1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
4 * configfs.h - definitions for the device driver filesystem
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.
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.
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.
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
25 * Copyright (c) 2002-2003 Patrick Mochel
26 * Copyright (c) 2002-2003 Open Source Development Labs
28 * configfs Copyright (C) 2005 Oracle. All rights reserved.
30 * Please read Documentation/filesystems/configfs/configfs.txt before using
31 * the configfs interface, ESPECIALLY the parts about reference counts and
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>
45 #include <linux/atomic.h>
47 #define CONFIGFS_ITEM_NAME_LEN 20
51 struct configfs_item_operations;
52 struct configfs_group_operations;
53 struct configfs_attribute;
54 struct configfs_subsystem;
58 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
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;
67 extern int config_item_set_name(struct config_item *, const char *, ...);
69 static inline char *config_item_name(struct config_item * item)
74 extern void config_item_init_type_name(struct config_item *item,
76 struct config_item_type *type);
78 extern struct config_item * config_item_get(struct config_item *);
79 extern void config_item_put(struct config_item *);
81 struct config_item_type {
82 struct module *ct_owner;
83 struct configfs_item_operations *ct_item_ops;
84 struct configfs_group_operations *ct_group_ops;
85 struct configfs_attribute **ct_attrs;
89 * group - a group of config_items of a specific type, belonging
90 * to a specific subsystem.
93 struct config_item cg_item;
94 struct list_head cg_children;
95 struct configfs_subsystem *cg_subsys;
96 struct config_group **default_groups;
99 extern void config_group_init(struct config_group *group);
100 extern void config_group_init_type_name(struct config_group *group,
102 struct config_item_type *type);
104 static inline struct config_group *to_config_group(struct config_item *item)
106 return item ? container_of(item,struct config_group,cg_item) : NULL;
109 static inline struct config_group *config_group_get(struct config_group *group)
111 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
114 static inline void config_group_put(struct config_group *group)
116 config_item_put(&group->cg_item);
119 extern struct config_item *config_group_find_item(struct config_group *,
123 struct configfs_attribute {
125 struct module *ca_owner;
130 * Users often need to create attribute structures for their configurable
131 * attributes, containing a configfs_attribute member and function pointers
132 * for the show() and store() operations on that attribute. If they don't
133 * need anything else on the extended attribute structure, they can use
134 * this macro to define it The argument _item is the name of the
135 * config_item structure.
137 #define CONFIGFS_ATTR_STRUCT(_item) \
138 struct _item##_attribute { \
139 struct configfs_attribute attr; \
140 ssize_t (*show)(struct _item *, char *); \
141 ssize_t (*store)(struct _item *, const char *, size_t); \
145 * With the extended attribute structure, users can use this macro
146 * (similar to sysfs' __ATTR) to make defining attributes easier.
148 * #define MYITEM_ATTR(_name, _mode, _show, _store) \
149 * struct myitem_attribute childless_attr_##_name = \
150 * __CONFIGFS_ATTR(_name, _mode, _show, _store)
152 #define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
155 .ca_name = __stringify(_name), \
157 .ca_owner = THIS_MODULE, \
162 /* Here is a readonly version, only requiring a show() operation */
163 #define __CONFIGFS_ATTR_RO(_name, _show) \
166 .ca_name = __stringify(_name), \
168 .ca_owner = THIS_MODULE, \
174 * With these extended attributes, the simple show_attribute() and
175 * store_attribute() operations need to call the show() and store() of the
176 * attributes. This is a common pattern, so we provide a macro to define
177 * them. The argument _item is the name of the config_item structure.
178 * This macro expects the attributes to be named "struct <name>_attribute"
179 * and the function to_<name>() to exist;
181 #define CONFIGFS_ATTR_OPS(_item) \
182 static ssize_t _item##_attr_show(struct config_item *item, \
183 struct configfs_attribute *attr, \
186 struct _item *_item = to_##_item(item); \
187 struct _item##_attribute *_item##_attr = \
188 container_of(attr, struct _item##_attribute, attr); \
191 if (_item##_attr->show) \
192 ret = _item##_attr->show(_item, page); \
195 static ssize_t _item##_attr_store(struct config_item *item, \
196 struct configfs_attribute *attr, \
197 const char *page, size_t count) \
199 struct _item *_item = to_##_item(item); \
200 struct _item##_attribute *_item##_attr = \
201 container_of(attr, struct _item##_attribute, attr); \
202 ssize_t ret = -EINVAL; \
204 if (_item##_attr->store) \
205 ret = _item##_attr->store(_item, page, count); \
210 * If allow_link() exists, the item can symlink(2) out to other
211 * items. If the item is a group, it may support mkdir(2).
212 * Groups supply one of make_group() and make_item(). If the
213 * group supports make_group(), one can create group children. If it
214 * supports make_item(), one can create config_item children. make_group()
215 * and make_item() return ERR_PTR() on errors. If it has
216 * default_groups on group->default_groups, it has automatically created
217 * group children. default_groups may coexist alongsize make_group() or
218 * make_item(), but if the group wishes to have only default_groups
219 * children (disallowing mkdir(2)), it need not provide either function.
220 * If the group has commit(), it supports pending and committed (active)
223 struct configfs_item_operations {
224 void (*release)(struct config_item *);
225 ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
226 ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
227 int (*allow_link)(struct config_item *src, struct config_item *target);
228 int (*drop_link)(struct config_item *src, struct config_item *target);
231 struct configfs_group_operations {
232 struct config_item *(*make_item)(struct config_group *group, const char *name);
233 struct config_group *(*make_group)(struct config_group *group, const char *name);
234 int (*commit_item)(struct config_item *item);
235 void (*disconnect_notify)(struct config_group *group, struct config_item *item);
236 void (*drop_item)(struct config_group *group, struct config_item *item);
239 struct configfs_subsystem {
240 struct config_group su_group;
241 struct mutex su_mutex;
244 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
247 container_of(group, struct configfs_subsystem, su_group) :
251 int configfs_register_subsystem(struct configfs_subsystem *subsys);
252 void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
254 /* These functions can sleep and can alloc with GFP_KERNEL */
255 /* WARNING: These cannot be called underneath configfs callbacks!! */
256 int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
257 void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
259 #endif /* _CONFIGFS_H_ */