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authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-13 23:04:17 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-13 23:04:17 -0500
commit9aa3d651a9199103eb6451aeb0ac1b66a6d770a6 (patch)
tree42cc631c54e1fcbdeedee8e955c4797634a91af7 /Documentation/filesystems/configfs/configfs_example_explicit.c
parent5d2eb548b309be34ecf3b91f0b7300a2b9d09b8c (diff)
parent517982229f78b2aebf00a8a337e84e8eeea70b8e (diff)
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Pull SCSI target updates from Nicholas Bellinger: "This series contains HCH's changes to absorb configfs attribute ->show() + ->store() function pointer usage from it's original tree-wide consumers, into common configfs code. It includes usb-gadget, target w/ drivers, netconsole and ocfs2 changes to realize the improved simplicity, that now renders the original include/target/configfs_macros.h CPP magic for fabric drivers and others, unnecessary and obsolete. And with common code in place, new configfs attributes can be added easier than ever before. Note, there are further improvements in-flight from other folks for v4.5 code in configfs land, plus number of target fixes for post -rc1 code" In the meantime, a new user of the now-removed old configfs API came in through the char/misc tree in commit 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices"). This merge resolution comes from Alexander Shishkin, who updated his stm class tracing abstraction to account for the removal of the old show_attribute and store_attribute methods in commit 517982229f78 ("configfs: remove old API") from this pull. As Alexander says about that patch: "There's no need to keep an extra wrapper structure per item and the awkward show_attribute/store_attribute item ops are no longer needed. This patch converts policy code to the new api, all the while making the code quite a bit smaller and easier on the eyes. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>" That patch was folded into the merge so that the tree should be fully bisectable. * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (23 commits) configfs: remove old API ocfs2/cluster: use per-attribute show and store methods ocfs2/cluster: move locking into attribute store methods netconsole: use per-attribute show and store methods target: use per-attribute show and store methods spear13xx_pcie_gadget: use per-attribute show and store methods dlm: use per-attribute show and store methods usb-gadget/f_serial: use per-attribute show and store methods usb-gadget/f_phonet: use per-attribute show and store methods usb-gadget/f_obex: use per-attribute show and store methods usb-gadget/f_uac2: use per-attribute show and store methods usb-gadget/f_uac1: use per-attribute show and store methods usb-gadget/f_mass_storage: use per-attribute show and store methods usb-gadget/f_sourcesink: use per-attribute show and store methods usb-gadget/f_printer: use per-attribute show and store methods usb-gadget/f_midi: use per-attribute show and store methods usb-gadget/f_loopback: use per-attribute show and store methods usb-gadget/ether: use per-attribute show and store methods usb-gadget/f_acm: use per-attribute show and store methods usb-gadget/f_hid: use per-attribute show and store methods ...
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1/*
2 * vim: noexpandtab ts=8 sts=0 sw=8:
3 *
4 * configfs_example_explicit.c - This file is a demonstration module
5 * containing a number of configfs subsystems. It explicitly defines
6 * each structure without using the helper macros defined in
7 * configfs.h.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public
20 * License along with this program; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 021110-1307, USA.
23 *
24 * Based on sysfs:
25 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
26 *
27 * configfs Copyright (C) 2005 Oracle. All rights reserved.
28 */
29
30#include <linux/init.h>
31#include <linux/module.h>
32#include <linux/slab.h>
33
34#include <linux/configfs.h>
35
36
37
38/*
39 * 01-childless
40 *
41 * This first example is a childless subsystem. It cannot create
42 * any config_items. It just has attributes.
43 *
44 * Note that we are enclosing the configfs_subsystem inside a container.
45 * This is not necessary if a subsystem has no attributes directly
46 * on the subsystem. See the next example, 02-simple-children, for
47 * such a subsystem.
48 */
49
50struct childless {
51 struct configfs_subsystem subsys;
52 int showme;
53 int storeme;
54};
55
56struct childless_attribute {
57 struct configfs_attribute attr;
58 ssize_t (*show)(struct childless *, char *);
59 ssize_t (*store)(struct childless *, const char *, size_t);
60};
61
62static inline struct childless *to_childless(struct config_item *item)
63{
64 return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL;
65}
66
67static ssize_t childless_showme_read(struct childless *childless,
68 char *page)
69{
70 ssize_t pos;
71
72 pos = sprintf(page, "%d\n", childless->showme);
73 childless->showme++;
74
75 return pos;
76}
77
78static ssize_t childless_storeme_read(struct childless *childless,
79 char *page)
80{
81 return sprintf(page, "%d\n", childless->storeme);
82}
83
84static ssize_t childless_storeme_write(struct childless *childless,
85 const char *page,
86 size_t count)
87{
88 unsigned long tmp;
89 char *p = (char *) page;
90
91 tmp = simple_strtoul(p, &p, 10);
92 if ((*p != '\0') && (*p != '\n'))
93 return -EINVAL;
94
95 if (tmp > INT_MAX)
96 return -ERANGE;
97
98 childless->storeme = tmp;
99
100 return count;
101}
102
103static ssize_t childless_description_read(struct childless *childless,
104 char *page)
105{
106 return sprintf(page,
107"[01-childless]\n"
108"\n"
109"The childless subsystem is the simplest possible subsystem in\n"
110"configfs. It does not support the creation of child config_items.\n"
111"It only has a few attributes. In fact, it isn't much different\n"
112"than a directory in /proc.\n");
113}
114
115static struct childless_attribute childless_attr_showme = {
116 .attr = { .ca_owner = THIS_MODULE, .ca_name = "showme", .ca_mode = S_IRUGO },
117 .show = childless_showme_read,
118};
119static struct childless_attribute childless_attr_storeme = {
120 .attr = { .ca_owner = THIS_MODULE, .ca_name = "storeme", .ca_mode = S_IRUGO | S_IWUSR },
121 .show = childless_storeme_read,
122 .store = childless_storeme_write,
123};
124static struct childless_attribute childless_attr_description = {
125 .attr = { .ca_owner = THIS_MODULE, .ca_name = "description", .ca_mode = S_IRUGO },
126 .show = childless_description_read,
127};
128
129static struct configfs_attribute *childless_attrs[] = {
130 &childless_attr_showme.attr,
131 &childless_attr_storeme.attr,
132 &childless_attr_description.attr,
133 NULL,
134};
135
136static ssize_t childless_attr_show(struct config_item *item,
137 struct configfs_attribute *attr,
138 char *page)
139{
140 struct childless *childless = to_childless(item);
141 struct childless_attribute *childless_attr =
142 container_of(attr, struct childless_attribute, attr);
143 ssize_t ret = 0;
144
145 if (childless_attr->show)
146 ret = childless_attr->show(childless, page);
147 return ret;
148}
149
150static ssize_t childless_attr_store(struct config_item *item,
151 struct configfs_attribute *attr,
152 const char *page, size_t count)
153{
154 struct childless *childless = to_childless(item);
155 struct childless_attribute *childless_attr =
156 container_of(attr, struct childless_attribute, attr);
157 ssize_t ret = -EINVAL;
158
159 if (childless_attr->store)
160 ret = childless_attr->store(childless, page, count);
161 return ret;
162}
163
164static struct configfs_item_operations childless_item_ops = {
165 .show_attribute = childless_attr_show,
166 .store_attribute = childless_attr_store,
167};
168
169static struct config_item_type childless_type = {
170 .ct_item_ops = &childless_item_ops,
171 .ct_attrs = childless_attrs,
172 .ct_owner = THIS_MODULE,
173};
174
175static struct childless childless_subsys = {
176 .subsys = {
177 .su_group = {
178 .cg_item = {
179 .ci_namebuf = "01-childless",
180 .ci_type = &childless_type,
181 },
182 },
183 },
184};
185
186
187/* ----------------------------------------------------------------- */
188
189/*
190 * 02-simple-children
191 *
192 * This example merely has a simple one-attribute child. Note that
193 * there is no extra attribute structure, as the child's attribute is
194 * known from the get-go. Also, there is no container for the
195 * subsystem, as it has no attributes of its own.
196 */
197
198struct simple_child {
199 struct config_item item;
200 int storeme;
201};
202
203static inline struct simple_child *to_simple_child(struct config_item *item)
204{
205 return item ? container_of(item, struct simple_child, item) : NULL;
206}
207
208static struct configfs_attribute simple_child_attr_storeme = {
209 .ca_owner = THIS_MODULE,
210 .ca_name = "storeme",
211 .ca_mode = S_IRUGO | S_IWUSR,
212};
213
214static struct configfs_attribute *simple_child_attrs[] = {
215 &simple_child_attr_storeme,
216 NULL,
217};
218
219static ssize_t simple_child_attr_show(struct config_item *item,
220 struct configfs_attribute *attr,
221 char *page)
222{
223 ssize_t count;
224 struct simple_child *simple_child = to_simple_child(item);
225
226 count = sprintf(page, "%d\n", simple_child->storeme);
227
228 return count;
229}
230
231static ssize_t simple_child_attr_store(struct config_item *item,
232 struct configfs_attribute *attr,
233 const char *page, size_t count)
234{
235 struct simple_child *simple_child = to_simple_child(item);
236 unsigned long tmp;
237 char *p = (char *) page;
238
239 tmp = simple_strtoul(p, &p, 10);
240 if (!p || (*p && (*p != '\n')))
241 return -EINVAL;
242
243 if (tmp > INT_MAX)
244 return -ERANGE;
245
246 simple_child->storeme = tmp;
247
248 return count;
249}
250
251static void simple_child_release(struct config_item *item)
252{
253 kfree(to_simple_child(item));
254}
255
256static struct configfs_item_operations simple_child_item_ops = {
257 .release = simple_child_release,
258 .show_attribute = simple_child_attr_show,
259 .store_attribute = simple_child_attr_store,
260};
261
262static struct config_item_type simple_child_type = {
263 .ct_item_ops = &simple_child_item_ops,
264 .ct_attrs = simple_child_attrs,
265 .ct_owner = THIS_MODULE,
266};
267
268
269struct simple_children {
270 struct config_group group;
271};
272
273static inline struct simple_children *to_simple_children(struct config_item *item)
274{
275 return item ? container_of(to_config_group(item), struct simple_children, group) : NULL;
276}
277
278static struct config_item *simple_children_make_item(struct config_group *group, const char *name)
279{
280 struct simple_child *simple_child;
281
282 simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
283 if (!simple_child)
284 return ERR_PTR(-ENOMEM);
285
286 config_item_init_type_name(&simple_child->item, name,
287 &simple_child_type);
288
289 simple_child->storeme = 0;
290
291 return &simple_child->item;
292}
293
294static struct configfs_attribute simple_children_attr_description = {
295 .ca_owner = THIS_MODULE,
296 .ca_name = "description",
297 .ca_mode = S_IRUGO,
298};
299
300static struct configfs_attribute *simple_children_attrs[] = {
301 &simple_children_attr_description,
302 NULL,
303};
304
305static ssize_t simple_children_attr_show(struct config_item *item,
306 struct configfs_attribute *attr,
307 char *page)
308{
309 return sprintf(page,
310"[02-simple-children]\n"
311"\n"
312"This subsystem allows the creation of child config_items. These\n"
313"items have only one attribute that is readable and writeable.\n");
314}
315
316static void simple_children_release(struct config_item *item)
317{
318 kfree(to_simple_children(item));
319}
320
321static struct configfs_item_operations simple_children_item_ops = {
322 .release = simple_children_release,
323 .show_attribute = simple_children_attr_show,
324};
325
326/*
327 * Note that, since no extra work is required on ->drop_item(),
328 * no ->drop_item() is provided.
329 */
330static struct configfs_group_operations simple_children_group_ops = {
331 .make_item = simple_children_make_item,
332};
333
334static struct config_item_type simple_children_type = {
335 .ct_item_ops = &simple_children_item_ops,
336 .ct_group_ops = &simple_children_group_ops,
337 .ct_attrs = simple_children_attrs,
338 .ct_owner = THIS_MODULE,
339};
340
341static struct configfs_subsystem simple_children_subsys = {
342 .su_group = {
343 .cg_item = {
344 .ci_namebuf = "02-simple-children",
345 .ci_type = &simple_children_type,
346 },
347 },
348};
349
350
351/* ----------------------------------------------------------------- */
352
353/*
354 * 03-group-children
355 *
356 * This example reuses the simple_children group from above. However,
357 * the simple_children group is not the subsystem itself, it is a
358 * child of the subsystem. Creation of a group in the subsystem creates
359 * a new simple_children group. That group can then have simple_child
360 * children of its own.
361 */
362
363static struct config_group *group_children_make_group(struct config_group *group, const char *name)
364{
365 struct simple_children *simple_children;
366
367 simple_children = kzalloc(sizeof(struct simple_children),
368 GFP_KERNEL);
369 if (!simple_children)
370 return ERR_PTR(-ENOMEM);
371
372 config_group_init_type_name(&simple_children->group, name,
373 &simple_children_type);
374
375 return &simple_children->group;
376}
377
378static struct configfs_attribute group_children_attr_description = {
379 .ca_owner = THIS_MODULE,
380 .ca_name = "description",
381 .ca_mode = S_IRUGO,
382};
383
384static struct configfs_attribute *group_children_attrs[] = {
385 &group_children_attr_description,
386 NULL,
387};
388
389static ssize_t group_children_attr_show(struct config_item *item,
390 struct configfs_attribute *attr,
391 char *page)
392{
393 return sprintf(page,
394"[03-group-children]\n"
395"\n"
396"This subsystem allows the creation of child config_groups. These\n"
397"groups are like the subsystem simple-children.\n");
398}
399
400static struct configfs_item_operations group_children_item_ops = {
401 .show_attribute = group_children_attr_show,
402};
403
404/*
405 * Note that, since no extra work is required on ->drop_item(),
406 * no ->drop_item() is provided.
407 */
408static struct configfs_group_operations group_children_group_ops = {
409 .make_group = group_children_make_group,
410};
411
412static struct config_item_type group_children_type = {
413 .ct_item_ops = &group_children_item_ops,
414 .ct_group_ops = &group_children_group_ops,
415 .ct_attrs = group_children_attrs,
416 .ct_owner = THIS_MODULE,
417};
418
419static struct configfs_subsystem group_children_subsys = {
420 .su_group = {
421 .cg_item = {
422 .ci_namebuf = "03-group-children",
423 .ci_type = &group_children_type,
424 },
425 },
426};
427
428/* ----------------------------------------------------------------- */
429
430/*
431 * We're now done with our subsystem definitions.
432 * For convenience in this module, here's a list of them all. It
433 * allows the init function to easily register them. Most modules
434 * will only have one subsystem, and will only call register_subsystem
435 * on it directly.
436 */
437static struct configfs_subsystem *example_subsys[] = {
438 &childless_subsys.subsys,
439 &simple_children_subsys,
440 &group_children_subsys,
441 NULL,
442};
443
444static int __init configfs_example_init(void)
445{
446 int ret;
447 int i;
448 struct configfs_subsystem *subsys;
449
450 for (i = 0; example_subsys[i]; i++) {
451 subsys = example_subsys[i];
452
453 config_group_init(&subsys->su_group);
454 mutex_init(&subsys->su_mutex);
455 ret = configfs_register_subsystem(subsys);
456 if (ret) {
457 printk(KERN_ERR "Error %d while registering subsystem %s\n",
458 ret,
459 subsys->su_group.cg_item.ci_namebuf);
460 goto out_unregister;
461 }
462 }
463
464 return 0;
465
466out_unregister:
467 for (i--; i >= 0; i--)
468 configfs_unregister_subsystem(example_subsys[i]);
469
470 return ret;
471}
472
473static void __exit configfs_example_exit(void)
474{
475 int i;
476
477 for (i = 0; example_subsys[i]; i++)
478 configfs_unregister_subsystem(example_subsys[i]);
479}
480
481module_init(configfs_example_init);
482module_exit(configfs_example_exit);
483MODULE_LICENSE("GPL");