442 lines
12 KiB
C
442 lines
12 KiB
C
/*
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* attribute_container.c - implementation of a simple container for classes
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*
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* Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
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*
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* This file is licensed under GPLv2
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*
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* The basic idea here is to enable a device to be attached to an
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* aritrary numer of classes without having to allocate storage for them.
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* Instead, the contained classes select the devices they need to attach
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* to via a matching function.
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*/
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#include <linux/attribute_container.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include "base.h"
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/* This is a private structure used to tie the classdev and the
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* container .. it should never be visible outside this file */
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struct internal_container {
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struct klist_node node;
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struct attribute_container *cont;
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struct device classdev;
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};
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static void internal_container_klist_get(struct klist_node *n)
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{
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struct internal_container *ic =
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container_of(n, struct internal_container, node);
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get_device(&ic->classdev);
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}
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static void internal_container_klist_put(struct klist_node *n)
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{
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struct internal_container *ic =
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container_of(n, struct internal_container, node);
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put_device(&ic->classdev);
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}
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/**
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* attribute_container_classdev_to_container - given a classdev, return the container
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*
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* @classdev: the class device created by attribute_container_add_device.
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*
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* Returns the container associated with this classdev.
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*/
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struct attribute_container *
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attribute_container_classdev_to_container(struct device *classdev)
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{
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struct internal_container *ic =
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container_of(classdev, struct internal_container, classdev);
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return ic->cont;
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}
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EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container);
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static LIST_HEAD(attribute_container_list);
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static DEFINE_MUTEX(attribute_container_mutex);
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/**
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* attribute_container_register - register an attribute container
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*
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* @cont: The container to register. This must be allocated by the
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* callee and should also be zeroed by it.
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*/
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int
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attribute_container_register(struct attribute_container *cont)
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{
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INIT_LIST_HEAD(&cont->node);
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klist_init(&cont->containers,internal_container_klist_get,
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internal_container_klist_put);
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mutex_lock(&attribute_container_mutex);
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list_add_tail(&cont->node, &attribute_container_list);
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mutex_unlock(&attribute_container_mutex);
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return 0;
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}
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EXPORT_SYMBOL_GPL(attribute_container_register);
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/**
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* attribute_container_unregister - remove a container registration
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*
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* @cont: previously registered container to remove
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*/
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int
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attribute_container_unregister(struct attribute_container *cont)
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{
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int retval = -EBUSY;
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mutex_lock(&attribute_container_mutex);
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spin_lock(&cont->containers.k_lock);
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if (!list_empty(&cont->containers.k_list))
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goto out;
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retval = 0;
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list_del(&cont->node);
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out:
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spin_unlock(&cont->containers.k_lock);
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mutex_unlock(&attribute_container_mutex);
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return retval;
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}
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EXPORT_SYMBOL_GPL(attribute_container_unregister);
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/* private function used as class release */
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static void attribute_container_release(struct device *classdev)
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{
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struct internal_container *ic
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= container_of(classdev, struct internal_container, classdev);
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struct device *dev = classdev->parent;
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kfree(ic);
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put_device(dev);
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}
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/**
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* attribute_container_add_device - see if any container is interested in dev
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*
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* @dev: device to add attributes to
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* @fn: function to trigger addition of class device.
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*
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* This function allocates storage for the class device(s) to be
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* attached to dev (one for each matching attribute_container). If no
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* fn is provided, the code will simply register the class device via
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* device_add. If a function is provided, it is expected to add
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* the class device at the appropriate time. One of the things that
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* might be necessary is to allocate and initialise the classdev and
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* then add it a later time. To do this, call this routine for
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* allocation and initialisation and then use
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* attribute_container_device_trigger() to call device_add() on
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* it. Note: after this, the class device contains a reference to dev
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* which is not relinquished until the release of the classdev.
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*/
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void
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attribute_container_add_device(struct device *dev,
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int (*fn)(struct attribute_container *,
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struct device *,
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struct device *))
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{
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struct attribute_container *cont;
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mutex_lock(&attribute_container_mutex);
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list_for_each_entry(cont, &attribute_container_list, node) {
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struct internal_container *ic;
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if (attribute_container_no_classdevs(cont))
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continue;
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if (!cont->match(cont, dev))
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continue;
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ic = kzalloc(sizeof(*ic), GFP_KERNEL);
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if (!ic) {
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dev_printk(KERN_ERR, dev, "failed to allocate class container\n");
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continue;
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}
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ic->cont = cont;
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device_initialize(&ic->classdev);
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ic->classdev.parent = get_device(dev);
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ic->classdev.class = cont->class;
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cont->class->dev_release = attribute_container_release;
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dev_set_name(&ic->classdev, dev_name(dev));
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if (fn)
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fn(cont, dev, &ic->classdev);
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else
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attribute_container_add_class_device(&ic->classdev);
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klist_add_tail(&ic->node, &cont->containers);
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}
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mutex_unlock(&attribute_container_mutex);
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}
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/* FIXME: can't break out of this unless klist_iter_exit is also
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* called before doing the break
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*/
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#define klist_for_each_entry(pos, head, member, iter) \
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for (klist_iter_init(head, iter); (pos = ({ \
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struct klist_node *n = klist_next(iter); \
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n ? container_of(n, typeof(*pos), member) : \
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({ klist_iter_exit(iter) ; NULL; }); \
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}) ) != NULL; )
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/**
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* attribute_container_remove_device - make device eligible for removal.
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*
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* @dev: The generic device
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* @fn: A function to call to remove the device
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*
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* This routine triggers device removal. If fn is NULL, then it is
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* simply done via device_unregister (note that if something
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* still has a reference to the classdev, then the memory occupied
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* will not be freed until the classdev is released). If you want a
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* two phase release: remove from visibility and then delete the
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* device, then you should use this routine with a fn that calls
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* device_del() and then use attribute_container_device_trigger()
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* to do the final put on the classdev.
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*/
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void
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attribute_container_remove_device(struct device *dev,
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void (*fn)(struct attribute_container *,
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struct device *,
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struct device *))
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{
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struct attribute_container *cont;
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mutex_lock(&attribute_container_mutex);
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list_for_each_entry(cont, &attribute_container_list, node) {
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struct internal_container *ic;
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struct klist_iter iter;
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if (attribute_container_no_classdevs(cont))
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continue;
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if (!cont->match(cont, dev))
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continue;
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klist_for_each_entry(ic, &cont->containers, node, &iter) {
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if (dev != ic->classdev.parent)
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continue;
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klist_del(&ic->node);
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if (fn)
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fn(cont, dev, &ic->classdev);
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else {
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attribute_container_remove_attrs(&ic->classdev);
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device_unregister(&ic->classdev);
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}
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}
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}
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mutex_unlock(&attribute_container_mutex);
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}
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/**
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* attribute_container_device_trigger - execute a trigger for each matching classdev
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*
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* @dev: The generic device to run the trigger for
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* @fn the function to execute for each classdev.
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*
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* This funcion is for executing a trigger when you need to know both
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* the container and the classdev. If you only care about the
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* container, then use attribute_container_trigger() instead.
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*/
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void
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attribute_container_device_trigger(struct device *dev,
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int (*fn)(struct attribute_container *,
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struct device *,
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struct device *))
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{
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struct attribute_container *cont;
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mutex_lock(&attribute_container_mutex);
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list_for_each_entry(cont, &attribute_container_list, node) {
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struct internal_container *ic;
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struct klist_iter iter;
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if (!cont->match(cont, dev))
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continue;
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if (attribute_container_no_classdevs(cont)) {
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fn(cont, dev, NULL);
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continue;
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}
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klist_for_each_entry(ic, &cont->containers, node, &iter) {
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if (dev == ic->classdev.parent)
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fn(cont, dev, &ic->classdev);
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}
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}
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mutex_unlock(&attribute_container_mutex);
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}
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/**
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* attribute_container_trigger - trigger a function for each matching container
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*
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* @dev: The generic device to activate the trigger for
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* @fn: the function to trigger
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*
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* This routine triggers a function that only needs to know the
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* matching containers (not the classdev) associated with a device.
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* It is more lightweight than attribute_container_device_trigger, so
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* should be used in preference unless the triggering function
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* actually needs to know the classdev.
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*/
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void
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attribute_container_trigger(struct device *dev,
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int (*fn)(struct attribute_container *,
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struct device *))
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{
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struct attribute_container *cont;
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mutex_lock(&attribute_container_mutex);
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list_for_each_entry(cont, &attribute_container_list, node) {
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if (cont->match(cont, dev))
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fn(cont, dev);
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}
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mutex_unlock(&attribute_container_mutex);
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}
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/**
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* attribute_container_add_attrs - add attributes
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*
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* @classdev: The class device
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*
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* This simply creates all the class device sysfs files from the
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* attributes listed in the container
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*/
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int
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attribute_container_add_attrs(struct device *classdev)
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{
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struct attribute_container *cont =
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attribute_container_classdev_to_container(classdev);
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struct device_attribute **attrs = cont->attrs;
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int i, error;
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BUG_ON(attrs && cont->grp);
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if (!attrs && !cont->grp)
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return 0;
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if (cont->grp)
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return sysfs_create_group(&classdev->kobj, cont->grp);
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for (i = 0; attrs[i]; i++) {
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sysfs_attr_init(&attrs[i]->attr);
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error = device_create_file(classdev, attrs[i]);
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if (error)
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return error;
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}
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return 0;
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}
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/**
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* attribute_container_add_class_device - same function as device_add
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*
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* @classdev: the class device to add
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*
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* This performs essentially the same function as device_add except for
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* attribute containers, namely add the classdev to the system and then
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* create the attribute files
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*/
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int
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attribute_container_add_class_device(struct device *classdev)
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{
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int error = device_add(classdev);
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if (error)
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return error;
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return attribute_container_add_attrs(classdev);
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}
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/**
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* attribute_container_add_class_device_adapter - simple adapter for triggers
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*
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* This function is identical to attribute_container_add_class_device except
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* that it is designed to be called from the triggers
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*/
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int
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attribute_container_add_class_device_adapter(struct attribute_container *cont,
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struct device *dev,
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struct device *classdev)
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{
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return attribute_container_add_class_device(classdev);
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}
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/**
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* attribute_container_remove_attrs - remove any attribute files
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*
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* @classdev: The class device to remove the files from
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*
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*/
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void
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attribute_container_remove_attrs(struct device *classdev)
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{
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struct attribute_container *cont =
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attribute_container_classdev_to_container(classdev);
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struct device_attribute **attrs = cont->attrs;
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int i;
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if (!attrs && !cont->grp)
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return;
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if (cont->grp) {
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sysfs_remove_group(&classdev->kobj, cont->grp);
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return ;
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}
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for (i = 0; attrs[i]; i++)
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device_remove_file(classdev, attrs[i]);
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}
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/**
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* attribute_container_class_device_del - equivalent of class_device_del
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*
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* @classdev: the class device
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*
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* This function simply removes all the attribute files and then calls
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* device_del.
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*/
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void
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attribute_container_class_device_del(struct device *classdev)
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{
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attribute_container_remove_attrs(classdev);
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device_del(classdev);
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}
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/**
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* attribute_container_find_class_device - find the corresponding class_device
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*
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* @cont: the container
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* @dev: the generic device
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*
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* Looks up the device in the container's list of class devices and returns
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* the corresponding class_device.
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*/
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struct device *
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attribute_container_find_class_device(struct attribute_container *cont,
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struct device *dev)
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{
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struct device *cdev = NULL;
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struct internal_container *ic;
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struct klist_iter iter;
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klist_for_each_entry(ic, &cont->containers, node, &iter) {
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if (ic->classdev.parent == dev) {
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cdev = &ic->classdev;
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/* FIXME: must exit iterator then break */
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klist_iter_exit(&iter);
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break;
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}
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}
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return cdev;
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}
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EXPORT_SYMBOL_GPL(attribute_container_find_class_device);
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