1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2 | /* |
3 | * configfs.h - definitions for the device driver filesystem |
4 | * |
5 | * Based on sysfs: |
6 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel |
7 | * |
8 | * Based on kobject.h: |
9 | * Copyright (c) 2002-2003 Patrick Mochel |
10 | * Copyright (c) 2002-2003 Open Source Development Labs |
11 | * |
12 | * configfs Copyright (C) 2005 Oracle. All rights reserved. |
13 | * |
14 | * Please read Documentation/filesystems/configfs.rst before using |
15 | * the configfs interface, ESPECIALLY the parts about reference counts and |
16 | * item destructors. |
17 | */ |
18 | |
19 | #ifndef _CONFIGFS_H_ |
20 | #define _CONFIGFS_H_ |
21 | |
22 | #include <linux/stat.h> /* S_IRUGO */ |
23 | #include <linux/types.h> /* ssize_t */ |
24 | #include <linux/list.h> /* struct list_head */ |
25 | #include <linux/kref.h> /* struct kref */ |
26 | #include <linux/mutex.h> /* struct mutex */ |
27 | |
28 | #define CONFIGFS_ITEM_NAME_LEN 20 |
29 | |
30 | struct module; |
31 | |
32 | struct configfs_item_operations; |
33 | struct configfs_group_operations; |
34 | struct configfs_attribute; |
35 | struct configfs_bin_attribute; |
36 | struct configfs_subsystem; |
37 | |
38 | struct config_item { |
39 | char *ci_name; |
40 | char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; |
41 | struct kref ci_kref; |
42 | struct list_head ci_entry; |
43 | struct config_item *ci_parent; |
44 | struct config_group *ci_group; |
45 | const struct config_item_type *ci_type; |
46 | struct dentry *ci_dentry; |
47 | }; |
48 | |
49 | extern __printf(2, 3) |
50 | int config_item_set_name(struct config_item *, const char *, ...); |
51 | |
52 | static inline char *config_item_name(struct config_item * item) |
53 | { |
54 | return item->ci_name; |
55 | } |
56 | |
57 | extern void config_item_init_type_name(struct config_item *item, |
58 | const char *name, |
59 | const struct config_item_type *type); |
60 | |
61 | extern struct config_item *config_item_get(struct config_item *); |
62 | extern struct config_item *config_item_get_unless_zero(struct config_item *); |
63 | extern void config_item_put(struct config_item *); |
64 | |
65 | struct config_item_type { |
66 | struct module *ct_owner; |
67 | struct configfs_item_operations *ct_item_ops; |
68 | struct configfs_group_operations *ct_group_ops; |
69 | struct configfs_attribute **ct_attrs; |
70 | struct configfs_bin_attribute **ct_bin_attrs; |
71 | }; |
72 | |
73 | /** |
74 | * group - a group of config_items of a specific type, belonging |
75 | * to a specific subsystem. |
76 | */ |
77 | struct config_group { |
78 | struct config_item cg_item; |
79 | struct list_head cg_children; |
80 | struct configfs_subsystem *cg_subsys; |
81 | struct list_head default_groups; |
82 | struct list_head group_entry; |
83 | }; |
84 | |
85 | extern void config_group_init(struct config_group *group); |
86 | extern void config_group_init_type_name(struct config_group *group, |
87 | const char *name, |
88 | const struct config_item_type *type); |
89 | |
90 | static inline struct config_group *to_config_group(struct config_item *item) |
91 | { |
92 | return item ? container_of(item,struct config_group,cg_item) : NULL; |
93 | } |
94 | |
95 | static inline struct config_group *config_group_get(struct config_group *group) |
96 | { |
97 | return group ? to_config_group(item: config_item_get(&group->cg_item)) : NULL; |
98 | } |
99 | |
100 | static inline void config_group_put(struct config_group *group) |
101 | { |
102 | config_item_put(&group->cg_item); |
103 | } |
104 | |
105 | extern struct config_item *config_group_find_item(struct config_group *, |
106 | const char *); |
107 | |
108 | |
109 | static inline void configfs_add_default_group(struct config_group *new_group, |
110 | struct config_group *group) |
111 | { |
112 | list_add_tail(new: &new_group->group_entry, head: &group->default_groups); |
113 | } |
114 | |
115 | struct configfs_attribute { |
116 | const char *ca_name; |
117 | struct module *ca_owner; |
118 | umode_t ca_mode; |
119 | ssize_t (*show)(struct config_item *, char *); |
120 | ssize_t (*store)(struct config_item *, const char *, size_t); |
121 | }; |
122 | |
123 | #define CONFIGFS_ATTR(_pfx, _name) \ |
124 | static struct configfs_attribute _pfx##attr_##_name = { \ |
125 | .ca_name = __stringify(_name), \ |
126 | .ca_mode = S_IRUGO | S_IWUSR, \ |
127 | .ca_owner = THIS_MODULE, \ |
128 | .show = _pfx##_name##_show, \ |
129 | .store = _pfx##_name##_store, \ |
130 | } |
131 | |
132 | #define CONFIGFS_ATTR_RO(_pfx, _name) \ |
133 | static struct configfs_attribute _pfx##attr_##_name = { \ |
134 | .ca_name = __stringify(_name), \ |
135 | .ca_mode = S_IRUGO, \ |
136 | .ca_owner = THIS_MODULE, \ |
137 | .show = _pfx##_name##_show, \ |
138 | } |
139 | |
140 | #define CONFIGFS_ATTR_WO(_pfx, _name) \ |
141 | static struct configfs_attribute _pfx##attr_##_name = { \ |
142 | .ca_name = __stringify(_name), \ |
143 | .ca_mode = S_IWUSR, \ |
144 | .ca_owner = THIS_MODULE, \ |
145 | .store = _pfx##_name##_store, \ |
146 | } |
147 | |
148 | struct file; |
149 | struct vm_area_struct; |
150 | |
151 | struct configfs_bin_attribute { |
152 | struct configfs_attribute cb_attr; /* std. attribute */ |
153 | void *cb_private; /* for user */ |
154 | size_t cb_max_size; /* max core size */ |
155 | ssize_t (*read)(struct config_item *, void *, size_t); |
156 | ssize_t (*write)(struct config_item *, const void *, size_t); |
157 | }; |
158 | |
159 | #define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \ |
160 | static struct configfs_bin_attribute _pfx##attr_##_name = { \ |
161 | .cb_attr = { \ |
162 | .ca_name = __stringify(_name), \ |
163 | .ca_mode = S_IRUGO | S_IWUSR, \ |
164 | .ca_owner = THIS_MODULE, \ |
165 | }, \ |
166 | .cb_private = _priv, \ |
167 | .cb_max_size = _maxsz, \ |
168 | .read = _pfx##_name##_read, \ |
169 | .write = _pfx##_name##_write, \ |
170 | } |
171 | |
172 | #define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \ |
173 | static struct configfs_bin_attribute _pfx##attr_##_name = { \ |
174 | .cb_attr = { \ |
175 | .ca_name = __stringify(_name), \ |
176 | .ca_mode = S_IRUGO, \ |
177 | .ca_owner = THIS_MODULE, \ |
178 | }, \ |
179 | .cb_private = _priv, \ |
180 | .cb_max_size = _maxsz, \ |
181 | .read = _pfx##_name##_read, \ |
182 | } |
183 | |
184 | #define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \ |
185 | static struct configfs_bin_attribute _pfx##attr_##_name = { \ |
186 | .cb_attr = { \ |
187 | .ca_name = __stringify(_name), \ |
188 | .ca_mode = S_IWUSR, \ |
189 | .ca_owner = THIS_MODULE, \ |
190 | }, \ |
191 | .cb_private = _priv, \ |
192 | .cb_max_size = _maxsz, \ |
193 | .write = _pfx##_name##_write, \ |
194 | } |
195 | |
196 | /* |
197 | * If allow_link() exists, the item can symlink(2) out to other |
198 | * items. If the item is a group, it may support mkdir(2). |
199 | * Groups supply one of make_group() and make_item(). If the |
200 | * group supports make_group(), one can create group children. If it |
201 | * supports make_item(), one can create config_item children. make_group() |
202 | * and make_item() return ERR_PTR() on errors. If it has |
203 | * default_groups on group->default_groups, it has automatically created |
204 | * group children. default_groups may coexist alongsize make_group() or |
205 | * make_item(), but if the group wishes to have only default_groups |
206 | * children (disallowing mkdir(2)), it need not provide either function. |
207 | */ |
208 | struct configfs_item_operations { |
209 | void (*release)(struct config_item *); |
210 | int (*allow_link)(struct config_item *src, struct config_item *target); |
211 | void (*drop_link)(struct config_item *src, struct config_item *target); |
212 | }; |
213 | |
214 | struct configfs_group_operations { |
215 | struct config_item *(*make_item)(struct config_group *group, const char *name); |
216 | struct config_group *(*make_group)(struct config_group *group, const char *name); |
217 | void (*disconnect_notify)(struct config_group *group, struct config_item *item); |
218 | void (*drop_item)(struct config_group *group, struct config_item *item); |
219 | }; |
220 | |
221 | struct configfs_subsystem { |
222 | struct config_group su_group; |
223 | struct mutex su_mutex; |
224 | }; |
225 | |
226 | static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) |
227 | { |
228 | return group ? |
229 | container_of(group, struct configfs_subsystem, su_group) : |
230 | NULL; |
231 | } |
232 | |
233 | int configfs_register_subsystem(struct configfs_subsystem *subsys); |
234 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys); |
235 | |
236 | int configfs_register_group(struct config_group *parent_group, |
237 | struct config_group *group); |
238 | void configfs_unregister_group(struct config_group *group); |
239 | |
240 | void configfs_remove_default_groups(struct config_group *group); |
241 | |
242 | struct config_group * |
243 | configfs_register_default_group(struct config_group *parent_group, |
244 | const char *name, |
245 | const struct config_item_type *item_type); |
246 | void configfs_unregister_default_group(struct config_group *group); |
247 | |
248 | /* These functions can sleep and can alloc with GFP_KERNEL */ |
249 | /* WARNING: These cannot be called underneath configfs callbacks!! */ |
250 | int configfs_depend_item(struct configfs_subsystem *subsys, |
251 | struct config_item *target); |
252 | void configfs_undepend_item(struct config_item *target); |
253 | |
254 | /* |
255 | * These functions can sleep and can alloc with GFP_KERNEL |
256 | * NOTE: These should be called only underneath configfs callbacks. |
257 | * NOTE: First parameter is a caller's subsystem, not target's. |
258 | * WARNING: These cannot be called on newly created item |
259 | * (in make_group()/make_item() callback) |
260 | */ |
261 | int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, |
262 | struct config_item *target); |
263 | |
264 | |
265 | static inline void configfs_undepend_item_unlocked(struct config_item *target) |
266 | { |
267 | configfs_undepend_item(target); |
268 | } |
269 | |
270 | #endif /* _CONFIGFS_H_ */ |
271 | |