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/configfs.txt before using
31 * the configfs interface, ESPECIALLY the parts about reference counts and
32 * item destructors.
33 */
34
35#ifndef _CONFIGFS_H_
36#define _CONFIGFS_H_
37
38#include <linux/kernel.h>
39#include <linux/types.h>
40#include <linux/list.h>
41#include <linux/kref.h>
42#include <linux/mutex.h>
43#include <linux/err.h>
44
45#include <linux/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 __printf(2, 3)
68int config_item_set_name(struct config_item *, const char *, ...);
69
70static inline char *config_item_name(struct config_item * item)
71{
72	return item->ci_name;
73}
74
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	umode_t			ca_mode;
128	ssize_t (*show)(struct config_item *, char *);
129	ssize_t (*store)(struct config_item *, const char *, size_t);
130};
131
132#define CONFIGFS_ATTR(_pfx, _name)			\
133static struct configfs_attribute _pfx##attr_##_name = {	\
134	.ca_name	= __stringify(_name),		\
135	.ca_mode	= S_IRUGO | S_IWUSR,		\
136	.ca_owner	= THIS_MODULE,			\
137	.show		= _pfx##_name##_show,		\
138	.store		= _pfx##_name##_store,		\
139}
140
141#define CONFIGFS_ATTR_RO(_pfx, _name)			\
142static struct configfs_attribute _pfx##attr_##_name = {	\
143	.ca_name	= __stringify(_name),		\
144	.ca_mode	= S_IRUGO,			\
145	.ca_owner	= THIS_MODULE,			\
146	.show		= _pfx##_name##_show,		\
147}
148
149#define CONFIGFS_ATTR_WO(_pfx, _name)			\
150static struct configfs_attribute _pfx##attr_##_name = {	\
151	.ca_name	= __stringify(_name),		\
152	.ca_mode	= S_IWUSR,			\
153	.ca_owner	= THIS_MODULE,			\
154	.store		= _pfx##_name##_store,		\
155}
156
157/*
158 * If allow_link() exists, the item can symlink(2) out to other
159 * items.  If the item is a group, it may support mkdir(2).
160 * Groups supply one of make_group() and make_item().  If the
161 * group supports make_group(), one can create group children.  If it
162 * supports make_item(), one can create config_item children.  make_group()
163 * and make_item() return ERR_PTR() on errors.  If it has
164 * default_groups on group->default_groups, it has automatically created
165 * group children.  default_groups may coexist alongsize make_group() or
166 * make_item(), but if the group wishes to have only default_groups
167 * children (disallowing mkdir(2)), it need not provide either function.
168 * If the group has commit(), it supports pending and committed (active)
169 * items.
170 */
171struct configfs_item_operations {
172	void (*release)(struct config_item *);
173	int (*allow_link)(struct config_item *src, struct config_item *target);
174	int (*drop_link)(struct config_item *src, struct config_item *target);
175};
176
177struct configfs_group_operations {
178	struct config_item *(*make_item)(struct config_group *group, const char *name);
179	struct config_group *(*make_group)(struct config_group *group, const char *name);
180	int (*commit_item)(struct config_item *item);
181	void (*disconnect_notify)(struct config_group *group, struct config_item *item);
182	void (*drop_item)(struct config_group *group, struct config_item *item);
183};
184
185struct configfs_subsystem {
186	struct config_group	su_group;
187	struct mutex		su_mutex;
188};
189
190static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
191{
192	return group ?
193		container_of(group, struct configfs_subsystem, su_group) :
194		NULL;
195}
196
197int configfs_register_subsystem(struct configfs_subsystem *subsys);
198void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
199
200int configfs_register_group(struct config_group *parent_group,
201			    struct config_group *group);
202void configfs_unregister_group(struct config_group *group);
203
204struct config_group *
205configfs_register_default_group(struct config_group *parent_group,
206				const char *name,
207				struct config_item_type *item_type);
208void configfs_unregister_default_group(struct config_group *group);
209
210/* These functions can sleep and can alloc with GFP_KERNEL */
211/* WARNING: These cannot be called underneath configfs callbacks!! */
212int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
213void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
214
215#endif /* _CONFIGFS_H_ */
216