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// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* item.c - library routines for handling generic config items
*
* Based on kobject:
* kobject is Copyright (c) 2002-2003 Patrick Mochel
*
* configfs Copyright (C) 2005 Oracle. All rights reserved.
*
* Please see the file Documentation/filesystems/configfs/configfs.txt for
* critical information about using the config_item interface.
*/
#include <linux/string.h>
#include <linux/module.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/configfs.h>
static inline struct config_item *to_item(struct list_head *entry)
{
return container_of(entry, struct config_item, ci_entry);
}
/* Evil kernel */
static void config_item_release(struct kref *kref);
/**
* config_item_init - initialize item.
* @item: item in question.
*/
static void config_item_init(struct config_item *item)
{
kref_init(&item->ci_kref);
INIT_LIST_HEAD(&item->ci_entry);
}
/**
* config_item_set_name - Set the name of an item
* @item: item.
* @fmt: The vsnprintf()'s format string.
*
* If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a
* dynamically allocated string that @item->ci_name points to.
* Otherwise, use the static @item->ci_namebuf array.
*/
int config_item_set_name(struct config_item *item, const char *fmt, ...)
{
int limit = CONFIGFS_ITEM_NAME_LEN;
int need;
va_list args;
char *name;
/*
* First, try the static array
*/
va_start(args, fmt);
need = vsnprintf(item->ci_namebuf, limit, fmt, args);
va_end(args);
if (need < limit)
name = item->ci_namebuf;
else {
va_start(args, fmt);
name = kvasprintf(GFP_KERNEL, fmt, args);
va_end(args);
if (!name)
return -EFAULT;
}
/* Free the old name, if necessary. */
if (item->ci_name && item->ci_name != item->ci_namebuf)
kfree(item->ci_name);
/* Now, set the new name */
item->ci_name = name;
return 0;
}
EXPORT_SYMBOL(config_item_set_name);
void config_item_init_type_name(struct config_item *item,
const char *name,
const struct config_item_type *type)
{
config_item_set_name(item, "%s", name);
item->ci_type = type;
config_item_init(item);
}
EXPORT_SYMBOL(config_item_init_type_name);
void config_group_init_type_name(struct config_group *group, const char *name,
const struct config_item_type *type)
{
config_item_set_name(&group->cg_item, "%s", name);
group->cg_item.ci_type = type;
config_group_init(group);
}
EXPORT_SYMBOL(config_group_init_type_name);
struct config_item *config_item_get(struct config_item *item)
{
if (item)
kref_get(&item->ci_kref);
return item;
}
EXPORT_SYMBOL(config_item_get);
struct config_item *config_item_get_unless_zero(struct config_item *item)
{
if (item && kref_get_unless_zero(&item->ci_kref))
return item;
return NULL;
}
EXPORT_SYMBOL(config_item_get_unless_zero);
static void config_item_cleanup(struct config_item *item)
{
const struct config_item_type *t = item->ci_type;
struct config_group *s = item->ci_group;
struct config_item *parent = item->ci_parent;
pr_debug("config_item %s: cleaning up\n", config_item_name(item));
if (item->ci_name != item->ci_namebuf)
kfree(item->ci_name);
item->ci_name = NULL;
if (t && t->ct_item_ops && t->ct_item_ops->release)
t->ct_item_ops->release(item);
if (s)
config_group_put(s);
if (parent)
config_item_put(parent);
}
static void config_item_release(struct kref *kref)
{
config_item_cleanup(container_of(kref, struct config_item, ci_kref));
}
/**
* config_item_put - decrement refcount for item.
* @item: item.
*
* Decrement the refcount, and if 0, call config_item_cleanup().
*/
void config_item_put(struct config_item *item)
{
if (item)
kref_put(&item->ci_kref, config_item_release);
}
EXPORT_SYMBOL(config_item_put);
/**
* config_group_init - initialize a group for use
* @group: config_group
*/
void config_group_init(struct config_group *group)
{
config_item_init(&group->cg_item);
INIT_LIST_HEAD(&group->cg_children);
INIT_LIST_HEAD(&group->default_groups);
}
EXPORT_SYMBOL(config_group_init);
/**
* config_group_find_item - search for item in group.
* @group: group we're looking in.
* @name: item's name.
*
* Iterate over @group->cg_list, looking for a matching config_item.
* If matching item is found take a reference and return the item.
* Caller must have locked group via @group->cg_subsys->su_mtx.
*/
struct config_item *config_group_find_item(struct config_group *group,
const char *name)
{
struct list_head *entry;
struct config_item *ret = NULL;
list_for_each(entry, &group->cg_children) {
struct config_item *item = to_item(entry);
if (config_item_name(item) &&
!strcmp(config_item_name(item), name)) {
ret = config_item_get(item);
break;
}
}
return ret;
}
EXPORT_SYMBOL(config_group_find_item);
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