linux/drivers/base/attribute_container.c
Greg Kroah-Hartman 3282570990 driver core: Remove redundant license text
Now that the SPDX tag is in all driver core files, that identifies the
license in a specific and legally-defined manner.  So the extra GPL text
wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-07 18:36:44 +01:00

442 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* attribute_container.c - implementation of a simple container for classes
*
* Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
*
* The basic idea here is to enable a device to be attached to an
* aritrary numer of classes without having to allocate storage for them.
* Instead, the contained classes select the devices they need to attach
* to via a matching function.
*/
#include <linux/attribute_container.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include "base.h"
/* This is a private structure used to tie the classdev and the
* container .. it should never be visible outside this file */
struct internal_container {
struct klist_node node;
struct attribute_container *cont;
struct device classdev;
};
static void internal_container_klist_get(struct klist_node *n)
{
struct internal_container *ic =
container_of(n, struct internal_container, node);
get_device(&ic->classdev);
}
static void internal_container_klist_put(struct klist_node *n)
{
struct internal_container *ic =
container_of(n, struct internal_container, node);
put_device(&ic->classdev);
}
/**
* attribute_container_classdev_to_container - given a classdev, return the container
*
* @classdev: the class device created by attribute_container_add_device.
*
* Returns the container associated with this classdev.
*/
struct attribute_container *
attribute_container_classdev_to_container(struct device *classdev)
{
struct internal_container *ic =
container_of(classdev, struct internal_container, classdev);
return ic->cont;
}
EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container);
static LIST_HEAD(attribute_container_list);
static DEFINE_MUTEX(attribute_container_mutex);
/**
* attribute_container_register - register an attribute container
*
* @cont: The container to register. This must be allocated by the
* callee and should also be zeroed by it.
*/
int
attribute_container_register(struct attribute_container *cont)
{
INIT_LIST_HEAD(&cont->node);
klist_init(&cont->containers, internal_container_klist_get,
internal_container_klist_put);
mutex_lock(&attribute_container_mutex);
list_add_tail(&cont->node, &attribute_container_list);
mutex_unlock(&attribute_container_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(attribute_container_register);
/**
* attribute_container_unregister - remove a container registration
*
* @cont: previously registered container to remove
*/
int
attribute_container_unregister(struct attribute_container *cont)
{
int retval = -EBUSY;
mutex_lock(&attribute_container_mutex);
spin_lock(&cont->containers.k_lock);
if (!list_empty(&cont->containers.k_list))
goto out;
retval = 0;
list_del(&cont->node);
out:
spin_unlock(&cont->containers.k_lock);
mutex_unlock(&attribute_container_mutex);
return retval;
}
EXPORT_SYMBOL_GPL(attribute_container_unregister);
/* private function used as class release */
static void attribute_container_release(struct device *classdev)
{
struct internal_container *ic
= container_of(classdev, struct internal_container, classdev);
struct device *dev = classdev->parent;
kfree(ic);
put_device(dev);
}
/**
* attribute_container_add_device - see if any container is interested in dev
*
* @dev: device to add attributes to
* @fn: function to trigger addition of class device.
*
* This function allocates storage for the class device(s) to be
* attached to dev (one for each matching attribute_container). If no
* fn is provided, the code will simply register the class device via
* device_add. If a function is provided, it is expected to add
* the class device at the appropriate time. One of the things that
* might be necessary is to allocate and initialise the classdev and
* then add it a later time. To do this, call this routine for
* allocation and initialisation and then use
* attribute_container_device_trigger() to call device_add() on
* it. Note: after this, the class device contains a reference to dev
* which is not relinquished until the release of the classdev.
*/
void
attribute_container_add_device(struct device *dev,
int (*fn)(struct attribute_container *,
struct device *,
struct device *))
{
struct attribute_container *cont;
mutex_lock(&attribute_container_mutex);
list_for_each_entry(cont, &attribute_container_list, node) {
struct internal_container *ic;
if (attribute_container_no_classdevs(cont))
continue;
if (!cont->match(cont, dev))
continue;
ic = kzalloc(sizeof(*ic), GFP_KERNEL);
if (!ic) {
dev_err(dev, "failed to allocate class container\n");
continue;
}
ic->cont = cont;
device_initialize(&ic->classdev);
ic->classdev.parent = get_device(dev);
ic->classdev.class = cont->class;
cont->class->dev_release = attribute_container_release;
dev_set_name(&ic->classdev, "%s", dev_name(dev));
if (fn)
fn(cont, dev, &ic->classdev);
else
attribute_container_add_class_device(&ic->classdev);
klist_add_tail(&ic->node, &cont->containers);
}
mutex_unlock(&attribute_container_mutex);
}
/* FIXME: can't break out of this unless klist_iter_exit is also
* called before doing the break
*/
#define klist_for_each_entry(pos, head, member, iter) \
for (klist_iter_init(head, iter); (pos = ({ \
struct klist_node *n = klist_next(iter); \
n ? container_of(n, typeof(*pos), member) : \
({ klist_iter_exit(iter) ; NULL; }); \
})) != NULL;)
/**
* attribute_container_remove_device - make device eligible for removal.
*
* @dev: The generic device
* @fn: A function to call to remove the device
*
* This routine triggers device removal. If fn is NULL, then it is
* simply done via device_unregister (note that if something
* still has a reference to the classdev, then the memory occupied
* will not be freed until the classdev is released). If you want a
* two phase release: remove from visibility and then delete the
* device, then you should use this routine with a fn that calls
* device_del() and then use attribute_container_device_trigger()
* to do the final put on the classdev.
*/
void
attribute_container_remove_device(struct device *dev,
void (*fn)(struct attribute_container *,
struct device *,
struct device *))
{
struct attribute_container *cont;
mutex_lock(&attribute_container_mutex);
list_for_each_entry(cont, &attribute_container_list, node) {
struct internal_container *ic;
struct klist_iter iter;
if (attribute_container_no_classdevs(cont))
continue;
if (!cont->match(cont, dev))
continue;
klist_for_each_entry(ic, &cont->containers, node, &iter) {
if (dev != ic->classdev.parent)
continue;
klist_del(&ic->node);
if (fn)
fn(cont, dev, &ic->classdev);
else {
attribute_container_remove_attrs(&ic->classdev);
device_unregister(&ic->classdev);
}
}
}
mutex_unlock(&attribute_container_mutex);
}
/**
* attribute_container_device_trigger - execute a trigger for each matching classdev
*
* @dev: The generic device to run the trigger for
* @fn the function to execute for each classdev.
*
* This function is for executing a trigger when you need to know both
* the container and the classdev. If you only care about the
* container, then use attribute_container_trigger() instead.
*/
void
attribute_container_device_trigger(struct device *dev,
int (*fn)(struct attribute_container *,
struct device *,
struct device *))
{
struct attribute_container *cont;
mutex_lock(&attribute_container_mutex);
list_for_each_entry(cont, &attribute_container_list, node) {
struct internal_container *ic;
struct klist_iter iter;
if (!cont->match(cont, dev))
continue;
if (attribute_container_no_classdevs(cont)) {
fn(cont, dev, NULL);
continue;
}
klist_for_each_entry(ic, &cont->containers, node, &iter) {
if (dev == ic->classdev.parent)
fn(cont, dev, &ic->classdev);
}
}
mutex_unlock(&attribute_container_mutex);
}
/**
* attribute_container_trigger - trigger a function for each matching container
*
* @dev: The generic device to activate the trigger for
* @fn: the function to trigger
*
* This routine triggers a function that only needs to know the
* matching containers (not the classdev) associated with a device.
* It is more lightweight than attribute_container_device_trigger, so
* should be used in preference unless the triggering function
* actually needs to know the classdev.
*/
void
attribute_container_trigger(struct device *dev,
int (*fn)(struct attribute_container *,
struct device *))
{
struct attribute_container *cont;
mutex_lock(&attribute_container_mutex);
list_for_each_entry(cont, &attribute_container_list, node) {
if (cont->match(cont, dev))
fn(cont, dev);
}
mutex_unlock(&attribute_container_mutex);
}
/**
* attribute_container_add_attrs - add attributes
*
* @classdev: The class device
*
* This simply creates all the class device sysfs files from the
* attributes listed in the container
*/
int
attribute_container_add_attrs(struct device *classdev)
{
struct attribute_container *cont =
attribute_container_classdev_to_container(classdev);
struct device_attribute **attrs = cont->attrs;
int i, error;
BUG_ON(attrs && cont->grp);
if (!attrs && !cont->grp)
return 0;
if (cont->grp)
return sysfs_create_group(&classdev->kobj, cont->grp);
for (i = 0; attrs[i]; i++) {
sysfs_attr_init(&attrs[i]->attr);
error = device_create_file(classdev, attrs[i]);
if (error)
return error;
}
return 0;
}
/**
* attribute_container_add_class_device - same function as device_add
*
* @classdev: the class device to add
*
* This performs essentially the same function as device_add except for
* attribute containers, namely add the classdev to the system and then
* create the attribute files
*/
int
attribute_container_add_class_device(struct device *classdev)
{
int error = device_add(classdev);
if (error)
return error;
return attribute_container_add_attrs(classdev);
}
/**
* attribute_container_add_class_device_adapter - simple adapter for triggers
*
* This function is identical to attribute_container_add_class_device except
* that it is designed to be called from the triggers
*/
int
attribute_container_add_class_device_adapter(struct attribute_container *cont,
struct device *dev,
struct device *classdev)
{
return attribute_container_add_class_device(classdev);
}
/**
* attribute_container_remove_attrs - remove any attribute files
*
* @classdev: The class device to remove the files from
*
*/
void
attribute_container_remove_attrs(struct device *classdev)
{
struct attribute_container *cont =
attribute_container_classdev_to_container(classdev);
struct device_attribute **attrs = cont->attrs;
int i;
if (!attrs && !cont->grp)
return;
if (cont->grp) {
sysfs_remove_group(&classdev->kobj, cont->grp);
return ;
}
for (i = 0; attrs[i]; i++)
device_remove_file(classdev, attrs[i]);
}
/**
* attribute_container_class_device_del - equivalent of class_device_del
*
* @classdev: the class device
*
* This function simply removes all the attribute files and then calls
* device_del.
*/
void
attribute_container_class_device_del(struct device *classdev)
{
attribute_container_remove_attrs(classdev);
device_del(classdev);
}
/**
* attribute_container_find_class_device - find the corresponding class_device
*
* @cont: the container
* @dev: the generic device
*
* Looks up the device in the container's list of class devices and returns
* the corresponding class_device.
*/
struct device *
attribute_container_find_class_device(struct attribute_container *cont,
struct device *dev)
{
struct device *cdev = NULL;
struct internal_container *ic;
struct klist_iter iter;
klist_for_each_entry(ic, &cont->containers, node, &iter) {
if (ic->classdev.parent == dev) {
cdev = &ic->classdev;
/* FIXME: must exit iterator then break */
klist_iter_exit(&iter);
break;
}
}
return cdev;
}
EXPORT_SYMBOL_GPL(attribute_container_find_class_device);