verboten. */struct device *class_find_device(struct class *class, void *data,				   int (*match)(struct device *, void *)){	struct device *dev;	int found = 0; 	if (!class)		return NULL; 	down(&class->sem);	list_for_each_entry(dev, &class->devices, node) {		dev = get_device(dev);		if (dev) {			if (match(dev, data)) {				found = 1;				break;			} else				put_device(dev);		} else			break;	}	up(&class->sem); 	return found ? dev : NULL;}EXPORT_SYMBOL_GPL(class_find_device); int class_interface_register(struct class_interface *class_intf){	struct class *parent;	struct device *dev; 	if (!class_intf || !class_intf->class)		return -ENODEV; 	parent = class_get(class_intf->class);	if (!parent)		return -EINVAL; 	down(&parent->sem);	list_add_tail(&class_intf->node, &parent->interfaces);	if (class_intf->add_dev) {		list_for_each_entry(dev, &parent->devices, node)			class_intf->add_dev(dev, class_intf);	}	up(&parent->sem); 	return 0;} void class_interface_unregister(struct class_interface *class_intf){	struct class *parent = class_intf->class;	struct device *dev; 	if (!parent)		return; 	down(&parent->sem);	list_del_init(&class_intf->node);	if (class_intf->remove_dev) {		list_for_each_entry(dev, &parent->devices, node)			class_intf->remove_dev(dev, class_intf);	}	up(&parent->sem); 	class_put(parent);} int __init classes_init(void){	class_kset = kset_create_and_add("class", NULL, NULL);	if (!class_kset)		return -ENOMEM;	return 0;} EXPORT_SYMBOL_GPL(class_create_file);EXPORT_SYMBOL_GPL(class_remove_file);EXPORT_SYMBOL_GPL(class_register);EXPORT_SYMBOL_GPL(class_unregister);EXPORT_SYMBOL_GPL(class_create);EXPORT_SYMBOL_GPL(class_destroy); EXPORT_SYMBOL_GPL(class_interface_register);EXPORT_SYMBOL_GPL(class_interface_unregister);