blk-cgroup: fix rcu lockdep warning in blkg_lookup()
[linux-block.git] / fs / char_dev.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/fs/char_dev.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
1da177e4
LT
8#include <linux/init.h>
9#include <linux/fs.h>
b446b60e 10#include <linux/kdev_t.h>
1da177e4
LT
11#include <linux/slab.h>
12#include <linux/string.h>
13
14#include <linux/major.h>
15#include <linux/errno.h>
16#include <linux/module.h>
68eef3b4 17#include <linux/seq_file.h>
1da177e4
LT
18
19#include <linux/kobject.h>
20#include <linux/kobj_map.h>
21#include <linux/cdev.h>
58383af6 22#include <linux/mutex.h>
5da6185b 23#include <linux/backing-dev.h>
31d1d48e 24#include <linux/tty.h>
1da177e4 25
07f3f05c 26#include "internal.h"
1da177e4 27
68279f9c 28static struct kobj_map *cdev_map __ro_after_init;
1da177e4 29
58383af6 30static DEFINE_MUTEX(chrdevs_lock);
1da177e4 31
8a932f73
LG
32#define CHRDEV_MAJOR_HASH_SIZE 255
33
1da177e4
LT
34static struct char_device_struct {
35 struct char_device_struct *next;
36 unsigned int major;
37 unsigned int baseminor;
38 int minorct;
7170be5f 39 char name[64];
1da177e4 40 struct cdev *cdev; /* will die */
68eef3b4 41} *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
1da177e4
LT
42
43/* index in the above */
e61eb2e9 44static inline int major_to_index(unsigned major)
1da177e4 45{
68eef3b4 46 return major % CHRDEV_MAJOR_HASH_SIZE;
7170be5f
NH
47}
48
68eef3b4 49#ifdef CONFIG_PROC_FS
7170be5f 50
68eef3b4 51void chrdev_show(struct seq_file *f, off_t offset)
7170be5f
NH
52{
53 struct char_device_struct *cd;
7170be5f 54
8a932f73
LG
55 mutex_lock(&chrdevs_lock);
56 for (cd = chrdevs[major_to_index(offset)]; cd; cd = cd->next) {
57 if (cd->major == offset)
68eef3b4 58 seq_printf(f, "%3d %s\n", cd->major, cd->name);
1da177e4 59 }
8a932f73 60 mutex_unlock(&chrdevs_lock);
7170be5f
NH
61}
62
68eef3b4 63#endif /* CONFIG_PROC_FS */
1da177e4 64
a5d31a3f
LG
65static int find_dynamic_major(void)
66{
67 int i;
68 struct char_device_struct *cd;
69
652d703b 70 for (i = ARRAY_SIZE(chrdevs)-1; i >= CHRDEV_MAJOR_DYN_END; i--) {
a5d31a3f
LG
71 if (chrdevs[i] == NULL)
72 return i;
73 }
74
75 for (i = CHRDEV_MAJOR_DYN_EXT_START;
652d703b 76 i >= CHRDEV_MAJOR_DYN_EXT_END; i--) {
a5d31a3f
LG
77 for (cd = chrdevs[major_to_index(i)]; cd; cd = cd->next)
78 if (cd->major == i)
79 break;
80
652d703b 81 if (cd == NULL)
a5d31a3f
LG
82 return i;
83 }
84
85 return -EBUSY;
86}
87
1da177e4
LT
88/*
89 * Register a single major with a specified minor range.
90 *
d358b173
CX
91 * If major == 0 this function will dynamically allocate an unused major.
92 * If major > 0 this function will attempt to reserve the range of minors
93 * with given major.
1da177e4 94 *
1da177e4
LT
95 */
96static struct char_device_struct *
97__register_chrdev_region(unsigned int major, unsigned int baseminor,
98 int minorct, const char *name)
99{
4b0be572 100 struct char_device_struct *cd, *curr, *prev = NULL;
7ef0b152 101 int ret;
1da177e4
LT
102 int i;
103
4b0be572
CX
104 if (major >= CHRDEV_MAJOR_MAX) {
105 pr_err("CHRDEV \"%s\" major requested (%u) is greater than the maximum (%u)\n",
106 name, major, CHRDEV_MAJOR_MAX-1);
107 return ERR_PTR(-EINVAL);
108 }
109
4712d379
CX
110 if (minorct > MINORMASK + 1 - baseminor) {
111 pr_err("CHRDEV \"%s\" minor range requested (%u-%u) is out of range of maximum range (%u-%u) for a single major\n",
112 name, baseminor, baseminor + minorct - 1, 0, MINORMASK);
113 return ERR_PTR(-EINVAL);
114 }
115
11b0b5ab 116 cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL);
1da177e4
LT
117 if (cd == NULL)
118 return ERR_PTR(-ENOMEM);
119
58383af6 120 mutex_lock(&chrdevs_lock);
1da177e4 121
1da177e4 122 if (major == 0) {
a5d31a3f
LG
123 ret = find_dynamic_major();
124 if (ret < 0) {
125 pr_err("CHRDEV \"%s\" dynamic allocation region is full\n",
126 name);
1da177e4
LT
127 goto out;
128 }
a5d31a3f 129 major = ret;
1da177e4
LT
130 }
131
7ef0b152 132 ret = -EBUSY;
1da177e4 133 i = major_to_index(major);
4b0be572
CX
134 for (curr = chrdevs[i]; curr; prev = curr, curr = curr->next) {
135 if (curr->major < major)
136 continue;
1da177e4 137
4b0be572 138 if (curr->major > major)
1da177e4 139 break;
01d553d0 140
4b0be572
CX
141 if (curr->baseminor + curr->minorct <= baseminor)
142 continue;
01d553d0 143
4b0be572
CX
144 if (curr->baseminor >= baseminor + minorct)
145 break;
01d553d0 146
4b0be572
CX
147 goto out;
148 }
de36e16d 149
4b0be572
CX
150 cd->major = major;
151 cd->baseminor = baseminor;
152 cd->minorct = minorct;
c642256b 153 strscpy(cd->name, name, sizeof(cd->name));
de36e16d 154
4b0be572
CX
155 if (!prev) {
156 cd->next = curr;
157 chrdevs[i] = cd;
158 } else {
159 cd->next = prev->next;
160 prev->next = cd;
1da177e4 161 }
01d553d0 162
58383af6 163 mutex_unlock(&chrdevs_lock);
1da177e4
LT
164 return cd;
165out:
58383af6 166 mutex_unlock(&chrdevs_lock);
1da177e4
LT
167 kfree(cd);
168 return ERR_PTR(ret);
169}
170
171static struct char_device_struct *
172__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
173{
174 struct char_device_struct *cd = NULL, **cp;
175 int i = major_to_index(major);
176
58383af6 177 mutex_lock(&chrdevs_lock);
1da177e4
LT
178 for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
179 if ((*cp)->major == major &&
180 (*cp)->baseminor == baseminor &&
181 (*cp)->minorct == minorct)
182 break;
183 if (*cp) {
184 cd = *cp;
185 *cp = cd->next;
186 }
58383af6 187 mutex_unlock(&chrdevs_lock);
1da177e4
LT
188 return cd;
189}
190
cf3e43db
JC
191/**
192 * register_chrdev_region() - register a range of device numbers
193 * @from: the first in the desired range of device numbers; must include
194 * the major number.
195 * @count: the number of consecutive device numbers required
196 * @name: the name of the device or driver.
197 *
198 * Return value is zero on success, a negative error code on failure.
199 */
1da177e4
LT
200int register_chrdev_region(dev_t from, unsigned count, const char *name)
201{
202 struct char_device_struct *cd;
203 dev_t to = from + count;
204 dev_t n, next;
205
206 for (n = from; n < to; n = next) {
207 next = MKDEV(MAJOR(n)+1, 0);
208 if (next > to)
209 next = to;
210 cd = __register_chrdev_region(MAJOR(n), MINOR(n),
211 next - n, name);
212 if (IS_ERR(cd))
213 goto fail;
214 }
215 return 0;
216fail:
217 to = n;
218 for (n = from; n < to; n = next) {
219 next = MKDEV(MAJOR(n)+1, 0);
220 kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
221 }
222 return PTR_ERR(cd);
223}
224
cf3e43db
JC
225/**
226 * alloc_chrdev_region() - register a range of char device numbers
227 * @dev: output parameter for first assigned number
228 * @baseminor: first of the requested range of minor numbers
229 * @count: the number of minor numbers required
230 * @name: the name of the associated device or driver
231 *
232 * Allocates a range of char device numbers. The major number will be
233 * chosen dynamically, and returned (along with the first minor number)
234 * in @dev. Returns zero or a negative error code.
235 */
1da177e4
LT
236int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
237 const char *name)
238{
239 struct char_device_struct *cd;
240 cd = __register_chrdev_region(0, baseminor, count, name);
241 if (IS_ERR(cd))
242 return PTR_ERR(cd);
243 *dev = MKDEV(cd->major, cd->baseminor);
244 return 0;
245}
246
d247e2c6 247/**
1905b1bf 248 * __register_chrdev() - create and register a cdev occupying a range of minors
d247e2c6 249 * @major: major device number or 0 for dynamic allocation
1905b1bf
TH
250 * @baseminor: first of the requested range of minor numbers
251 * @count: the number of minor numbers required
d247e2c6
REB
252 * @name: name of this range of devices
253 * @fops: file operations associated with this devices
254 *
255 * If @major == 0 this functions will dynamically allocate a major and return
256 * its number.
257 *
258 * If @major > 0 this function will attempt to reserve a device with the given
259 * major number and will return zero on success.
260 *
261 * Returns a -ve errno on failure.
262 *
263 * The name of this device has nothing to do with the name of the device in
264 * /dev. It only helps to keep track of the different owners of devices. If
265 * your module name has only one type of devices it's ok to use e.g. the name
266 * of the module here.
d247e2c6 267 */
1905b1bf
TH
268int __register_chrdev(unsigned int major, unsigned int baseminor,
269 unsigned int count, const char *name,
270 const struct file_operations *fops)
1da177e4
LT
271{
272 struct char_device_struct *cd;
273 struct cdev *cdev;
1da177e4
LT
274 int err = -ENOMEM;
275
1905b1bf 276 cd = __register_chrdev_region(major, baseminor, count, name);
1da177e4
LT
277 if (IS_ERR(cd))
278 return PTR_ERR(cd);
1ff97647 279
1da177e4
LT
280 cdev = cdev_alloc();
281 if (!cdev)
282 goto out2;
283
284 cdev->owner = fops->owner;
285 cdev->ops = fops;
286 kobject_set_name(&cdev->kobj, "%s", name);
1ff97647 287
1905b1bf 288 err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);
1da177e4
LT
289 if (err)
290 goto out;
291
292 cd->cdev = cdev;
293
294 return major ? 0 : cd->major;
295out:
296 kobject_put(&cdev->kobj);
297out2:
1905b1bf 298 kfree(__unregister_chrdev_region(cd->major, baseminor, count));
1da177e4
LT
299 return err;
300}
301
cf3e43db 302/**
594069bc 303 * unregister_chrdev_region() - unregister a range of device numbers
cf3e43db
JC
304 * @from: the first in the range of numbers to unregister
305 * @count: the number of device numbers to unregister
306 *
307 * This function will unregister a range of @count device numbers,
308 * starting with @from. The caller should normally be the one who
309 * allocated those numbers in the first place...
310 */
1da177e4
LT
311void unregister_chrdev_region(dev_t from, unsigned count)
312{
313 dev_t to = from + count;
314 dev_t n, next;
315
316 for (n = from; n < to; n = next) {
317 next = MKDEV(MAJOR(n)+1, 0);
318 if (next > to)
319 next = to;
320 kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
321 }
322}
323
1905b1bf
TH
324/**
325 * __unregister_chrdev - unregister and destroy a cdev
326 * @major: major device number
327 * @baseminor: first of the range of minor numbers
328 * @count: the number of minor numbers this cdev is occupying
329 * @name: name of this range of devices
330 *
331 * Unregister and destroy the cdev occupying the region described by
332 * @major, @baseminor and @count. This function undoes what
333 * __register_chrdev() did.
334 */
335void __unregister_chrdev(unsigned int major, unsigned int baseminor,
336 unsigned int count, const char *name)
1da177e4
LT
337{
338 struct char_device_struct *cd;
1905b1bf
TH
339
340 cd = __unregister_chrdev_region(major, baseminor, count);
1da177e4
LT
341 if (cd && cd->cdev)
342 cdev_del(cd->cdev);
343 kfree(cd);
1da177e4
LT
344}
345
346static DEFINE_SPINLOCK(cdev_lock);
347
348static struct kobject *cdev_get(struct cdev *p)
349{
350 struct module *owner = p->owner;
351 struct kobject *kobj;
352
e311ba29 353 if (!try_module_get(owner))
1da177e4 354 return NULL;
68faa679 355 kobj = kobject_get_unless_zero(&p->kobj);
1da177e4
LT
356 if (!kobj)
357 module_put(owner);
358 return kobj;
359}
360
361void cdev_put(struct cdev *p)
362{
363 if (p) {
7da6844c 364 struct module *owner = p->owner;
1da177e4 365 kobject_put(&p->kobj);
7da6844c 366 module_put(owner);
1da177e4
LT
367 }
368}
369
370/*
371 * Called every time a character special file is opened
372 */
922f9cfa 373static int chrdev_open(struct inode *inode, struct file *filp)
1da177e4 374{
e84f9e57 375 const struct file_operations *fops;
1da177e4
LT
376 struct cdev *p;
377 struct cdev *new = NULL;
378 int ret = 0;
379
380 spin_lock(&cdev_lock);
381 p = inode->i_cdev;
382 if (!p) {
383 struct kobject *kobj;
384 int idx;
385 spin_unlock(&cdev_lock);
386 kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
387 if (!kobj)
388 return -ENXIO;
389 new = container_of(kobj, struct cdev, kobj);
390 spin_lock(&cdev_lock);
a30427d9
JC
391 /* Check i_cdev again in case somebody beat us to it while
392 we dropped the lock. */
1da177e4
LT
393 p = inode->i_cdev;
394 if (!p) {
395 inode->i_cdev = p = new;
1da177e4
LT
396 list_add(&inode->i_devices, &p->list);
397 new = NULL;
398 } else if (!cdev_get(p))
399 ret = -ENXIO;
400 } else if (!cdev_get(p))
401 ret = -ENXIO;
402 spin_unlock(&cdev_lock);
403 cdev_put(new);
404 if (ret)
405 return ret;
a518ab93
CH
406
407 ret = -ENXIO;
e84f9e57
AV
408 fops = fops_get(p->ops);
409 if (!fops)
a518ab93
CH
410 goto out_cdev_put;
411
e84f9e57 412 replace_fops(filp, fops);
a518ab93 413 if (filp->f_op->open) {
1ff97647 414 ret = filp->f_op->open(inode, filp);
a518ab93
CH
415 if (ret)
416 goto out_cdev_put;
417 }
418
419 return 0;
420
421 out_cdev_put:
422 cdev_put(p);
1da177e4
LT
423 return ret;
424}
425
426void cd_forget(struct inode *inode)
427{
428 spin_lock(&cdev_lock);
429 list_del_init(&inode->i_devices);
430 inode->i_cdev = NULL;
3bc52c45 431 inode->i_mapping = &inode->i_data;
1da177e4
LT
432 spin_unlock(&cdev_lock);
433}
434
75c96f85 435static void cdev_purge(struct cdev *cdev)
1da177e4
LT
436{
437 spin_lock(&cdev_lock);
438 while (!list_empty(&cdev->list)) {
439 struct inode *inode;
440 inode = container_of(cdev->list.next, struct inode, i_devices);
441 list_del_init(&inode->i_devices);
442 inode->i_cdev = NULL;
443 }
444 spin_unlock(&cdev_lock);
445}
446
447/*
448 * Dummy default file-operations: the only thing this does
449 * is contain the open that then fills in the correct operations
450 * depending on the special file...
451 */
4b6f5d20 452const struct file_operations def_chr_fops = {
1da177e4 453 .open = chrdev_open,
6038f373 454 .llseek = noop_llseek,
1da177e4
LT
455};
456
457static struct kobject *exact_match(dev_t dev, int *part, void *data)
458{
459 struct cdev *p = data;
460 return &p->kobj;
461}
462
463static int exact_lock(dev_t dev, void *data)
464{
465 struct cdev *p = data;
466 return cdev_get(p) ? 0 : -1;
467}
468
cf3e43db
JC
469/**
470 * cdev_add() - add a char device to the system
471 * @p: the cdev structure for the device
472 * @dev: the first device number for which this device is responsible
473 * @count: the number of consecutive minor numbers corresponding to this
474 * device
475 *
476 * cdev_add() adds the device represented by @p to the system, making it
477 * live immediately. A negative error code is returned on failure.
478 */
1da177e4
LT
479int cdev_add(struct cdev *p, dev_t dev, unsigned count)
480{
2f0157f1
DT
481 int error;
482
1da177e4
LT
483 p->dev = dev;
484 p->count = count;
2f0157f1 485
4634c973
SX
486 if (WARN_ON(dev == WHITEOUT_DEV)) {
487 error = -EBUSY;
488 goto err;
489 }
a3c751a5 490
2f0157f1
DT
491 error = kobj_map(cdev_map, dev, count, NULL,
492 exact_match, exact_lock, p);
493 if (error)
4634c973 494 goto err;
2f0157f1
DT
495
496 kobject_get(p->kobj.parent);
497
498 return 0;
4634c973
SX
499
500err:
501 kfree_const(p->kobj.name);
502 p->kobj.name = NULL;
503 return error;
1da177e4
LT
504}
505
233ed09d
LG
506/**
507 * cdev_set_parent() - set the parent kobject for a char device
508 * @p: the cdev structure
509 * @kobj: the kobject to take a reference to
510 *
511 * cdev_set_parent() sets a parent kobject which will be referenced
512 * appropriately so the parent is not freed before the cdev. This
513 * should be called before cdev_add.
514 */
515void cdev_set_parent(struct cdev *p, struct kobject *kobj)
516{
517 WARN_ON(!kobj->state_initialized);
518 p->kobj.parent = kobj;
519}
520
521/**
522 * cdev_device_add() - add a char device and it's corresponding
523 * struct device, linkink
524 * @dev: the device structure
525 * @cdev: the cdev structure
526 *
527 * cdev_device_add() adds the char device represented by @cdev to the system,
528 * just as cdev_add does. It then adds @dev to the system using device_add
529 * The dev_t for the char device will be taken from the struct device which
530 * needs to be initialized first. This helper function correctly takes a
531 * reference to the parent device so the parent will not get released until
532 * all references to the cdev are released.
533 *
534 * This helper uses dev->devt for the device number. If it is not set
535 * it will not add the cdev and it will be equivalent to device_add.
536 *
537 * This function should be used whenever the struct cdev and the
538 * struct device are members of the same structure whose lifetime is
539 * managed by the struct device.
540 *
541 * NOTE: Callers must assume that userspace was able to open the cdev and
542 * can call cdev fops callbacks at any time, even if this function fails.
543 */
544int cdev_device_add(struct cdev *cdev, struct device *dev)
545{
546 int rc = 0;
547
548 if (dev->devt) {
549 cdev_set_parent(cdev, &dev->kobj);
550
551 rc = cdev_add(cdev, dev->devt, 1);
552 if (rc)
553 return rc;
554 }
555
556 rc = device_add(dev);
11fa7fef 557 if (rc && dev->devt)
233ed09d
LG
558 cdev_del(cdev);
559
560 return rc;
561}
562
563/**
564 * cdev_device_del() - inverse of cdev_device_add
565 * @dev: the device structure
566 * @cdev: the cdev structure
567 *
568 * cdev_device_del() is a helper function to call cdev_del and device_del.
569 * It should be used whenever cdev_device_add is used.
570 *
571 * If dev->devt is not set it will not remove the cdev and will be equivalent
572 * to device_del.
573 *
574 * NOTE: This guarantees that associated sysfs callbacks are not running
575 * or runnable, however any cdevs already open will remain and their fops
576 * will still be callable even after this function returns.
577 */
578void cdev_device_del(struct cdev *cdev, struct device *dev)
579{
580 device_del(dev);
581 if (dev->devt)
582 cdev_del(cdev);
583}
584
1da177e4
LT
585static void cdev_unmap(dev_t dev, unsigned count)
586{
587 kobj_unmap(cdev_map, dev, count);
588}
589
cf3e43db
JC
590/**
591 * cdev_del() - remove a cdev from the system
592 * @p: the cdev structure to be removed
593 *
594 * cdev_del() removes @p from the system, possibly freeing the structure
595 * itself.
233ed09d
LG
596 *
597 * NOTE: This guarantees that cdev device will no longer be able to be
598 * opened, however any cdevs already open will remain and their fops will
599 * still be callable even after cdev_del returns.
cf3e43db 600 */
1da177e4
LT
601void cdev_del(struct cdev *p)
602{
603 cdev_unmap(p->dev, p->count);
604 kobject_put(&p->kobj);
605}
606
607
608static void cdev_default_release(struct kobject *kobj)
609{
610 struct cdev *p = container_of(kobj, struct cdev, kobj);
2f0157f1
DT
611 struct kobject *parent = kobj->parent;
612
1da177e4 613 cdev_purge(p);
2f0157f1 614 kobject_put(parent);
1da177e4
LT
615}
616
617static void cdev_dynamic_release(struct kobject *kobj)
618{
619 struct cdev *p = container_of(kobj, struct cdev, kobj);
2f0157f1
DT
620 struct kobject *parent = kobj->parent;
621
1da177e4
LT
622 cdev_purge(p);
623 kfree(p);
2f0157f1 624 kobject_put(parent);
1da177e4
LT
625}
626
627static struct kobj_type ktype_cdev_default = {
628 .release = cdev_default_release,
629};
630
631static struct kobj_type ktype_cdev_dynamic = {
632 .release = cdev_dynamic_release,
633};
634
cf3e43db
JC
635/**
636 * cdev_alloc() - allocate a cdev structure
637 *
638 * Allocates and returns a cdev structure, or NULL on failure.
639 */
1da177e4
LT
640struct cdev *cdev_alloc(void)
641{
11b0b5ab 642 struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
1da177e4 643 if (p) {
1da177e4 644 INIT_LIST_HEAD(&p->list);
f9cb074b 645 kobject_init(&p->kobj, &ktype_cdev_dynamic);
1da177e4
LT
646 }
647 return p;
648}
649
cf3e43db
JC
650/**
651 * cdev_init() - initialize a cdev structure
652 * @cdev: the structure to initialize
653 * @fops: the file_operations for this device
654 *
655 * Initializes @cdev, remembering @fops, making it ready to add to the
656 * system with cdev_add().
657 */
99ac48f5 658void cdev_init(struct cdev *cdev, const struct file_operations *fops)
1da177e4
LT
659{
660 memset(cdev, 0, sizeof *cdev);
661 INIT_LIST_HEAD(&cdev->list);
f9cb074b 662 kobject_init(&cdev->kobj, &ktype_cdev_default);
1da177e4
LT
663 cdev->ops = fops;
664}
665
666static struct kobject *base_probe(dev_t dev, int *part, void *data)
667{
668 if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
669 /* Make old-style 2.4 aliases work */
670 request_module("char-major-%d", MAJOR(dev));
671 return NULL;
672}
673
674void __init chrdev_init(void)
675{
676 cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
677}
678
679
680/* Let modules do char dev stuff */
681EXPORT_SYMBOL(register_chrdev_region);
682EXPORT_SYMBOL(unregister_chrdev_region);
683EXPORT_SYMBOL(alloc_chrdev_region);
684EXPORT_SYMBOL(cdev_init);
685EXPORT_SYMBOL(cdev_alloc);
686EXPORT_SYMBOL(cdev_del);
687EXPORT_SYMBOL(cdev_add);
233ed09d
LG
688EXPORT_SYMBOL(cdev_set_parent);
689EXPORT_SYMBOL(cdev_device_add);
690EXPORT_SYMBOL(cdev_device_del);
1905b1bf
TH
691EXPORT_SYMBOL(__register_chrdev);
692EXPORT_SYMBOL(__unregister_chrdev);