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1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * configfs.h - definitions for the device driver filesystem
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
20 *
21 * Based on sysfs:
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23 *
24 * Based on kobject.h:
25 * Copyright (c) 2002-2003 Patrick Mochel
26 * Copyright (c) 2002-2003 Open Source Development Labs
27 *
28 * configfs Copyright (C) 2005 Oracle. All rights reserved.
29 *
30 * Please read Documentation/filesystems/configfs.txt before using the
31 * configfs interface, ESPECIALLY the parts about reference counts and
32 * item destructors.
33 */
34
35#ifndef _CONFIGFS_H_
36#define _CONFIGFS_H_
37
38#ifdef __KERNEL__
39
40#include <linux/types.h>
41#include <linux/list.h>
42#include <linux/kref.h>
43#include <linux/mutex.h>
44
45#include <asm/atomic.h>
46
47#define CONFIGFS_ITEM_NAME_LEN 20
48
49struct module;
50
51struct configfs_item_operations;
52struct configfs_group_operations;
53struct configfs_attribute;
54struct configfs_subsystem;
55
56struct config_item {
57 char *ci_name;
58 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
59 struct kref ci_kref;
60 struct list_head ci_entry;
61 struct config_item *ci_parent;
62 struct config_group *ci_group;
63 struct config_item_type *ci_type;
64 struct dentry *ci_dentry;
65};
66
67extern int config_item_set_name(struct config_item *, const char *, ...);
68
69static inline char *config_item_name(struct config_item * item)
70{
71 return item->ci_name;
72}
73
74extern void config_item_init(struct config_item *);
75extern void config_item_init_type_name(struct config_item *item,
76 const char *name,
77 struct config_item_type *type);
78
79extern struct config_item * config_item_get(struct config_item *);
80extern void config_item_put(struct config_item *);
81
82struct config_item_type {
83 struct module *ct_owner;
84 struct configfs_item_operations *ct_item_ops;
85 struct configfs_group_operations *ct_group_ops;
86 struct configfs_attribute **ct_attrs;
87};
88
89/**
90 * group - a group of config_items of a specific type, belonging
91 * to a specific subsystem.
92 */
93struct config_group {
94 struct config_item cg_item;
95 struct list_head cg_children;
96 struct configfs_subsystem *cg_subsys;
97 struct config_group **default_groups;
98};
99
100extern void config_group_init(struct config_group *group);
101extern void config_group_init_type_name(struct config_group *group,
102 const char *name,
103 struct config_item_type *type);
104
105static inline struct config_group *to_config_group(struct config_item *item)
106{
107 return item ? container_of(item,struct config_group,cg_item) : NULL;
108}
109
110static inline struct config_group *config_group_get(struct config_group *group)
111{
112 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
113}
114
115static inline void config_group_put(struct config_group *group)
116{
117 config_item_put(&group->cg_item);
118}
119
120extern struct config_item *config_group_find_item(struct config_group *,
121 const char *);
122
123
124struct configfs_attribute {
125 const char *ca_name;
126 struct module *ca_owner;
127 mode_t ca_mode;
128};
129
130/*
131 * Users often need to create attribute structures for their configurable
132 * attributes, containing a configfs_attribute member and function pointers
133 * for the show() and store() operations on that attribute. They can use
134 * this macro (similar to sysfs' __ATTR) to make defining attributes easier.
135 */
136#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
137{ \
138 .attr = { \
139 .ca_name = __stringify(_name), \
140 .ca_mode = _mode, \
141 .ca_owner = THIS_MODULE, \
142 }, \
143 .show = _show, \
144 .store = _store, \
145}
146
147/*
148 * If allow_link() exists, the item can symlink(2) out to other
149 * items. If the item is a group, it may support mkdir(2).
150 * Groups supply one of make_group() and make_item(). If the
151 * group supports make_group(), one can create group children. If it
152 * supports make_item(), one can create config_item children. If it has
153 * default_groups on group->default_groups, it has automatically created
154 * group children. default_groups may coexist alongsize make_group() or
155 * make_item(), but if the group wishes to have only default_groups
156 * children (disallowing mkdir(2)), it need not provide either function.
157 * If the group has commit(), it supports pending and commited (active)
158 * items.
159 */
160struct configfs_item_operations {
161 void (*release)(struct config_item *);
162 ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
163 ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
164 int (*allow_link)(struct config_item *src, struct config_item *target);
165 int (*drop_link)(struct config_item *src, struct config_item *target);
166};
167
168struct configfs_group_operations {
169 struct config_item *(*make_item)(struct config_group *group, const char *name);
170 struct config_group *(*make_group)(struct config_group *group, const char *name);
171 int (*commit_item)(struct config_item *item);
172 void (*disconnect_notify)(struct config_group *group, struct config_item *item);
173 void (*drop_item)(struct config_group *group, struct config_item *item);
174};
175
176struct configfs_subsystem {
177 struct config_group su_group;
178 struct mutex su_mutex;
179};
180
181static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
182{
183 return group ?
184 container_of(group, struct configfs_subsystem, su_group) :
185 NULL;
186}
187
188int configfs_register_subsystem(struct configfs_subsystem *subsys);
189void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
190
191/* These functions can sleep and can alloc with GFP_KERNEL */
192/* WARNING: These cannot be called underneath configfs callbacks!! */
193int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
194void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
195
196#endif /* __KERNEL__ */
197
198#endif /* _CONFIGFS_H_ */