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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
* configfs.h - definitions for the device driver filesystem
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* General Public License for more details.
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
* Based on sysfs:
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
* Based on kobject.h:
* Copyright (c) 2002-2003 Patrick Mochel
* Copyright (c) 2002-2003 Open Source Development Labs
* configfs Copyright (C) 2005 Oracle. All rights reserved.
* Please read Documentation/filesystems/configfs/configfs.txt before using
* the configfs interface, ESPECIALLY the parts about reference counts and
* item destructors.
#ifndef _CONFIGFS_H_
#define _CONFIGFS_H_
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/atomic.h>
struct module;
struct configfs_item_operations;
struct configfs_group_operations;
struct configfs_attribute;
struct configfs_subsystem;
struct config_item {
char *ci_name;
char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
struct kref ci_kref;
struct list_head ci_entry;
struct config_item *ci_parent;
struct config_group *ci_group;
struct config_item_type *ci_type;
struct dentry *ci_dentry;
extern __printf(2, 3)
int config_item_set_name(struct config_item *, const char *, ...);
static inline char *config_item_name(struct config_item * item)
return item->ci_name;
extern void config_item_init_type_name(struct config_item *item,
const char *name,
struct config_item_type *type);
extern struct config_item * config_item_get(struct config_item *);
extern void config_item_put(struct config_item *);
struct config_item_type {
struct module *ct_owner;
struct configfs_item_operations *ct_item_ops;
struct configfs_group_operations *ct_group_ops;
struct configfs_attribute **ct_attrs;
* group - a group of config_items of a specific type, belonging
* to a specific subsystem.
struct config_group {
struct config_item cg_item;
struct list_head cg_children;
struct configfs_subsystem *cg_subsys;
struct config_group **default_groups;
extern void config_group_init(struct config_group *group);
extern void config_group_init_type_name(struct config_group *group,
const char *name,
struct config_item_type *type);
static inline struct config_group *to_config_group(struct config_item *item)
return item ? container_of(item,struct config_group,cg_item) : NULL;
static inline struct config_group *config_group_get(struct config_group *group)
return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
static inline void config_group_put(struct config_group *group)
extern struct config_item *config_group_find_item(struct config_group *,
const char *);
struct configfs_attribute {
const char *ca_name;
struct module *ca_owner;
umode_t ca_mode;
ssize_t (*show)(struct config_item *, char *);
ssize_t (*store)(struct config_item *, const char *, size_t);
#define CONFIGFS_ATTR(_pfx, _name) \
static struct configfs_attribute _pfx##attr_##_name = { \
.ca_name = __stringify(_name), \
.ca_mode = S_IRUGO | S_IWUSR, \
.ca_owner = THIS_MODULE, \
.show = _pfx##_name##_show, \
.store = _pfx##_name##_store, \
#define CONFIGFS_ATTR_RO(_pfx, _name) \
static struct configfs_attribute _pfx##attr_##_name = { \
.ca_name = __stringify(_name), \
.ca_mode = S_IRUGO, \
.ca_owner = THIS_MODULE, \
.show = _pfx##_name##_show, \
#define CONFIGFS_ATTR_WO(_pfx, _name) \
static struct configfs_attribute _pfx##attr_##_name = { \
.ca_name = __stringify(_name), \
.ca_mode = S_IWUSR, \
.ca_owner = THIS_MODULE, \
.store = _pfx##_name##_store, \
* If allow_link() exists, the item can symlink(2) out to other
* items. If the item is a group, it may support mkdir(2).
* Groups supply one of make_group() and make_item(). If the
* group supports make_group(), one can create group children. If it
* supports make_item(), one can create config_item children. make_group()
* and make_item() return ERR_PTR() on errors. If it has
* default_groups on group->default_groups, it has automatically created
* group children. default_groups may coexist alongsize make_group() or
* make_item(), but if the group wishes to have only default_groups
* children (disallowing mkdir(2)), it need not provide either function.
* If the group has commit(), it supports pending and committed (active)
* items.
struct configfs_item_operations {
void (*release)(struct config_item *);
int (*allow_link)(struct config_item *src, struct config_item *target);
int (*drop_link)(struct config_item *src, struct config_item *target);
struct configfs_group_operations {
struct config_item *(*make_item)(struct config_group *group, const char *name);
struct config_group *(*make_group)(struct config_group *group, const char *name);
int (*commit_item)(struct config_item *item);
void (*disconnect_notify)(struct config_group *group, struct config_item *item);
void (*drop_item)(struct config_group *group, struct config_item *item);
struct configfs_subsystem {
struct config_group su_group;
struct mutex su_mutex;
static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
return group ?
container_of(group, struct configfs_subsystem, su_group) :
int configfs_register_subsystem(struct configfs_subsystem *subsys);
void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
int configfs_register_group(struct config_group *parent_group,
struct config_group *group);
void configfs_unregister_group(struct config_group *group);
struct config_group *
configfs_register_default_group(struct config_group *parent_group,
const char *name,
struct config_item_type *item_type);
void configfs_unregister_default_group(struct config_group *group);
/* These functions can sleep and can alloc with GFP_KERNEL */
/* WARNING: These cannot be called underneath configfs callbacks!! */
int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
#endif /* _CONFIGFS_H_ */