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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/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 <asm/atomic.h>
46 :
47 : #define CONFIGFS_ITEM_NAME_LEN 20
48 :
49 : struct module;
50 :
51 : struct configfs_item_operations;
52 : struct configfs_group_operations;
53 : struct configfs_attribute;
54 : struct configfs_subsystem;
55 :
56 : struct 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 :
67 : extern int config_item_set_name(struct config_item *, const char *, ...);
68 :
69 : static inline char *config_item_name(struct config_item * item)
70 : {
71 3 : return item->ci_name;
72 : }
73 :
74 : extern void config_item_init(struct config_item *);
75 : extern void config_item_init_type_name(struct config_item *item,
76 : const char *name,
77 : struct config_item_type *type);
78 :
79 : extern struct config_item * config_item_get(struct config_item *);
80 : extern void config_item_put(struct config_item *);
81 1 :
82 : struct 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 1 :
89 : /**
90 : * group - a group of config_items of a specific type, belonging
91 : * to a specific subsystem.
92 : */
93 : struct 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 :
100 : extern void config_group_init(struct config_group *group);
101 : extern void config_group_init_type_name(struct config_group *group,
102 : const char *name,
103 : struct config_item_type *type);
104 :
105 : static inline struct config_group *to_config_group(struct config_item *item)
106 : {
107 175 : return item ? container_of(item,struct config_group,cg_item) : NULL;
108 25 : }
109 :
110 : static inline struct config_group *config_group_get(struct config_group *group)
111 : {
112 22 : return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
113 2 : }
114 2 :
115 : static inline void config_group_put(struct config_group *group)
116 : {
117 12 : config_item_put(&group->cg_item);
118 6 : }
119 :
120 : extern struct config_item *config_group_find_item(struct config_group *,
121 1 : const char *);
122 :
123 :
124 : struct configfs_attribute {
125 : const char *ca_name;
126 : struct module *ca_owner;
127 : mode_t ca_mode;
128 : };
129 1 :
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. If they don't
134 : * need anything else on the extended attribute structure, they can use
135 : * this macro to define it The argument _item is the name of the
136 : * config_item structure.
137 : */
138 : #define CONFIGFS_ATTR_STRUCT(_item) \
139 : struct _item##_attribute { \
140 : struct configfs_attribute attr; \
141 : ssize_t (*show)(struct _item *, char *); \
142 : ssize_t (*store)(struct _item *, const char *, size_t); \
143 : }
144 :
145 : /*
146 : * With the extended attribute structure, users can use this macro
147 : * (similar to sysfs' __ATTR) to make defining attributes easier.
148 : * An example:
149 : * #define MYITEM_ATTR(_name, _mode, _show, _store) \
150 : * struct myitem_attribute childless_attr_##_name = \
151 : * __CONFIGFS_ATTR(_name, _mode, _show, _store)
152 : */
153 : #define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
154 : { \
155 : .attr = { \
156 : .ca_name = __stringify(_name), \
157 : .ca_mode = _mode, \
158 : .ca_owner = THIS_MODULE, \
159 : }, \
160 : .show = _show, \
161 : .store = _store, \
162 : }
163 : /* Here is a readonly version, only requiring a show() operation */
164 : #define __CONFIGFS_ATTR_RO(_name, _show) \
165 : { \
166 : .attr = { \
167 : .ca_name = __stringify(_name), \
168 : .ca_mode = 0444, \
169 : .ca_owner = THIS_MODULE, \
170 : }, \
171 : .show = _show, \
172 : }
173 :
174 : /*
175 : * With these extended attributes, the simple show_attribute() and
176 : * store_attribute() operations need to call the show() and store() of the
177 : * attributes. This is a common pattern, so we provide a macro to define
178 : * them. The argument _item is the name of the config_item structure.
179 : * This macro expects the attributes to be named "struct <name>_attribute"
180 : * and the function to_<name>() to exist;
181 : */
182 : #define CONFIGFS_ATTR_OPS(_item) \
183 : static ssize_t _item##_attr_show(struct config_item *item, \
184 : struct configfs_attribute *attr, \
185 : char *page) \
186 : { \
187 : struct _item *_item = to_##_item(item); \
188 : struct _item##_attribute *_item##_attr = \
189 : container_of(attr, struct _item##_attribute, attr); \
190 : ssize_t ret = 0; \
191 : \
192 : if (_item##_attr->show) \
193 : ret = _item##_attr->show(_item, page); \
194 : return ret; \
195 : } \
196 : static ssize_t _item##_attr_store(struct config_item *item, \
197 : struct configfs_attribute *attr, \
198 : const char *page, size_t count) \
199 : { \
200 : struct _item *_item = to_##_item(item); \
201 : struct _item##_attribute *_item##_attr = \
202 : container_of(attr, struct _item##_attribute, attr); \
203 : ssize_t ret = -EINVAL; \
204 : \
205 : if (_item##_attr->store) \
206 : ret = _item##_attr->store(_item, page, count); \
207 : return ret; \
208 : }
209 :
210 : /*
211 : * If allow_link() exists, the item can symlink(2) out to other
212 : * items. If the item is a group, it may support mkdir(2).
213 : * Groups supply one of make_group() and make_item(). If the
214 : * group supports make_group(), one can create group children. If it
215 : * supports make_item(), one can create config_item children. make_group()
216 : * and make_item() return ERR_PTR() on errors. If it has
217 : * default_groups on group->default_groups, it has automatically created
218 : * group children. default_groups may coexist alongsize make_group() or
219 : * make_item(), but if the group wishes to have only default_groups
220 : * children (disallowing mkdir(2)), it need not provide either function.
221 : * If the group has commit(), it supports pending and commited (active)
222 : * items.
223 : */
224 : struct configfs_item_operations {
225 : void (*release)(struct config_item *);
226 : ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
227 : ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
228 : int (*allow_link)(struct config_item *src, struct config_item *target);
229 : int (*drop_link)(struct config_item *src, struct config_item *target);
230 : };
231 1 :
232 : struct configfs_group_operations {
233 : struct config_item *(*make_item)(struct config_group *group, const char *name);
234 : struct config_group *(*make_group)(struct config_group *group, const char *name);
235 : int (*commit_item)(struct config_item *item);
236 : void (*disconnect_notify)(struct config_group *group, struct config_item *item);
237 : void (*drop_item)(struct config_group *group, struct config_item *item);
238 : };
239 1 :
240 : struct configfs_subsystem {
241 : struct config_group su_group;
242 : struct mutex su_mutex;
243 : };
244 :
245 : static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
246 : {
247 2 : return group ?
248 6 : container_of(group, struct configfs_subsystem, su_group) :
249 : NULL;
250 : }
251 :
252 : int configfs_register_subsystem(struct configfs_subsystem *subsys);
253 : void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
254 :
255 : /* These functions can sleep and can alloc with GFP_KERNEL */
256 : /* WARNING: These cannot be called underneath configfs callbacks!! */
257 : int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
258 : void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
259 1 :
260 : #endif /* _CONFIGFS_H_ */
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