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 | ||
f9b9a621 TH |
50 | static bool sysfs_is_bin(struct sysfs_dirent *sd) |
51 | { | |
52 | return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR; | |
53 | } | |
54 | ||
13c589d5 TH |
55 | static struct sysfs_open_file *sysfs_of(struct file *file) |
56 | { | |
57 | return ((struct seq_file *)file->private_data)->private; | |
58 | } | |
59 | ||
375b611e TH |
60 | /* |
61 | * Determine ktype->sysfs_ops for the given sysfs_dirent. This function | |
62 | * must be called while holding an active reference. | |
63 | */ | |
64 | static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) | |
65 | { | |
7c6e2d36 | 66 | struct kobject *kobj = sd->s_parent->priv; |
375b611e | 67 | |
785a162d TH |
68 | if (!sysfs_ignore_lockdep(sd)) |
69 | lockdep_assert_held(sd); | |
375b611e TH |
70 | return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; |
71 | } | |
72 | ||
13c589d5 TH |
73 | /* |
74 | * Reads on sysfs are handled through seq_file, which takes care of hairy | |
75 | * details like buffering and seeking. The following function pipes | |
76 | * sysfs_ops->show() result through seq_file. | |
1da177e4 | 77 | */ |
c2b19daf | 78 | static int sysfs_kf_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 79 | { |
13c589d5 | 80 | struct sysfs_open_file *of = sf->private; |
7c6e2d36 | 81 | struct kobject *kobj = of->sd->s_parent->priv; |
c2b19daf | 82 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
1da177e4 | 83 | ssize_t count; |
c2b19daf | 84 | char *buf; |
1da177e4 | 85 | |
13c589d5 TH |
86 | /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
87 | count = seq_get_buf(sf, &buf); | |
88 | if (count < PAGE_SIZE) { | |
89 | seq_commit(sf, -1); | |
90 | return 0; | |
91 | } | |
1da177e4 | 92 | |
13c589d5 | 93 | /* |
c2b19daf TH |
94 | * Invoke show(). Control may reach here via seq file lseek even |
95 | * if @ops->show() isn't implemented. | |
13c589d5 | 96 | */ |
c2b19daf | 97 | if (ops->show) { |
7c6e2d36 | 98 | count = ops->show(kobj, of->sd->priv, buf); |
c2b19daf TH |
99 | if (count < 0) |
100 | return count; | |
101 | } | |
0ab66088 | 102 | |
8118a859 MX |
103 | /* |
104 | * The code works fine with PAGE_SIZE return but it's likely to | |
105 | * indicate truncated result or overflow in normal use cases. | |
106 | */ | |
815d2d50 AM |
107 | if (count >= (ssize_t)PAGE_SIZE) { |
108 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
109 | (unsigned long)ops->show); | |
110 | /* Try to struggle along */ | |
111 | count = PAGE_SIZE - 1; | |
112 | } | |
13c589d5 TH |
113 | seq_commit(sf, count); |
114 | return 0; | |
1da177e4 LT |
115 | } |
116 | ||
c2b19daf TH |
117 | static ssize_t sysfs_kf_bin_read(struct sysfs_open_file *of, char *buf, |
118 | size_t count, loff_t pos) | |
2f0c6b75 | 119 | { |
7c6e2d36 TH |
120 | struct bin_attribute *battr = of->sd->priv; |
121 | struct kobject *kobj = of->sd->s_parent->priv; | |
c2b19daf | 122 | loff_t size = file_inode(of->file)->i_size; |
2f0c6b75 | 123 | |
c2b19daf | 124 | if (!count) |
2f0c6b75 TH |
125 | return 0; |
126 | ||
127 | if (size) { | |
c2b19daf | 128 | if (pos > size) |
2f0c6b75 | 129 | return 0; |
c2b19daf TH |
130 | if (pos + count > size) |
131 | count = size - pos; | |
2f0c6b75 TH |
132 | } |
133 | ||
c2b19daf TH |
134 | if (!battr->read) |
135 | return -EIO; | |
136 | ||
137 | return battr->read(of->file, kobj, battr, buf, pos, count); | |
138 | } | |
139 | ||
140 | static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) | |
141 | { | |
142 | struct sysfs_open_file *of = sf->private; | |
143 | ||
144 | /* | |
145 | * @of->mutex nests outside active ref and is just to ensure that | |
146 | * the ops aren't called concurrently for the same open file. | |
147 | */ | |
148 | mutex_lock(&of->mutex); | |
149 | if (!sysfs_get_active(of->sd)) | |
150 | return ERR_PTR(-ENODEV); | |
151 | ||
152 | /* | |
153 | * The same behavior and code as single_open(). Returns !NULL if | |
154 | * pos is at the beginning; otherwise, NULL. | |
155 | */ | |
156 | return NULL + !*ppos; | |
157 | } | |
158 | ||
159 | static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) | |
160 | { | |
161 | /* | |
162 | * The same behavior and code as single_open(), always terminate | |
163 | * after the initial read. | |
164 | */ | |
165 | ++*ppos; | |
166 | return NULL; | |
167 | } | |
168 | ||
169 | static void kernfs_seq_stop(struct seq_file *sf, void *v) | |
170 | { | |
171 | struct sysfs_open_file *of = sf->private; | |
172 | ||
173 | sysfs_put_active(of->sd); | |
174 | mutex_unlock(&of->mutex); | |
175 | } | |
176 | ||
177 | static int kernfs_seq_show(struct seq_file *sf, void *v) | |
178 | { | |
179 | struct sysfs_open_file *of = sf->private; | |
180 | ||
181 | of->event = atomic_read(&of->sd->s_attr.open->event); | |
182 | ||
183 | return sysfs_kf_seq_show(sf, v); | |
184 | } | |
185 | ||
186 | static const struct seq_operations kernfs_seq_ops = { | |
187 | .start = kernfs_seq_start, | |
188 | .next = kernfs_seq_next, | |
189 | .stop = kernfs_seq_stop, | |
190 | .show = kernfs_seq_show, | |
191 | }; | |
192 | ||
193 | /* | |
194 | * As reading a bin file can have side-effects, the exact offset and bytes | |
195 | * specified in read(2) call should be passed to the read callback making | |
196 | * it difficult to use seq_file. Implement simplistic custom buffering for | |
197 | * bin files. | |
198 | */ | |
199 | static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, | |
200 | char __user *user_buf, size_t count, | |
201 | loff_t *ppos) | |
202 | { | |
203 | ssize_t len = min_t(size_t, count, PAGE_SIZE); | |
204 | char *buf; | |
205 | ||
206 | buf = kmalloc(len, GFP_KERNEL); | |
2f0c6b75 TH |
207 | if (!buf) |
208 | return -ENOMEM; | |
209 | ||
c2b19daf TH |
210 | /* |
211 | * @of->mutex nests outside active ref and is just to ensure that | |
212 | * the ops aren't called concurrently for the same open file. | |
213 | */ | |
2f0c6b75 TH |
214 | mutex_lock(&of->mutex); |
215 | if (!sysfs_get_active(of->sd)) { | |
c2b19daf | 216 | len = -ENODEV; |
2f0c6b75 TH |
217 | mutex_unlock(&of->mutex); |
218 | goto out_free; | |
219 | } | |
220 | ||
c2b19daf | 221 | len = sysfs_kf_bin_read(of, buf, len, *ppos); |
2f0c6b75 TH |
222 | |
223 | sysfs_put_active(of->sd); | |
224 | mutex_unlock(&of->mutex); | |
225 | ||
c2b19daf | 226 | if (len < 0) |
2f0c6b75 TH |
227 | goto out_free; |
228 | ||
c2b19daf TH |
229 | if (copy_to_user(user_buf, buf, len)) { |
230 | len = -EFAULT; | |
2f0c6b75 TH |
231 | goto out_free; |
232 | } | |
233 | ||
c2b19daf | 234 | *ppos += len; |
2f0c6b75 TH |
235 | |
236 | out_free: | |
237 | kfree(buf); | |
c2b19daf TH |
238 | return len; |
239 | } | |
240 | ||
241 | /** | |
242 | * kernfs_file_read - kernfs vfs read callback | |
243 | * @file: file pointer | |
244 | * @user_buf: data to write | |
245 | * @count: number of bytes | |
246 | * @ppos: starting offset | |
247 | */ | |
248 | static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, | |
249 | size_t count, loff_t *ppos) | |
250 | { | |
251 | struct sysfs_open_file *of = sysfs_of(file); | |
252 | ||
253 | if (sysfs_is_bin(of->sd)) | |
254 | return kernfs_file_direct_read(of, user_buf, count, ppos); | |
255 | else | |
256 | return seq_read(file, user_buf, count, ppos); | |
2f0c6b75 TH |
257 | } |
258 | ||
50b38ca0 TH |
259 | /* kernfs write callback for regular sysfs files */ |
260 | static ssize_t sysfs_kf_write(struct sysfs_open_file *of, char *buf, | |
261 | size_t count, loff_t pos) | |
1da177e4 | 262 | { |
50b38ca0 | 263 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
7c6e2d36 | 264 | struct kobject *kobj = of->sd->s_parent->priv; |
0ab66088 | 265 | |
50b38ca0 TH |
266 | if (!count) |
267 | return 0; | |
0ab66088 | 268 | |
50b38ca0 TH |
269 | return ops->store(kobj, of->sd->priv, buf, count); |
270 | } | |
f9b9a621 | 271 | |
50b38ca0 TH |
272 | /* kernfs write callback for bin sysfs files */ |
273 | static ssize_t sysfs_kf_bin_write(struct sysfs_open_file *of, char *buf, | |
274 | size_t count, loff_t pos) | |
275 | { | |
276 | struct bin_attribute *battr = of->sd->priv; | |
277 | struct kobject *kobj = of->sd->s_parent->priv; | |
278 | loff_t size = file_inode(of->file)->i_size; | |
f9b9a621 | 279 | |
50b38ca0 TH |
280 | if (size) { |
281 | if (size <= pos) | |
282 | return 0; | |
283 | count = min_t(ssize_t, count, size - pos); | |
f9b9a621 | 284 | } |
50b38ca0 TH |
285 | if (!count) |
286 | return 0; | |
0ab66088 | 287 | |
50b38ca0 TH |
288 | if (!battr->write) |
289 | return -EIO; | |
1da177e4 | 290 | |
50b38ca0 | 291 | return battr->write(of->file, kobj, battr, buf, pos, count); |
1da177e4 LT |
292 | } |
293 | ||
1da177e4 | 294 | /** |
50b38ca0 | 295 | * kernfs_file_write - kernfs vfs write callback |
8ef445f0 TH |
296 | * @file: file pointer |
297 | * @user_buf: data to write | |
298 | * @count: number of bytes | |
299 | * @ppos: starting offset | |
300 | * | |
50b38ca0 TH |
301 | * Copy data in from userland and pass it to the matching kernfs write |
302 | * operation. | |
1da177e4 | 303 | * |
8ef445f0 TH |
304 | * There is no easy way for us to know if userspace is only doing a partial |
305 | * write, so we don't support them. We expect the entire buffer to come on | |
306 | * the first write. Hint: if you're writing a value, first read the file, | |
307 | * modify only the the value you're changing, then write entire buffer | |
308 | * back. | |
1da177e4 | 309 | */ |
50b38ca0 TH |
310 | static ssize_t kernfs_file_write(struct file *file, const char __user *user_buf, |
311 | size_t count, loff_t *ppos) | |
1da177e4 | 312 | { |
13c589d5 | 313 | struct sysfs_open_file *of = sysfs_of(file); |
f9b9a621 | 314 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
8ef445f0 | 315 | char *buf; |
1da177e4 | 316 | |
8ef445f0 TH |
317 | buf = kmalloc(len + 1, GFP_KERNEL); |
318 | if (!buf) | |
319 | return -ENOMEM; | |
320 | ||
321 | if (copy_from_user(buf, user_buf, len)) { | |
322 | len = -EFAULT; | |
323 | goto out_free; | |
324 | } | |
325 | buf[len] = '\0'; /* guarantee string termination */ | |
326 | ||
50b38ca0 TH |
327 | /* |
328 | * @of->mutex nests outside active ref and is just to ensure that | |
329 | * the ops aren't called concurrently for the same open file. | |
330 | */ | |
331 | mutex_lock(&of->mutex); | |
332 | if (!sysfs_get_active(of->sd)) { | |
333 | mutex_unlock(&of->mutex); | |
334 | len = -ENODEV; | |
335 | goto out_free; | |
336 | } | |
337 | ||
338 | if (sysfs_is_bin(of->sd)) | |
339 | len = sysfs_kf_bin_write(of, buf, len, *ppos); | |
340 | else | |
341 | len = sysfs_kf_write(of, buf, len, *ppos); | |
342 | ||
343 | sysfs_put_active(of->sd); | |
344 | mutex_unlock(&of->mutex); | |
345 | ||
1da177e4 LT |
346 | if (len > 0) |
347 | *ppos += len; | |
8ef445f0 TH |
348 | out_free: |
349 | kfree(buf); | |
1da177e4 LT |
350 | return len; |
351 | } | |
352 | ||
fdbffaa4 TH |
353 | static int sysfs_kf_bin_mmap(struct sysfs_open_file *of, |
354 | struct vm_area_struct *vma) | |
355 | { | |
356 | struct bin_attribute *battr = of->sd->priv; | |
357 | struct kobject *kobj = of->sd->s_parent->priv; | |
358 | ||
359 | if (!battr->mmap) | |
360 | return -ENODEV; | |
361 | ||
362 | return battr->mmap(of->file, kobj, battr, vma); | |
363 | } | |
364 | ||
365 | static void kernfs_vma_open(struct vm_area_struct *vma) | |
73d97146 TH |
366 | { |
367 | struct file *file = vma->vm_file; | |
368 | struct sysfs_open_file *of = sysfs_of(file); | |
369 | ||
370 | if (!of->vm_ops) | |
371 | return; | |
372 | ||
373 | if (!sysfs_get_active(of->sd)) | |
374 | return; | |
375 | ||
376 | if (of->vm_ops->open) | |
377 | of->vm_ops->open(vma); | |
378 | ||
379 | sysfs_put_active(of->sd); | |
380 | } | |
381 | ||
fdbffaa4 | 382 | static int kernfs_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
73d97146 TH |
383 | { |
384 | struct file *file = vma->vm_file; | |
385 | struct sysfs_open_file *of = sysfs_of(file); | |
386 | int ret; | |
387 | ||
388 | if (!of->vm_ops) | |
389 | return VM_FAULT_SIGBUS; | |
390 | ||
391 | if (!sysfs_get_active(of->sd)) | |
392 | return VM_FAULT_SIGBUS; | |
393 | ||
394 | ret = VM_FAULT_SIGBUS; | |
395 | if (of->vm_ops->fault) | |
396 | ret = of->vm_ops->fault(vma, vmf); | |
397 | ||
398 | sysfs_put_active(of->sd); | |
399 | return ret; | |
400 | } | |
401 | ||
fdbffaa4 TH |
402 | static int kernfs_vma_page_mkwrite(struct vm_area_struct *vma, |
403 | struct vm_fault *vmf) | |
73d97146 TH |
404 | { |
405 | struct file *file = vma->vm_file; | |
406 | struct sysfs_open_file *of = sysfs_of(file); | |
407 | int ret; | |
408 | ||
409 | if (!of->vm_ops) | |
410 | return VM_FAULT_SIGBUS; | |
411 | ||
412 | if (!sysfs_get_active(of->sd)) | |
413 | return VM_FAULT_SIGBUS; | |
414 | ||
415 | ret = 0; | |
416 | if (of->vm_ops->page_mkwrite) | |
417 | ret = of->vm_ops->page_mkwrite(vma, vmf); | |
418 | else | |
419 | file_update_time(file); | |
420 | ||
421 | sysfs_put_active(of->sd); | |
422 | return ret; | |
423 | } | |
424 | ||
fdbffaa4 TH |
425 | static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr, |
426 | void *buf, int len, int write) | |
73d97146 TH |
427 | { |
428 | struct file *file = vma->vm_file; | |
429 | struct sysfs_open_file *of = sysfs_of(file); | |
430 | int ret; | |
431 | ||
432 | if (!of->vm_ops) | |
433 | return -EINVAL; | |
434 | ||
435 | if (!sysfs_get_active(of->sd)) | |
436 | return -EINVAL; | |
437 | ||
438 | ret = -EINVAL; | |
439 | if (of->vm_ops->access) | |
440 | ret = of->vm_ops->access(vma, addr, buf, len, write); | |
441 | ||
442 | sysfs_put_active(of->sd); | |
443 | return ret; | |
444 | } | |
445 | ||
446 | #ifdef CONFIG_NUMA | |
fdbffaa4 TH |
447 | static int kernfs_vma_set_policy(struct vm_area_struct *vma, |
448 | struct mempolicy *new) | |
73d97146 TH |
449 | { |
450 | struct file *file = vma->vm_file; | |
451 | struct sysfs_open_file *of = sysfs_of(file); | |
452 | int ret; | |
453 | ||
454 | if (!of->vm_ops) | |
455 | return 0; | |
456 | ||
457 | if (!sysfs_get_active(of->sd)) | |
458 | return -EINVAL; | |
459 | ||
460 | ret = 0; | |
461 | if (of->vm_ops->set_policy) | |
462 | ret = of->vm_ops->set_policy(vma, new); | |
463 | ||
464 | sysfs_put_active(of->sd); | |
465 | return ret; | |
466 | } | |
467 | ||
fdbffaa4 TH |
468 | static struct mempolicy *kernfs_vma_get_policy(struct vm_area_struct *vma, |
469 | unsigned long addr) | |
73d97146 TH |
470 | { |
471 | struct file *file = vma->vm_file; | |
472 | struct sysfs_open_file *of = sysfs_of(file); | |
473 | struct mempolicy *pol; | |
474 | ||
475 | if (!of->vm_ops) | |
476 | return vma->vm_policy; | |
477 | ||
478 | if (!sysfs_get_active(of->sd)) | |
479 | return vma->vm_policy; | |
480 | ||
481 | pol = vma->vm_policy; | |
482 | if (of->vm_ops->get_policy) | |
483 | pol = of->vm_ops->get_policy(vma, addr); | |
484 | ||
485 | sysfs_put_active(of->sd); | |
486 | return pol; | |
487 | } | |
488 | ||
fdbffaa4 TH |
489 | static int kernfs_vma_migrate(struct vm_area_struct *vma, |
490 | const nodemask_t *from, const nodemask_t *to, | |
491 | unsigned long flags) | |
73d97146 TH |
492 | { |
493 | struct file *file = vma->vm_file; | |
494 | struct sysfs_open_file *of = sysfs_of(file); | |
495 | int ret; | |
496 | ||
497 | if (!of->vm_ops) | |
498 | return 0; | |
499 | ||
500 | if (!sysfs_get_active(of->sd)) | |
501 | return 0; | |
502 | ||
503 | ret = 0; | |
504 | if (of->vm_ops->migrate) | |
505 | ret = of->vm_ops->migrate(vma, from, to, flags); | |
506 | ||
507 | sysfs_put_active(of->sd); | |
508 | return ret; | |
509 | } | |
510 | #endif | |
511 | ||
fdbffaa4 TH |
512 | static const struct vm_operations_struct kernfs_vm_ops = { |
513 | .open = kernfs_vma_open, | |
514 | .fault = kernfs_vma_fault, | |
515 | .page_mkwrite = kernfs_vma_page_mkwrite, | |
516 | .access = kernfs_vma_access, | |
73d97146 | 517 | #ifdef CONFIG_NUMA |
fdbffaa4 TH |
518 | .set_policy = kernfs_vma_set_policy, |
519 | .get_policy = kernfs_vma_get_policy, | |
520 | .migrate = kernfs_vma_migrate, | |
73d97146 TH |
521 | #endif |
522 | }; | |
523 | ||
fdbffaa4 | 524 | static int kernfs_file_mmap(struct file *file, struct vm_area_struct *vma) |
73d97146 TH |
525 | { |
526 | struct sysfs_open_file *of = sysfs_of(file); | |
73d97146 TH |
527 | int rc; |
528 | ||
529 | mutex_lock(&of->mutex); | |
530 | ||
73d97146 TH |
531 | rc = -ENODEV; |
532 | if (!sysfs_get_active(of->sd)) | |
533 | goto out_unlock; | |
534 | ||
fdbffaa4 TH |
535 | if (sysfs_is_bin(of->sd)) |
536 | rc = sysfs_kf_bin_mmap(of, vma); | |
73d97146 TH |
537 | if (rc) |
538 | goto out_put; | |
539 | ||
540 | /* | |
541 | * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() | |
542 | * to satisfy versions of X which crash if the mmap fails: that | |
543 | * substitutes a new vm_file, and we don't then want bin_vm_ops. | |
544 | */ | |
545 | if (vma->vm_file != file) | |
546 | goto out_put; | |
547 | ||
548 | rc = -EINVAL; | |
549 | if (of->mmapped && of->vm_ops != vma->vm_ops) | |
550 | goto out_put; | |
551 | ||
552 | /* | |
553 | * It is not possible to successfully wrap close. | |
554 | * So error if someone is trying to use close. | |
555 | */ | |
556 | rc = -EINVAL; | |
557 | if (vma->vm_ops && vma->vm_ops->close) | |
558 | goto out_put; | |
559 | ||
560 | rc = 0; | |
561 | of->mmapped = 1; | |
562 | of->vm_ops = vma->vm_ops; | |
fdbffaa4 | 563 | vma->vm_ops = &kernfs_vm_ops; |
73d97146 TH |
564 | out_put: |
565 | sysfs_put_active(of->sd); | |
566 | out_unlock: | |
567 | mutex_unlock(&of->mutex); | |
568 | ||
569 | return rc; | |
570 | } | |
571 | ||
85a4ffad TH |
572 | /** |
573 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
574 | * @sd: target sysfs_dirent | |
58282d8d | 575 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
576 | * |
577 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 578 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
579 | * |
580 | * LOCKING: | |
581 | * Kernel thread context (may sleep). | |
582 | * | |
583 | * RETURNS: | |
584 | * 0 on success, -errno on failure. | |
585 | */ | |
586 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 587 | struct sysfs_open_file *of) |
85a4ffad TH |
588 | { |
589 | struct sysfs_open_dirent *od, *new_od = NULL; | |
590 | ||
591 | retry: | |
c75ec764 | 592 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 593 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
594 | |
595 | if (!sd->s_attr.open && new_od) { | |
596 | sd->s_attr.open = new_od; | |
597 | new_od = NULL; | |
598 | } | |
599 | ||
600 | od = sd->s_attr.open; | |
601 | if (od) { | |
602 | atomic_inc(&od->refcnt); | |
58282d8d | 603 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
604 | } |
605 | ||
83db93f4 | 606 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 607 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
608 | |
609 | if (od) { | |
610 | kfree(new_od); | |
611 | return 0; | |
612 | } | |
613 | ||
614 | /* not there, initialize a new one and retry */ | |
615 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
616 | if (!new_od) | |
617 | return -ENOMEM; | |
618 | ||
619 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
620 | atomic_set(&new_od->event, 1); |
621 | init_waitqueue_head(&new_od->poll); | |
58282d8d | 622 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
623 | goto retry; |
624 | } | |
625 | ||
626 | /** | |
627 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
628 | * @sd: target sysfs_dirent | |
58282d8d | 629 | * @of: associated sysfs_open_file |
85a4ffad | 630 | * |
58282d8d TH |
631 | * Put @sd->s_attr.open and unlink @of from the files list. If |
632 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
633 | * |
634 | * LOCKING: | |
635 | * None. | |
636 | */ | |
637 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 638 | struct sysfs_open_file *of) |
85a4ffad TH |
639 | { |
640 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 641 | unsigned long flags; |
85a4ffad | 642 | |
c75ec764 | 643 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 644 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 645 | |
73d97146 TH |
646 | if (of) |
647 | list_del(&of->list); | |
648 | ||
85a4ffad TH |
649 | if (atomic_dec_and_test(&od->refcnt)) |
650 | sd->s_attr.open = NULL; | |
651 | else | |
652 | od = NULL; | |
653 | ||
83db93f4 | 654 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 655 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
656 | |
657 | kfree(od); | |
658 | } | |
659 | ||
c6fb4495 | 660 | static int kernfs_file_open(struct inode *inode, struct file *file) |
1da177e4 | 661 | { |
3e519038 | 662 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
7c6e2d36 | 663 | struct kobject *kobj = attr_sd->s_parent->priv; |
58282d8d | 664 | struct sysfs_open_file *of; |
027a485d | 665 | bool has_read, has_write, has_mmap; |
000f2a4d | 666 | int error = -EACCES; |
1da177e4 | 667 | |
0ab66088 | 668 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 669 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 670 | return -ENODEV; |
1da177e4 | 671 | |
49fe6047 | 672 | if (sysfs_is_bin(attr_sd)) { |
7c6e2d36 | 673 | struct bin_attribute *battr = attr_sd->priv; |
1da177e4 | 674 | |
49fe6047 TH |
675 | has_read = battr->read || battr->mmap; |
676 | has_write = battr->write || battr->mmap; | |
027a485d | 677 | has_mmap = battr->mmap; |
49fe6047 TH |
678 | } else { |
679 | const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); | |
1da177e4 | 680 | |
49fe6047 TH |
681 | /* every kobject with an attribute needs a ktype assigned */ |
682 | if (WARN(!ops, KERN_ERR | |
683 | "missing sysfs attribute operations for kobject: %s\n", | |
684 | kobject_name(kobj))) | |
7b595756 | 685 | goto err_out; |
49fe6047 TH |
686 | |
687 | has_read = ops->show; | |
688 | has_write = ops->store; | |
027a485d | 689 | has_mmap = false; |
1da177e4 LT |
690 | } |
691 | ||
49fe6047 TH |
692 | /* check perms and supported operations */ |
693 | if ((file->f_mode & FMODE_WRITE) && | |
694 | (!(inode->i_mode & S_IWUGO) || !has_write)) | |
695 | goto err_out; | |
696 | ||
697 | if ((file->f_mode & FMODE_READ) && | |
698 | (!(inode->i_mode & S_IRUGO) || !has_read)) | |
699 | goto err_out; | |
700 | ||
13c589d5 | 701 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 702 | error = -ENOMEM; |
58282d8d TH |
703 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
704 | if (!of) | |
7b595756 | 705 | goto err_out; |
1da177e4 | 706 | |
027a485d TH |
707 | /* |
708 | * The following is done to give a different lockdep key to | |
709 | * @of->mutex for files which implement mmap. This is a rather | |
710 | * crude way to avoid false positive lockdep warning around | |
711 | * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and | |
712 | * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under | |
713 | * which mm->mmap_sem nests, while holding @of->mutex. As each | |
714 | * open file has a separate mutex, it's okay as long as those don't | |
715 | * happen on the same file. At this point, we can't easily give | |
716 | * each file a separate locking class. Let's differentiate on | |
717 | * whether the file has mmap or not for now. | |
718 | */ | |
719 | if (has_mmap) | |
720 | mutex_init(&of->mutex); | |
721 | else | |
722 | mutex_init(&of->mutex); | |
723 | ||
bcafe4ee TH |
724 | of->sd = attr_sd; |
725 | of->file = file; | |
13c589d5 TH |
726 | |
727 | /* | |
49fe6047 TH |
728 | * Always instantiate seq_file even if read access doesn't use |
729 | * seq_file or is not requested. This unifies private data access | |
730 | * and readable regular files are the vast majority anyway. | |
13c589d5 | 731 | */ |
49fe6047 | 732 | if (sysfs_is_bin(attr_sd)) |
c2b19daf | 733 | error = seq_open(file, NULL); |
49fe6047 | 734 | else |
c2b19daf | 735 | error = seq_open(file, &kernfs_seq_ops); |
13c589d5 TH |
736 | if (error) |
737 | goto err_free; | |
738 | ||
c2b19daf TH |
739 | ((struct seq_file *)file->private_data)->private = of; |
740 | ||
13c589d5 TH |
741 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ |
742 | if (file->f_mode & FMODE_WRITE) | |
743 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 744 | |
85a4ffad | 745 | /* make sure we have open dirent struct */ |
58282d8d | 746 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 747 | if (error) |
13c589d5 | 748 | goto err_close; |
85a4ffad | 749 | |
b05f0548 | 750 | /* open succeeded, put active references */ |
e72ceb8c | 751 | sysfs_put_active(attr_sd); |
0ab66088 TH |
752 | return 0; |
753 | ||
13c589d5 | 754 | err_close: |
c2b19daf | 755 | seq_release(inode, file); |
13c589d5 | 756 | err_free: |
58282d8d | 757 | kfree(of); |
13c589d5 | 758 | err_out: |
e72ceb8c | 759 | sysfs_put_active(attr_sd); |
1da177e4 LT |
760 | return error; |
761 | } | |
762 | ||
c6fb4495 | 763 | static int kernfs_file_release(struct inode *inode, struct file *filp) |
1da177e4 | 764 | { |
85a4ffad | 765 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 766 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 767 | |
58282d8d | 768 | sysfs_put_open_dirent(sd, of); |
c2b19daf | 769 | seq_release(inode, filp); |
58282d8d | 770 | kfree(of); |
50ab1a72 | 771 | |
1da177e4 LT |
772 | return 0; |
773 | } | |
774 | ||
73d97146 TH |
775 | void sysfs_unmap_bin_file(struct sysfs_dirent *sd) |
776 | { | |
777 | struct sysfs_open_dirent *od; | |
778 | struct sysfs_open_file *of; | |
779 | ||
780 | if (!sysfs_is_bin(sd)) | |
781 | return; | |
782 | ||
783 | spin_lock_irq(&sysfs_open_dirent_lock); | |
784 | od = sd->s_attr.open; | |
785 | if (od) | |
786 | atomic_inc(&od->refcnt); | |
787 | spin_unlock_irq(&sysfs_open_dirent_lock); | |
788 | if (!od) | |
789 | return; | |
790 | ||
791 | mutex_lock(&sysfs_open_file_mutex); | |
792 | list_for_each_entry(of, &od->files, list) { | |
793 | struct inode *inode = file_inode(of->file); | |
794 | unmap_mapping_range(inode->i_mapping, 0, 0, 1); | |
795 | } | |
796 | mutex_unlock(&sysfs_open_file_mutex); | |
797 | ||
798 | sysfs_put_open_dirent(sd, NULL); | |
799 | } | |
800 | ||
4508a7a7 N |
801 | /* Sysfs attribute files are pollable. The idea is that you read |
802 | * the content and then you use 'poll' or 'select' to wait for | |
803 | * the content to change. When the content changes (assuming the | |
804 | * manager for the kobject supports notification), poll will | |
805 | * return POLLERR|POLLPRI, and select will return the fd whether | |
806 | * it is waiting for read, write, or exceptions. | |
807 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 808 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
809 | * Reminder: this only works for attributes which actively support |
810 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 811 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
812 | * an appropriate error code). When in doubt, set a suitable timeout value. |
813 | */ | |
c6fb4495 | 814 | static unsigned int kernfs_file_poll(struct file *filp, poll_table *wait) |
4508a7a7 | 815 | { |
13c589d5 | 816 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 817 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 818 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
819 | |
820 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 821 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 822 | goto trigger; |
4508a7a7 | 823 | |
a4e8b912 | 824 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 825 | |
e72ceb8c | 826 | sysfs_put_active(attr_sd); |
0ab66088 | 827 | |
58282d8d | 828 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 829 | goto trigger; |
4508a7a7 | 830 | |
1af3557a | 831 | return DEFAULT_POLLMASK; |
0ab66088 TH |
832 | |
833 | trigger: | |
1af3557a | 834 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
835 | } |
836 | ||
f1282c84 NB |
837 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
838 | { | |
839 | struct sysfs_open_dirent *od; | |
83db93f4 | 840 | unsigned long flags; |
f1282c84 | 841 | |
83db93f4 | 842 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 843 | |
fc60bb83 ND |
844 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
845 | od = sd->s_attr.open; | |
846 | if (od) { | |
847 | atomic_inc(&od->event); | |
848 | wake_up_interruptible(&od->poll); | |
849 | } | |
f1282c84 NB |
850 | } |
851 | ||
83db93f4 | 852 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
853 | } |
854 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
855 | ||
8c0e3998 | 856 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 857 | { |
51225039 | 858 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 859 | |
51225039 TH |
860 | mutex_lock(&sysfs_mutex); |
861 | ||
862 | if (sd && dir) | |
cfec0bc8 | 863 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 864 | if (sd && attr) |
cfec0bc8 | 865 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
866 | if (sd) |
867 | sysfs_notify_dirent(sd); | |
51225039 TH |
868 | |
869 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
870 | } |
871 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
872 | ||
c6fb4495 | 873 | const struct file_operations kernfs_file_operations = { |
c2b19daf | 874 | .read = kernfs_file_read, |
50b38ca0 | 875 | .write = kernfs_file_write, |
044e3bc3 | 876 | .llseek = generic_file_llseek, |
fdbffaa4 | 877 | .mmap = kernfs_file_mmap, |
c6fb4495 TH |
878 | .open = kernfs_file_open, |
879 | .release = kernfs_file_release, | |
880 | .poll = kernfs_file_poll, | |
f9b9a621 TH |
881 | }; |
882 | ||
58292cbe TH |
883 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
884 | const struct attribute *attr, int type, | |
885 | umode_t amode, const void *ns) | |
1da177e4 | 886 | { |
0f423895 | 887 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 888 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 889 | struct sysfs_dirent *sd; |
23dc2799 | 890 | int rc; |
1da177e4 | 891 | |
3007e997 TH |
892 | sd = sysfs_new_dirent(attr->name, mode, type); |
893 | if (!sd) | |
894 | return -ENOMEM; | |
487505c2 EB |
895 | |
896 | sd->s_ns = ns; | |
7c6e2d36 | 897 | sd->priv = (void *)attr; |
a2db6842 | 898 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 899 | |
d69ac5a0 TH |
900 | sysfs_addrm_start(&acxt); |
901 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 902 | sysfs_addrm_finish(&acxt); |
a26cd722 | 903 | |
23dc2799 | 904 | if (rc) |
967e35dc | 905 | sysfs_put(sd); |
3007e997 | 906 | |
23dc2799 | 907 | return rc; |
1da177e4 LT |
908 | } |
909 | ||
910 | ||
0f423895 JB |
911 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
912 | int type) | |
913 | { | |
58292cbe | 914 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
915 | } |
916 | ||
1da177e4 | 917 | /** |
58292cbe TH |
918 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
919 | * @kobj: object we're creating for | |
920 | * @attr: attribute descriptor | |
921 | * @ns: namespace the new file should belong to | |
1da177e4 | 922 | */ |
58292cbe TH |
923 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
924 | const void *ns) | |
1da177e4 | 925 | { |
608e266a | 926 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 927 | |
58292cbe TH |
928 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
929 | attr->mode, ns); | |
1da177e4 LT |
930 | |
931 | } | |
58292cbe | 932 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 933 | |
1c205ae1 AK |
934 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
935 | { | |
936 | int err = 0; | |
937 | int i; | |
938 | ||
939 | for (i = 0; ptr[i] && !err; i++) | |
940 | err = sysfs_create_file(kobj, ptr[i]); | |
941 | if (err) | |
942 | while (--i >= 0) | |
943 | sysfs_remove_file(kobj, ptr[i]); | |
944 | return err; | |
945 | } | |
1b866757 | 946 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 947 | |
dfa87c82 AS |
948 | /** |
949 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
950 | * @kobj: object we're acting for. | |
951 | * @attr: attribute descriptor. | |
952 | * @group: group name. | |
953 | */ | |
954 | int sysfs_add_file_to_group(struct kobject *kobj, | |
955 | const struct attribute *attr, const char *group) | |
956 | { | |
608e266a | 957 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
958 | int error; |
959 | ||
11f24fbd | 960 | if (group) |
388975cc | 961 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
962 | else |
963 | dir_sd = sysfs_get(kobj->sd); | |
964 | ||
608e266a TH |
965 | if (!dir_sd) |
966 | return -ENOENT; | |
967 | ||
968 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
969 | sysfs_put(dir_sd); | |
970 | ||
dfa87c82 AS |
971 | return error; |
972 | } | |
973 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
974 | ||
31e5abe9 KS |
975 | /** |
976 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
977 | * @kobj: object we're acting for. | |
978 | * @attr: attribute descriptor. | |
979 | * @mode: file permissions. | |
980 | * | |
981 | */ | |
49c19400 | 982 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 983 | umode_t mode) |
31e5abe9 | 984 | { |
06fc0d66 | 985 | struct sysfs_dirent *sd; |
bc062b1b | 986 | struct iattr newattrs; |
51225039 TH |
987 | int rc; |
988 | ||
5d60418e | 989 | sd = sysfs_get_dirent(kobj->sd, attr->name); |
06fc0d66 | 990 | if (!sd) |
5d60418e | 991 | return -ENOENT; |
f88123ea | 992 | |
06fc0d66 | 993 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 994 | newattrs.ia_valid = ATTR_MODE; |
f88123ea | 995 | |
5d60418e TH |
996 | rc = kernfs_setattr(sd, &newattrs); |
997 | ||
998 | sysfs_put(sd); | |
51225039 | 999 | return rc; |
31e5abe9 KS |
1000 | } |
1001 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
1002 | ||
1da177e4 | 1003 | /** |
58292cbe TH |
1004 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
1005 | * @kobj: object we're acting for | |
1006 | * @attr: attribute descriptor | |
1007 | * @ns: namespace tag of the file to remove | |
1da177e4 | 1008 | * |
58292cbe | 1009 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 1010 | */ |
58292cbe TH |
1011 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
1012 | const void *ns) | |
1da177e4 | 1013 | { |
58292cbe | 1014 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 1015 | |
879f40d1 | 1016 | kernfs_remove_by_name_ns(dir_sd, attr->name, ns); |
1da177e4 | 1017 | } |
58292cbe | 1018 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 1019 | |
1b18dc2b | 1020 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
1021 | { |
1022 | int i; | |
1023 | for (i = 0; ptr[i]; i++) | |
1024 | sysfs_remove_file(kobj, ptr[i]); | |
1025 | } | |
1b866757 | 1026 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 1027 | |
dfa87c82 AS |
1028 | /** |
1029 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
1030 | * @kobj: object we're acting for. | |
1031 | * @attr: attribute descriptor. | |
1032 | * @group: group name. | |
1033 | */ | |
1034 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
1035 | const struct attribute *attr, const char *group) | |
1036 | { | |
608e266a | 1037 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 1038 | |
11f24fbd | 1039 | if (group) |
388975cc | 1040 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
1041 | else |
1042 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 1043 | if (dir_sd) { |
879f40d1 | 1044 | kernfs_remove_by_name(dir_sd, attr->name); |
608e266a | 1045 | sysfs_put(dir_sd); |
dfa87c82 AS |
1046 | } |
1047 | } | |
1048 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
1049 | ||
3124eb16 TH |
1050 | /** |
1051 | * sysfs_create_bin_file - create binary file for object. | |
1052 | * @kobj: object. | |
1053 | * @attr: attribute descriptor. | |
1054 | */ | |
1055 | int sysfs_create_bin_file(struct kobject *kobj, | |
1056 | const struct bin_attribute *attr) | |
1057 | { | |
1058 | BUG_ON(!kobj || !kobj->sd || !attr); | |
1059 | ||
1060 | return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); | |
1061 | } | |
1062 | EXPORT_SYMBOL_GPL(sysfs_create_bin_file); | |
1063 | ||
1064 | /** | |
1065 | * sysfs_remove_bin_file - remove binary file for object. | |
1066 | * @kobj: object. | |
1067 | * @attr: attribute descriptor. | |
1068 | */ | |
1069 | void sysfs_remove_bin_file(struct kobject *kobj, | |
1070 | const struct bin_attribute *attr) | |
1071 | { | |
879f40d1 | 1072 | kernfs_remove_by_name(kobj->sd, attr->attr.name); |
3124eb16 TH |
1073 | } |
1074 | EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); | |
1075 | ||
d9a9cdfb | 1076 | struct sysfs_schedule_callback_struct { |
66942064 AC |
1077 | struct list_head workq_list; |
1078 | struct kobject *kobj; | |
d9a9cdfb AS |
1079 | void (*func)(void *); |
1080 | void *data; | |
523ded71 | 1081 | struct module *owner; |
d9a9cdfb AS |
1082 | struct work_struct work; |
1083 | }; | |
1084 | ||
d110271e | 1085 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
1086 | static DEFINE_MUTEX(sysfs_workq_mutex); |
1087 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
1088 | static void sysfs_schedule_callback_work(struct work_struct *work) |
1089 | { | |
1090 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
1091 | struct sysfs_schedule_callback_struct, work); | |
1092 | ||
1093 | (ss->func)(ss->data); | |
1094 | kobject_put(ss->kobj); | |
523ded71 | 1095 | module_put(ss->owner); |
66942064 AC |
1096 | mutex_lock(&sysfs_workq_mutex); |
1097 | list_del(&ss->workq_list); | |
1098 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
1099 | kfree(ss); |
1100 | } | |
1101 | ||
1102 | /** | |
1103 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
1104 | * @kobj: object we're acting for. | |
1105 | * @func: callback function to invoke later. | |
1106 | * @data: argument to pass to @func. | |
523ded71 | 1107 | * @owner: module owning the callback code |
d9a9cdfb AS |
1108 | * |
1109 | * sysfs attribute methods must not unregister themselves or their parent | |
1110 | * kobject (which would amount to the same thing). Attempts to do so will | |
1111 | * deadlock, since unregistration is mutually exclusive with driver | |
1112 | * callbacks. | |
1113 | * | |
1114 | * Instead methods can call this routine, which will attempt to allocate | |
1115 | * and schedule a workqueue request to call back @func with @data as its | |
1116 | * argument in the workqueue's process context. @kobj will be pinned | |
1117 | * until @func returns. | |
1118 | * | |
1119 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
1120 | * be allocated, -ENODEV if a reference to @owner isn't available, |
1121 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
1122 | */ |
1123 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 1124 | void *data, struct module *owner) |
d9a9cdfb | 1125 | { |
66942064 | 1126 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 1127 | |
523ded71 AS |
1128 | if (!try_module_get(owner)) |
1129 | return -ENODEV; | |
66942064 AC |
1130 | |
1131 | mutex_lock(&sysfs_workq_mutex); | |
1132 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
1133 | if (ss->kobj == kobj) { | |
d110271e | 1134 | module_put(owner); |
66942064 AC |
1135 | mutex_unlock(&sysfs_workq_mutex); |
1136 | return -EAGAIN; | |
1137 | } | |
1138 | mutex_unlock(&sysfs_workq_mutex); | |
1139 | ||
d110271e | 1140 | if (sysfs_workqueue == NULL) { |
086a377e | 1141 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
1142 | if (sysfs_workqueue == NULL) { |
1143 | module_put(owner); | |
1144 | return -ENOMEM; | |
1145 | } | |
1146 | } | |
1147 | ||
d9a9cdfb | 1148 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
1149 | if (!ss) { |
1150 | module_put(owner); | |
d9a9cdfb | 1151 | return -ENOMEM; |
523ded71 | 1152 | } |
d9a9cdfb AS |
1153 | kobject_get(kobj); |
1154 | ss->kobj = kobj; | |
1155 | ss->func = func; | |
1156 | ss->data = data; | |
523ded71 | 1157 | ss->owner = owner; |
d9a9cdfb | 1158 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
1159 | INIT_LIST_HEAD(&ss->workq_list); |
1160 | mutex_lock(&sysfs_workq_mutex); | |
1161 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
1162 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 1163 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
1164 | return 0; |
1165 | } | |
1166 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |