// SPDX-License-Identifier: GPL-2.0 /* * attribute_container.c - implementation of a simple container for classes * * Copyright (c) 2005 - James Bottomley <[email protected]> * * 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 { … }; static void internal_container_klist_get(struct klist_node *n) { … } static void internal_container_klist_put(struct klist_node *n) { … } /** * 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) { … } EXPORT_SYMBOL_GPL(…); 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) { … } EXPORT_SYMBOL_GPL(…); /** * attribute_container_unregister - remove a container registration * * @cont: previously registered container to remove */ int attribute_container_unregister(struct attribute_container *cont) { … } EXPORT_SYMBOL_GPL(…); /* private function used as class release */ static void attribute_container_release(struct device *classdev) { … } /** * 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 *)) { … } /* 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) … /** * 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 *)) { … } static int do_attribute_container_device_trigger_safe(struct device *dev, struct attribute_container *cont, int (*fn)(struct attribute_container *, struct device *, struct device *), int (*undo)(struct attribute_container *, struct device *, struct device *)) { … } /** * attribute_container_device_trigger_safe - execute a trigger for each * matching classdev or fail all of them. * * @dev: The generic device to run the trigger for * @fn: the function to execute for each classdev. * @undo: A function to undo the work previously done in case of error * * This function is a safe version of * attribute_container_device_trigger. It stops on the first error and * undo the partial work that has been done, on previous classdev. It * is guaranteed that either they all succeeded, or none of them * succeeded. */ int attribute_container_device_trigger_safe(struct device *dev, int (*fn)(struct attribute_container *, struct device *, struct device *), int (*undo)(struct attribute_container *, struct device *, struct device *)) { … } /** * 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 *)) { … } /** * 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 *)) { … } /** * 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) { … } /** * 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) { … } /** * attribute_container_add_class_device_adapter - simple adapter for triggers * * @cont: the container to register. * @dev: the generic device to activate the trigger for * @classdev: the class device to add * * 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) { … } /** * 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) { … } /** * 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_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) { … } EXPORT_SYMBOL_GPL(…);
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