Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * file.c - operations for regular (text) files. | |
3 | */ | |
4 | ||
5 | #include <linux/module.h> | |
1da177e4 | 6 | #include <linux/kobject.h> |
5f45f1a7 | 7 | #include <linux/namei.h> |
4508a7a7 | 8 | #include <linux/poll.h> |
94bebf4d | 9 | #include <linux/list.h> |
52e8c209 | 10 | #include <linux/mutex.h> |
1da177e4 | 11 | #include <asm/uaccess.h> |
1da177e4 LT |
12 | |
13 | #include "sysfs.h" | |
14 | ||
823bccfc | 15 | #define to_sattr(a) container_of(a,struct subsys_attribute, attr) |
1da177e4 | 16 | |
3d41088f | 17 | /* |
1da177e4 LT |
18 | * Subsystem file operations. |
19 | * These operations allow subsystems to have files that can be | |
20 | * read/written. | |
21 | */ | |
22 | static ssize_t | |
23 | subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page) | |
24 | { | |
823bccfc | 25 | struct kset *kset = to_kset(kobj); |
1da177e4 | 26 | struct subsys_attribute * sattr = to_sattr(attr); |
c76d0abd | 27 | ssize_t ret = -EIO; |
1da177e4 LT |
28 | |
29 | if (sattr->show) | |
823bccfc | 30 | ret = sattr->show(kset, page); |
1da177e4 LT |
31 | return ret; |
32 | } | |
33 | ||
34 | static ssize_t | |
35 | subsys_attr_store(struct kobject * kobj, struct attribute * attr, | |
36 | const char * page, size_t count) | |
37 | { | |
823bccfc | 38 | struct kset *kset = to_kset(kobj); |
1da177e4 | 39 | struct subsys_attribute * sattr = to_sattr(attr); |
c76d0abd | 40 | ssize_t ret = -EIO; |
1da177e4 LT |
41 | |
42 | if (sattr->store) | |
823bccfc | 43 | ret = sattr->store(kset, page, count); |
1da177e4 LT |
44 | return ret; |
45 | } | |
46 | ||
47 | static struct sysfs_ops subsys_sysfs_ops = { | |
48 | .show = subsys_attr_show, | |
49 | .store = subsys_attr_store, | |
50 | }; | |
51 | ||
85a4ffad TH |
52 | /* |
53 | * There's one sysfs_buffer for each open file and one | |
54 | * sysfs_open_dirent for each sysfs_dirent with one or more open | |
55 | * files. | |
56 | * | |
57 | * filp->private_data points to sysfs_buffer and | |
58 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open | |
59 | * is protected by sysfs_open_dirent_lock. | |
60 | */ | |
61 | static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED; | |
62 | ||
63 | struct sysfs_open_dirent { | |
64 | atomic_t refcnt; | |
a4e8b912 TH |
65 | atomic_t event; |
66 | wait_queue_head_t poll; | |
85a4ffad TH |
67 | struct list_head buffers; /* goes through sysfs_buffer.list */ |
68 | }; | |
69 | ||
73107cb3 TH |
70 | struct sysfs_buffer { |
71 | size_t count; | |
72 | loff_t pos; | |
73 | char * page; | |
74 | struct sysfs_ops * ops; | |
52e8c209 | 75 | struct mutex mutex; |
73107cb3 TH |
76 | int needs_read_fill; |
77 | int event; | |
85a4ffad | 78 | struct list_head list; |
73107cb3 | 79 | }; |
1da177e4 LT |
80 | |
81 | /** | |
82 | * fill_read_buffer - allocate and fill buffer from object. | |
83 | * @dentry: dentry pointer. | |
84 | * @buffer: data buffer for file. | |
85 | * | |
86 | * Allocate @buffer->page, if it hasn't been already, then call the | |
87 | * kobject's show() method to fill the buffer with this attribute's | |
88 | * data. | |
82244b16 ON |
89 | * This is called only once, on the file's first read unless an error |
90 | * is returned. | |
1da177e4 LT |
91 | */ |
92 | static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) | |
93 | { | |
0ab66088 | 94 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 95 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1da177e4 LT |
96 | struct sysfs_ops * ops = buffer->ops; |
97 | int ret = 0; | |
98 | ssize_t count; | |
99 | ||
100 | if (!buffer->page) | |
101 | buffer->page = (char *) get_zeroed_page(GFP_KERNEL); | |
102 | if (!buffer->page) | |
103 | return -ENOMEM; | |
104 | ||
0ab66088 TH |
105 | /* need attr_sd for attr and ops, its parent for kobj */ |
106 | if (!sysfs_get_active_two(attr_sd)) | |
107 | return -ENODEV; | |
108 | ||
a4e8b912 | 109 | buffer->event = atomic_read(&attr_sd->s_attr.open->event); |
b1fc3d61 | 110 | count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); |
0ab66088 TH |
111 | |
112 | sysfs_put_active_two(attr_sd); | |
113 | ||
1da177e4 | 114 | BUG_ON(count > (ssize_t)PAGE_SIZE); |
82244b16 ON |
115 | if (count >= 0) { |
116 | buffer->needs_read_fill = 0; | |
1da177e4 | 117 | buffer->count = count; |
82244b16 | 118 | } else { |
1da177e4 | 119 | ret = count; |
82244b16 | 120 | } |
1da177e4 LT |
121 | return ret; |
122 | } | |
123 | ||
1da177e4 LT |
124 | /** |
125 | * sysfs_read_file - read an attribute. | |
126 | * @file: file pointer. | |
127 | * @buf: buffer to fill. | |
128 | * @count: number of bytes to read. | |
129 | * @ppos: starting offset in file. | |
130 | * | |
131 | * Userspace wants to read an attribute file. The attribute descriptor | |
132 | * is in the file's ->d_fsdata. The target object is in the directory's | |
133 | * ->d_fsdata. | |
134 | * | |
135 | * We call fill_read_buffer() to allocate and fill the buffer from the | |
136 | * object's show() method exactly once (if the read is happening from | |
137 | * the beginning of the file). That should fill the entire buffer with | |
138 | * all the data the object has to offer for that attribute. | |
139 | * We then call flush_read_buffer() to copy the buffer to userspace | |
140 | * in the increments specified. | |
141 | */ | |
142 | ||
143 | static ssize_t | |
144 | sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
145 | { | |
146 | struct sysfs_buffer * buffer = file->private_data; | |
147 | ssize_t retval = 0; | |
148 | ||
52e8c209 | 149 | mutex_lock(&buffer->mutex); |
1da177e4 | 150 | if (buffer->needs_read_fill) { |
73107cb3 | 151 | retval = fill_read_buffer(file->f_path.dentry,buffer); |
e7b0d26a | 152 | if (retval) |
1da177e4 LT |
153 | goto out; |
154 | } | |
5c1fdf41 ZB |
155 | pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", |
156 | __FUNCTION__, count, *ppos, buffer->page); | |
92f4c701 AM |
157 | retval = simple_read_from_buffer(buf, count, ppos, buffer->page, |
158 | buffer->count); | |
1da177e4 | 159 | out: |
52e8c209 | 160 | mutex_unlock(&buffer->mutex); |
1da177e4 LT |
161 | return retval; |
162 | } | |
163 | ||
1da177e4 LT |
164 | /** |
165 | * fill_write_buffer - copy buffer from userspace. | |
166 | * @buffer: data buffer for file. | |
67be2dd1 | 167 | * @buf: data from user. |
1da177e4 LT |
168 | * @count: number of bytes in @userbuf. |
169 | * | |
170 | * Allocate @buffer->page if it hasn't been already, then | |
171 | * copy the user-supplied buffer into it. | |
172 | */ | |
173 | ||
174 | static int | |
175 | fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count) | |
176 | { | |
177 | int error; | |
178 | ||
179 | if (!buffer->page) | |
180 | buffer->page = (char *)get_zeroed_page(GFP_KERNEL); | |
181 | if (!buffer->page) | |
182 | return -ENOMEM; | |
183 | ||
184 | if (count >= PAGE_SIZE) | |
6e0dd741 | 185 | count = PAGE_SIZE - 1; |
1da177e4 LT |
186 | error = copy_from_user(buffer->page,buf,count); |
187 | buffer->needs_read_fill = 1; | |
035ed7a4 TM |
188 | /* if buf is assumed to contain a string, terminate it by \0, |
189 | so e.g. sscanf() can scan the string easily */ | |
190 | buffer->page[count] = 0; | |
1da177e4 LT |
191 | return error ? -EFAULT : count; |
192 | } | |
193 | ||
194 | ||
195 | /** | |
196 | * flush_write_buffer - push buffer to kobject. | |
3d41088f | 197 | * @dentry: dentry to the attribute |
1da177e4 | 198 | * @buffer: data buffer for file. |
3d41088f | 199 | * @count: number of bytes |
1da177e4 LT |
200 | * |
201 | * Get the correct pointers for the kobject and the attribute we're | |
202 | * dealing with, then call the store() method for the attribute, | |
203 | * passing the buffer that we acquired in fill_write_buffer(). | |
204 | */ | |
205 | ||
0ab66088 | 206 | static int |
1da177e4 LT |
207 | flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) |
208 | { | |
3e519038 | 209 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 210 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1da177e4 | 211 | struct sysfs_ops * ops = buffer->ops; |
0ab66088 TH |
212 | int rc; |
213 | ||
214 | /* need attr_sd for attr and ops, its parent for kobj */ | |
215 | if (!sysfs_get_active_two(attr_sd)) | |
216 | return -ENODEV; | |
217 | ||
b1fc3d61 | 218 | rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count); |
0ab66088 TH |
219 | |
220 | sysfs_put_active_two(attr_sd); | |
1da177e4 | 221 | |
0ab66088 | 222 | return rc; |
1da177e4 LT |
223 | } |
224 | ||
225 | ||
226 | /** | |
227 | * sysfs_write_file - write an attribute. | |
228 | * @file: file pointer | |
229 | * @buf: data to write | |
230 | * @count: number of bytes | |
231 | * @ppos: starting offset | |
232 | * | |
233 | * Similar to sysfs_read_file(), though working in the opposite direction. | |
234 | * We allocate and fill the data from the user in fill_write_buffer(), | |
235 | * then push it to the kobject in flush_write_buffer(). | |
236 | * There is no easy way for us to know if userspace is only doing a partial | |
237 | * write, so we don't support them. We expect the entire buffer to come | |
238 | * on the first write. | |
239 | * Hint: if you're writing a value, first read the file, modify only the | |
240 | * the value you're changing, then write entire buffer back. | |
241 | */ | |
242 | ||
243 | static ssize_t | |
244 | sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
245 | { | |
246 | struct sysfs_buffer * buffer = file->private_data; | |
247 | ssize_t len; | |
248 | ||
52e8c209 | 249 | mutex_lock(&buffer->mutex); |
1da177e4 LT |
250 | len = fill_write_buffer(buffer, buf, count); |
251 | if (len > 0) | |
f427f5d5 | 252 | len = flush_write_buffer(file->f_path.dentry, buffer, len); |
1da177e4 LT |
253 | if (len > 0) |
254 | *ppos += len; | |
52e8c209 | 255 | mutex_unlock(&buffer->mutex); |
1da177e4 LT |
256 | return len; |
257 | } | |
258 | ||
85a4ffad TH |
259 | /** |
260 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
261 | * @sd: target sysfs_dirent | |
262 | * @buffer: sysfs_buffer for this instance of open | |
263 | * | |
264 | * If @sd->s_attr.open exists, increment its reference count; | |
265 | * otherwise, create one. @buffer is chained to the buffers | |
266 | * list. | |
267 | * | |
268 | * LOCKING: | |
269 | * Kernel thread context (may sleep). | |
270 | * | |
271 | * RETURNS: | |
272 | * 0 on success, -errno on failure. | |
273 | */ | |
274 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
275 | struct sysfs_buffer *buffer) | |
276 | { | |
277 | struct sysfs_open_dirent *od, *new_od = NULL; | |
278 | ||
279 | retry: | |
280 | spin_lock(&sysfs_open_dirent_lock); | |
281 | ||
282 | if (!sd->s_attr.open && new_od) { | |
283 | sd->s_attr.open = new_od; | |
284 | new_od = NULL; | |
285 | } | |
286 | ||
287 | od = sd->s_attr.open; | |
288 | if (od) { | |
289 | atomic_inc(&od->refcnt); | |
290 | list_add_tail(&buffer->list, &od->buffers); | |
291 | } | |
292 | ||
293 | spin_unlock(&sysfs_open_dirent_lock); | |
294 | ||
295 | if (od) { | |
296 | kfree(new_od); | |
297 | return 0; | |
298 | } | |
299 | ||
300 | /* not there, initialize a new one and retry */ | |
301 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
302 | if (!new_od) | |
303 | return -ENOMEM; | |
304 | ||
305 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
306 | atomic_set(&new_od->event, 1); |
307 | init_waitqueue_head(&new_od->poll); | |
85a4ffad TH |
308 | INIT_LIST_HEAD(&new_od->buffers); |
309 | goto retry; | |
310 | } | |
311 | ||
312 | /** | |
313 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
314 | * @sd: target sysfs_dirent | |
315 | * @buffer: associated sysfs_buffer | |
316 | * | |
317 | * Put @sd->s_attr.open and unlink @buffer from the buffers list. | |
318 | * If reference count reaches zero, disassociate and free it. | |
319 | * | |
320 | * LOCKING: | |
321 | * None. | |
322 | */ | |
323 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
324 | struct sysfs_buffer *buffer) | |
325 | { | |
326 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
327 | ||
328 | spin_lock(&sysfs_open_dirent_lock); | |
329 | ||
330 | list_del(&buffer->list); | |
331 | if (atomic_dec_and_test(&od->refcnt)) | |
332 | sd->s_attr.open = NULL; | |
333 | else | |
334 | od = NULL; | |
335 | ||
336 | spin_unlock(&sysfs_open_dirent_lock); | |
337 | ||
338 | kfree(od); | |
339 | } | |
340 | ||
94bebf4d | 341 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 342 | { |
3e519038 | 343 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
b1fc3d61 | 344 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1da177e4 LT |
345 | struct sysfs_buffer * buffer; |
346 | struct sysfs_ops * ops = NULL; | |
0ab66088 | 347 | int error; |
1da177e4 | 348 | |
0ab66088 TH |
349 | /* need attr_sd for attr and ops, its parent for kobj */ |
350 | if (!sysfs_get_active_two(attr_sd)) | |
351 | return -ENODEV; | |
1da177e4 | 352 | |
1da177e4 LT |
353 | /* if the kobject has no ktype, then we assume that it is a subsystem |
354 | * itself, and use ops for it. | |
355 | */ | |
356 | if (kobj->kset && kobj->kset->ktype) | |
357 | ops = kobj->kset->ktype->sysfs_ops; | |
358 | else if (kobj->ktype) | |
359 | ops = kobj->ktype->sysfs_ops; | |
360 | else | |
361 | ops = &subsys_sysfs_ops; | |
362 | ||
73107cb3 TH |
363 | error = -EACCES; |
364 | ||
1da177e4 LT |
365 | /* No sysfs operations, either from having no subsystem, |
366 | * or the subsystem have no operations. | |
367 | */ | |
368 | if (!ops) | |
7b595756 | 369 | goto err_out; |
1da177e4 LT |
370 | |
371 | /* File needs write support. | |
372 | * The inode's perms must say it's ok, | |
373 | * and we must have a store method. | |
374 | */ | |
375 | if (file->f_mode & FMODE_WRITE) { | |
1da177e4 | 376 | if (!(inode->i_mode & S_IWUGO) || !ops->store) |
7b595756 | 377 | goto err_out; |
1da177e4 LT |
378 | } |
379 | ||
380 | /* File needs read support. | |
381 | * The inode's perms must say it's ok, and we there | |
382 | * must be a show method for it. | |
383 | */ | |
384 | if (file->f_mode & FMODE_READ) { | |
385 | if (!(inode->i_mode & S_IRUGO) || !ops->show) | |
7b595756 | 386 | goto err_out; |
1da177e4 LT |
387 | } |
388 | ||
389 | /* No error? Great, allocate a buffer for the file, and store it | |
390 | * it in file->private_data for easy access. | |
391 | */ | |
0ab66088 | 392 | error = -ENOMEM; |
58d49283 | 393 | buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); |
0ab66088 | 394 | if (!buffer) |
7b595756 | 395 | goto err_out; |
1da177e4 | 396 | |
52e8c209 | 397 | mutex_init(&buffer->mutex); |
0ab66088 TH |
398 | buffer->needs_read_fill = 1; |
399 | buffer->ops = ops; | |
0ab66088 TH |
400 | file->private_data = buffer; |
401 | ||
85a4ffad TH |
402 | /* make sure we have open dirent struct */ |
403 | error = sysfs_get_open_dirent(attr_sd, buffer); | |
404 | if (error) | |
405 | goto err_free; | |
406 | ||
b05f0548 | 407 | /* open succeeded, put active references */ |
0ab66088 | 408 | sysfs_put_active_two(attr_sd); |
0ab66088 TH |
409 | return 0; |
410 | ||
85a4ffad TH |
411 | err_free: |
412 | kfree(buffer); | |
7b595756 | 413 | err_out: |
0ab66088 | 414 | sysfs_put_active_two(attr_sd); |
1da177e4 LT |
415 | return error; |
416 | } | |
417 | ||
85a4ffad | 418 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 419 | { |
85a4ffad | 420 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
73107cb3 | 421 | struct sysfs_buffer *buffer = filp->private_data; |
1da177e4 | 422 | |
85a4ffad TH |
423 | sysfs_put_open_dirent(sd, buffer); |
424 | ||
50ab1a72 TH |
425 | if (buffer->page) |
426 | free_page((unsigned long)buffer->page); | |
427 | kfree(buffer); | |
428 | ||
1da177e4 LT |
429 | return 0; |
430 | } | |
431 | ||
4508a7a7 N |
432 | /* Sysfs attribute files are pollable. The idea is that you read |
433 | * the content and then you use 'poll' or 'select' to wait for | |
434 | * the content to change. When the content changes (assuming the | |
435 | * manager for the kobject supports notification), poll will | |
436 | * return POLLERR|POLLPRI, and select will return the fd whether | |
437 | * it is waiting for read, write, or exceptions. | |
438 | * Once poll/select indicates that the value has changed, you | |
439 | * need to close and re-open the file, as simply seeking and reading | |
440 | * again will not get new data, or reset the state of 'poll'. | |
441 | * Reminder: this only works for attributes which actively support | |
442 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 443 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
444 | * an appropriate error code). When in doubt, set a suitable timeout value. |
445 | */ | |
446 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
447 | { | |
448 | struct sysfs_buffer * buffer = filp->private_data; | |
0ab66088 | 449 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 450 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
451 | |
452 | /* need parent for the kobj, grab both */ | |
453 | if (!sysfs_get_active_two(attr_sd)) | |
454 | goto trigger; | |
4508a7a7 | 455 | |
a4e8b912 | 456 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 457 | |
0ab66088 TH |
458 | sysfs_put_active_two(attr_sd); |
459 | ||
a4e8b912 | 460 | if (buffer->event != atomic_read(&od->event)) |
0ab66088 | 461 | goto trigger; |
4508a7a7 | 462 | |
0ab66088 TH |
463 | return 0; |
464 | ||
465 | trigger: | |
466 | buffer->needs_read_fill = 1; | |
467 | return POLLERR|POLLPRI; | |
4508a7a7 N |
468 | } |
469 | ||
51225039 | 470 | void sysfs_notify(struct kobject *k, char *dir, char *attr) |
4508a7a7 | 471 | { |
51225039 | 472 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 473 | |
51225039 TH |
474 | mutex_lock(&sysfs_mutex); |
475 | ||
476 | if (sd && dir) | |
477 | sd = sysfs_find_dirent(sd, dir); | |
478 | if (sd && attr) | |
479 | sd = sysfs_find_dirent(sd, attr); | |
480 | if (sd) { | |
a4e8b912 TH |
481 | struct sysfs_open_dirent *od; |
482 | ||
483 | spin_lock(&sysfs_open_dirent_lock); | |
484 | ||
485 | od = sd->s_attr.open; | |
486 | if (od) { | |
487 | atomic_inc(&od->event); | |
488 | wake_up_interruptible(&od->poll); | |
489 | } | |
490 | ||
491 | spin_unlock(&sysfs_open_dirent_lock); | |
4508a7a7 | 492 | } |
51225039 TH |
493 | |
494 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
495 | } |
496 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
497 | ||
4b6f5d20 | 498 | const struct file_operations sysfs_file_operations = { |
1da177e4 LT |
499 | .read = sysfs_read_file, |
500 | .write = sysfs_write_file, | |
501 | .llseek = generic_file_llseek, | |
502 | .open = sysfs_open_file, | |
503 | .release = sysfs_release, | |
4508a7a7 | 504 | .poll = sysfs_poll, |
1da177e4 LT |
505 | }; |
506 | ||
507 | ||
608e266a TH |
508 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
509 | int type) | |
1da177e4 | 510 | { |
1da177e4 | 511 | umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; |
fb6896da | 512 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 513 | struct sysfs_dirent *sd; |
23dc2799 | 514 | int rc; |
1da177e4 | 515 | |
3007e997 TH |
516 | sd = sysfs_new_dirent(attr->name, mode, type); |
517 | if (!sd) | |
518 | return -ENOMEM; | |
b1fc3d61 | 519 | sd->s_attr.attr = (void *)attr; |
1da177e4 | 520 | |
fb6896da | 521 | sysfs_addrm_start(&acxt, dir_sd); |
23dc2799 TH |
522 | rc = sysfs_add_one(&acxt, sd); |
523 | sysfs_addrm_finish(&acxt); | |
a26cd722 | 524 | |
23dc2799 | 525 | if (rc) |
967e35dc | 526 | sysfs_put(sd); |
3007e997 | 527 | |
23dc2799 | 528 | return rc; |
1da177e4 LT |
529 | } |
530 | ||
531 | ||
532 | /** | |
533 | * sysfs_create_file - create an attribute file for an object. | |
534 | * @kobj: object we're creating for. | |
535 | * @attr: atrribute descriptor. | |
536 | */ | |
537 | ||
538 | int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) | |
539 | { | |
608e266a | 540 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 541 | |
608e266a | 542 | return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR); |
1da177e4 LT |
543 | |
544 | } | |
545 | ||
546 | ||
dfa87c82 AS |
547 | /** |
548 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
549 | * @kobj: object we're acting for. | |
550 | * @attr: attribute descriptor. | |
551 | * @group: group name. | |
552 | */ | |
553 | int sysfs_add_file_to_group(struct kobject *kobj, | |
554 | const struct attribute *attr, const char *group) | |
555 | { | |
608e266a | 556 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
557 | int error; |
558 | ||
608e266a TH |
559 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
560 | if (!dir_sd) | |
561 | return -ENOENT; | |
562 | ||
563 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
564 | sysfs_put(dir_sd); | |
565 | ||
dfa87c82 AS |
566 | return error; |
567 | } | |
568 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
569 | ||
31e5abe9 KS |
570 | /** |
571 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
572 | * @kobj: object we're acting for. | |
573 | * @attr: attribute descriptor. | |
574 | * @mode: file permissions. | |
575 | * | |
576 | */ | |
577 | int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) | |
578 | { | |
51225039 TH |
579 | struct sysfs_dirent *victim_sd = NULL; |
580 | struct dentry *victim = NULL; | |
bc062b1b MS |
581 | struct inode * inode; |
582 | struct iattr newattrs; | |
51225039 TH |
583 | int rc; |
584 | ||
585 | rc = -ENOENT; | |
586 | victim_sd = sysfs_get_dirent(kobj->sd, attr->name); | |
587 | if (!victim_sd) | |
588 | goto out; | |
589 | ||
932ea2e3 | 590 | mutex_lock(&sysfs_rename_mutex); |
51225039 | 591 | victim = sysfs_get_dentry(victim_sd); |
932ea2e3 | 592 | mutex_unlock(&sysfs_rename_mutex); |
51225039 TH |
593 | if (IS_ERR(victim)) { |
594 | rc = PTR_ERR(victim); | |
595 | victim = NULL; | |
596 | goto out; | |
31e5abe9 | 597 | } |
31e5abe9 | 598 | |
51225039 | 599 | inode = victim->d_inode; |
f88123ea | 600 | |
51225039 | 601 | mutex_lock(&inode->i_mutex); |
f88123ea | 602 | |
51225039 TH |
603 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
604 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
605 | rc = notify_change(victim, &newattrs); | |
f88123ea TH |
606 | |
607 | if (rc == 0) { | |
608 | mutex_lock(&sysfs_mutex); | |
609 | victim_sd->s_mode = newattrs.ia_mode; | |
610 | mutex_unlock(&sysfs_mutex); | |
611 | } | |
612 | ||
51225039 TH |
613 | mutex_unlock(&inode->i_mutex); |
614 | out: | |
615 | dput(victim); | |
616 | sysfs_put(victim_sd); | |
617 | return rc; | |
31e5abe9 KS |
618 | } |
619 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
620 | ||
621 | ||
1da177e4 LT |
622 | /** |
623 | * sysfs_remove_file - remove an object attribute. | |
624 | * @kobj: object we're acting for. | |
625 | * @attr: attribute descriptor. | |
626 | * | |
627 | * Hash the attribute name and kill the victim. | |
628 | */ | |
629 | ||
630 | void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) | |
631 | { | |
608e266a | 632 | sysfs_hash_and_remove(kobj->sd, attr->name); |
1da177e4 LT |
633 | } |
634 | ||
635 | ||
dfa87c82 AS |
636 | /** |
637 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
638 | * @kobj: object we're acting for. | |
639 | * @attr: attribute descriptor. | |
640 | * @group: group name. | |
641 | */ | |
642 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
643 | const struct attribute *attr, const char *group) | |
644 | { | |
608e266a | 645 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 646 | |
608e266a TH |
647 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
648 | if (dir_sd) { | |
649 | sysfs_hash_and_remove(dir_sd, attr->name); | |
650 | sysfs_put(dir_sd); | |
dfa87c82 AS |
651 | } |
652 | } | |
653 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
654 | ||
d9a9cdfb AS |
655 | struct sysfs_schedule_callback_struct { |
656 | struct kobject *kobj; | |
657 | void (*func)(void *); | |
658 | void *data; | |
523ded71 | 659 | struct module *owner; |
d9a9cdfb AS |
660 | struct work_struct work; |
661 | }; | |
662 | ||
663 | static void sysfs_schedule_callback_work(struct work_struct *work) | |
664 | { | |
665 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
666 | struct sysfs_schedule_callback_struct, work); | |
667 | ||
668 | (ss->func)(ss->data); | |
669 | kobject_put(ss->kobj); | |
523ded71 | 670 | module_put(ss->owner); |
d9a9cdfb AS |
671 | kfree(ss); |
672 | } | |
673 | ||
674 | /** | |
675 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
676 | * @kobj: object we're acting for. | |
677 | * @func: callback function to invoke later. | |
678 | * @data: argument to pass to @func. | |
523ded71 | 679 | * @owner: module owning the callback code |
d9a9cdfb AS |
680 | * |
681 | * sysfs attribute methods must not unregister themselves or their parent | |
682 | * kobject (which would amount to the same thing). Attempts to do so will | |
683 | * deadlock, since unregistration is mutually exclusive with driver | |
684 | * callbacks. | |
685 | * | |
686 | * Instead methods can call this routine, which will attempt to allocate | |
687 | * and schedule a workqueue request to call back @func with @data as its | |
688 | * argument in the workqueue's process context. @kobj will be pinned | |
689 | * until @func returns. | |
690 | * | |
691 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
523ded71 | 692 | * be allocated, -ENODEV if a reference to @owner isn't available. |
d9a9cdfb AS |
693 | */ |
694 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 695 | void *data, struct module *owner) |
d9a9cdfb AS |
696 | { |
697 | struct sysfs_schedule_callback_struct *ss; | |
698 | ||
523ded71 AS |
699 | if (!try_module_get(owner)) |
700 | return -ENODEV; | |
d9a9cdfb | 701 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
702 | if (!ss) { |
703 | module_put(owner); | |
d9a9cdfb | 704 | return -ENOMEM; |
523ded71 | 705 | } |
d9a9cdfb AS |
706 | kobject_get(kobj); |
707 | ss->kobj = kobj; | |
708 | ss->func = func; | |
709 | ss->data = data; | |
523ded71 | 710 | ss->owner = owner; |
d9a9cdfb AS |
711 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
712 | schedule_work(&ss->work); | |
713 | return 0; | |
714 | } | |
715 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); | |
716 | ||
dfa87c82 | 717 | |
1da177e4 LT |
718 | EXPORT_SYMBOL_GPL(sysfs_create_file); |
719 | EXPORT_SYMBOL_GPL(sysfs_remove_file); |