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alistair23-linux/drivers/base/class.c
Bill Nottingham 3e51377dc4 [PATCH] fix class symlinks in sysfs 
The class symlinks in sysfs don't properly handle changing device names.

To demonstrate, rename your network device from eth0 to eth1. Your
pci (or usb, or whatever) device will still have a 'net:eth0' link,
except now it points to /sys/class/net/eth1.

The attached patch makes sure the class symlink name changes when
the class device name changes. It isn't 100% correct, it should be
using sysfs_rename_link. Unfortunately, sysfs_rename_link doesn't exist.

Signed-off-by: Bill Nottingham <notting@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-22 07:58:24 -07:00

800 lines
19 KiB
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Raw Blame History

/*
* 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/config.h>
#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 "base.h"
#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
#define to_class(obj) container_of(obj, struct class, subsys.kset.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 ktype_class = {
.sysfs_ops = &class_sysfs_ops,
.release = class_release,
};
/* Hotplug events for classes go to the class_obj subsys */
static decl_subsys(class, &ktype_class, NULL);
int class_create_file(struct class * cls, const struct class_attribute * attr)
{
int error;
if (cls) {
error = sysfs_create_file(&cls->subsys.kset.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.kset.kobj, &attr->attr);
}
struct class * class_get(struct class * cls)
{
if (cls)
return container_of(subsys_get(&cls->subsys), struct class, subsys);
return NULL;
}
void class_put(struct class * cls)
{
subsys_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 Err;
}
}
Done:
return error;
Err:
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->children);
INIT_LIST_HEAD(&cls->interfaces);
init_MUTEX(&cls->sem);
error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
if (error)
return error;
subsys_set_kset(cls, class_subsys);
error = subsystem_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);
subsystem_unregister(&cls->subsys);
}
static void class_create_release(struct class *cls)
{
kfree(cls);
}
static void class_device_create_release(struct class_device *class_dev)
{
kfree(class_dev);
}
/**
* 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 class_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, 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;
cls->release = class_device_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
* @cs: 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);
}
/* Class Device Stuff */
int class_device_create_file(struct class_device * class_dev,
const struct class_device_attribute * attr)
{
int error = -EINVAL;
if (class_dev)
error = sysfs_create_file(&class_dev->kobj, &attr->attr);
return error;
}
void class_device_remove_file(struct class_device * class_dev,
const struct class_device_attribute * attr)
{
if (class_dev)
sysfs_remove_file(&class_dev->kobj, &attr->attr);
}
int class_device_create_bin_file(struct class_device *class_dev,
struct bin_attribute *attr)
{
int error = -EINVAL;
if (class_dev)
error = sysfs_create_bin_file(&class_dev->kobj, attr);
return error;
}
void class_device_remove_bin_file(struct class_device *class_dev,
struct bin_attribute *attr)
{
if (class_dev)
sysfs_remove_bin_file(&class_dev->kobj, attr);
}
static ssize_t
class_device_attr_show(struct kobject * kobj, struct attribute * attr,
char * buf)
{
struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
struct class_device * cd = to_class_dev(kobj);
ssize_t ret = 0;
if (class_dev_attr->show)
ret = class_dev_attr->show(cd, buf);
return ret;
}
static ssize_t
class_device_attr_store(struct kobject * kobj, struct attribute * attr,
const char * buf, size_t count)
{
struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
struct class_device * cd = to_class_dev(kobj);
ssize_t ret = 0;
if (class_dev_attr->store)
ret = class_dev_attr->store(cd, buf, count);
return ret;
}
static struct sysfs_ops class_dev_sysfs_ops = {
.show = class_device_attr_show,
.store = class_device_attr_store,
};
static void class_dev_release(struct kobject * kobj)
{
struct class_device *cd = to_class_dev(kobj);
struct class * cls = cd->class;
pr_debug("device class '%s': release.\n", cd->class_id);
kfree(cd->devt_attr);
cd->devt_attr = NULL;
if (cls->release)
cls->release(cd);
else {
printk(KERN_ERR "Device class '%s' does not have a release() function, "
"it is broken and must be fixed.\n",
cd->class_id);
WARN_ON(1);
}
}
static struct kobj_type ktype_class_device = {
.sysfs_ops = &class_dev_sysfs_ops,
.release = class_dev_release,
};
static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &ktype_class_device) {
struct class_device *class_dev = to_class_dev(kobj);
if (class_dev->class)
return 1;
}
return 0;
}
static const char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
{
struct class_device *class_dev = to_class_dev(kobj);
return class_dev->class->name;
}
static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
int num_envp, char *buffer, int buffer_size)
{
struct class_device *class_dev = to_class_dev(kobj);
int i = 0;
int length = 0;
int retval = 0;
pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
if (class_dev->dev) {
/* add physical device, backing this device */
struct device *dev = class_dev->dev;
char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
&length, "PHYSDEVPATH=%s", path);
kfree(path);
if (dev->bus)
add_hotplug_env_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVBUS=%s", dev->bus->name);
if (dev->driver)
add_hotplug_env_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVDRIVER=%s", dev->driver->name);
}
if (MAJOR(class_dev->devt)) {
add_hotplug_env_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MAJOR=%u", MAJOR(class_dev->devt));
add_hotplug_env_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MINOR=%u", MINOR(class_dev->devt));
}
/* terminate, set to next free slot, shrink available space */
envp[i] = NULL;
envp = &envp[i];
num_envp -= i;
buffer = &buffer[length];
buffer_size -= length;
if (class_dev->class->hotplug) {
/* have the bus specific function add its stuff */
retval = class_dev->class->hotplug (class_dev, envp, num_envp,
buffer, buffer_size);
if (retval) {
pr_debug ("%s - hotplug() returned %d\n",
__FUNCTION__, retval);
}
}
return retval;
}
static struct kset_hotplug_ops class_hotplug_ops = {
.filter = class_hotplug_filter,
.name = class_hotplug_name,
.hotplug = class_hotplug,
};
static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
static int class_device_add_attrs(struct class_device * cd)
{
int i;
int error = 0;
struct class * cls = cd->class;
if (cls->class_dev_attrs) {
for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
error = class_device_create_file(cd,
&cls->class_dev_attrs[i]);
if (error)
goto Err;
}
}
Done:
return error;
Err:
while (--i >= 0)
class_device_remove_file(cd,&cls->class_dev_attrs[i]);
goto Done;
}
static void class_device_remove_attrs(struct class_device * cd)
{
int i;
struct class * cls = cd->class;
if (cls->class_dev_attrs) {
for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
class_device_remove_file(cd,&cls->class_dev_attrs[i]);
}
}
static ssize_t show_dev(struct class_device *class_dev, char *buf)
{
return print_dev_t(buf, class_dev->devt);
}
void class_device_initialize(struct class_device *class_dev)
{
kobj_set_kset_s(class_dev, class_obj_subsys);
kobject_init(&class_dev->kobj);
INIT_LIST_HEAD(&class_dev->node);
}
static char *make_class_name(struct class_device *class_dev)
{
char *name;
int size;
size = strlen(class_dev->class->name) +
strlen(kobject_name(&class_dev->kobj)) + 2;
name = kmalloc(size, GFP_KERNEL);
if (!name)
return ERR_PTR(-ENOMEM);
strcpy(name, class_dev->class->name);
strcat(name, ":");
strcat(name, kobject_name(&class_dev->kobj));
return name;
}
int class_device_add(struct class_device *class_dev)
{
struct class * parent = NULL;
struct class_interface * class_intf;
char *class_name = NULL;
int error;
class_dev = class_device_get(class_dev);
if (!class_dev)
return -EINVAL;
if (!strlen(class_dev->class_id)) {
error = -EINVAL;
goto register_done;
}
parent = class_get(class_dev->class);
pr_debug("CLASS: registering class device: ID = '%s'\n",
class_dev->class_id);
/* first, register with generic layer. */
kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
if (parent)
class_dev->kobj.parent = &parent->subsys.kset.kobj;
if ((error = kobject_add(&class_dev->kobj)))
goto register_done;
/* add the needed attributes to this device */
if (MAJOR(class_dev->devt)) {
struct class_device_attribute *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr) {
error = -ENOMEM;
kobject_del(&class_dev->kobj);
goto register_done;
}
attr->attr.name = "dev";
attr->attr.mode = S_IRUGO;
attr->attr.owner = parent->owner;
attr->show = show_dev;
attr->store = NULL;
class_device_create_file(class_dev, attr);
class_dev->devt_attr = attr;
}
class_device_add_attrs(class_dev);
if (class_dev->dev) {
class_name = make_class_name(class_dev);
sysfs_create_link(&class_dev->kobj,
&class_dev->dev->kobj, "device");
sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
class_name);
}
/* notify any interfaces this device is now here */
if (parent) {
down(&parent->sem);
list_add_tail(&class_dev->node, &parent->children);
list_for_each_entry(class_intf, &parent->interfaces, node)
if (class_intf->add)
class_intf->add(class_dev);
up(&parent->sem);
}
kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
register_done:
if (error && parent)
class_put(parent);
class_device_put(class_dev);
kfree(class_name);
return error;
}
int class_device_register(struct class_device *class_dev)
{
class_device_initialize(class_dev);
return class_device_add(class_dev);
}
/**
* class_device_create - creates a class device and registers it with sysfs
* @cs: pointer to the struct class that this device should be registered to.
* @dev: the dev_t for the char device to be added.
* @device: a pointer to a struct device that is assiociated with this class device.
* @fmt: string for the class device's name
*
* This function can be used by char device classes. A struct
* class_device will be created in sysfs, registered to the specified
* class. A "dev" file will be created, showing the dev_t for the
* device. The pointer to the struct class_device will be returned from
* the call. Any further sysfs files that might be required can be
* created using this pointer.
*
* Note: the struct class passed to this function must have previously
* been created with a call to class_create().
*/
struct class_device *class_device_create(struct class *cls, dev_t devt,
struct device *device, char *fmt, ...)
{
va_list args;
struct class_device *class_dev = NULL;
int retval = -ENODEV;
if (cls == NULL || IS_ERR(cls))
goto error;
class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
if (!class_dev) {
retval = -ENOMEM;
goto error;
}
class_dev->devt = devt;
class_dev->dev = device;
class_dev->class = cls;
va_start(args, fmt);
vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
va_end(args);
retval = class_device_register(class_dev);
if (retval)
goto error;
return class_dev;
error:
kfree(class_dev);
return ERR_PTR(retval);
}
void class_device_del(struct class_device *class_dev)
{
struct class * parent = class_dev->class;
struct class_interface * class_intf;
char *class_name = NULL;
if (parent) {
down(&parent->sem);
list_del_init(&class_dev->node);
list_for_each_entry(class_intf, &parent->interfaces, node)
if (class_intf->remove)
class_intf->remove(class_dev);
up(&parent->sem);
}
if (class_dev->dev) {
class_name = make_class_name(class_dev);
sysfs_remove_link(&class_dev->kobj, "device");
sysfs_remove_link(&class_dev->dev->kobj, class_name);
}
if (class_dev->devt_attr)
class_device_remove_file(class_dev, class_dev->devt_attr);
class_device_remove_attrs(class_dev);
kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
kobject_del(&class_dev->kobj);
if (parent)
class_put(parent);
kfree(class_name);
}
void class_device_unregister(struct class_device *class_dev)
{
pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
class_dev->class_id);
class_device_del(class_dev);
class_device_put(class_dev);
}
/**
* class_device_destroy - removes a class device that was created with class_device_create()
* @cls: the pointer to the struct class that this device was registered * with.
* @dev: the dev_t of the device that was previously registered.
*
* This call unregisters and cleans up a class device that was created with a
* call to class_device_create()
*/
void class_device_destroy(struct class *cls, dev_t devt)
{
struct class_device *class_dev = NULL;
struct class_device *class_dev_tmp;
down(&cls->sem);
list_for_each_entry(class_dev_tmp, &cls->children, node) {
if (class_dev_tmp->devt == devt) {
class_dev = class_dev_tmp;
break;
}
}
up(&cls->sem);
if (class_dev)
class_device_unregister(class_dev);
}
int class_device_rename(struct class_device *class_dev, char *new_name)
{
int error = 0;
char *old_class_name = NULL, *new_class_name = NULL;
class_dev = class_device_get(class_dev);
if (!class_dev)
return -EINVAL;
pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
new_name);
if (class_dev->dev)
old_class_name = make_class_name(class_dev);
strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
error = kobject_rename(&class_dev->kobj, new_name);
if (class_dev->dev) {
new_class_name = make_class_name(class_dev);
sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
new_class_name);
sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
}
class_device_put(class_dev);
kfree(old_class_name);
kfree(new_class_name);
return error;
}
struct class_device * class_device_get(struct class_device *class_dev)
{
if (class_dev)
return to_class_dev(kobject_get(&class_dev->kobj));
return NULL;
}
void class_device_put(struct class_device *class_dev)
{
kobject_put(&class_dev->kobj);
}
int class_interface_register(struct class_interface *class_intf)
{
struct class *parent;
struct class_device *class_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) {
list_for_each_entry(class_dev, &parent->children, node)
class_intf->add(class_dev);
}
up(&parent->sem);
return 0;
}
void class_interface_unregister(struct class_interface *class_intf)
{
struct class * parent = class_intf->class;
struct class_device *class_dev;
if (!parent)
return;
down(&parent->sem);
list_del_init(&class_intf->node);
if (class_intf->remove) {
list_for_each_entry(class_dev, &parent->children, node)
class_intf->remove(class_dev);
}
up(&parent->sem);
class_put(parent);
}
int __init classes_init(void)
{
int retval;
retval = subsystem_register(&class_subsys);
if (retval)
return retval;
/* ick, this is ugly, the things we go through to keep from showing up
* in sysfs... */
subsystem_init(&class_obj_subsys);
if (!class_obj_subsys.kset.subsys)
class_obj_subsys.kset.subsys = &class_obj_subsys;
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_get);
EXPORT_SYMBOL_GPL(class_put);
EXPORT_SYMBOL_GPL(class_create);
EXPORT_SYMBOL_GPL(class_destroy);
EXPORT_SYMBOL_GPL(class_device_register);
EXPORT_SYMBOL_GPL(class_device_unregister);
EXPORT_SYMBOL_GPL(class_device_initialize);
EXPORT_SYMBOL_GPL(class_device_add);
EXPORT_SYMBOL_GPL(class_device_del);
EXPORT_SYMBOL_GPL(class_device_get);
EXPORT_SYMBOL_GPL(class_device_put);
EXPORT_SYMBOL_GPL(class_device_create);
EXPORT_SYMBOL_GPL(class_device_destroy);
EXPORT_SYMBOL_GPL(class_device_create_file);
EXPORT_SYMBOL_GPL(class_device_remove_file);
EXPORT_SYMBOL_GPL(class_device_create_bin_file);
EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
EXPORT_SYMBOL_GPL(class_interface_register);
EXPORT_SYMBOL_GPL(class_interface_unregister);
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