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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * configfs_example_macros.c - This file is a demonstration module
4 * containing a number of configfs subsystems. It uses the helper
5 * macros defined by configfs.h
6 *
7 * Based on sysfs:
8 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
9 *
10 * configfs Copyright (C) 2005 Oracle. All rights reserved.
11 */
12
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/configfs.h>
18
19/*
20 * 01-childless
21 *
22 * This first example is a childless subsystem. It cannot create
23 * any config_items. It just has attributes.
24 *
25 * Note that we are enclosing the configfs_subsystem inside a container.
26 * This is not necessary if a subsystem has no attributes directly
27 * on the subsystem. See the next example, 02-simple-children, for
28 * such a subsystem.
29 */
30
31struct childless {
32 struct configfs_subsystem subsys;
33 int showme;
34 int storeme;
35};
36
37static inline struct childless *to_childless(struct config_item *item)
38{
39 return container_of(to_configfs_subsystem(to_config_group(item)),
40 struct childless, subsys);
41}
42
43static ssize_t childless_showme_show(struct config_item *item, char *page)
44{
45 struct childless *childless = to_childless(item);
46 ssize_t pos;
47
48 pos = sprintf(page, "%d\n", childless->showme);
49 childless->showme++;
50
51 return pos;
52}
53
54static ssize_t childless_storeme_show(struct config_item *item, char *page)
55{
56 return sprintf(page, "%d\n", to_childless(item)->storeme);
57}
58
59static ssize_t childless_storeme_store(struct config_item *item,
60 const char *page, size_t count)
61{
62 struct childless *childless = to_childless(item);
63 int ret;
64
65 ret = kstrtoint(page, 10, &childless->storeme);
66 if (ret)
67 return ret;
68
69 return count;
70}
71
72static ssize_t childless_description_show(struct config_item *item, char *page)
73{
74 return sprintf(page,
75"[01-childless]\n"
76"\n"
77"The childless subsystem is the simplest possible subsystem in\n"
78"configfs. It does not support the creation of child config_items.\n"
79"It only has a few attributes. In fact, it isn't much different\n"
80"than a directory in /proc.\n");
81}
82
83CONFIGFS_ATTR_RO(childless_, showme);
84CONFIGFS_ATTR(childless_, storeme);
85CONFIGFS_ATTR_RO(childless_, description);
86
87static struct configfs_attribute *childless_attrs[] = {
88 &childless_attr_showme,
89 &childless_attr_storeme,
90 &childless_attr_description,
91 NULL,
92};
93
94static const struct config_item_type childless_type = {
95 .ct_attrs = childless_attrs,
96 .ct_owner = THIS_MODULE,
97};
98
99static struct childless childless_subsys = {
100 .subsys = {
101 .su_group = {
102 .cg_item = {
103 .ci_namebuf = "01-childless",
104 .ci_type = &childless_type,
105 },
106 },
107 },
108};
109
110/* ----------------------------------------------------------------- */
111
112/*
113 * 02-simple-children
114 *
115 * This example merely has a simple one-attribute child. Note that
116 * there is no extra attribute structure, as the child's attribute is
117 * known from the get-go. Also, there is no container for the
118 * subsystem, as it has no attributes of its own.
119 */
120
121struct simple_child {
122 struct config_item item;
123 int storeme;
124};
125
126static inline struct simple_child *to_simple_child(struct config_item *item)
127{
128 return container_of(item, struct simple_child, item);
129}
130
131static ssize_t simple_child_storeme_show(struct config_item *item, char *page)
132{
133 return sprintf(page, "%d\n", to_simple_child(item)->storeme);
134}
135
136static ssize_t simple_child_storeme_store(struct config_item *item,
137 const char *page, size_t count)
138{
139 struct simple_child *simple_child = to_simple_child(item);
140 int ret;
141
142 ret = kstrtoint(page, 10, &simple_child->storeme);
143 if (ret)
144 return ret;
145
146 return count;
147}
148
149CONFIGFS_ATTR(simple_child_, storeme);
150
151static struct configfs_attribute *simple_child_attrs[] = {
152 &simple_child_attr_storeme,
153 NULL,
154};
155
156static void simple_child_release(struct config_item *item)
157{
158 kfree(to_simple_child(item));
159}
160
161static struct configfs_item_operations simple_child_item_ops = {
162 .release = simple_child_release,
163};
164
165static const struct config_item_type simple_child_type = {
166 .ct_item_ops = &simple_child_item_ops,
167 .ct_attrs = simple_child_attrs,
168 .ct_owner = THIS_MODULE,
169};
170
171struct simple_children {
172 struct config_group group;
173};
174
175static inline struct simple_children *to_simple_children(struct config_item *item)
176{
177 return container_of(to_config_group(item),
178 struct simple_children, group);
179}
180
181static struct config_item *simple_children_make_item(struct config_group *group,
182 const char *name)
183{
184 struct simple_child *simple_child;
185
186 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
187 if (!simple_child)
188 return ERR_PTR(-ENOMEM);
189
190 config_item_init_type_name(&simple_child->item, name,
191 &simple_child_type);
192
193 return &simple_child->item;
194}
195
196static ssize_t simple_children_description_show(struct config_item *item,
197 char *page)
198{
199 return sprintf(page,
200"[02-simple-children]\n"
201"\n"
202"This subsystem allows the creation of child config_items. These\n"
203"items have only one attribute that is readable and writeable.\n");
204}
205
206CONFIGFS_ATTR_RO(simple_children_, description);
207
208static struct configfs_attribute *simple_children_attrs[] = {
209 &simple_children_attr_description,
210 NULL,
211};
212
213static void simple_children_release(struct config_item *item)
214{
215 kfree(to_simple_children(item));
216}
217
218static struct configfs_item_operations simple_children_item_ops = {
219 .release = simple_children_release,
220};
221
222/*
223 * Note that, since no extra work is required on ->drop_item(),
224 * no ->drop_item() is provided.
225 */
226static struct configfs_group_operations simple_children_group_ops = {
227 .make_item = simple_children_make_item,
228};
229
230static const struct config_item_type simple_children_type = {
231 .ct_item_ops = &simple_children_item_ops,
232 .ct_group_ops = &simple_children_group_ops,
233 .ct_attrs = simple_children_attrs,
234 .ct_owner = THIS_MODULE,
235};
236
237static struct configfs_subsystem simple_children_subsys = {
238 .su_group = {
239 .cg_item = {
240 .ci_namebuf = "02-simple-children",
241 .ci_type = &simple_children_type,
242 },
243 },
244};
245
246/* ----------------------------------------------------------------- */
247
248/*
249 * 03-group-children
250 *
251 * This example reuses the simple_children group from above. However,
252 * the simple_children group is not the subsystem itself, it is a
253 * child of the subsystem. Creation of a group in the subsystem creates
254 * a new simple_children group. That group can then have simple_child
255 * children of its own.
256 */
257
258static struct config_group *group_children_make_group(
259 struct config_group *group, const char *name)
260{
261 struct simple_children *simple_children;
262
263 simple_children = kzalloc(sizeof(struct simple_children),
264 GFP_KERNEL);
265 if (!simple_children)
266 return ERR_PTR(-ENOMEM);
267
268 config_group_init_type_name(&simple_children->group, name,
269 &simple_children_type);
270
271 return &simple_children->group;
272}
273
274static ssize_t group_children_description_show(struct config_item *item,
275 char *page)
276{
277 return sprintf(page,
278"[03-group-children]\n"
279"\n"
280"This subsystem allows the creation of child config_groups. These\n"
281"groups are like the subsystem simple-children.\n");
282}
283
284CONFIGFS_ATTR_RO(group_children_, description);
285
286static struct configfs_attribute *group_children_attrs[] = {
287 &group_children_attr_description,
288 NULL,
289};
290
291/*
292 * Note that, since no extra work is required on ->drop_item(),
293 * no ->drop_item() is provided.
294 */
295static struct configfs_group_operations group_children_group_ops = {
296 .make_group = group_children_make_group,
297};
298
299static const struct config_item_type group_children_type = {
300 .ct_group_ops = &group_children_group_ops,
301 .ct_attrs = group_children_attrs,
302 .ct_owner = THIS_MODULE,
303};
304
305static struct configfs_subsystem group_children_subsys = {
306 .su_group = {
307 .cg_item = {
308 .ci_namebuf = "03-group-children",
309 .ci_type = &group_children_type,
310 },
311 },
312};
313
314/* ----------------------------------------------------------------- */
315
316/*
317 * We're now done with our subsystem definitions.
318 * For convenience in this module, here's a list of them all. It
319 * allows the init function to easily register them. Most modules
320 * will only have one subsystem, and will only call register_subsystem
321 * on it directly.
322 */
323static struct configfs_subsystem *example_subsys[] = {
324 &childless_subsys.subsys,
325 &simple_children_subsys,
326 &group_children_subsys,
327 NULL,
328};
329
330static int __init configfs_example_init(void)
331{
332 struct configfs_subsystem *subsys;
333 int ret, i;
334
335 for (i = 0; example_subsys[i]; i++) {
336 subsys = example_subsys[i];
337
338 config_group_init(&subsys->su_group);
339 mutex_init(&subsys->su_mutex);
340 ret = configfs_register_subsystem(subsys);
341 if (ret) {
342 pr_err("Error %d while registering subsystem %s\n",
343 ret, subsys->su_group.cg_item.ci_namebuf);
344 goto out_unregister;
345 }
346 }
347
348 return 0;
349
350out_unregister:
351 for (i--; i >= 0; i--)
352 configfs_unregister_subsystem(example_subsys[i]);
353
354 return ret;
355}
356
357static void __exit configfs_example_exit(void)
358{
359 int i;
360
361 for (i = 0; example_subsys[i]; i++)
362 configfs_unregister_subsystem(example_subsys[i]);
363}
364
365module_init(configfs_example_init);
366module_exit(configfs_example_exit);
367MODULE_DESCRIPTION("Sample configfs module");
368MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * vim: noexpandtab ts=8 sts=0 sw=8:
4 *
5 * configfs_example_macros.c - This file is a demonstration module
6 * containing a number of configfs subsystems. It uses the helper
7 * macros defined by configfs.h
8 *
9 * Based on sysfs:
10 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
11 *
12 * configfs Copyright (C) 2005 Oracle. All rights reserved.
13 */
14
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18
19#include <linux/configfs.h>
20
21
22
23/*
24 * 01-childless
25 *
26 * This first example is a childless subsystem. It cannot create
27 * any config_items. It just has attributes.
28 *
29 * Note that we are enclosing the configfs_subsystem inside a container.
30 * This is not necessary if a subsystem has no attributes directly
31 * on the subsystem. See the next example, 02-simple-children, for
32 * such a subsystem.
33 */
34
35struct childless {
36 struct configfs_subsystem subsys;
37 int showme;
38 int storeme;
39};
40
41static inline struct childless *to_childless(struct config_item *item)
42{
43 return item ? container_of(to_configfs_subsystem(to_config_group(item)),
44 struct childless, subsys) : NULL;
45}
46
47static ssize_t childless_showme_show(struct config_item *item, char *page)
48{
49 struct childless *childless = to_childless(item);
50 ssize_t pos;
51
52 pos = sprintf(page, "%d\n", childless->showme);
53 childless->showme++;
54
55 return pos;
56}
57
58static ssize_t childless_storeme_show(struct config_item *item, char *page)
59{
60 return sprintf(page, "%d\n", to_childless(item)->storeme);
61}
62
63static ssize_t childless_storeme_store(struct config_item *item,
64 const char *page, size_t count)
65{
66 struct childless *childless = to_childless(item);
67 unsigned long tmp;
68 char *p = (char *) page;
69
70 tmp = simple_strtoul(p, &p, 10);
71 if (!p || (*p && (*p != '\n')))
72 return -EINVAL;
73
74 if (tmp > INT_MAX)
75 return -ERANGE;
76
77 childless->storeme = tmp;
78
79 return count;
80}
81
82static ssize_t childless_description_show(struct config_item *item, char *page)
83{
84 return sprintf(page,
85"[01-childless]\n"
86"\n"
87"The childless subsystem is the simplest possible subsystem in\n"
88"configfs. It does not support the creation of child config_items.\n"
89"It only has a few attributes. In fact, it isn't much different\n"
90"than a directory in /proc.\n");
91}
92
93CONFIGFS_ATTR_RO(childless_, showme);
94CONFIGFS_ATTR(childless_, storeme);
95CONFIGFS_ATTR_RO(childless_, description);
96
97static struct configfs_attribute *childless_attrs[] = {
98 &childless_attr_showme,
99 &childless_attr_storeme,
100 &childless_attr_description,
101 NULL,
102};
103
104static const struct config_item_type childless_type = {
105 .ct_attrs = childless_attrs,
106 .ct_owner = THIS_MODULE,
107};
108
109static struct childless childless_subsys = {
110 .subsys = {
111 .su_group = {
112 .cg_item = {
113 .ci_namebuf = "01-childless",
114 .ci_type = &childless_type,
115 },
116 },
117 },
118};
119
120
121/* ----------------------------------------------------------------- */
122
123/*
124 * 02-simple-children
125 *
126 * This example merely has a simple one-attribute child. Note that
127 * there is no extra attribute structure, as the child's attribute is
128 * known from the get-go. Also, there is no container for the
129 * subsystem, as it has no attributes of its own.
130 */
131
132struct simple_child {
133 struct config_item item;
134 int storeme;
135};
136
137static inline struct simple_child *to_simple_child(struct config_item *item)
138{
139 return item ? container_of(item, struct simple_child, item) : NULL;
140}
141
142static ssize_t simple_child_storeme_show(struct config_item *item, char *page)
143{
144 return sprintf(page, "%d\n", to_simple_child(item)->storeme);
145}
146
147static ssize_t simple_child_storeme_store(struct config_item *item,
148 const char *page, size_t count)
149{
150 struct simple_child *simple_child = to_simple_child(item);
151 unsigned long tmp;
152 char *p = (char *) page;
153
154 tmp = simple_strtoul(p, &p, 10);
155 if (!p || (*p && (*p != '\n')))
156 return -EINVAL;
157
158 if (tmp > INT_MAX)
159 return -ERANGE;
160
161 simple_child->storeme = tmp;
162
163 return count;
164}
165
166CONFIGFS_ATTR(simple_child_, storeme);
167
168static struct configfs_attribute *simple_child_attrs[] = {
169 &simple_child_attr_storeme,
170 NULL,
171};
172
173static void simple_child_release(struct config_item *item)
174{
175 kfree(to_simple_child(item));
176}
177
178static struct configfs_item_operations simple_child_item_ops = {
179 .release = simple_child_release,
180};
181
182static const struct config_item_type simple_child_type = {
183 .ct_item_ops = &simple_child_item_ops,
184 .ct_attrs = simple_child_attrs,
185 .ct_owner = THIS_MODULE,
186};
187
188
189struct simple_children {
190 struct config_group group;
191};
192
193static inline struct simple_children *to_simple_children(struct config_item *item)
194{
195 return item ? container_of(to_config_group(item),
196 struct simple_children, group) : NULL;
197}
198
199static struct config_item *simple_children_make_item(struct config_group *group,
200 const char *name)
201{
202 struct simple_child *simple_child;
203
204 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
205 if (!simple_child)
206 return ERR_PTR(-ENOMEM);
207
208 config_item_init_type_name(&simple_child->item, name,
209 &simple_child_type);
210
211 simple_child->storeme = 0;
212
213 return &simple_child->item;
214}
215
216static ssize_t simple_children_description_show(struct config_item *item,
217 char *page)
218{
219 return sprintf(page,
220"[02-simple-children]\n"
221"\n"
222"This subsystem allows the creation of child config_items. These\n"
223"items have only one attribute that is readable and writeable.\n");
224}
225
226CONFIGFS_ATTR_RO(simple_children_, description);
227
228static struct configfs_attribute *simple_children_attrs[] = {
229 &simple_children_attr_description,
230 NULL,
231};
232
233static void simple_children_release(struct config_item *item)
234{
235 kfree(to_simple_children(item));
236}
237
238static struct configfs_item_operations simple_children_item_ops = {
239 .release = simple_children_release,
240};
241
242/*
243 * Note that, since no extra work is required on ->drop_item(),
244 * no ->drop_item() is provided.
245 */
246static struct configfs_group_operations simple_children_group_ops = {
247 .make_item = simple_children_make_item,
248};
249
250static const struct config_item_type simple_children_type = {
251 .ct_item_ops = &simple_children_item_ops,
252 .ct_group_ops = &simple_children_group_ops,
253 .ct_attrs = simple_children_attrs,
254 .ct_owner = THIS_MODULE,
255};
256
257static struct configfs_subsystem simple_children_subsys = {
258 .su_group = {
259 .cg_item = {
260 .ci_namebuf = "02-simple-children",
261 .ci_type = &simple_children_type,
262 },
263 },
264};
265
266
267/* ----------------------------------------------------------------- */
268
269/*
270 * 03-group-children
271 *
272 * This example reuses the simple_children group from above. However,
273 * the simple_children group is not the subsystem itself, it is a
274 * child of the subsystem. Creation of a group in the subsystem creates
275 * a new simple_children group. That group can then have simple_child
276 * children of its own.
277 */
278
279static struct config_group *group_children_make_group(
280 struct config_group *group, const char *name)
281{
282 struct simple_children *simple_children;
283
284 simple_children = kzalloc(sizeof(struct simple_children),
285 GFP_KERNEL);
286 if (!simple_children)
287 return ERR_PTR(-ENOMEM);
288
289 config_group_init_type_name(&simple_children->group, name,
290 &simple_children_type);
291
292 return &simple_children->group;
293}
294
295static ssize_t group_children_description_show(struct config_item *item,
296 char *page)
297{
298 return sprintf(page,
299"[03-group-children]\n"
300"\n"
301"This subsystem allows the creation of child config_groups. These\n"
302"groups are like the subsystem simple-children.\n");
303}
304
305CONFIGFS_ATTR_RO(group_children_, description);
306
307static struct configfs_attribute *group_children_attrs[] = {
308 &group_children_attr_description,
309 NULL,
310};
311
312/*
313 * Note that, since no extra work is required on ->drop_item(),
314 * no ->drop_item() is provided.
315 */
316static struct configfs_group_operations group_children_group_ops = {
317 .make_group = group_children_make_group,
318};
319
320static const struct config_item_type group_children_type = {
321 .ct_group_ops = &group_children_group_ops,
322 .ct_attrs = group_children_attrs,
323 .ct_owner = THIS_MODULE,
324};
325
326static struct configfs_subsystem group_children_subsys = {
327 .su_group = {
328 .cg_item = {
329 .ci_namebuf = "03-group-children",
330 .ci_type = &group_children_type,
331 },
332 },
333};
334
335/* ----------------------------------------------------------------- */
336
337/*
338 * We're now done with our subsystem definitions.
339 * For convenience in this module, here's a list of them all. It
340 * allows the init function to easily register them. Most modules
341 * will only have one subsystem, and will only call register_subsystem
342 * on it directly.
343 */
344static struct configfs_subsystem *example_subsys[] = {
345 &childless_subsys.subsys,
346 &simple_children_subsys,
347 &group_children_subsys,
348 NULL,
349};
350
351static int __init configfs_example_init(void)
352{
353 int ret;
354 int i;
355 struct configfs_subsystem *subsys;
356
357 for (i = 0; example_subsys[i]; i++) {
358 subsys = example_subsys[i];
359
360 config_group_init(&subsys->su_group);
361 mutex_init(&subsys->su_mutex);
362 ret = configfs_register_subsystem(subsys);
363 if (ret) {
364 printk(KERN_ERR "Error %d while registering subsystem %s\n",
365 ret,
366 subsys->su_group.cg_item.ci_namebuf);
367 goto out_unregister;
368 }
369 }
370
371 return 0;
372
373out_unregister:
374 for (i--; i >= 0; i--)
375 configfs_unregister_subsystem(example_subsys[i]);
376
377 return ret;
378}
379
380static void __exit configfs_example_exit(void)
381{
382 int i;
383
384 for (i = 0; example_subsys[i]; i++)
385 configfs_unregister_subsystem(example_subsys[i]);
386}
387
388module_init(configfs_example_init);
389module_exit(configfs_example_exit);
390MODULE_LICENSE("GPL");