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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> |
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 | { | |
77 | struct kobject *kobj = sd->s_parent->s_dir.kobj; | |
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 | */ |
13c589d5 | 89 | static int sysfs_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 90 | { |
13c589d5 TH |
91 | struct sysfs_open_file *of = sf->private; |
92 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; | |
375b611e | 93 | const struct sysfs_ops *ops; |
13c589d5 | 94 | char *buf; |
1da177e4 LT |
95 | ssize_t count; |
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 TH |
104 | /* |
105 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
106 | * nests outside active ref and is just to ensure that the ops | |
107 | * aren't called concurrently for the same open file. | |
108 | */ | |
109 | mutex_lock(&of->mutex); | |
110 | if (!sysfs_get_active(of->sd)) { | |
111 | mutex_unlock(&of->mutex); | |
0ab66088 | 112 | return -ENODEV; |
13c589d5 | 113 | } |
0ab66088 | 114 | |
13c589d5 | 115 | of->event = atomic_read(&of->sd->s_attr.open->event); |
375b611e | 116 | |
13c589d5 TH |
117 | /* |
118 | * Lookup @ops and invoke show(). Control may reach here via seq | |
119 | * file lseek even if @ops->show() isn't implemented. | |
120 | */ | |
121 | ops = sysfs_file_ops(of->sd); | |
122 | if (ops->show) | |
123 | count = ops->show(kobj, of->sd->s_attr.attr, buf); | |
124 | else | |
125 | count = 0; | |
0ab66088 | 126 | |
13c589d5 TH |
127 | sysfs_put_active(of->sd); |
128 | mutex_unlock(&of->mutex); | |
129 | ||
130 | if (count < 0) | |
131 | return count; | |
0ab66088 | 132 | |
8118a859 MX |
133 | /* |
134 | * The code works fine with PAGE_SIZE return but it's likely to | |
135 | * indicate truncated result or overflow in normal use cases. | |
136 | */ | |
815d2d50 AM |
137 | if (count >= (ssize_t)PAGE_SIZE) { |
138 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
139 | (unsigned long)ops->show); | |
140 | /* Try to struggle along */ | |
141 | count = PAGE_SIZE - 1; | |
142 | } | |
13c589d5 TH |
143 | seq_commit(sf, count); |
144 | return 0; | |
1da177e4 LT |
145 | } |
146 | ||
2f0c6b75 TH |
147 | /* |
148 | * Read method for bin files. As reading a bin file can have side-effects, | |
149 | * the exact offset and bytes specified in read(2) call should be passed to | |
150 | * the read callback making it difficult to use seq_file. Implement | |
151 | * simplistic custom buffering for bin files. | |
152 | */ | |
153 | static ssize_t sysfs_bin_read(struct file *file, char __user *userbuf, | |
154 | size_t bytes, loff_t *off) | |
155 | { | |
156 | struct sysfs_open_file *of = sysfs_of(file); | |
56b3f3b8 | 157 | struct bin_attribute *battr = of->sd->s_attr.bin_attr; |
2f0c6b75 | 158 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; |
d723a92d | 159 | loff_t size = file_inode(file)->i_size; |
2f0c6b75 TH |
160 | int count = min_t(size_t, bytes, PAGE_SIZE); |
161 | loff_t offs = *off; | |
162 | char *buf; | |
163 | ||
164 | if (!bytes) | |
165 | return 0; | |
166 | ||
167 | if (size) { | |
168 | if (offs > size) | |
169 | return 0; | |
170 | if (offs + count > size) | |
171 | count = size - offs; | |
172 | } | |
173 | ||
174 | buf = kmalloc(count, GFP_KERNEL); | |
175 | if (!buf) | |
176 | return -ENOMEM; | |
177 | ||
178 | /* need of->sd for battr, its parent for kobj */ | |
179 | mutex_lock(&of->mutex); | |
180 | if (!sysfs_get_active(of->sd)) { | |
181 | count = -ENODEV; | |
182 | mutex_unlock(&of->mutex); | |
183 | goto out_free; | |
184 | } | |
185 | ||
186 | if (battr->read) | |
187 | count = battr->read(file, kobj, battr, buf, offs, count); | |
188 | else | |
189 | count = -EIO; | |
190 | ||
191 | sysfs_put_active(of->sd); | |
192 | mutex_unlock(&of->mutex); | |
193 | ||
194 | if (count < 0) | |
195 | goto out_free; | |
196 | ||
197 | if (copy_to_user(userbuf, buf, count)) { | |
198 | count = -EFAULT; | |
199 | goto out_free; | |
200 | } | |
201 | ||
202 | pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count); | |
203 | ||
204 | *off = offs + count; | |
205 | ||
206 | out_free: | |
207 | kfree(buf); | |
208 | return count; | |
209 | } | |
210 | ||
1da177e4 | 211 | /** |
8ef445f0 TH |
212 | * flush_write_buffer - push buffer to kobject |
213 | * @of: open file | |
214 | * @buf: data buffer for file | |
f9b9a621 | 215 | * @off: file offset to write to |
8ef445f0 | 216 | * @count: number of bytes |
1da177e4 | 217 | * |
8ef445f0 TH |
218 | * Get the correct pointers for the kobject and the attribute we're dealing |
219 | * with, then call the store() method for it with @buf. | |
1da177e4 | 220 | */ |
f9b9a621 | 221 | static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off, |
8ef445f0 | 222 | size_t count) |
1da177e4 | 223 | { |
bcafe4ee | 224 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; |
8ef445f0 | 225 | int rc = 0; |
0ab66088 | 226 | |
8ef445f0 TH |
227 | /* |
228 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
229 | * nests outside active ref and is just to ensure that the ops | |
230 | * aren't called concurrently for the same open file. | |
231 | */ | |
232 | mutex_lock(&of->mutex); | |
233 | if (!sysfs_get_active(of->sd)) { | |
234 | mutex_unlock(&of->mutex); | |
0ab66088 | 235 | return -ENODEV; |
8ef445f0 | 236 | } |
0ab66088 | 237 | |
f9b9a621 | 238 | if (sysfs_is_bin(of->sd)) { |
56b3f3b8 | 239 | struct bin_attribute *battr = of->sd->s_attr.bin_attr; |
f9b9a621 TH |
240 | |
241 | rc = -EIO; | |
242 | if (battr->write) | |
243 | rc = battr->write(of->file, kobj, battr, buf, off, | |
244 | count); | |
245 | } else { | |
246 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); | |
247 | ||
248 | rc = ops->store(kobj, of->sd->s_attr.attr, buf, count); | |
249 | } | |
0ab66088 | 250 | |
bcafe4ee | 251 | sysfs_put_active(of->sd); |
8ef445f0 | 252 | mutex_unlock(&of->mutex); |
1da177e4 | 253 | |
0ab66088 | 254 | return rc; |
1da177e4 LT |
255 | } |
256 | ||
1da177e4 | 257 | /** |
8ef445f0 TH |
258 | * sysfs_write_file - write an attribute |
259 | * @file: file pointer | |
260 | * @user_buf: data to write | |
261 | * @count: number of bytes | |
262 | * @ppos: starting offset | |
263 | * | |
264 | * Copy data in from userland and pass it to the matching | |
265 | * sysfs_ops->store() by invoking flush_write_buffer(). | |
1da177e4 | 266 | * |
8ef445f0 TH |
267 | * There is no easy way for us to know if userspace is only doing a partial |
268 | * write, so we don't support them. We expect the entire buffer to come on | |
269 | * the first write. Hint: if you're writing a value, first read the file, | |
270 | * modify only the the value you're changing, then write entire buffer | |
271 | * back. | |
1da177e4 | 272 | */ |
8ef445f0 | 273 | static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, |
ddfd6d07 | 274 | size_t count, loff_t *ppos) |
1da177e4 | 275 | { |
13c589d5 | 276 | struct sysfs_open_file *of = sysfs_of(file); |
f9b9a621 | 277 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
b9c06225 | 278 | loff_t size = file_inode(file)->i_size; |
8ef445f0 | 279 | char *buf; |
1da177e4 | 280 | |
b9c06225 | 281 | if (sysfs_is_bin(of->sd) && size) { |
f9b9a621 TH |
282 | if (size <= *ppos) |
283 | return 0; | |
284 | len = min_t(ssize_t, len, size - *ppos); | |
285 | } | |
286 | ||
8ef445f0 TH |
287 | if (!len) |
288 | return 0; | |
289 | ||
290 | buf = kmalloc(len + 1, GFP_KERNEL); | |
291 | if (!buf) | |
292 | return -ENOMEM; | |
293 | ||
294 | if (copy_from_user(buf, user_buf, len)) { | |
295 | len = -EFAULT; | |
296 | goto out_free; | |
297 | } | |
298 | buf[len] = '\0'; /* guarantee string termination */ | |
299 | ||
f9b9a621 | 300 | len = flush_write_buffer(of, buf, *ppos, len); |
1da177e4 LT |
301 | if (len > 0) |
302 | *ppos += len; | |
8ef445f0 TH |
303 | out_free: |
304 | kfree(buf); | |
1da177e4 LT |
305 | return len; |
306 | } | |
307 | ||
73d97146 TH |
308 | static void sysfs_bin_vma_open(struct vm_area_struct *vma) |
309 | { | |
310 | struct file *file = vma->vm_file; | |
311 | struct sysfs_open_file *of = sysfs_of(file); | |
312 | ||
313 | if (!of->vm_ops) | |
314 | return; | |
315 | ||
316 | if (!sysfs_get_active(of->sd)) | |
317 | return; | |
318 | ||
319 | if (of->vm_ops->open) | |
320 | of->vm_ops->open(vma); | |
321 | ||
322 | sysfs_put_active(of->sd); | |
323 | } | |
324 | ||
325 | static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
326 | { | |
327 | struct file *file = vma->vm_file; | |
328 | struct sysfs_open_file *of = sysfs_of(file); | |
329 | int ret; | |
330 | ||
331 | if (!of->vm_ops) | |
332 | return VM_FAULT_SIGBUS; | |
333 | ||
334 | if (!sysfs_get_active(of->sd)) | |
335 | return VM_FAULT_SIGBUS; | |
336 | ||
337 | ret = VM_FAULT_SIGBUS; | |
338 | if (of->vm_ops->fault) | |
339 | ret = of->vm_ops->fault(vma, vmf); | |
340 | ||
341 | sysfs_put_active(of->sd); | |
342 | return ret; | |
343 | } | |
344 | ||
345 | static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma, | |
346 | struct vm_fault *vmf) | |
347 | { | |
348 | struct file *file = vma->vm_file; | |
349 | struct sysfs_open_file *of = sysfs_of(file); | |
350 | int ret; | |
351 | ||
352 | if (!of->vm_ops) | |
353 | return VM_FAULT_SIGBUS; | |
354 | ||
355 | if (!sysfs_get_active(of->sd)) | |
356 | return VM_FAULT_SIGBUS; | |
357 | ||
358 | ret = 0; | |
359 | if (of->vm_ops->page_mkwrite) | |
360 | ret = of->vm_ops->page_mkwrite(vma, vmf); | |
361 | else | |
362 | file_update_time(file); | |
363 | ||
364 | sysfs_put_active(of->sd); | |
365 | return ret; | |
366 | } | |
367 | ||
368 | static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr, | |
369 | void *buf, int len, int write) | |
370 | { | |
371 | struct file *file = vma->vm_file; | |
372 | struct sysfs_open_file *of = sysfs_of(file); | |
373 | int ret; | |
374 | ||
375 | if (!of->vm_ops) | |
376 | return -EINVAL; | |
377 | ||
378 | if (!sysfs_get_active(of->sd)) | |
379 | return -EINVAL; | |
380 | ||
381 | ret = -EINVAL; | |
382 | if (of->vm_ops->access) | |
383 | ret = of->vm_ops->access(vma, addr, buf, len, write); | |
384 | ||
385 | sysfs_put_active(of->sd); | |
386 | return ret; | |
387 | } | |
388 | ||
389 | #ifdef CONFIG_NUMA | |
390 | static int sysfs_bin_set_policy(struct vm_area_struct *vma, | |
391 | struct mempolicy *new) | |
392 | { | |
393 | struct file *file = vma->vm_file; | |
394 | struct sysfs_open_file *of = sysfs_of(file); | |
395 | int ret; | |
396 | ||
397 | if (!of->vm_ops) | |
398 | return 0; | |
399 | ||
400 | if (!sysfs_get_active(of->sd)) | |
401 | return -EINVAL; | |
402 | ||
403 | ret = 0; | |
404 | if (of->vm_ops->set_policy) | |
405 | ret = of->vm_ops->set_policy(vma, new); | |
406 | ||
407 | sysfs_put_active(of->sd); | |
408 | return ret; | |
409 | } | |
410 | ||
411 | static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma, | |
412 | unsigned long addr) | |
413 | { | |
414 | struct file *file = vma->vm_file; | |
415 | struct sysfs_open_file *of = sysfs_of(file); | |
416 | struct mempolicy *pol; | |
417 | ||
418 | if (!of->vm_ops) | |
419 | return vma->vm_policy; | |
420 | ||
421 | if (!sysfs_get_active(of->sd)) | |
422 | return vma->vm_policy; | |
423 | ||
424 | pol = vma->vm_policy; | |
425 | if (of->vm_ops->get_policy) | |
426 | pol = of->vm_ops->get_policy(vma, addr); | |
427 | ||
428 | sysfs_put_active(of->sd); | |
429 | return pol; | |
430 | } | |
431 | ||
432 | static int sysfs_bin_migrate(struct vm_area_struct *vma, const nodemask_t *from, | |
433 | const nodemask_t *to, unsigned long flags) | |
434 | { | |
435 | struct file *file = vma->vm_file; | |
436 | struct sysfs_open_file *of = sysfs_of(file); | |
437 | int ret; | |
438 | ||
439 | if (!of->vm_ops) | |
440 | return 0; | |
441 | ||
442 | if (!sysfs_get_active(of->sd)) | |
443 | return 0; | |
444 | ||
445 | ret = 0; | |
446 | if (of->vm_ops->migrate) | |
447 | ret = of->vm_ops->migrate(vma, from, to, flags); | |
448 | ||
449 | sysfs_put_active(of->sd); | |
450 | return ret; | |
451 | } | |
452 | #endif | |
453 | ||
454 | static const struct vm_operations_struct sysfs_bin_vm_ops = { | |
455 | .open = sysfs_bin_vma_open, | |
456 | .fault = sysfs_bin_fault, | |
457 | .page_mkwrite = sysfs_bin_page_mkwrite, | |
458 | .access = sysfs_bin_access, | |
459 | #ifdef CONFIG_NUMA | |
460 | .set_policy = sysfs_bin_set_policy, | |
461 | .get_policy = sysfs_bin_get_policy, | |
462 | .migrate = sysfs_bin_migrate, | |
463 | #endif | |
464 | }; | |
465 | ||
466 | static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma) | |
467 | { | |
468 | struct sysfs_open_file *of = sysfs_of(file); | |
56b3f3b8 | 469 | struct bin_attribute *battr = of->sd->s_attr.bin_attr; |
73d97146 TH |
470 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; |
471 | int rc; | |
472 | ||
473 | mutex_lock(&of->mutex); | |
474 | ||
475 | /* need of->sd for battr, its parent for kobj */ | |
476 | rc = -ENODEV; | |
477 | if (!sysfs_get_active(of->sd)) | |
478 | goto out_unlock; | |
479 | ||
73d97146 TH |
480 | if (!battr->mmap) |
481 | goto out_put; | |
482 | ||
483 | rc = battr->mmap(file, kobj, battr, vma); | |
484 | if (rc) | |
485 | goto out_put; | |
486 | ||
487 | /* | |
488 | * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() | |
489 | * to satisfy versions of X which crash if the mmap fails: that | |
490 | * substitutes a new vm_file, and we don't then want bin_vm_ops. | |
491 | */ | |
492 | if (vma->vm_file != file) | |
493 | goto out_put; | |
494 | ||
495 | rc = -EINVAL; | |
496 | if (of->mmapped && of->vm_ops != vma->vm_ops) | |
497 | goto out_put; | |
498 | ||
499 | /* | |
500 | * It is not possible to successfully wrap close. | |
501 | * So error if someone is trying to use close. | |
502 | */ | |
503 | rc = -EINVAL; | |
504 | if (vma->vm_ops && vma->vm_ops->close) | |
505 | goto out_put; | |
506 | ||
507 | rc = 0; | |
508 | of->mmapped = 1; | |
509 | of->vm_ops = vma->vm_ops; | |
510 | vma->vm_ops = &sysfs_bin_vm_ops; | |
511 | out_put: | |
512 | sysfs_put_active(of->sd); | |
513 | out_unlock: | |
514 | mutex_unlock(&of->mutex); | |
515 | ||
516 | return rc; | |
517 | } | |
518 | ||
85a4ffad TH |
519 | /** |
520 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
521 | * @sd: target sysfs_dirent | |
58282d8d | 522 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
523 | * |
524 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 525 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
526 | * |
527 | * LOCKING: | |
528 | * Kernel thread context (may sleep). | |
529 | * | |
530 | * RETURNS: | |
531 | * 0 on success, -errno on failure. | |
532 | */ | |
533 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 534 | struct sysfs_open_file *of) |
85a4ffad TH |
535 | { |
536 | struct sysfs_open_dirent *od, *new_od = NULL; | |
537 | ||
538 | retry: | |
c75ec764 | 539 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 540 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
541 | |
542 | if (!sd->s_attr.open && new_od) { | |
543 | sd->s_attr.open = new_od; | |
544 | new_od = NULL; | |
545 | } | |
546 | ||
547 | od = sd->s_attr.open; | |
548 | if (od) { | |
549 | atomic_inc(&od->refcnt); | |
58282d8d | 550 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
551 | } |
552 | ||
83db93f4 | 553 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 554 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
555 | |
556 | if (od) { | |
557 | kfree(new_od); | |
558 | return 0; | |
559 | } | |
560 | ||
561 | /* not there, initialize a new one and retry */ | |
562 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
563 | if (!new_od) | |
564 | return -ENOMEM; | |
565 | ||
566 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
567 | atomic_set(&new_od->event, 1); |
568 | init_waitqueue_head(&new_od->poll); | |
58282d8d | 569 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
570 | goto retry; |
571 | } | |
572 | ||
573 | /** | |
574 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
575 | * @sd: target sysfs_dirent | |
58282d8d | 576 | * @of: associated sysfs_open_file |
85a4ffad | 577 | * |
58282d8d TH |
578 | * Put @sd->s_attr.open and unlink @of from the files list. If |
579 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
580 | * |
581 | * LOCKING: | |
582 | * None. | |
583 | */ | |
584 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 585 | struct sysfs_open_file *of) |
85a4ffad TH |
586 | { |
587 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 588 | unsigned long flags; |
85a4ffad | 589 | |
c75ec764 | 590 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 591 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 592 | |
73d97146 TH |
593 | if (of) |
594 | list_del(&of->list); | |
595 | ||
85a4ffad TH |
596 | if (atomic_dec_and_test(&od->refcnt)) |
597 | sd->s_attr.open = NULL; | |
598 | else | |
599 | od = NULL; | |
600 | ||
83db93f4 | 601 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 602 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
603 | |
604 | kfree(od); | |
605 | } | |
606 | ||
94bebf4d | 607 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 608 | { |
3e519038 | 609 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
b1fc3d61 | 610 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
58282d8d | 611 | struct sysfs_open_file *of; |
49fe6047 | 612 | bool has_read, has_write; |
000f2a4d | 613 | int error = -EACCES; |
1da177e4 | 614 | |
0ab66088 | 615 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 616 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 617 | return -ENODEV; |
1da177e4 | 618 | |
49fe6047 | 619 | if (sysfs_is_bin(attr_sd)) { |
56b3f3b8 | 620 | struct bin_attribute *battr = attr_sd->s_attr.bin_attr; |
1da177e4 | 621 | |
49fe6047 TH |
622 | has_read = battr->read || battr->mmap; |
623 | has_write = battr->write || battr->mmap; | |
624 | } else { | |
625 | const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); | |
1da177e4 | 626 | |
49fe6047 TH |
627 | /* every kobject with an attribute needs a ktype assigned */ |
628 | if (WARN(!ops, KERN_ERR | |
629 | "missing sysfs attribute operations for kobject: %s\n", | |
630 | kobject_name(kobj))) | |
7b595756 | 631 | goto err_out; |
49fe6047 TH |
632 | |
633 | has_read = ops->show; | |
634 | has_write = ops->store; | |
1da177e4 LT |
635 | } |
636 | ||
49fe6047 TH |
637 | /* check perms and supported operations */ |
638 | if ((file->f_mode & FMODE_WRITE) && | |
639 | (!(inode->i_mode & S_IWUGO) || !has_write)) | |
640 | goto err_out; | |
641 | ||
642 | if ((file->f_mode & FMODE_READ) && | |
643 | (!(inode->i_mode & S_IRUGO) || !has_read)) | |
644 | goto err_out; | |
645 | ||
13c589d5 | 646 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 647 | error = -ENOMEM; |
58282d8d TH |
648 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
649 | if (!of) | |
7b595756 | 650 | goto err_out; |
1da177e4 | 651 | |
58282d8d | 652 | mutex_init(&of->mutex); |
bcafe4ee TH |
653 | of->sd = attr_sd; |
654 | of->file = file; | |
13c589d5 TH |
655 | |
656 | /* | |
49fe6047 TH |
657 | * Always instantiate seq_file even if read access doesn't use |
658 | * seq_file or is not requested. This unifies private data access | |
659 | * and readable regular files are the vast majority anyway. | |
13c589d5 | 660 | */ |
49fe6047 TH |
661 | if (sysfs_is_bin(attr_sd)) |
662 | error = single_open(file, NULL, of); | |
663 | else | |
664 | error = single_open(file, sysfs_seq_show, of); | |
13c589d5 TH |
665 | if (error) |
666 | goto err_free; | |
667 | ||
668 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ | |
669 | if (file->f_mode & FMODE_WRITE) | |
670 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 671 | |
85a4ffad | 672 | /* make sure we have open dirent struct */ |
58282d8d | 673 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 674 | if (error) |
13c589d5 | 675 | goto err_close; |
85a4ffad | 676 | |
b05f0548 | 677 | /* open succeeded, put active references */ |
e72ceb8c | 678 | sysfs_put_active(attr_sd); |
0ab66088 TH |
679 | return 0; |
680 | ||
13c589d5 TH |
681 | err_close: |
682 | single_release(inode, file); | |
683 | err_free: | |
58282d8d | 684 | kfree(of); |
13c589d5 | 685 | err_out: |
e72ceb8c | 686 | sysfs_put_active(attr_sd); |
1da177e4 LT |
687 | return error; |
688 | } | |
689 | ||
85a4ffad | 690 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 691 | { |
85a4ffad | 692 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 693 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 694 | |
58282d8d | 695 | sysfs_put_open_dirent(sd, of); |
13c589d5 | 696 | single_release(inode, filp); |
58282d8d | 697 | kfree(of); |
50ab1a72 | 698 | |
1da177e4 LT |
699 | return 0; |
700 | } | |
701 | ||
73d97146 TH |
702 | void sysfs_unmap_bin_file(struct sysfs_dirent *sd) |
703 | { | |
704 | struct sysfs_open_dirent *od; | |
705 | struct sysfs_open_file *of; | |
706 | ||
707 | if (!sysfs_is_bin(sd)) | |
708 | return; | |
709 | ||
710 | spin_lock_irq(&sysfs_open_dirent_lock); | |
711 | od = sd->s_attr.open; | |
712 | if (od) | |
713 | atomic_inc(&od->refcnt); | |
714 | spin_unlock_irq(&sysfs_open_dirent_lock); | |
715 | if (!od) | |
716 | return; | |
717 | ||
718 | mutex_lock(&sysfs_open_file_mutex); | |
719 | list_for_each_entry(of, &od->files, list) { | |
720 | struct inode *inode = file_inode(of->file); | |
721 | unmap_mapping_range(inode->i_mapping, 0, 0, 1); | |
722 | } | |
723 | mutex_unlock(&sysfs_open_file_mutex); | |
724 | ||
725 | sysfs_put_open_dirent(sd, NULL); | |
726 | } | |
727 | ||
4508a7a7 N |
728 | /* Sysfs attribute files are pollable. The idea is that you read |
729 | * the content and then you use 'poll' or 'select' to wait for | |
730 | * the content to change. When the content changes (assuming the | |
731 | * manager for the kobject supports notification), poll will | |
732 | * return POLLERR|POLLPRI, and select will return the fd whether | |
733 | * it is waiting for read, write, or exceptions. | |
734 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 735 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
736 | * Reminder: this only works for attributes which actively support |
737 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 738 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
739 | * an appropriate error code). When in doubt, set a suitable timeout value. |
740 | */ | |
741 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
742 | { | |
13c589d5 | 743 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 744 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 745 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
746 | |
747 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 748 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 749 | goto trigger; |
4508a7a7 | 750 | |
a4e8b912 | 751 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 752 | |
e72ceb8c | 753 | sysfs_put_active(attr_sd); |
0ab66088 | 754 | |
58282d8d | 755 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 756 | goto trigger; |
4508a7a7 | 757 | |
1af3557a | 758 | return DEFAULT_POLLMASK; |
0ab66088 TH |
759 | |
760 | trigger: | |
1af3557a | 761 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
762 | } |
763 | ||
f1282c84 NB |
764 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
765 | { | |
766 | struct sysfs_open_dirent *od; | |
83db93f4 | 767 | unsigned long flags; |
f1282c84 | 768 | |
83db93f4 | 769 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 770 | |
fc60bb83 ND |
771 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
772 | od = sd->s_attr.open; | |
773 | if (od) { | |
774 | atomic_inc(&od->event); | |
775 | wake_up_interruptible(&od->poll); | |
776 | } | |
f1282c84 NB |
777 | } |
778 | ||
83db93f4 | 779 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
780 | } |
781 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
782 | ||
8c0e3998 | 783 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 784 | { |
51225039 | 785 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 786 | |
51225039 TH |
787 | mutex_lock(&sysfs_mutex); |
788 | ||
789 | if (sd && dir) | |
cfec0bc8 | 790 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 791 | if (sd && attr) |
cfec0bc8 | 792 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
793 | if (sd) |
794 | sysfs_notify_dirent(sd); | |
51225039 TH |
795 | |
796 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
797 | } |
798 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
799 | ||
4b6f5d20 | 800 | const struct file_operations sysfs_file_operations = { |
13c589d5 | 801 | .read = seq_read, |
1da177e4 | 802 | .write = sysfs_write_file, |
044e3bc3 | 803 | .llseek = generic_file_llseek, |
1da177e4 LT |
804 | .open = sysfs_open_file, |
805 | .release = sysfs_release, | |
4508a7a7 | 806 | .poll = sysfs_poll, |
1da177e4 LT |
807 | }; |
808 | ||
f9b9a621 | 809 | const struct file_operations sysfs_bin_operations = { |
2f0c6b75 | 810 | .read = sysfs_bin_read, |
f9b9a621 TH |
811 | .write = sysfs_write_file, |
812 | .llseek = generic_file_llseek, | |
73d97146 | 813 | .mmap = sysfs_bin_mmap, |
49fe6047 TH |
814 | .open = sysfs_open_file, |
815 | .release = sysfs_release, | |
816 | .poll = sysfs_poll, | |
f9b9a621 TH |
817 | }; |
818 | ||
58292cbe TH |
819 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
820 | const struct attribute *attr, int type, | |
821 | umode_t amode, const void *ns) | |
1da177e4 | 822 | { |
0f423895 | 823 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 824 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 825 | struct sysfs_dirent *sd; |
23dc2799 | 826 | int rc; |
1da177e4 | 827 | |
3007e997 TH |
828 | sd = sysfs_new_dirent(attr->name, mode, type); |
829 | if (!sd) | |
830 | return -ENOMEM; | |
487505c2 EB |
831 | |
832 | sd->s_ns = ns; | |
b1fc3d61 | 833 | sd->s_attr.attr = (void *)attr; |
a2db6842 | 834 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 835 | |
d69ac5a0 TH |
836 | sysfs_addrm_start(&acxt); |
837 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 838 | sysfs_addrm_finish(&acxt); |
a26cd722 | 839 | |
23dc2799 | 840 | if (rc) |
967e35dc | 841 | sysfs_put(sd); |
3007e997 | 842 | |
23dc2799 | 843 | return rc; |
1da177e4 LT |
844 | } |
845 | ||
846 | ||
0f423895 JB |
847 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
848 | int type) | |
849 | { | |
58292cbe | 850 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
851 | } |
852 | ||
1da177e4 | 853 | /** |
58292cbe TH |
854 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
855 | * @kobj: object we're creating for | |
856 | * @attr: attribute descriptor | |
857 | * @ns: namespace the new file should belong to | |
1da177e4 | 858 | */ |
58292cbe TH |
859 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
860 | const void *ns) | |
1da177e4 | 861 | { |
608e266a | 862 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 863 | |
58292cbe TH |
864 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
865 | attr->mode, ns); | |
1da177e4 LT |
866 | |
867 | } | |
58292cbe | 868 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 869 | |
1c205ae1 AK |
870 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
871 | { | |
872 | int err = 0; | |
873 | int i; | |
874 | ||
875 | for (i = 0; ptr[i] && !err; i++) | |
876 | err = sysfs_create_file(kobj, ptr[i]); | |
877 | if (err) | |
878 | while (--i >= 0) | |
879 | sysfs_remove_file(kobj, ptr[i]); | |
880 | return err; | |
881 | } | |
1b866757 | 882 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 883 | |
dfa87c82 AS |
884 | /** |
885 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
886 | * @kobj: object we're acting for. | |
887 | * @attr: attribute descriptor. | |
888 | * @group: group name. | |
889 | */ | |
890 | int sysfs_add_file_to_group(struct kobject *kobj, | |
891 | const struct attribute *attr, const char *group) | |
892 | { | |
608e266a | 893 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
894 | int error; |
895 | ||
11f24fbd | 896 | if (group) |
388975cc | 897 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
898 | else |
899 | dir_sd = sysfs_get(kobj->sd); | |
900 | ||
608e266a TH |
901 | if (!dir_sd) |
902 | return -ENOENT; | |
903 | ||
904 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
905 | sysfs_put(dir_sd); | |
906 | ||
dfa87c82 AS |
907 | return error; |
908 | } | |
909 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
910 | ||
31e5abe9 KS |
911 | /** |
912 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
913 | * @kobj: object we're acting for. | |
914 | * @attr: attribute descriptor. | |
915 | * @mode: file permissions. | |
916 | * | |
917 | */ | |
49c19400 | 918 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 919 | umode_t mode) |
31e5abe9 | 920 | { |
06fc0d66 | 921 | struct sysfs_dirent *sd; |
bc062b1b | 922 | struct iattr newattrs; |
51225039 TH |
923 | int rc; |
924 | ||
06fc0d66 | 925 | mutex_lock(&sysfs_mutex); |
51225039 | 926 | |
06fc0d66 | 927 | rc = -ENOENT; |
cfec0bc8 | 928 | sd = sysfs_find_dirent(kobj->sd, attr->name, NULL); |
06fc0d66 | 929 | if (!sd) |
51225039 | 930 | goto out; |
f88123ea | 931 | |
06fc0d66 | 932 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 933 | newattrs.ia_valid = ATTR_MODE; |
06fc0d66 | 934 | rc = sysfs_sd_setattr(sd, &newattrs); |
f88123ea | 935 | |
51225039 | 936 | out: |
06fc0d66 | 937 | mutex_unlock(&sysfs_mutex); |
51225039 | 938 | return rc; |
31e5abe9 KS |
939 | } |
940 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
941 | ||
1da177e4 | 942 | /** |
58292cbe TH |
943 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
944 | * @kobj: object we're acting for | |
945 | * @attr: attribute descriptor | |
946 | * @ns: namespace tag of the file to remove | |
1da177e4 | 947 | * |
58292cbe | 948 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 949 | */ |
58292cbe TH |
950 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
951 | const void *ns) | |
1da177e4 | 952 | { |
58292cbe | 953 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 954 | |
879f40d1 | 955 | kernfs_remove_by_name_ns(dir_sd, attr->name, ns); |
1da177e4 | 956 | } |
58292cbe | 957 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 958 | |
1b18dc2b | 959 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
960 | { |
961 | int i; | |
962 | for (i = 0; ptr[i]; i++) | |
963 | sysfs_remove_file(kobj, ptr[i]); | |
964 | } | |
1b866757 | 965 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 966 | |
dfa87c82 AS |
967 | /** |
968 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
969 | * @kobj: object we're acting for. | |
970 | * @attr: attribute descriptor. | |
971 | * @group: group name. | |
972 | */ | |
973 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
974 | const struct attribute *attr, const char *group) | |
975 | { | |
608e266a | 976 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 977 | |
11f24fbd | 978 | if (group) |
388975cc | 979 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
980 | else |
981 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 982 | if (dir_sd) { |
879f40d1 | 983 | kernfs_remove_by_name(dir_sd, attr->name); |
608e266a | 984 | sysfs_put(dir_sd); |
dfa87c82 AS |
985 | } |
986 | } | |
987 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
988 | ||
3124eb16 TH |
989 | /** |
990 | * sysfs_create_bin_file - create binary file for object. | |
991 | * @kobj: object. | |
992 | * @attr: attribute descriptor. | |
993 | */ | |
994 | int sysfs_create_bin_file(struct kobject *kobj, | |
995 | const struct bin_attribute *attr) | |
996 | { | |
997 | BUG_ON(!kobj || !kobj->sd || !attr); | |
998 | ||
999 | return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); | |
1000 | } | |
1001 | EXPORT_SYMBOL_GPL(sysfs_create_bin_file); | |
1002 | ||
1003 | /** | |
1004 | * sysfs_remove_bin_file - remove binary file for object. | |
1005 | * @kobj: object. | |
1006 | * @attr: attribute descriptor. | |
1007 | */ | |
1008 | void sysfs_remove_bin_file(struct kobject *kobj, | |
1009 | const struct bin_attribute *attr) | |
1010 | { | |
879f40d1 | 1011 | kernfs_remove_by_name(kobj->sd, attr->attr.name); |
3124eb16 TH |
1012 | } |
1013 | EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); | |
1014 | ||
d9a9cdfb | 1015 | struct sysfs_schedule_callback_struct { |
66942064 AC |
1016 | struct list_head workq_list; |
1017 | struct kobject *kobj; | |
d9a9cdfb AS |
1018 | void (*func)(void *); |
1019 | void *data; | |
523ded71 | 1020 | struct module *owner; |
d9a9cdfb AS |
1021 | struct work_struct work; |
1022 | }; | |
1023 | ||
d110271e | 1024 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
1025 | static DEFINE_MUTEX(sysfs_workq_mutex); |
1026 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
1027 | static void sysfs_schedule_callback_work(struct work_struct *work) |
1028 | { | |
1029 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
1030 | struct sysfs_schedule_callback_struct, work); | |
1031 | ||
1032 | (ss->func)(ss->data); | |
1033 | kobject_put(ss->kobj); | |
523ded71 | 1034 | module_put(ss->owner); |
66942064 AC |
1035 | mutex_lock(&sysfs_workq_mutex); |
1036 | list_del(&ss->workq_list); | |
1037 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
1038 | kfree(ss); |
1039 | } | |
1040 | ||
1041 | /** | |
1042 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
1043 | * @kobj: object we're acting for. | |
1044 | * @func: callback function to invoke later. | |
1045 | * @data: argument to pass to @func. | |
523ded71 | 1046 | * @owner: module owning the callback code |
d9a9cdfb AS |
1047 | * |
1048 | * sysfs attribute methods must not unregister themselves or their parent | |
1049 | * kobject (which would amount to the same thing). Attempts to do so will | |
1050 | * deadlock, since unregistration is mutually exclusive with driver | |
1051 | * callbacks. | |
1052 | * | |
1053 | * Instead methods can call this routine, which will attempt to allocate | |
1054 | * and schedule a workqueue request to call back @func with @data as its | |
1055 | * argument in the workqueue's process context. @kobj will be pinned | |
1056 | * until @func returns. | |
1057 | * | |
1058 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
1059 | * be allocated, -ENODEV if a reference to @owner isn't available, |
1060 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
1061 | */ |
1062 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 1063 | void *data, struct module *owner) |
d9a9cdfb | 1064 | { |
66942064 | 1065 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 1066 | |
523ded71 AS |
1067 | if (!try_module_get(owner)) |
1068 | return -ENODEV; | |
66942064 AC |
1069 | |
1070 | mutex_lock(&sysfs_workq_mutex); | |
1071 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
1072 | if (ss->kobj == kobj) { | |
d110271e | 1073 | module_put(owner); |
66942064 AC |
1074 | mutex_unlock(&sysfs_workq_mutex); |
1075 | return -EAGAIN; | |
1076 | } | |
1077 | mutex_unlock(&sysfs_workq_mutex); | |
1078 | ||
d110271e | 1079 | if (sysfs_workqueue == NULL) { |
086a377e | 1080 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
1081 | if (sysfs_workqueue == NULL) { |
1082 | module_put(owner); | |
1083 | return -ENOMEM; | |
1084 | } | |
1085 | } | |
1086 | ||
d9a9cdfb | 1087 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
1088 | if (!ss) { |
1089 | module_put(owner); | |
d9a9cdfb | 1090 | return -ENOMEM; |
523ded71 | 1091 | } |
d9a9cdfb AS |
1092 | kobject_get(kobj); |
1093 | ss->kobj = kobj; | |
1094 | ss->func = func; | |
1095 | ss->data = data; | |
523ded71 | 1096 | ss->owner = owner; |
d9a9cdfb | 1097 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
1098 | INIT_LIST_HEAD(&ss->workq_list); |
1099 | mutex_lock(&sysfs_workq_mutex); | |
1100 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
1101 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 1102 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
1103 | return 0; |
1104 | } | |
1105 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |