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Commit | Line | Data |
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1da177e4 | 1 | /* |
6d66f5cd TH |
2 | * fs/sysfs/file.c - sysfs regular (text) file implementation |
3 | * | |
4 | * Copyright (c) 2001-3 Patrick Mochel | |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
1da177e4 | 14 | #include <linux/kobject.h> |
815d2d50 | 15 | #include <linux/kallsyms.h> |
c6f87733 | 16 | #include <linux/slab.h> |
93265d13 | 17 | #include <linux/fsnotify.h> |
5f45f1a7 | 18 | #include <linux/namei.h> |
4508a7a7 | 19 | #include <linux/poll.h> |
94bebf4d | 20 | #include <linux/list.h> |
52e8c209 | 21 | #include <linux/mutex.h> |
ae87221d | 22 | #include <linux/limits.h> |
060cc749 | 23 | #include <linux/uaccess.h> |
13c589d5 | 24 | #include <linux/seq_file.h> |
1da177e4 LT |
25 | |
26 | #include "sysfs.h" | |
27 | ||
85a4ffad | 28 | /* |
58282d8d | 29 | * There's one sysfs_open_file for each open file and one sysfs_open_dirent |
c75ec764 | 30 | * for each sysfs_dirent with one or more open files. |
85a4ffad | 31 | * |
c75ec764 TH |
32 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is |
33 | * protected by sysfs_open_dirent_lock. | |
34 | * | |
13c589d5 TH |
35 | * filp->private_data points to seq_file whose ->private points to |
36 | * sysfs_open_file. sysfs_open_files are chained at | |
58282d8d | 37 | * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex. |
85a4ffad | 38 | */ |
d7b37889 | 39 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
c75ec764 | 40 | static DEFINE_MUTEX(sysfs_open_file_mutex); |
85a4ffad TH |
41 | |
42 | struct sysfs_open_dirent { | |
43 | atomic_t refcnt; | |
a4e8b912 TH |
44 | atomic_t event; |
45 | wait_queue_head_t poll; | |
58282d8d | 46 | struct list_head files; /* goes through sysfs_open_file.list */ |
85a4ffad TH |
47 | }; |
48 | ||
58282d8d | 49 | struct sysfs_open_file { |
bcafe4ee TH |
50 | struct sysfs_dirent *sd; |
51 | struct file *file; | |
52e8c209 | 52 | struct mutex mutex; |
73107cb3 | 53 | int event; |
85a4ffad | 54 | struct list_head list; |
73107cb3 | 55 | }; |
1da177e4 | 56 | |
13c589d5 TH |
57 | static struct sysfs_open_file *sysfs_of(struct file *file) |
58 | { | |
59 | return ((struct seq_file *)file->private_data)->private; | |
60 | } | |
61 | ||
375b611e TH |
62 | /* |
63 | * Determine ktype->sysfs_ops for the given sysfs_dirent. This function | |
64 | * must be called while holding an active reference. | |
65 | */ | |
66 | static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) | |
67 | { | |
68 | struct kobject *kobj = sd->s_parent->s_dir.kobj; | |
69 | ||
70 | lockdep_assert_held(sd); | |
71 | return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; | |
72 | } | |
73 | ||
13c589d5 TH |
74 | /* |
75 | * Reads on sysfs are handled through seq_file, which takes care of hairy | |
76 | * details like buffering and seeking. The following function pipes | |
77 | * sysfs_ops->show() result through seq_file. | |
1da177e4 | 78 | */ |
13c589d5 | 79 | static int sysfs_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 80 | { |
13c589d5 TH |
81 | struct sysfs_open_file *of = sf->private; |
82 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; | |
375b611e | 83 | const struct sysfs_ops *ops; |
13c589d5 | 84 | char *buf; |
1da177e4 LT |
85 | ssize_t count; |
86 | ||
13c589d5 TH |
87 | /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
88 | count = seq_get_buf(sf, &buf); | |
89 | if (count < PAGE_SIZE) { | |
90 | seq_commit(sf, -1); | |
91 | return 0; | |
92 | } | |
1da177e4 | 93 | |
13c589d5 TH |
94 | /* |
95 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
96 | * nests outside active ref and is just to ensure that the ops | |
97 | * aren't called concurrently for the same open file. | |
98 | */ | |
99 | mutex_lock(&of->mutex); | |
100 | if (!sysfs_get_active(of->sd)) { | |
101 | mutex_unlock(&of->mutex); | |
0ab66088 | 102 | return -ENODEV; |
13c589d5 | 103 | } |
0ab66088 | 104 | |
13c589d5 | 105 | of->event = atomic_read(&of->sd->s_attr.open->event); |
375b611e | 106 | |
13c589d5 TH |
107 | /* |
108 | * Lookup @ops and invoke show(). Control may reach here via seq | |
109 | * file lseek even if @ops->show() isn't implemented. | |
110 | */ | |
111 | ops = sysfs_file_ops(of->sd); | |
112 | if (ops->show) | |
113 | count = ops->show(kobj, of->sd->s_attr.attr, buf); | |
114 | else | |
115 | count = 0; | |
0ab66088 | 116 | |
13c589d5 TH |
117 | sysfs_put_active(of->sd); |
118 | mutex_unlock(&of->mutex); | |
119 | ||
120 | if (count < 0) | |
121 | return count; | |
0ab66088 | 122 | |
8118a859 MX |
123 | /* |
124 | * The code works fine with PAGE_SIZE return but it's likely to | |
125 | * indicate truncated result or overflow in normal use cases. | |
126 | */ | |
815d2d50 AM |
127 | if (count >= (ssize_t)PAGE_SIZE) { |
128 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
129 | (unsigned long)ops->show); | |
130 | /* Try to struggle along */ | |
131 | count = PAGE_SIZE - 1; | |
132 | } | |
13c589d5 TH |
133 | seq_commit(sf, count); |
134 | return 0; | |
1da177e4 LT |
135 | } |
136 | ||
1da177e4 | 137 | /** |
8ef445f0 TH |
138 | * flush_write_buffer - push buffer to kobject |
139 | * @of: open file | |
140 | * @buf: data buffer for file | |
141 | * @count: number of bytes | |
1da177e4 | 142 | * |
8ef445f0 TH |
143 | * Get the correct pointers for the kobject and the attribute we're dealing |
144 | * with, then call the store() method for it with @buf. | |
1da177e4 | 145 | */ |
8ef445f0 TH |
146 | static int flush_write_buffer(struct sysfs_open_file *of, char *buf, |
147 | size_t count) | |
1da177e4 | 148 | { |
bcafe4ee | 149 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; |
375b611e | 150 | const struct sysfs_ops *ops; |
8ef445f0 | 151 | int rc = 0; |
0ab66088 | 152 | |
8ef445f0 TH |
153 | /* |
154 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
155 | * nests outside active ref and is just to ensure that the ops | |
156 | * aren't called concurrently for the same open file. | |
157 | */ | |
158 | mutex_lock(&of->mutex); | |
159 | if (!sysfs_get_active(of->sd)) { | |
160 | mutex_unlock(&of->mutex); | |
0ab66088 | 161 | return -ENODEV; |
8ef445f0 | 162 | } |
0ab66088 | 163 | |
bcafe4ee | 164 | ops = sysfs_file_ops(of->sd); |
8ef445f0 | 165 | rc = ops->store(kobj, of->sd->s_attr.attr, buf, count); |
0ab66088 | 166 | |
bcafe4ee | 167 | sysfs_put_active(of->sd); |
8ef445f0 | 168 | mutex_unlock(&of->mutex); |
1da177e4 | 169 | |
0ab66088 | 170 | return rc; |
1da177e4 LT |
171 | } |
172 | ||
1da177e4 | 173 | /** |
8ef445f0 TH |
174 | * sysfs_write_file - write an attribute |
175 | * @file: file pointer | |
176 | * @user_buf: data to write | |
177 | * @count: number of bytes | |
178 | * @ppos: starting offset | |
179 | * | |
180 | * Copy data in from userland and pass it to the matching | |
181 | * sysfs_ops->store() by invoking flush_write_buffer(). | |
1da177e4 | 182 | * |
8ef445f0 TH |
183 | * There is no easy way for us to know if userspace is only doing a partial |
184 | * write, so we don't support them. We expect the entire buffer to come on | |
185 | * the first write. Hint: if you're writing a value, first read the file, | |
186 | * modify only the the value you're changing, then write entire buffer | |
187 | * back. | |
1da177e4 | 188 | */ |
8ef445f0 | 189 | static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, |
ddfd6d07 | 190 | size_t count, loff_t *ppos) |
1da177e4 | 191 | { |
13c589d5 | 192 | struct sysfs_open_file *of = sysfs_of(file); |
8ef445f0 TH |
193 | ssize_t len = min_t(size_t, count, PAGE_SIZE - 1); |
194 | char *buf; | |
1da177e4 | 195 | |
8ef445f0 TH |
196 | if (!len) |
197 | return 0; | |
198 | ||
199 | buf = kmalloc(len + 1, GFP_KERNEL); | |
200 | if (!buf) | |
201 | return -ENOMEM; | |
202 | ||
203 | if (copy_from_user(buf, user_buf, len)) { | |
204 | len = -EFAULT; | |
205 | goto out_free; | |
206 | } | |
207 | buf[len] = '\0'; /* guarantee string termination */ | |
208 | ||
209 | len = flush_write_buffer(of, buf, len); | |
1da177e4 LT |
210 | if (len > 0) |
211 | *ppos += len; | |
8ef445f0 TH |
212 | out_free: |
213 | kfree(buf); | |
1da177e4 LT |
214 | return len; |
215 | } | |
216 | ||
85a4ffad TH |
217 | /** |
218 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
219 | * @sd: target sysfs_dirent | |
58282d8d | 220 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
221 | * |
222 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 223 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
224 | * |
225 | * LOCKING: | |
226 | * Kernel thread context (may sleep). | |
227 | * | |
228 | * RETURNS: | |
229 | * 0 on success, -errno on failure. | |
230 | */ | |
231 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 232 | struct sysfs_open_file *of) |
85a4ffad TH |
233 | { |
234 | struct sysfs_open_dirent *od, *new_od = NULL; | |
235 | ||
236 | retry: | |
c75ec764 | 237 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 238 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
239 | |
240 | if (!sd->s_attr.open && new_od) { | |
241 | sd->s_attr.open = new_od; | |
242 | new_od = NULL; | |
243 | } | |
244 | ||
245 | od = sd->s_attr.open; | |
246 | if (od) { | |
247 | atomic_inc(&od->refcnt); | |
58282d8d | 248 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
249 | } |
250 | ||
83db93f4 | 251 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 252 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
253 | |
254 | if (od) { | |
255 | kfree(new_od); | |
256 | return 0; | |
257 | } | |
258 | ||
259 | /* not there, initialize a new one and retry */ | |
260 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
261 | if (!new_od) | |
262 | return -ENOMEM; | |
263 | ||
264 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
265 | atomic_set(&new_od->event, 1); |
266 | init_waitqueue_head(&new_od->poll); | |
58282d8d | 267 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
268 | goto retry; |
269 | } | |
270 | ||
271 | /** | |
272 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
273 | * @sd: target sysfs_dirent | |
58282d8d | 274 | * @of: associated sysfs_open_file |
85a4ffad | 275 | * |
58282d8d TH |
276 | * Put @sd->s_attr.open and unlink @of from the files list. If |
277 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
278 | * |
279 | * LOCKING: | |
280 | * None. | |
281 | */ | |
282 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 283 | struct sysfs_open_file *of) |
85a4ffad TH |
284 | { |
285 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 286 | unsigned long flags; |
85a4ffad | 287 | |
c75ec764 | 288 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 289 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 290 | |
58282d8d | 291 | list_del(&of->list); |
85a4ffad TH |
292 | if (atomic_dec_and_test(&od->refcnt)) |
293 | sd->s_attr.open = NULL; | |
294 | else | |
295 | od = NULL; | |
296 | ||
83db93f4 | 297 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 298 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
299 | |
300 | kfree(od); | |
301 | } | |
302 | ||
94bebf4d | 303 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 304 | { |
3e519038 | 305 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
b1fc3d61 | 306 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
58282d8d | 307 | struct sysfs_open_file *of; |
52cf25d0 | 308 | const struct sysfs_ops *ops; |
000f2a4d | 309 | int error = -EACCES; |
1da177e4 | 310 | |
0ab66088 | 311 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 312 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 313 | return -ENODEV; |
1da177e4 | 314 | |
000f2a4d | 315 | /* every kobject with an attribute needs a ktype assigned */ |
375b611e TH |
316 | ops = sysfs_file_ops(attr_sd); |
317 | if (WARN(!ops, KERN_ERR | |
318 | "missing sysfs attribute operations for kobject: %s\n", | |
319 | kobject_name(kobj))) | |
7b595756 | 320 | goto err_out; |
1da177e4 LT |
321 | |
322 | /* File needs write support. | |
ab9bf4be | 323 | * The inode's perms must say it's ok, |
1da177e4 LT |
324 | * and we must have a store method. |
325 | */ | |
326 | if (file->f_mode & FMODE_WRITE) { | |
1da177e4 | 327 | if (!(inode->i_mode & S_IWUGO) || !ops->store) |
7b595756 | 328 | goto err_out; |
1da177e4 LT |
329 | } |
330 | ||
331 | /* File needs read support. | |
332 | * The inode's perms must say it's ok, and we there | |
333 | * must be a show method for it. | |
334 | */ | |
335 | if (file->f_mode & FMODE_READ) { | |
336 | if (!(inode->i_mode & S_IRUGO) || !ops->show) | |
7b595756 | 337 | goto err_out; |
1da177e4 LT |
338 | } |
339 | ||
13c589d5 | 340 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 341 | error = -ENOMEM; |
58282d8d TH |
342 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
343 | if (!of) | |
7b595756 | 344 | goto err_out; |
1da177e4 | 345 | |
58282d8d | 346 | mutex_init(&of->mutex); |
bcafe4ee TH |
347 | of->sd = attr_sd; |
348 | of->file = file; | |
13c589d5 TH |
349 | |
350 | /* | |
351 | * Always instantiate seq_file even if read access is not | |
352 | * implemented or requested. This unifies private data access and | |
353 | * most files are readable anyway. | |
354 | */ | |
355 | error = single_open(file, sysfs_seq_show, of); | |
356 | if (error) | |
357 | goto err_free; | |
358 | ||
359 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ | |
360 | if (file->f_mode & FMODE_WRITE) | |
361 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 362 | |
85a4ffad | 363 | /* make sure we have open dirent struct */ |
58282d8d | 364 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 365 | if (error) |
13c589d5 | 366 | goto err_close; |
85a4ffad | 367 | |
b05f0548 | 368 | /* open succeeded, put active references */ |
e72ceb8c | 369 | sysfs_put_active(attr_sd); |
0ab66088 TH |
370 | return 0; |
371 | ||
13c589d5 TH |
372 | err_close: |
373 | single_release(inode, file); | |
374 | err_free: | |
58282d8d | 375 | kfree(of); |
13c589d5 | 376 | err_out: |
e72ceb8c | 377 | sysfs_put_active(attr_sd); |
1da177e4 LT |
378 | return error; |
379 | } | |
380 | ||
85a4ffad | 381 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 382 | { |
85a4ffad | 383 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 384 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 385 | |
58282d8d | 386 | sysfs_put_open_dirent(sd, of); |
13c589d5 | 387 | single_release(inode, filp); |
58282d8d | 388 | kfree(of); |
50ab1a72 | 389 | |
1da177e4 LT |
390 | return 0; |
391 | } | |
392 | ||
4508a7a7 N |
393 | /* Sysfs attribute files are pollable. The idea is that you read |
394 | * the content and then you use 'poll' or 'select' to wait for | |
395 | * the content to change. When the content changes (assuming the | |
396 | * manager for the kobject supports notification), poll will | |
397 | * return POLLERR|POLLPRI, and select will return the fd whether | |
398 | * it is waiting for read, write, or exceptions. | |
399 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 400 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
401 | * Reminder: this only works for attributes which actively support |
402 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 403 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
404 | * an appropriate error code). When in doubt, set a suitable timeout value. |
405 | */ | |
406 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
407 | { | |
13c589d5 | 408 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 409 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 410 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
411 | |
412 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 413 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 414 | goto trigger; |
4508a7a7 | 415 | |
a4e8b912 | 416 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 417 | |
e72ceb8c | 418 | sysfs_put_active(attr_sd); |
0ab66088 | 419 | |
58282d8d | 420 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 421 | goto trigger; |
4508a7a7 | 422 | |
1af3557a | 423 | return DEFAULT_POLLMASK; |
0ab66088 TH |
424 | |
425 | trigger: | |
1af3557a | 426 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
427 | } |
428 | ||
f1282c84 NB |
429 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
430 | { | |
431 | struct sysfs_open_dirent *od; | |
83db93f4 | 432 | unsigned long flags; |
f1282c84 | 433 | |
83db93f4 | 434 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 435 | |
fc60bb83 ND |
436 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
437 | od = sd->s_attr.open; | |
438 | if (od) { | |
439 | atomic_inc(&od->event); | |
440 | wake_up_interruptible(&od->poll); | |
441 | } | |
f1282c84 NB |
442 | } |
443 | ||
83db93f4 | 444 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
445 | } |
446 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
447 | ||
8c0e3998 | 448 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 449 | { |
51225039 | 450 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 451 | |
51225039 TH |
452 | mutex_lock(&sysfs_mutex); |
453 | ||
454 | if (sd && dir) | |
cfec0bc8 | 455 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 456 | if (sd && attr) |
cfec0bc8 | 457 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
458 | if (sd) |
459 | sysfs_notify_dirent(sd); | |
51225039 TH |
460 | |
461 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
462 | } |
463 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
464 | ||
4b6f5d20 | 465 | const struct file_operations sysfs_file_operations = { |
13c589d5 | 466 | .read = seq_read, |
1da177e4 | 467 | .write = sysfs_write_file, |
13c589d5 | 468 | .llseek = seq_lseek, |
1da177e4 LT |
469 | .open = sysfs_open_file, |
470 | .release = sysfs_release, | |
4508a7a7 | 471 | .poll = sysfs_poll, |
1da177e4 LT |
472 | }; |
473 | ||
58292cbe TH |
474 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
475 | const struct attribute *attr, int type, | |
476 | umode_t amode, const void *ns) | |
1da177e4 | 477 | { |
0f423895 | 478 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 479 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 480 | struct sysfs_dirent *sd; |
23dc2799 | 481 | int rc; |
1da177e4 | 482 | |
3007e997 TH |
483 | sd = sysfs_new_dirent(attr->name, mode, type); |
484 | if (!sd) | |
485 | return -ENOMEM; | |
487505c2 EB |
486 | |
487 | sd->s_ns = ns; | |
b1fc3d61 | 488 | sd->s_attr.attr = (void *)attr; |
a2db6842 | 489 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 490 | |
d69ac5a0 TH |
491 | sysfs_addrm_start(&acxt); |
492 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 493 | sysfs_addrm_finish(&acxt); |
a26cd722 | 494 | |
23dc2799 | 495 | if (rc) |
967e35dc | 496 | sysfs_put(sd); |
3007e997 | 497 | |
23dc2799 | 498 | return rc; |
1da177e4 LT |
499 | } |
500 | ||
501 | ||
0f423895 JB |
502 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
503 | int type) | |
504 | { | |
58292cbe | 505 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
506 | } |
507 | ||
1da177e4 | 508 | /** |
58292cbe TH |
509 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
510 | * @kobj: object we're creating for | |
511 | * @attr: attribute descriptor | |
512 | * @ns: namespace the new file should belong to | |
1da177e4 | 513 | */ |
58292cbe TH |
514 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
515 | const void *ns) | |
1da177e4 | 516 | { |
608e266a | 517 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 518 | |
58292cbe TH |
519 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
520 | attr->mode, ns); | |
1da177e4 LT |
521 | |
522 | } | |
58292cbe | 523 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 524 | |
1c205ae1 AK |
525 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
526 | { | |
527 | int err = 0; | |
528 | int i; | |
529 | ||
530 | for (i = 0; ptr[i] && !err; i++) | |
531 | err = sysfs_create_file(kobj, ptr[i]); | |
532 | if (err) | |
533 | while (--i >= 0) | |
534 | sysfs_remove_file(kobj, ptr[i]); | |
535 | return err; | |
536 | } | |
1b866757 | 537 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 538 | |
dfa87c82 AS |
539 | /** |
540 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
541 | * @kobj: object we're acting for. | |
542 | * @attr: attribute descriptor. | |
543 | * @group: group name. | |
544 | */ | |
545 | int sysfs_add_file_to_group(struct kobject *kobj, | |
546 | const struct attribute *attr, const char *group) | |
547 | { | |
608e266a | 548 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
549 | int error; |
550 | ||
11f24fbd | 551 | if (group) |
388975cc | 552 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
553 | else |
554 | dir_sd = sysfs_get(kobj->sd); | |
555 | ||
608e266a TH |
556 | if (!dir_sd) |
557 | return -ENOENT; | |
558 | ||
559 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
560 | sysfs_put(dir_sd); | |
561 | ||
dfa87c82 AS |
562 | return error; |
563 | } | |
564 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
565 | ||
31e5abe9 KS |
566 | /** |
567 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
568 | * @kobj: object we're acting for. | |
569 | * @attr: attribute descriptor. | |
570 | * @mode: file permissions. | |
571 | * | |
572 | */ | |
49c19400 | 573 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 574 | umode_t mode) |
31e5abe9 | 575 | { |
06fc0d66 | 576 | struct sysfs_dirent *sd; |
bc062b1b | 577 | struct iattr newattrs; |
51225039 TH |
578 | int rc; |
579 | ||
06fc0d66 | 580 | mutex_lock(&sysfs_mutex); |
51225039 | 581 | |
06fc0d66 | 582 | rc = -ENOENT; |
cfec0bc8 | 583 | sd = sysfs_find_dirent(kobj->sd, attr->name, NULL); |
06fc0d66 | 584 | if (!sd) |
51225039 | 585 | goto out; |
f88123ea | 586 | |
06fc0d66 | 587 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 588 | newattrs.ia_valid = ATTR_MODE; |
06fc0d66 | 589 | rc = sysfs_sd_setattr(sd, &newattrs); |
f88123ea | 590 | |
51225039 | 591 | out: |
06fc0d66 | 592 | mutex_unlock(&sysfs_mutex); |
51225039 | 593 | return rc; |
31e5abe9 KS |
594 | } |
595 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
596 | ||
1da177e4 | 597 | /** |
58292cbe TH |
598 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
599 | * @kobj: object we're acting for | |
600 | * @attr: attribute descriptor | |
601 | * @ns: namespace tag of the file to remove | |
1da177e4 | 602 | * |
58292cbe | 603 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 604 | */ |
58292cbe TH |
605 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
606 | const void *ns) | |
1da177e4 | 607 | { |
58292cbe | 608 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 609 | |
cfec0bc8 | 610 | sysfs_hash_and_remove(dir_sd, attr->name, ns); |
1da177e4 | 611 | } |
58292cbe | 612 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 613 | |
1b18dc2b | 614 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
615 | { |
616 | int i; | |
617 | for (i = 0; ptr[i]; i++) | |
618 | sysfs_remove_file(kobj, ptr[i]); | |
619 | } | |
1b866757 | 620 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 621 | |
dfa87c82 AS |
622 | /** |
623 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
624 | * @kobj: object we're acting for. | |
625 | * @attr: attribute descriptor. | |
626 | * @group: group name. | |
627 | */ | |
628 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
629 | const struct attribute *attr, const char *group) | |
630 | { | |
608e266a | 631 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 632 | |
11f24fbd | 633 | if (group) |
388975cc | 634 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
635 | else |
636 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 637 | if (dir_sd) { |
cfec0bc8 | 638 | sysfs_hash_and_remove(dir_sd, attr->name, NULL); |
608e266a | 639 | sysfs_put(dir_sd); |
dfa87c82 AS |
640 | } |
641 | } | |
642 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
643 | ||
d9a9cdfb | 644 | struct sysfs_schedule_callback_struct { |
66942064 AC |
645 | struct list_head workq_list; |
646 | struct kobject *kobj; | |
d9a9cdfb AS |
647 | void (*func)(void *); |
648 | void *data; | |
523ded71 | 649 | struct module *owner; |
d9a9cdfb AS |
650 | struct work_struct work; |
651 | }; | |
652 | ||
d110271e | 653 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
654 | static DEFINE_MUTEX(sysfs_workq_mutex); |
655 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
656 | static void sysfs_schedule_callback_work(struct work_struct *work) |
657 | { | |
658 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
659 | struct sysfs_schedule_callback_struct, work); | |
660 | ||
661 | (ss->func)(ss->data); | |
662 | kobject_put(ss->kobj); | |
523ded71 | 663 | module_put(ss->owner); |
66942064 AC |
664 | mutex_lock(&sysfs_workq_mutex); |
665 | list_del(&ss->workq_list); | |
666 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
667 | kfree(ss); |
668 | } | |
669 | ||
670 | /** | |
671 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
672 | * @kobj: object we're acting for. | |
673 | * @func: callback function to invoke later. | |
674 | * @data: argument to pass to @func. | |
523ded71 | 675 | * @owner: module owning the callback code |
d9a9cdfb AS |
676 | * |
677 | * sysfs attribute methods must not unregister themselves or their parent | |
678 | * kobject (which would amount to the same thing). Attempts to do so will | |
679 | * deadlock, since unregistration is mutually exclusive with driver | |
680 | * callbacks. | |
681 | * | |
682 | * Instead methods can call this routine, which will attempt to allocate | |
683 | * and schedule a workqueue request to call back @func with @data as its | |
684 | * argument in the workqueue's process context. @kobj will be pinned | |
685 | * until @func returns. | |
686 | * | |
687 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
688 | * be allocated, -ENODEV if a reference to @owner isn't available, |
689 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
690 | */ |
691 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 692 | void *data, struct module *owner) |
d9a9cdfb | 693 | { |
66942064 | 694 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 695 | |
523ded71 AS |
696 | if (!try_module_get(owner)) |
697 | return -ENODEV; | |
66942064 AC |
698 | |
699 | mutex_lock(&sysfs_workq_mutex); | |
700 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
701 | if (ss->kobj == kobj) { | |
d110271e | 702 | module_put(owner); |
66942064 AC |
703 | mutex_unlock(&sysfs_workq_mutex); |
704 | return -EAGAIN; | |
705 | } | |
706 | mutex_unlock(&sysfs_workq_mutex); | |
707 | ||
d110271e | 708 | if (sysfs_workqueue == NULL) { |
086a377e | 709 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
710 | if (sysfs_workqueue == NULL) { |
711 | module_put(owner); | |
712 | return -ENOMEM; | |
713 | } | |
714 | } | |
715 | ||
d9a9cdfb | 716 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
717 | if (!ss) { |
718 | module_put(owner); | |
d9a9cdfb | 719 | return -ENOMEM; |
523ded71 | 720 | } |
d9a9cdfb AS |
721 | kobject_get(kobj); |
722 | ss->kobj = kobj; | |
723 | ss->func = func; | |
724 | ss->data = data; | |
523ded71 | 725 | ss->owner = owner; |
d9a9cdfb | 726 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
727 | INIT_LIST_HEAD(&ss->workq_list); |
728 | mutex_lock(&sysfs_workq_mutex); | |
729 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
730 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 731 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
732 | return 0; |
733 | } | |
734 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |