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/* * drivers/base/devres.c - device resource management * * Copyright (c) 2006  SUSE Linux Products GmbH * Copyright (c) 2006  Tejun Heo <teheo@suse.de> * * This file is released under the GPLv2. */ #include <linux/device.h>#include <linux/module.h>#include <linux/slab.h> #include "base.h" struct devres_node {	struct list_head		entry;	dr_release_t			release;#ifdef CONFIG_DEBUG_DEVRES	const char			*name;	size_t				size;#endif}; struct devres {	struct devres_node		node;	/* -- 3 pointers */	unsigned long long		data[];	/* guarantee ull alignment */}; struct devres_group {	struct devres_node		node[2];	void				*id;	int				color;	/* -- 8 pointers */}; #ifdef CONFIG_DEBUG_DEVRESstatic int log_devres = 0;module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR); static void set_node_dbginfo(struct devres_node *node, const char *name,			     size_t size){	node->name = name;	node->size = size;} static void devres_log(struct device *dev, struct devres_node *node,		       const char *op){	if (unlikely(log_devres))		dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",			op, node, node->name, (unsigned long)node->size);}#else /* CONFIG_DEBUG_DEVRES */#define set_node_dbginfo(node, n, s)	do {} while (0)#define devres_log(dev, node, op)	do {} while (0)#endif /* CONFIG_DEBUG_DEVRES */ /* * Release functions for devres group.  These callbacks are used only * for identification. */static void group_open_release(struct device *dev, void *res){	/* noop */} static void group_close_release(struct device *dev, void *res){	/* noop */} static struct devres_group * node_to_group(struct devres_node *node){	if (node->release == &group_open_release)		return container_of(node, struct devres_group, node[0]);	if (node->release == &group_close_release)		return container_of(node, struct devres_group, node[1]);	return NULL;} static __always_inline struct devres * alloc_dr(dr_release_t release,						size_t size, gfp_t gfp){	size_t tot_size = sizeof(struct devres) + size;	struct devres *dr; 	dr = kmalloc_track_caller(tot_size, gfp);	if (unlikely(!dr))		return NULL; 	memset(dr, 0, offsetof(struct devres, data)); 	INIT_LIST_HEAD(&dr->node.entry);	dr->node.release = release;	return dr;} static void add_dr(struct device *dev, struct devres_node *node){	devres_log(dev, node, "ADD");	BUG_ON(!list_empty(&node->entry));	list_add_tail(&node->entry, &dev->devres_head);} #ifdef CONFIG_DEBUG_DEVRESvoid * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,		      const char *name){	struct devres *dr; 	dr = alloc_dr(release, size, gfp | __GFP_ZERO);	if (unlikely(!dr))		return NULL;	set_node_dbginfo(&dr->node, name, size);	return dr->data;}EXPORT_SYMBOL_GPL(__devres_alloc);#else/** * devres_alloc - Allocate device resource data * @release: Release function devres will be associated with * @size: Allocation size * @gfp: Allocation flags * * Allocate devres of @size bytes.  The allocated area is zeroed, then * associated with @release.  The returned pointer can be passed to * other devres_*() functions. * * RETURNS: * Pointer to allocated devres on success, NULL on failure. */void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp){	struct devres *dr; 	dr = alloc_dr(release, size, gfp | __GFP_ZERO);	if (unlikely(!dr))		return NULL;	return dr->data;}EXPORT_SYMBOL_GPL(devres_alloc);#endif /** * devres_for_each_res - Resource iterator * @dev: Device to iterate resource from * @release: Look for resources associated with this release function * @match: Match function (optional) * @match_data: Data for the match function * @fn: Function to be called for each matched resource. * @data: Data for @fn, the 3rd parameter of @fn * * Call @fn for each devres of @dev which is associated with @release * and for which @match returns 1. * * RETURNS: * 	void */void devres_for_each_res(struct device *dev, dr_release_t release,			dr_match_t match, void *match_data,			void (*fn)(struct device *, void *, void *),			void *data){	struct devres_node *node;	struct devres_node *tmp;	unsigned long flags; 	if (!fn)		return; 	spin_lock_irqsave(&dev->devres_lock, flags);	list_for_each_entry_safe_reverse(node, tmp,			&dev->devres_head, entry) {		struct devres *dr = container_of(node, struct devres, node); 		if (node->release != release)			continue;		if (match && !match(dev, dr->data, match_data))			continue;		fn(dev, dr->data, data);	}	spin_unlock_irqrestore(&dev->devres_lock, flags);}EXPORT_SYMBOL_GPL(devres_for_each_res); /** * devres_free - Free device resource data * @res: Pointer to devres data to free * * Free devres created with devres_alloc(). */void devres_free(void *res){	if (res) {		struct devres *dr = container_of(res, struct devres, data); 		BUG_ON(!list_empty(&dr->node.entry));		kfree(dr);	}}EXPORT_SYMBOL_GPL(devres_free); /** * devres_add - Register device resource * @dev: Device to add resource to * @res: Resource to register * * Register devres @res to @dev.  @res should have been allocated * using devres_alloc().  On driver detach, the associated release * function will be invoked and devres will be freed automatically. */void devres_add(struct device *dev, void *res){	struct devres *dr = container_of(res, struct devres, data);	unsigned long flags; 	spin_lock_irqsave(&dev->devres_lock, flags);	add_dr(dev, &dr->node);	spin_unlock_irqrestore(&dev->devres_lock, flags);}EXPORT_SYMBOL_GPL(devres_add); static struct devres *find_dr(struct device *dev, dr_release_t release,			      dr_match_t match, void *match_data){	struct devres_node *node; 	list_for_each_entry_reverse(node, &dev->devres_head, entry) {		struct devres *dr = container_of(node, struct devres, node); 		if (node->release != release)			continue;		if (match && !match(dev, dr->data, match_data))			continue;		return dr;	} 	return NULL;} /** * devres_find - Find device resource * @dev: Device to lookup resource from * @release: Look for resources associated with this release function * @match: Match function (optional) * @match_data: Data for the match function * * Find the latest devres of @dev which is associated with @release * and for which @match returns 1.  If @match is NULL, it's considered * to match all. * * RETURNS: * Pointer to found devres, NULL if not found. */void * devres_find(struct device *dev, dr_release_t release,		   dr_match_t match, void *match_data){	struct devres *dr;	unsigned long flags; 	spin_lock_irqsave(&dev->devres_lock, flags);	dr = find_dr(dev, release, match, match_data);	spin_unlock_irqrestore(&dev->devres_lock, flags); 	if (dr)		return dr->data;	return NULL;}EXPORT_SYMBOL_GPL(devres_find); /** * devres_get - Find devres, if non-existent, add one atomically * @dev: Device to lookup or add devres for * @new_res: Pointer to new initialized devres to add if not found * @match: Match function (optional) * @match_data: Data for the match function * * Find the latest devres of @dev which has the same release function * as @new_res and for which @match return 1.  If found, @new_res is * freed; otherwise, @new_res is added atomically. * * RETURNS: * Pointer to found or added devres. */void * devres_get(struct device *dev, void *new_res,		  dr_match_t match, void *match_data){	struct devres *new_dr = container_of(new_res, struct devres, data);	struct devres *dr;	unsigned long flags; 	spin_lock_irqsave(&dev->devres_lock, flags);	dr = find_dr(dev, new_dr->node.release, match, match_data);	if (!dr) {		add_dr(dev, &new_dr->node);		dr = new_dr;		new_dr = NULL;	}	spin_unlock_irqrestore(&dev->devres_lock, flags);	devres_free(new_dr); 	return dr->data;}EXPORT_SYMBOL_GPL(devres_get); /** * devres_remove - Find a device resource and remove it * @dev: Device to find resource from * @release: Look for resources associated with this release function * @match: Match function (optional) * @match_data: Data for the match function * * Find the latest devres of @dev associated with @release and for * which @match returns 1.  If @match is NULL, it's considered to * match all.  If found, the resource is removed atomically and * returned. * * RETURNS: * Pointer to removed devres on success, NULL if not found. */void * devres_remove(struct device *dev, dr_release_t release,		     dr_match_t match, void *match_data){	struct devres *dr;	unsigned long flags; 	spin_lock_irqsave(&dev->devres_lock, flags);	dr = find_dr(dev, release, match, match_data);	if (dr) {		list_del_init(&dr->node.entry);		devres_log(dev, &dr->node, "REM");	}	spin_unlock_irqrestore(&dev->devres_lock, flags); 	if (dr)		return dr->data;	return NULL;}EXPORT_SYMBOL_GPL(devres_remove); /** * devres_destroy - Find a device resource and destroy it * @dev: Device to find resource from * @release: Look for resources associated with this release function * @match: Match function (optional) * @match_data: Data for the match function * * Find the latest devres of @dev associated with @release and for * which @match returns 1.  If @match is NULL, it's considered to * match all.  If found, the resource is removed atomically and freed. * * Note that the release function for the resource will not be called, * only the devres-allocated data will be freed.  The caller becomes * responsible for freeing any other data. * * RETURNS: * 0 if devres is found and freed, -ENOENT if not found. */int devres_destroy(struct device *dev, dr_release_t release,		   dr_match_t match, void *match_data){	void *res; 	res = devres_remove(dev, release, match, match_data);	if (unlikely(!res))		return -ENOENT; 	devres_free(res);	return 0;}EXPORT_SYMBOL_GPL(devres_destroy);  /** * devres_release - Find a device resource and destroy it, calling release * @dev: Device to find resource from * @release: Look for resources associated with this release function * @match: Match function (optional) * @match_data: Data for the match function * * Find the latest devres of @dev associated with @release and for * which @match returns 1.  If @match is NULL, it's considered to * match all.  If found, the resource is removed atomically, the * release function called and the resource freed. * * RETURNS: * 0 if devres is found and freed, -ENOENT if not found. */int devres_release(struct device *dev, dr_release_t release,		   dr_match_t match, void *match_data){	void *res; 	res = devres_remove(dev, release, match, match_data);	if (unlikely(!res))		return -ENOENT; 	(*release)(dev, res);	devres_free(res);	return 0;}EXPORT_SYMBOL_GPL(devres_release); static int remove_nodes(struct device *dev,			struct list_head *first, struct list_head *end,			struct list_head *todo){	int cnt = 0, nr_groups = 0;	struct list_head *cur; 	/* First pass - move normal devres entries to @todo and clear	 * devres_group colors.	 */	cur = first;	while (cur != end) {		struct devres_node *node;		struct devres_group *grp; 		node = list_entry(cur, struct devres_node, entry);		cur = cur->next; 		grp = node_to_group(node);		if (grp) {			/* clear color of group markers in the first pass */			grp->color = 0;			nr_groups++;		} else {			/* regular devres entry */			if (&node->entry == first)				first = first->next;			list_move_tail(&node->entry, todo);			cnt++;		}	} 	if (!nr_groups)		return cnt; 	/* Second pass - Scan groups and color them.  A group gets	 * color value of two iff the group is wholly contained in	 * [cur, end).  That is, for a closed group, both opening and	 * closing markers should be in the range, while just the	 * opening marker is enough for an open group.	 */	cur = first;	while (cur != end) {		struct devres_node *node;		struct devres_group *grp; 		node = list_entry(cur, struct devres_node, entry);		cur = cur->next; 		grp = node_to_group(node);		BUG_ON(!grp || list_empty(&grp->node[0].entry)); 		grp->color++;		if (list_empty(&grp->node[1].entry))			grp->color++; 		BUG_ON(grp->color <= 0 || grp->color > 2);		if (grp->color == 2) {			/* No need to update cur or end.  The removed			 * nodes are always before both.			 */			list_move_tail(&grp->node[0].entry, todo);			list_del_init(&grp->node[1].entry);		}	} 	return cnt;} static int release_nodes(struct device *dev, struct list_head *first,			 struct list_head *end, unsigned long flags)	__releases(&dev->devres_lock){	LIST_HEAD(todo);	int cnt;	struct devres *dr, *tmp; 	cnt = remove_nodes(dev, first, end, &todo); 	spin_unlock_irqrestore(&dev->devres_lock, flags); 	/* Release.  Note that both devres and devres_group are	 * handled as devres in the following loop.  This is safe.	 */	list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {		devres_log(dev, &dr->node, "REL");		dr->node.release(dev, dr->data);		kfree(dr);	} 	return cnt;} /**

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