Commit | Line | Data |
---|---|---|
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> |
73d97146 | 25 | #include <linux/mm.h> |
1da177e4 LT |
26 | |
27 | #include "sysfs.h" | |
28 | ||
85a4ffad | 29 | /* |
58282d8d | 30 | * There's one sysfs_open_file for each open file and one sysfs_open_dirent |
c75ec764 | 31 | * for each sysfs_dirent with one or more open files. |
85a4ffad | 32 | * |
c75ec764 TH |
33 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is |
34 | * protected by sysfs_open_dirent_lock. | |
35 | * | |
13c589d5 TH |
36 | * filp->private_data points to seq_file whose ->private points to |
37 | * sysfs_open_file. sysfs_open_files are chained at | |
58282d8d | 38 | * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex. |
85a4ffad | 39 | */ |
d7b37889 | 40 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
c75ec764 | 41 | static DEFINE_MUTEX(sysfs_open_file_mutex); |
85a4ffad TH |
42 | |
43 | struct sysfs_open_dirent { | |
44 | atomic_t refcnt; | |
a4e8b912 TH |
45 | atomic_t event; |
46 | wait_queue_head_t poll; | |
58282d8d | 47 | struct list_head files; /* goes through sysfs_open_file.list */ |
85a4ffad TH |
48 | }; |
49 | ||
58282d8d | 50 | struct sysfs_open_file { |
bcafe4ee TH |
51 | struct sysfs_dirent *sd; |
52 | struct file *file; | |
52e8c209 | 53 | struct mutex mutex; |
73107cb3 | 54 | int event; |
85a4ffad | 55 | struct list_head list; |
73d97146 TH |
56 | |
57 | bool mmapped; | |
58 | const struct vm_operations_struct *vm_ops; | |
73107cb3 | 59 | }; |
1da177e4 | 60 | |
f9b9a621 TH |
61 | static bool sysfs_is_bin(struct sysfs_dirent *sd) |
62 | { | |
63 | return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR; | |
64 | } | |
65 | ||
13c589d5 TH |
66 | static struct sysfs_open_file *sysfs_of(struct file *file) |
67 | { | |
68 | return ((struct seq_file *)file->private_data)->private; | |
69 | } | |
70 | ||
375b611e TH |
71 | /* |
72 | * Determine ktype->sysfs_ops for the given sysfs_dirent. This function | |
73 | * must be called while holding an active reference. | |
74 | */ | |
75 | static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) | |
76 | { | |
7c6e2d36 | 77 | struct kobject *kobj = sd->s_parent->priv; |
375b611e | 78 | |
785a162d TH |
79 | if (!sysfs_ignore_lockdep(sd)) |
80 | lockdep_assert_held(sd); | |
375b611e TH |
81 | return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; |
82 | } | |
83 | ||
13c589d5 TH |
84 | /* |
85 | * Reads on sysfs are handled through seq_file, which takes care of hairy | |
86 | * details like buffering and seeking. The following function pipes | |
87 | * sysfs_ops->show() result through seq_file. | |
1da177e4 | 88 | */ |
c2b19daf | 89 | static int sysfs_kf_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 90 | { |
13c589d5 | 91 | struct sysfs_open_file *of = sf->private; |
7c6e2d36 | 92 | struct kobject *kobj = of->sd->s_parent->priv; |
c2b19daf | 93 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
1da177e4 | 94 | ssize_t count; |
c2b19daf | 95 | char *buf; |
1da177e4 | 96 | |
13c589d5 TH |
97 | /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
98 | count = seq_get_buf(sf, &buf); | |
99 | if (count < PAGE_SIZE) { | |
100 | seq_commit(sf, -1); | |
101 | return 0; | |
102 | } | |
1da177e4 | 103 | |
13c589d5 | 104 | /* |
c2b19daf TH |
105 | * Invoke show(). Control may reach here via seq file lseek even |
106 | * if @ops->show() isn't implemented. | |
13c589d5 | 107 | */ |
c2b19daf | 108 | if (ops->show) { |
7c6e2d36 | 109 | count = ops->show(kobj, of->sd->priv, buf); |
c2b19daf TH |
110 | if (count < 0) |
111 | return count; | |
112 | } | |
0ab66088 | 113 | |
8118a859 MX |
114 | /* |
115 | * The code works fine with PAGE_SIZE return but it's likely to | |
116 | * indicate truncated result or overflow in normal use cases. | |
117 | */ | |
815d2d50 AM |
118 | if (count >= (ssize_t)PAGE_SIZE) { |
119 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
120 | (unsigned long)ops->show); | |
121 | /* Try to struggle along */ | |
122 | count = PAGE_SIZE - 1; | |
123 | } | |
13c589d5 TH |
124 | seq_commit(sf, count); |
125 | return 0; | |
1da177e4 LT |
126 | } |
127 | ||
c2b19daf TH |
128 | static ssize_t sysfs_kf_bin_read(struct sysfs_open_file *of, char *buf, |
129 | size_t count, loff_t pos) | |
2f0c6b75 | 130 | { |
7c6e2d36 TH |
131 | struct bin_attribute *battr = of->sd->priv; |
132 | struct kobject *kobj = of->sd->s_parent->priv; | |
c2b19daf | 133 | loff_t size = file_inode(of->file)->i_size; |
2f0c6b75 | 134 | |
c2b19daf | 135 | if (!count) |
2f0c6b75 TH |
136 | return 0; |
137 | ||
138 | if (size) { | |
c2b19daf | 139 | if (pos > size) |
2f0c6b75 | 140 | return 0; |
c2b19daf TH |
141 | if (pos + count > size) |
142 | count = size - pos; | |
2f0c6b75 TH |
143 | } |
144 | ||
c2b19daf TH |
145 | if (!battr->read) |
146 | return -EIO; | |
147 | ||
148 | return battr->read(of->file, kobj, battr, buf, pos, count); | |
149 | } | |
150 | ||
151 | static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) | |
152 | { | |
153 | struct sysfs_open_file *of = sf->private; | |
154 | ||
155 | /* | |
156 | * @of->mutex nests outside active ref and is just to ensure that | |
157 | * the ops aren't called concurrently for the same open file. | |
158 | */ | |
159 | mutex_lock(&of->mutex); | |
160 | if (!sysfs_get_active(of->sd)) | |
161 | return ERR_PTR(-ENODEV); | |
162 | ||
163 | /* | |
164 | * The same behavior and code as single_open(). Returns !NULL if | |
165 | * pos is at the beginning; otherwise, NULL. | |
166 | */ | |
167 | return NULL + !*ppos; | |
168 | } | |
169 | ||
170 | static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) | |
171 | { | |
172 | /* | |
173 | * The same behavior and code as single_open(), always terminate | |
174 | * after the initial read. | |
175 | */ | |
176 | ++*ppos; | |
177 | return NULL; | |
178 | } | |
179 | ||
180 | static void kernfs_seq_stop(struct seq_file *sf, void *v) | |
181 | { | |
182 | struct sysfs_open_file *of = sf->private; | |
183 | ||
184 | sysfs_put_active(of->sd); | |
185 | mutex_unlock(&of->mutex); | |
186 | } | |
187 | ||
188 | static int kernfs_seq_show(struct seq_file *sf, void *v) | |
189 | { | |
190 | struct sysfs_open_file *of = sf->private; | |
191 | ||
192 | of->event = atomic_read(&of->sd->s_attr.open->event); | |
193 | ||
194 | return sysfs_kf_seq_show(sf, v); | |
195 | } | |
196 | ||
197 | static const struct seq_operations kernfs_seq_ops = { | |
198 | .start = kernfs_seq_start, | |
199 | .next = kernfs_seq_next, | |
200 | .stop = kernfs_seq_stop, | |
201 | .show = kernfs_seq_show, | |
202 | }; | |
203 | ||
204 | /* | |
205 | * As reading a bin file can have side-effects, the exact offset and bytes | |
206 | * specified in read(2) call should be passed to the read callback making | |
207 | * it difficult to use seq_file. Implement simplistic custom buffering for | |
208 | * bin files. | |
209 | */ | |
210 | static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, | |
211 | char __user *user_buf, size_t count, | |
212 | loff_t *ppos) | |
213 | { | |
214 | ssize_t len = min_t(size_t, count, PAGE_SIZE); | |
215 | char *buf; | |
216 | ||
217 | buf = kmalloc(len, GFP_KERNEL); | |
2f0c6b75 TH |
218 | if (!buf) |
219 | return -ENOMEM; | |
220 | ||
c2b19daf TH |
221 | /* |
222 | * @of->mutex nests outside active ref and is just to ensure that | |
223 | * the ops aren't called concurrently for the same open file. | |
224 | */ | |
2f0c6b75 TH |
225 | mutex_lock(&of->mutex); |
226 | if (!sysfs_get_active(of->sd)) { | |
c2b19daf | 227 | len = -ENODEV; |
2f0c6b75 TH |
228 | mutex_unlock(&of->mutex); |
229 | goto out_free; | |
230 | } | |
231 | ||
c2b19daf | 232 | len = sysfs_kf_bin_read(of, buf, len, *ppos); |
2f0c6b75 TH |
233 | |
234 | sysfs_put_active(of->sd); | |
235 | mutex_unlock(&of->mutex); | |
236 | ||
c2b19daf | 237 | if (len < 0) |
2f0c6b75 TH |
238 | goto out_free; |
239 | ||
c2b19daf TH |
240 | if (copy_to_user(user_buf, buf, len)) { |
241 | len = -EFAULT; | |
2f0c6b75 TH |
242 | goto out_free; |
243 | } | |
244 | ||
c2b19daf | 245 | *ppos += len; |
2f0c6b75 TH |
246 | |
247 | out_free: | |
248 | kfree(buf); | |
c2b19daf TH |
249 | return len; |
250 | } | |
251 | ||
252 | /** | |
253 | * kernfs_file_read - kernfs vfs read callback | |
254 | * @file: file pointer | |
255 | * @user_buf: data to write | |
256 | * @count: number of bytes | |
257 | * @ppos: starting offset | |
258 | */ | |
259 | static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, | |
260 | size_t count, loff_t *ppos) | |
261 | { | |
262 | struct sysfs_open_file *of = sysfs_of(file); | |
263 | ||
264 | if (sysfs_is_bin(of->sd)) | |
265 | return kernfs_file_direct_read(of, user_buf, count, ppos); | |
266 | else | |
267 | return seq_read(file, user_buf, count, ppos); | |
2f0c6b75 TH |
268 | } |
269 | ||
1da177e4 | 270 | /** |
8ef445f0 TH |
271 | * flush_write_buffer - push buffer to kobject |
272 | * @of: open file | |
273 | * @buf: data buffer for file | |
f9b9a621 | 274 | * @off: file offset to write to |
8ef445f0 | 275 | * @count: number of bytes |
1da177e4 | 276 | * |
8ef445f0 TH |
277 | * Get the correct pointers for the kobject and the attribute we're dealing |
278 | * with, then call the store() method for it with @buf. | |
1da177e4 | 279 | */ |
f9b9a621 | 280 | static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off, |
8ef445f0 | 281 | size_t count) |
1da177e4 | 282 | { |
7c6e2d36 | 283 | struct kobject *kobj = of->sd->s_parent->priv; |
8ef445f0 | 284 | int rc = 0; |
0ab66088 | 285 | |
8ef445f0 TH |
286 | /* |
287 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
288 | * nests outside active ref and is just to ensure that the ops | |
289 | * aren't called concurrently for the same open file. | |
290 | */ | |
291 | mutex_lock(&of->mutex); | |
292 | if (!sysfs_get_active(of->sd)) { | |
293 | mutex_unlock(&of->mutex); | |
0ab66088 | 294 | return -ENODEV; |
8ef445f0 | 295 | } |
0ab66088 | 296 | |
f9b9a621 | 297 | if (sysfs_is_bin(of->sd)) { |
7c6e2d36 | 298 | struct bin_attribute *battr = of->sd->priv; |
f9b9a621 TH |
299 | |
300 | rc = -EIO; | |
301 | if (battr->write) | |
302 | rc = battr->write(of->file, kobj, battr, buf, off, | |
303 | count); | |
304 | } else { | |
305 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); | |
306 | ||
7c6e2d36 | 307 | rc = ops->store(kobj, of->sd->priv, buf, count); |
f9b9a621 | 308 | } |
0ab66088 | 309 | |
bcafe4ee | 310 | sysfs_put_active(of->sd); |
8ef445f0 | 311 | mutex_unlock(&of->mutex); |
1da177e4 | 312 | |
0ab66088 | 313 | return rc; |
1da177e4 LT |
314 | } |
315 | ||
1da177e4 | 316 | /** |
8ef445f0 TH |
317 | * sysfs_write_file - write an attribute |
318 | * @file: file pointer | |
319 | * @user_buf: data to write | |
320 | * @count: number of bytes | |
321 | * @ppos: starting offset | |
322 | * | |
323 | * Copy data in from userland and pass it to the matching | |
324 | * sysfs_ops->store() by invoking flush_write_buffer(). | |
1da177e4 | 325 | * |
8ef445f0 TH |
326 | * There is no easy way for us to know if userspace is only doing a partial |
327 | * write, so we don't support them. We expect the entire buffer to come on | |
328 | * the first write. Hint: if you're writing a value, first read the file, | |
329 | * modify only the the value you're changing, then write entire buffer | |
330 | * back. | |
1da177e4 | 331 | */ |
8ef445f0 | 332 | static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, |
ddfd6d07 | 333 | size_t count, loff_t *ppos) |
1da177e4 | 334 | { |
13c589d5 | 335 | struct sysfs_open_file *of = sysfs_of(file); |
f9b9a621 | 336 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
b9c06225 | 337 | loff_t size = file_inode(file)->i_size; |
8ef445f0 | 338 | char *buf; |
1da177e4 | 339 | |
b9c06225 | 340 | if (sysfs_is_bin(of->sd) && size) { |
f9b9a621 TH |
341 | if (size <= *ppos) |
342 | return 0; | |
343 | len = min_t(ssize_t, len, size - *ppos); | |
344 | } | |
345 | ||
8ef445f0 TH |
346 | if (!len) |
347 | return 0; | |
348 | ||
349 | buf = kmalloc(len + 1, GFP_KERNEL); | |
350 | if (!buf) | |
351 | return -ENOMEM; | |
352 | ||
353 | if (copy_from_user(buf, user_buf, len)) { | |
354 | len = -EFAULT; | |
355 | goto out_free; | |
356 | } | |
357 | buf[len] = '\0'; /* guarantee string termination */ | |
358 | ||
f9b9a621 | 359 | len = flush_write_buffer(of, buf, *ppos, len); |
1da177e4 LT |
360 | if (len > 0) |
361 | *ppos += len; | |
8ef445f0 TH |
362 | out_free: |
363 | kfree(buf); | |
1da177e4 LT |
364 | return len; |
365 | } | |
366 | ||
73d97146 TH |
367 | static void sysfs_bin_vma_open(struct vm_area_struct *vma) |
368 | { | |
369 | struct file *file = vma->vm_file; | |
370 | struct sysfs_open_file *of = sysfs_of(file); | |
371 | ||
372 | if (!of->vm_ops) | |
373 | return; | |
374 | ||
375 | if (!sysfs_get_active(of->sd)) | |
376 | return; | |
377 | ||
378 | if (of->vm_ops->open) | |
379 | of->vm_ops->open(vma); | |
380 | ||
381 | sysfs_put_active(of->sd); | |
382 | } | |
383 | ||
384 | static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
385 | { | |
386 | struct file *file = vma->vm_file; | |
387 | struct sysfs_open_file *of = sysfs_of(file); | |
388 | int ret; | |
389 | ||
390 | if (!of->vm_ops) | |
391 | return VM_FAULT_SIGBUS; | |
392 | ||
393 | if (!sysfs_get_active(of->sd)) | |
394 | return VM_FAULT_SIGBUS; | |
395 | ||
396 | ret = VM_FAULT_SIGBUS; | |
397 | if (of->vm_ops->fault) | |
398 | ret = of->vm_ops->fault(vma, vmf); | |
399 | ||
400 | sysfs_put_active(of->sd); | |
401 | return ret; | |
402 | } | |
403 | ||
404 | static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma, | |
405 | struct vm_fault *vmf) | |
406 | { | |
407 | struct file *file = vma->vm_file; | |
408 | struct sysfs_open_file *of = sysfs_of(file); | |
409 | int ret; | |
410 | ||
411 | if (!of->vm_ops) | |
412 | return VM_FAULT_SIGBUS; | |
413 | ||
414 | if (!sysfs_get_active(of->sd)) | |
415 | return VM_FAULT_SIGBUS; | |
416 | ||
417 | ret = 0; | |
418 | if (of->vm_ops->page_mkwrite) | |
419 | ret = of->vm_ops->page_mkwrite(vma, vmf); | |
420 | else | |
421 | file_update_time(file); | |
422 | ||
423 | sysfs_put_active(of->sd); | |
424 | return ret; | |
425 | } | |
426 | ||
427 | static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr, | |
428 | void *buf, int len, int write) | |
429 | { | |
430 | struct file *file = vma->vm_file; | |
431 | struct sysfs_open_file *of = sysfs_of(file); | |
432 | int ret; | |
433 | ||
434 | if (!of->vm_ops) | |
435 | return -EINVAL; | |
436 | ||
437 | if (!sysfs_get_active(of->sd)) | |
438 | return -EINVAL; | |
439 | ||
440 | ret = -EINVAL; | |
441 | if (of->vm_ops->access) | |
442 | ret = of->vm_ops->access(vma, addr, buf, len, write); | |
443 | ||
444 | sysfs_put_active(of->sd); | |
445 | return ret; | |
446 | } | |
447 | ||
448 | #ifdef CONFIG_NUMA | |
449 | static int sysfs_bin_set_policy(struct vm_area_struct *vma, | |
450 | struct mempolicy *new) | |
451 | { | |
452 | struct file *file = vma->vm_file; | |
453 | struct sysfs_open_file *of = sysfs_of(file); | |
454 | int ret; | |
455 | ||
456 | if (!of->vm_ops) | |
457 | return 0; | |
458 | ||
459 | if (!sysfs_get_active(of->sd)) | |
460 | return -EINVAL; | |
461 | ||
462 | ret = 0; | |
463 | if (of->vm_ops->set_policy) | |
464 | ret = of->vm_ops->set_policy(vma, new); | |
465 | ||
466 | sysfs_put_active(of->sd); | |
467 | return ret; | |
468 | } | |
469 | ||
470 | static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma, | |
471 | unsigned long addr) | |
472 | { | |
473 | struct file *file = vma->vm_file; | |
474 | struct sysfs_open_file *of = sysfs_of(file); | |
475 | struct mempolicy *pol; | |
476 | ||
477 | if (!of->vm_ops) | |
478 | return vma->vm_policy; | |
479 | ||
480 | if (!sysfs_get_active(of->sd)) | |
481 | return vma->vm_policy; | |
482 | ||
483 | pol = vma->vm_policy; | |
484 | if (of->vm_ops->get_policy) | |
485 | pol = of->vm_ops->get_policy(vma, addr); | |
486 | ||
487 | sysfs_put_active(of->sd); | |
488 | return pol; | |
489 | } | |
490 | ||
491 | static int sysfs_bin_migrate(struct vm_area_struct *vma, const nodemask_t *from, | |
492 | const nodemask_t *to, unsigned long flags) | |
493 | { | |
494 | struct file *file = vma->vm_file; | |
495 | struct sysfs_open_file *of = sysfs_of(file); | |
496 | int ret; | |
497 | ||
498 | if (!of->vm_ops) | |
499 | return 0; | |
500 | ||
501 | if (!sysfs_get_active(of->sd)) | |
502 | return 0; | |
503 | ||
504 | ret = 0; | |
505 | if (of->vm_ops->migrate) | |
506 | ret = of->vm_ops->migrate(vma, from, to, flags); | |
507 | ||
508 | sysfs_put_active(of->sd); | |
509 | return ret; | |
510 | } | |
511 | #endif | |
512 | ||
513 | static const struct vm_operations_struct sysfs_bin_vm_ops = { | |
514 | .open = sysfs_bin_vma_open, | |
515 | .fault = sysfs_bin_fault, | |
516 | .page_mkwrite = sysfs_bin_page_mkwrite, | |
517 | .access = sysfs_bin_access, | |
518 | #ifdef CONFIG_NUMA | |
519 | .set_policy = sysfs_bin_set_policy, | |
520 | .get_policy = sysfs_bin_get_policy, | |
521 | .migrate = sysfs_bin_migrate, | |
522 | #endif | |
523 | }; | |
524 | ||
525 | static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma) | |
526 | { | |
527 | struct sysfs_open_file *of = sysfs_of(file); | |
7c6e2d36 TH |
528 | struct bin_attribute *battr = of->sd->priv; |
529 | struct kobject *kobj = of->sd->s_parent->priv; | |
73d97146 TH |
530 | int rc; |
531 | ||
532 | mutex_lock(&of->mutex); | |
533 | ||
534 | /* need of->sd for battr, its parent for kobj */ | |
535 | rc = -ENODEV; | |
536 | if (!sysfs_get_active(of->sd)) | |
537 | goto out_unlock; | |
538 | ||
73d97146 TH |
539 | if (!battr->mmap) |
540 | goto out_put; | |
541 | ||
542 | rc = battr->mmap(file, kobj, battr, vma); | |
543 | if (rc) | |
544 | goto out_put; | |
545 | ||
546 | /* | |
547 | * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() | |
548 | * to satisfy versions of X which crash if the mmap fails: that | |
549 | * substitutes a new vm_file, and we don't then want bin_vm_ops. | |
550 | */ | |
551 | if (vma->vm_file != file) | |
552 | goto out_put; | |
553 | ||
554 | rc = -EINVAL; | |
555 | if (of->mmapped && of->vm_ops != vma->vm_ops) | |
556 | goto out_put; | |
557 | ||
558 | /* | |
559 | * It is not possible to successfully wrap close. | |
560 | * So error if someone is trying to use close. | |
561 | */ | |
562 | rc = -EINVAL; | |
563 | if (vma->vm_ops && vma->vm_ops->close) | |
564 | goto out_put; | |
565 | ||
566 | rc = 0; | |
567 | of->mmapped = 1; | |
568 | of->vm_ops = vma->vm_ops; | |
569 | vma->vm_ops = &sysfs_bin_vm_ops; | |
570 | out_put: | |
571 | sysfs_put_active(of->sd); | |
572 | out_unlock: | |
573 | mutex_unlock(&of->mutex); | |
574 | ||
575 | return rc; | |
576 | } | |
577 | ||
85a4ffad TH |
578 | /** |
579 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
580 | * @sd: target sysfs_dirent | |
58282d8d | 581 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
582 | * |
583 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 584 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
585 | * |
586 | * LOCKING: | |
587 | * Kernel thread context (may sleep). | |
588 | * | |
589 | * RETURNS: | |
590 | * 0 on success, -errno on failure. | |
591 | */ | |
592 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 593 | struct sysfs_open_file *of) |
85a4ffad TH |
594 | { |
595 | struct sysfs_open_dirent *od, *new_od = NULL; | |
596 | ||
597 | retry: | |
c75ec764 | 598 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 599 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
600 | |
601 | if (!sd->s_attr.open && new_od) { | |
602 | sd->s_attr.open = new_od; | |
603 | new_od = NULL; | |
604 | } | |
605 | ||
606 | od = sd->s_attr.open; | |
607 | if (od) { | |
608 | atomic_inc(&od->refcnt); | |
58282d8d | 609 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
610 | } |
611 | ||
83db93f4 | 612 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 613 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
614 | |
615 | if (od) { | |
616 | kfree(new_od); | |
617 | return 0; | |
618 | } | |
619 | ||
620 | /* not there, initialize a new one and retry */ | |
621 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
622 | if (!new_od) | |
623 | return -ENOMEM; | |
624 | ||
625 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
626 | atomic_set(&new_od->event, 1); |
627 | init_waitqueue_head(&new_od->poll); | |
58282d8d | 628 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
629 | goto retry; |
630 | } | |
631 | ||
632 | /** | |
633 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
634 | * @sd: target sysfs_dirent | |
58282d8d | 635 | * @of: associated sysfs_open_file |
85a4ffad | 636 | * |
58282d8d TH |
637 | * Put @sd->s_attr.open and unlink @of from the files list. If |
638 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
639 | * |
640 | * LOCKING: | |
641 | * None. | |
642 | */ | |
643 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 644 | struct sysfs_open_file *of) |
85a4ffad TH |
645 | { |
646 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 647 | unsigned long flags; |
85a4ffad | 648 | |
c75ec764 | 649 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 650 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 651 | |
73d97146 TH |
652 | if (of) |
653 | list_del(&of->list); | |
654 | ||
85a4ffad TH |
655 | if (atomic_dec_and_test(&od->refcnt)) |
656 | sd->s_attr.open = NULL; | |
657 | else | |
658 | od = NULL; | |
659 | ||
83db93f4 | 660 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 661 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
662 | |
663 | kfree(od); | |
664 | } | |
665 | ||
94bebf4d | 666 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 667 | { |
3e519038 | 668 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
7c6e2d36 | 669 | struct kobject *kobj = attr_sd->s_parent->priv; |
58282d8d | 670 | struct sysfs_open_file *of; |
027a485d | 671 | bool has_read, has_write, has_mmap; |
000f2a4d | 672 | int error = -EACCES; |
1da177e4 | 673 | |
0ab66088 | 674 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 675 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 676 | return -ENODEV; |
1da177e4 | 677 | |
49fe6047 | 678 | if (sysfs_is_bin(attr_sd)) { |
7c6e2d36 | 679 | struct bin_attribute *battr = attr_sd->priv; |
1da177e4 | 680 | |
49fe6047 TH |
681 | has_read = battr->read || battr->mmap; |
682 | has_write = battr->write || battr->mmap; | |
027a485d | 683 | has_mmap = battr->mmap; |
49fe6047 TH |
684 | } else { |
685 | const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); | |
1da177e4 | 686 | |
49fe6047 TH |
687 | /* every kobject with an attribute needs a ktype assigned */ |
688 | if (WARN(!ops, KERN_ERR | |
689 | "missing sysfs attribute operations for kobject: %s\n", | |
690 | kobject_name(kobj))) | |
7b595756 | 691 | goto err_out; |
49fe6047 TH |
692 | |
693 | has_read = ops->show; | |
694 | has_write = ops->store; | |
027a485d | 695 | has_mmap = false; |
1da177e4 LT |
696 | } |
697 | ||
49fe6047 TH |
698 | /* check perms and supported operations */ |
699 | if ((file->f_mode & FMODE_WRITE) && | |
700 | (!(inode->i_mode & S_IWUGO) || !has_write)) | |
701 | goto err_out; | |
702 | ||
703 | if ((file->f_mode & FMODE_READ) && | |
704 | (!(inode->i_mode & S_IRUGO) || !has_read)) | |
705 | goto err_out; | |
706 | ||
13c589d5 | 707 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 708 | error = -ENOMEM; |
58282d8d TH |
709 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
710 | if (!of) | |
7b595756 | 711 | goto err_out; |
1da177e4 | 712 | |
027a485d TH |
713 | /* |
714 | * The following is done to give a different lockdep key to | |
715 | * @of->mutex for files which implement mmap. This is a rather | |
716 | * crude way to avoid false positive lockdep warning around | |
717 | * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and | |
718 | * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under | |
719 | * which mm->mmap_sem nests, while holding @of->mutex. As each | |
720 | * open file has a separate mutex, it's okay as long as those don't | |
721 | * happen on the same file. At this point, we can't easily give | |
722 | * each file a separate locking class. Let's differentiate on | |
723 | * whether the file has mmap or not for now. | |
724 | */ | |
725 | if (has_mmap) | |
726 | mutex_init(&of->mutex); | |
727 | else | |
728 | mutex_init(&of->mutex); | |
729 | ||
bcafe4ee TH |
730 | of->sd = attr_sd; |
731 | of->file = file; | |
13c589d5 TH |
732 | |
733 | /* | |
49fe6047 TH |
734 | * Always instantiate seq_file even if read access doesn't use |
735 | * seq_file or is not requested. This unifies private data access | |
736 | * and readable regular files are the vast majority anyway. | |
13c589d5 | 737 | */ |
49fe6047 | 738 | if (sysfs_is_bin(attr_sd)) |
c2b19daf | 739 | error = seq_open(file, NULL); |
49fe6047 | 740 | else |
c2b19daf | 741 | error = seq_open(file, &kernfs_seq_ops); |
13c589d5 TH |
742 | if (error) |
743 | goto err_free; | |
744 | ||
c2b19daf TH |
745 | ((struct seq_file *)file->private_data)->private = of; |
746 | ||
13c589d5 TH |
747 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ |
748 | if (file->f_mode & FMODE_WRITE) | |
749 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 750 | |
85a4ffad | 751 | /* make sure we have open dirent struct */ |
58282d8d | 752 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 753 | if (error) |
13c589d5 | 754 | goto err_close; |
85a4ffad | 755 | |
b05f0548 | 756 | /* open succeeded, put active references */ |
e72ceb8c | 757 | sysfs_put_active(attr_sd); |
0ab66088 TH |
758 | return 0; |
759 | ||
13c589d5 | 760 | err_close: |
c2b19daf | 761 | seq_release(inode, file); |
13c589d5 | 762 | err_free: |
58282d8d | 763 | kfree(of); |
13c589d5 | 764 | err_out: |
e72ceb8c | 765 | sysfs_put_active(attr_sd); |
1da177e4 LT |
766 | return error; |
767 | } | |
768 | ||
85a4ffad | 769 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 770 | { |
85a4ffad | 771 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 772 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 773 | |
58282d8d | 774 | sysfs_put_open_dirent(sd, of); |
c2b19daf | 775 | seq_release(inode, filp); |
58282d8d | 776 | kfree(of); |
50ab1a72 | 777 | |
1da177e4 LT |
778 | return 0; |
779 | } | |
780 | ||
73d97146 TH |
781 | void sysfs_unmap_bin_file(struct sysfs_dirent *sd) |
782 | { | |
783 | struct sysfs_open_dirent *od; | |
784 | struct sysfs_open_file *of; | |
785 | ||
786 | if (!sysfs_is_bin(sd)) | |
787 | return; | |
788 | ||
789 | spin_lock_irq(&sysfs_open_dirent_lock); | |
790 | od = sd->s_attr.open; | |
791 | if (od) | |
792 | atomic_inc(&od->refcnt); | |
793 | spin_unlock_irq(&sysfs_open_dirent_lock); | |
794 | if (!od) | |
795 | return; | |
796 | ||
797 | mutex_lock(&sysfs_open_file_mutex); | |
798 | list_for_each_entry(of, &od->files, list) { | |
799 | struct inode *inode = file_inode(of->file); | |
800 | unmap_mapping_range(inode->i_mapping, 0, 0, 1); | |
801 | } | |
802 | mutex_unlock(&sysfs_open_file_mutex); | |
803 | ||
804 | sysfs_put_open_dirent(sd, NULL); | |
805 | } | |
806 | ||
4508a7a7 N |
807 | /* Sysfs attribute files are pollable. The idea is that you read |
808 | * the content and then you use 'poll' or 'select' to wait for | |
809 | * the content to change. When the content changes (assuming the | |
810 | * manager for the kobject supports notification), poll will | |
811 | * return POLLERR|POLLPRI, and select will return the fd whether | |
812 | * it is waiting for read, write, or exceptions. | |
813 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 814 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
815 | * Reminder: this only works for attributes which actively support |
816 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 817 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
818 | * an appropriate error code). When in doubt, set a suitable timeout value. |
819 | */ | |
820 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
821 | { | |
13c589d5 | 822 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 823 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 824 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
825 | |
826 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 827 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 828 | goto trigger; |
4508a7a7 | 829 | |
a4e8b912 | 830 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 831 | |
e72ceb8c | 832 | sysfs_put_active(attr_sd); |
0ab66088 | 833 | |
58282d8d | 834 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 835 | goto trigger; |
4508a7a7 | 836 | |
1af3557a | 837 | return DEFAULT_POLLMASK; |
0ab66088 TH |
838 | |
839 | trigger: | |
1af3557a | 840 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
841 | } |
842 | ||
f1282c84 NB |
843 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
844 | { | |
845 | struct sysfs_open_dirent *od; | |
83db93f4 | 846 | unsigned long flags; |
f1282c84 | 847 | |
83db93f4 | 848 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 849 | |
fc60bb83 ND |
850 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
851 | od = sd->s_attr.open; | |
852 | if (od) { | |
853 | atomic_inc(&od->event); | |
854 | wake_up_interruptible(&od->poll); | |
855 | } | |
f1282c84 NB |
856 | } |
857 | ||
83db93f4 | 858 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
859 | } |
860 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
861 | ||
8c0e3998 | 862 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 863 | { |
51225039 | 864 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 865 | |
51225039 TH |
866 | mutex_lock(&sysfs_mutex); |
867 | ||
868 | if (sd && dir) | |
cfec0bc8 | 869 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 870 | if (sd && attr) |
cfec0bc8 | 871 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
872 | if (sd) |
873 | sysfs_notify_dirent(sd); | |
51225039 TH |
874 | |
875 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
876 | } |
877 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
878 | ||
4b6f5d20 | 879 | const struct file_operations sysfs_file_operations = { |
c2b19daf | 880 | .read = kernfs_file_read, |
1da177e4 | 881 | .write = sysfs_write_file, |
044e3bc3 | 882 | .llseek = generic_file_llseek, |
1da177e4 LT |
883 | .open = sysfs_open_file, |
884 | .release = sysfs_release, | |
4508a7a7 | 885 | .poll = sysfs_poll, |
1da177e4 LT |
886 | }; |
887 | ||
f9b9a621 | 888 | const struct file_operations sysfs_bin_operations = { |
c2b19daf | 889 | .read = kernfs_file_read, |
f9b9a621 TH |
890 | .write = sysfs_write_file, |
891 | .llseek = generic_file_llseek, | |
73d97146 | 892 | .mmap = sysfs_bin_mmap, |
49fe6047 TH |
893 | .open = sysfs_open_file, |
894 | .release = sysfs_release, | |
895 | .poll = sysfs_poll, | |
f9b9a621 TH |
896 | }; |
897 | ||
58292cbe TH |
898 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
899 | const struct attribute *attr, int type, | |
900 | umode_t amode, const void *ns) | |
1da177e4 | 901 | { |
0f423895 | 902 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 903 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 904 | struct sysfs_dirent *sd; |
23dc2799 | 905 | int rc; |
1da177e4 | 906 | |
3007e997 TH |
907 | sd = sysfs_new_dirent(attr->name, mode, type); |
908 | if (!sd) | |
909 | return -ENOMEM; | |
487505c2 EB |
910 | |
911 | sd->s_ns = ns; | |
7c6e2d36 | 912 | sd->priv = (void *)attr; |
a2db6842 | 913 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 914 | |
d69ac5a0 TH |
915 | sysfs_addrm_start(&acxt); |
916 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 917 | sysfs_addrm_finish(&acxt); |
a26cd722 | 918 | |
23dc2799 | 919 | if (rc) |
967e35dc | 920 | sysfs_put(sd); |
3007e997 | 921 | |
23dc2799 | 922 | return rc; |
1da177e4 LT |
923 | } |
924 | ||
925 | ||
0f423895 JB |
926 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
927 | int type) | |
928 | { | |
58292cbe | 929 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
930 | } |
931 | ||
1da177e4 | 932 | /** |
58292cbe TH |
933 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
934 | * @kobj: object we're creating for | |
935 | * @attr: attribute descriptor | |
936 | * @ns: namespace the new file should belong to | |
1da177e4 | 937 | */ |
58292cbe TH |
938 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
939 | const void *ns) | |
1da177e4 | 940 | { |
608e266a | 941 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 942 | |
58292cbe TH |
943 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
944 | attr->mode, ns); | |
1da177e4 LT |
945 | |
946 | } | |
58292cbe | 947 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 948 | |
1c205ae1 AK |
949 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
950 | { | |
951 | int err = 0; | |
952 | int i; | |
953 | ||
954 | for (i = 0; ptr[i] && !err; i++) | |
955 | err = sysfs_create_file(kobj, ptr[i]); | |
956 | if (err) | |
957 | while (--i >= 0) | |
958 | sysfs_remove_file(kobj, ptr[i]); | |
959 | return err; | |
960 | } | |
1b866757 | 961 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 962 | |
dfa87c82 AS |
963 | /** |
964 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
965 | * @kobj: object we're acting for. | |
966 | * @attr: attribute descriptor. | |
967 | * @group: group name. | |
968 | */ | |
969 | int sysfs_add_file_to_group(struct kobject *kobj, | |
970 | const struct attribute *attr, const char *group) | |
971 | { | |
608e266a | 972 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
973 | int error; |
974 | ||
11f24fbd | 975 | if (group) |
388975cc | 976 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
977 | else |
978 | dir_sd = sysfs_get(kobj->sd); | |
979 | ||
608e266a TH |
980 | if (!dir_sd) |
981 | return -ENOENT; | |
982 | ||
983 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
984 | sysfs_put(dir_sd); | |
985 | ||
dfa87c82 AS |
986 | return error; |
987 | } | |
988 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
989 | ||
31e5abe9 KS |
990 | /** |
991 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
992 | * @kobj: object we're acting for. | |
993 | * @attr: attribute descriptor. | |
994 | * @mode: file permissions. | |
995 | * | |
996 | */ | |
49c19400 | 997 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 998 | umode_t mode) |
31e5abe9 | 999 | { |
06fc0d66 | 1000 | struct sysfs_dirent *sd; |
bc062b1b | 1001 | struct iattr newattrs; |
51225039 TH |
1002 | int rc; |
1003 | ||
5d60418e | 1004 | sd = sysfs_get_dirent(kobj->sd, attr->name); |
06fc0d66 | 1005 | if (!sd) |
5d60418e | 1006 | return -ENOENT; |
f88123ea | 1007 | |
06fc0d66 | 1008 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 1009 | newattrs.ia_valid = ATTR_MODE; |
f88123ea | 1010 | |
5d60418e TH |
1011 | rc = kernfs_setattr(sd, &newattrs); |
1012 | ||
1013 | sysfs_put(sd); | |
51225039 | 1014 | return rc; |
31e5abe9 KS |
1015 | } |
1016 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
1017 | ||
1da177e4 | 1018 | /** |
58292cbe TH |
1019 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
1020 | * @kobj: object we're acting for | |
1021 | * @attr: attribute descriptor | |
1022 | * @ns: namespace tag of the file to remove | |
1da177e4 | 1023 | * |
58292cbe | 1024 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 1025 | */ |
58292cbe TH |
1026 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
1027 | const void *ns) | |
1da177e4 | 1028 | { |
58292cbe | 1029 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 1030 | |
879f40d1 | 1031 | kernfs_remove_by_name_ns(dir_sd, attr->name, ns); |
1da177e4 | 1032 | } |
58292cbe | 1033 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 1034 | |
1b18dc2b | 1035 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
1036 | { |
1037 | int i; | |
1038 | for (i = 0; ptr[i]; i++) | |
1039 | sysfs_remove_file(kobj, ptr[i]); | |
1040 | } | |
1b866757 | 1041 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 1042 | |
dfa87c82 AS |
1043 | /** |
1044 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
1045 | * @kobj: object we're acting for. | |
1046 | * @attr: attribute descriptor. | |
1047 | * @group: group name. | |
1048 | */ | |
1049 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
1050 | const struct attribute *attr, const char *group) | |
1051 | { | |
608e266a | 1052 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 1053 | |
11f24fbd | 1054 | if (group) |
388975cc | 1055 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
1056 | else |
1057 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 1058 | if (dir_sd) { |
879f40d1 | 1059 | kernfs_remove_by_name(dir_sd, attr->name); |
608e266a | 1060 | sysfs_put(dir_sd); |
dfa87c82 AS |
1061 | } |
1062 | } | |
1063 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
1064 | ||
3124eb16 TH |
1065 | /** |
1066 | * sysfs_create_bin_file - create binary file for object. | |
1067 | * @kobj: object. | |
1068 | * @attr: attribute descriptor. | |
1069 | */ | |
1070 | int sysfs_create_bin_file(struct kobject *kobj, | |
1071 | const struct bin_attribute *attr) | |
1072 | { | |
1073 | BUG_ON(!kobj || !kobj->sd || !attr); | |
1074 | ||
1075 | return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); | |
1076 | } | |
1077 | EXPORT_SYMBOL_GPL(sysfs_create_bin_file); | |
1078 | ||
1079 | /** | |
1080 | * sysfs_remove_bin_file - remove binary file for object. | |
1081 | * @kobj: object. | |
1082 | * @attr: attribute descriptor. | |
1083 | */ | |
1084 | void sysfs_remove_bin_file(struct kobject *kobj, | |
1085 | const struct bin_attribute *attr) | |
1086 | { | |
879f40d1 | 1087 | kernfs_remove_by_name(kobj->sd, attr->attr.name); |
3124eb16 TH |
1088 | } |
1089 | EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); | |
1090 | ||
d9a9cdfb | 1091 | struct sysfs_schedule_callback_struct { |
66942064 AC |
1092 | struct list_head workq_list; |
1093 | struct kobject *kobj; | |
d9a9cdfb AS |
1094 | void (*func)(void *); |
1095 | void *data; | |
523ded71 | 1096 | struct module *owner; |
d9a9cdfb AS |
1097 | struct work_struct work; |
1098 | }; | |
1099 | ||
d110271e | 1100 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
1101 | static DEFINE_MUTEX(sysfs_workq_mutex); |
1102 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
1103 | static void sysfs_schedule_callback_work(struct work_struct *work) |
1104 | { | |
1105 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
1106 | struct sysfs_schedule_callback_struct, work); | |
1107 | ||
1108 | (ss->func)(ss->data); | |
1109 | kobject_put(ss->kobj); | |
523ded71 | 1110 | module_put(ss->owner); |
66942064 AC |
1111 | mutex_lock(&sysfs_workq_mutex); |
1112 | list_del(&ss->workq_list); | |
1113 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
1114 | kfree(ss); |
1115 | } | |
1116 | ||
1117 | /** | |
1118 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
1119 | * @kobj: object we're acting for. | |
1120 | * @func: callback function to invoke later. | |
1121 | * @data: argument to pass to @func. | |
523ded71 | 1122 | * @owner: module owning the callback code |
d9a9cdfb AS |
1123 | * |
1124 | * sysfs attribute methods must not unregister themselves or their parent | |
1125 | * kobject (which would amount to the same thing). Attempts to do so will | |
1126 | * deadlock, since unregistration is mutually exclusive with driver | |
1127 | * callbacks. | |
1128 | * | |
1129 | * Instead methods can call this routine, which will attempt to allocate | |
1130 | * and schedule a workqueue request to call back @func with @data as its | |
1131 | * argument in the workqueue's process context. @kobj will be pinned | |
1132 | * until @func returns. | |
1133 | * | |
1134 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
1135 | * be allocated, -ENODEV if a reference to @owner isn't available, |
1136 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
1137 | */ |
1138 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 1139 | void *data, struct module *owner) |
d9a9cdfb | 1140 | { |
66942064 | 1141 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 1142 | |
523ded71 AS |
1143 | if (!try_module_get(owner)) |
1144 | return -ENODEV; | |
66942064 AC |
1145 | |
1146 | mutex_lock(&sysfs_workq_mutex); | |
1147 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
1148 | if (ss->kobj == kobj) { | |
d110271e | 1149 | module_put(owner); |
66942064 AC |
1150 | mutex_unlock(&sysfs_workq_mutex); |
1151 | return -EAGAIN; | |
1152 | } | |
1153 | mutex_unlock(&sysfs_workq_mutex); | |
1154 | ||
d110271e | 1155 | if (sysfs_workqueue == NULL) { |
086a377e | 1156 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
1157 | if (sysfs_workqueue == NULL) { |
1158 | module_put(owner); | |
1159 | return -ENOMEM; | |
1160 | } | |
1161 | } | |
1162 | ||
d9a9cdfb | 1163 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
1164 | if (!ss) { |
1165 | module_put(owner); | |
d9a9cdfb | 1166 | return -ENOMEM; |
523ded71 | 1167 | } |
d9a9cdfb AS |
1168 | kobject_get(kobj); |
1169 | ss->kobj = kobj; | |
1170 | ss->func = func; | |
1171 | ss->data = data; | |
523ded71 | 1172 | ss->owner = owner; |
d9a9cdfb | 1173 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
1174 | INIT_LIST_HEAD(&ss->workq_list); |
1175 | mutex_lock(&sysfs_workq_mutex); | |
1176 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
1177 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 1178 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
1179 | return 0; |
1180 | } | |
1181 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |