261 lines
8.6 KiB
C
261 lines
8.6 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* configfs.h - definitions for the device driver filesystem
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* Based on kobject.h:
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* Copyright (c) 2002-2003 Patrick Mochel
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* Copyright (c) 2002-2003 Open Source Development Labs
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*
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* Please read Documentation/filesystems/configfs/configfs.txt before using
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* the configfs interface, ESPECIALLY the parts about reference counts and
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* item destructors.
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*/
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#ifndef _CONFIGFS_H_
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#define _CONFIGFS_H_
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/kref.h>
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#include <linux/mutex.h>
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#include <linux/err.h>
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#include <linux/atomic.h>
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#define CONFIGFS_ITEM_NAME_LEN 20
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struct module;
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struct configfs_item_operations;
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struct configfs_group_operations;
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struct configfs_attribute;
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struct configfs_subsystem;
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struct config_item {
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char *ci_name;
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char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
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struct kref ci_kref;
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struct list_head ci_entry;
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struct config_item *ci_parent;
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struct config_group *ci_group;
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struct config_item_type *ci_type;
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struct dentry *ci_dentry;
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};
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extern int config_item_set_name(struct config_item *, const char *, ...);
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static inline char *config_item_name(struct config_item * item)
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{
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return item->ci_name;
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}
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extern void config_item_init(struct config_item *);
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extern void config_item_init_type_name(struct config_item *item,
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const char *name,
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struct config_item_type *type);
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extern struct config_item * config_item_get(struct config_item *);
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extern void config_item_put(struct config_item *);
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struct config_item_type {
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struct module *ct_owner;
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struct configfs_item_operations *ct_item_ops;
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struct configfs_group_operations *ct_group_ops;
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struct configfs_attribute **ct_attrs;
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};
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/**
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* group - a group of config_items of a specific type, belonging
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* to a specific subsystem.
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*/
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struct config_group {
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struct config_item cg_item;
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struct list_head cg_children;
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struct configfs_subsystem *cg_subsys;
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struct config_group **default_groups;
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};
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extern void config_group_init(struct config_group *group);
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extern void config_group_init_type_name(struct config_group *group,
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const char *name,
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struct config_item_type *type);
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static inline struct config_group *to_config_group(struct config_item *item)
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{
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return item ? container_of(item,struct config_group,cg_item) : NULL;
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}
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static inline struct config_group *config_group_get(struct config_group *group)
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{
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return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
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}
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static inline void config_group_put(struct config_group *group)
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{
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config_item_put(&group->cg_item);
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}
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extern struct config_item *config_group_find_item(struct config_group *,
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const char *);
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struct configfs_attribute {
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const char *ca_name;
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struct module *ca_owner;
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mode_t ca_mode;
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};
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/*
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* Users often need to create attribute structures for their configurable
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* attributes, containing a configfs_attribute member and function pointers
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* for the show() and store() operations on that attribute. If they don't
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* need anything else on the extended attribute structure, they can use
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* this macro to define it The argument _item is the name of the
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* config_item structure.
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*/
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#define CONFIGFS_ATTR_STRUCT(_item) \
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struct _item##_attribute { \
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struct configfs_attribute attr; \
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ssize_t (*show)(struct _item *, char *); \
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ssize_t (*store)(struct _item *, const char *, size_t); \
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}
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/*
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* With the extended attribute structure, users can use this macro
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* (similar to sysfs' __ATTR) to make defining attributes easier.
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* An example:
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* #define MYITEM_ATTR(_name, _mode, _show, _store) \
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* struct myitem_attribute childless_attr_##_name = \
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* __CONFIGFS_ATTR(_name, _mode, _show, _store)
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*/
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#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
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{ \
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.attr = { \
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.ca_name = __stringify(_name), \
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.ca_mode = _mode, \
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.ca_owner = THIS_MODULE, \
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}, \
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.show = _show, \
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.store = _store, \
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}
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/* Here is a readonly version, only requiring a show() operation */
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#define __CONFIGFS_ATTR_RO(_name, _show) \
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{ \
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.attr = { \
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.ca_name = __stringify(_name), \
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.ca_mode = 0444, \
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.ca_owner = THIS_MODULE, \
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}, \
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.show = _show, \
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}
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/*
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* With these extended attributes, the simple show_attribute() and
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* store_attribute() operations need to call the show() and store() of the
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* attributes. This is a common pattern, so we provide a macro to define
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* them. The argument _item is the name of the config_item structure.
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* This macro expects the attributes to be named "struct <name>_attribute"
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* and the function to_<name>() to exist;
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*/
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#define CONFIGFS_ATTR_OPS(_item) \
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static ssize_t _item##_attr_show(struct config_item *item, \
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struct configfs_attribute *attr, \
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char *page) \
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{ \
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struct _item *_item = to_##_item(item); \
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struct _item##_attribute *_item##_attr = \
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container_of(attr, struct _item##_attribute, attr); \
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ssize_t ret = 0; \
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\
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if (_item##_attr->show) \
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ret = _item##_attr->show(_item, page); \
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return ret; \
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} \
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static ssize_t _item##_attr_store(struct config_item *item, \
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struct configfs_attribute *attr, \
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const char *page, size_t count) \
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{ \
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struct _item *_item = to_##_item(item); \
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struct _item##_attribute *_item##_attr = \
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container_of(attr, struct _item##_attribute, attr); \
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ssize_t ret = -EINVAL; \
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\
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if (_item##_attr->store) \
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ret = _item##_attr->store(_item, page, count); \
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return ret; \
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}
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/*
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* If allow_link() exists, the item can symlink(2) out to other
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* items. If the item is a group, it may support mkdir(2).
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* Groups supply one of make_group() and make_item(). If the
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* group supports make_group(), one can create group children. If it
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* supports make_item(), one can create config_item children. make_group()
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* and make_item() return ERR_PTR() on errors. If it has
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* default_groups on group->default_groups, it has automatically created
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* group children. default_groups may coexist alongsize make_group() or
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* make_item(), but if the group wishes to have only default_groups
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* children (disallowing mkdir(2)), it need not provide either function.
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* If the group has commit(), it supports pending and committed (active)
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* items.
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*/
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struct configfs_item_operations {
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void (*release)(struct config_item *);
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ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
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ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
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int (*allow_link)(struct config_item *src, struct config_item *target);
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int (*drop_link)(struct config_item *src, struct config_item *target);
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};
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struct configfs_group_operations {
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struct config_item *(*make_item)(struct config_group *group, const char *name);
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struct config_group *(*make_group)(struct config_group *group, const char *name);
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int (*commit_item)(struct config_item *item);
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void (*disconnect_notify)(struct config_group *group, struct config_item *item);
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void (*drop_item)(struct config_group *group, struct config_item *item);
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};
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struct configfs_subsystem {
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struct config_group su_group;
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struct mutex su_mutex;
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};
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static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
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{
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return group ?
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container_of(group, struct configfs_subsystem, su_group) :
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NULL;
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}
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int configfs_register_subsystem(struct configfs_subsystem *subsys);
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void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
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/* These functions can sleep and can alloc with GFP_KERNEL */
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/* WARNING: These cannot be called underneath configfs callbacks!! */
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int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
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void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
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#endif /* _CONFIGFS_H_ */
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