Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/char_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/init.h> |
8 | #include <linux/fs.h> | |
b446b60e | 9 | #include <linux/kdev_t.h> |
1da177e4 LT |
10 | #include <linux/slab.h> |
11 | #include <linux/string.h> | |
12 | ||
13 | #include <linux/major.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/module.h> | |
68eef3b4 | 16 | #include <linux/seq_file.h> |
1da177e4 LT |
17 | |
18 | #include <linux/kobject.h> | |
19 | #include <linux/kobj_map.h> | |
20 | #include <linux/cdev.h> | |
58383af6 | 21 | #include <linux/mutex.h> |
5da6185b | 22 | #include <linux/backing-dev.h> |
31d1d48e | 23 | #include <linux/tty.h> |
1da177e4 | 24 | |
07f3f05c | 25 | #include "internal.h" |
1da177e4 | 26 | |
5da6185b DH |
27 | /* |
28 | * capabilities for /dev/mem, /dev/kmem and similar directly mappable character | |
29 | * devices | |
30 | * - permits shared-mmap for read, write and/or exec | |
31 | * - does not permit private mmap in NOMMU mode (can't do COW) | |
32 | * - no readahead or I/O queue unplugging required | |
33 | */ | |
34 | struct backing_dev_info directly_mappable_cdev_bdi = { | |
d993831f | 35 | .name = "char", |
5da6185b DH |
36 | .capabilities = ( |
37 | #ifdef CONFIG_MMU | |
38 | /* permit private copies of the data to be taken */ | |
39 | BDI_CAP_MAP_COPY | | |
40 | #endif | |
41 | /* permit direct mmap, for read, write or exec */ | |
42 | BDI_CAP_MAP_DIRECT | | |
371d217e JK |
43 | BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP | |
44 | /* no writeback happens */ | |
45 | BDI_CAP_NO_ACCT_AND_WRITEBACK), | |
5da6185b DH |
46 | }; |
47 | ||
1da177e4 LT |
48 | static struct kobj_map *cdev_map; |
49 | ||
58383af6 | 50 | static DEFINE_MUTEX(chrdevs_lock); |
1da177e4 LT |
51 | |
52 | static struct char_device_struct { | |
53 | struct char_device_struct *next; | |
54 | unsigned int major; | |
55 | unsigned int baseminor; | |
56 | int minorct; | |
7170be5f | 57 | char name[64]; |
1da177e4 | 58 | struct cdev *cdev; /* will die */ |
68eef3b4 | 59 | } *chrdevs[CHRDEV_MAJOR_HASH_SIZE]; |
1da177e4 LT |
60 | |
61 | /* index in the above */ | |
e61eb2e9 | 62 | static inline int major_to_index(unsigned major) |
1da177e4 | 63 | { |
68eef3b4 | 64 | return major % CHRDEV_MAJOR_HASH_SIZE; |
7170be5f NH |
65 | } |
66 | ||
68eef3b4 | 67 | #ifdef CONFIG_PROC_FS |
7170be5f | 68 | |
68eef3b4 | 69 | void chrdev_show(struct seq_file *f, off_t offset) |
7170be5f NH |
70 | { |
71 | struct char_device_struct *cd; | |
7170be5f | 72 | |
68eef3b4 JK |
73 | if (offset < CHRDEV_MAJOR_HASH_SIZE) { |
74 | mutex_lock(&chrdevs_lock); | |
75 | for (cd = chrdevs[offset]; cd; cd = cd->next) | |
76 | seq_printf(f, "%3d %s\n", cd->major, cd->name); | |
77 | mutex_unlock(&chrdevs_lock); | |
1da177e4 | 78 | } |
7170be5f NH |
79 | } |
80 | ||
68eef3b4 | 81 | #endif /* CONFIG_PROC_FS */ |
1da177e4 LT |
82 | |
83 | /* | |
84 | * Register a single major with a specified minor range. | |
85 | * | |
86 | * If major == 0 this functions will dynamically allocate a major and return | |
87 | * its number. | |
88 | * | |
89 | * If major > 0 this function will attempt to reserve the passed range of | |
90 | * minors and will return zero on success. | |
91 | * | |
92 | * Returns a -ve errno on failure. | |
93 | */ | |
94 | static struct char_device_struct * | |
95 | __register_chrdev_region(unsigned int major, unsigned int baseminor, | |
96 | int minorct, const char *name) | |
97 | { | |
98 | struct char_device_struct *cd, **cp; | |
99 | int ret = 0; | |
100 | int i; | |
101 | ||
11b0b5ab | 102 | cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL); |
1da177e4 LT |
103 | if (cd == NULL) |
104 | return ERR_PTR(-ENOMEM); | |
105 | ||
58383af6 | 106 | mutex_lock(&chrdevs_lock); |
1da177e4 LT |
107 | |
108 | /* temporary */ | |
109 | if (major == 0) { | |
110 | for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) { | |
111 | if (chrdevs[i] == NULL) | |
112 | break; | |
113 | } | |
114 | ||
115 | if (i == 0) { | |
116 | ret = -EBUSY; | |
117 | goto out; | |
118 | } | |
119 | major = i; | |
1da177e4 LT |
120 | } |
121 | ||
122 | cd->major = major; | |
123 | cd->baseminor = baseminor; | |
124 | cd->minorct = minorct; | |
8c401888 | 125 | strlcpy(cd->name, name, sizeof(cd->name)); |
1da177e4 LT |
126 | |
127 | i = major_to_index(major); | |
128 | ||
129 | for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) | |
130 | if ((*cp)->major > major || | |
01d553d0 AW |
131 | ((*cp)->major == major && |
132 | (((*cp)->baseminor >= baseminor) || | |
133 | ((*cp)->baseminor + (*cp)->minorct > baseminor)))) | |
1da177e4 | 134 | break; |
01d553d0 AW |
135 | |
136 | /* Check for overlapping minor ranges. */ | |
137 | if (*cp && (*cp)->major == major) { | |
138 | int old_min = (*cp)->baseminor; | |
139 | int old_max = (*cp)->baseminor + (*cp)->minorct - 1; | |
140 | int new_min = baseminor; | |
141 | int new_max = baseminor + minorct - 1; | |
142 | ||
143 | /* New driver overlaps from the left. */ | |
144 | if (new_max >= old_min && new_max <= old_max) { | |
145 | ret = -EBUSY; | |
146 | goto out; | |
147 | } | |
148 | ||
149 | /* New driver overlaps from the right. */ | |
150 | if (new_min <= old_max && new_min >= old_min) { | |
151 | ret = -EBUSY; | |
152 | goto out; | |
153 | } | |
1da177e4 | 154 | } |
01d553d0 | 155 | |
1da177e4 LT |
156 | cd->next = *cp; |
157 | *cp = cd; | |
58383af6 | 158 | mutex_unlock(&chrdevs_lock); |
1da177e4 LT |
159 | return cd; |
160 | out: | |
58383af6 | 161 | mutex_unlock(&chrdevs_lock); |
1da177e4 LT |
162 | kfree(cd); |
163 | return ERR_PTR(ret); | |
164 | } | |
165 | ||
166 | static struct char_device_struct * | |
167 | __unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct) | |
168 | { | |
169 | struct char_device_struct *cd = NULL, **cp; | |
170 | int i = major_to_index(major); | |
171 | ||
58383af6 | 172 | mutex_lock(&chrdevs_lock); |
1da177e4 LT |
173 | for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) |
174 | if ((*cp)->major == major && | |
175 | (*cp)->baseminor == baseminor && | |
176 | (*cp)->minorct == minorct) | |
177 | break; | |
178 | if (*cp) { | |
179 | cd = *cp; | |
180 | *cp = cd->next; | |
181 | } | |
58383af6 | 182 | mutex_unlock(&chrdevs_lock); |
1da177e4 LT |
183 | return cd; |
184 | } | |
185 | ||
cf3e43db JC |
186 | /** |
187 | * register_chrdev_region() - register a range of device numbers | |
188 | * @from: the first in the desired range of device numbers; must include | |
189 | * the major number. | |
190 | * @count: the number of consecutive device numbers required | |
191 | * @name: the name of the device or driver. | |
192 | * | |
193 | * Return value is zero on success, a negative error code on failure. | |
194 | */ | |
1da177e4 LT |
195 | int register_chrdev_region(dev_t from, unsigned count, const char *name) |
196 | { | |
197 | struct char_device_struct *cd; | |
198 | dev_t to = from + count; | |
199 | dev_t n, next; | |
200 | ||
201 | for (n = from; n < to; n = next) { | |
202 | next = MKDEV(MAJOR(n)+1, 0); | |
203 | if (next > to) | |
204 | next = to; | |
205 | cd = __register_chrdev_region(MAJOR(n), MINOR(n), | |
206 | next - n, name); | |
207 | if (IS_ERR(cd)) | |
208 | goto fail; | |
209 | } | |
210 | return 0; | |
211 | fail: | |
212 | to = n; | |
213 | for (n = from; n < to; n = next) { | |
214 | next = MKDEV(MAJOR(n)+1, 0); | |
215 | kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); | |
216 | } | |
217 | return PTR_ERR(cd); | |
218 | } | |
219 | ||
cf3e43db JC |
220 | /** |
221 | * alloc_chrdev_region() - register a range of char device numbers | |
222 | * @dev: output parameter for first assigned number | |
223 | * @baseminor: first of the requested range of minor numbers | |
224 | * @count: the number of minor numbers required | |
225 | * @name: the name of the associated device or driver | |
226 | * | |
227 | * Allocates a range of char device numbers. The major number will be | |
228 | * chosen dynamically, and returned (along with the first minor number) | |
229 | * in @dev. Returns zero or a negative error code. | |
230 | */ | |
1da177e4 LT |
231 | int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, |
232 | const char *name) | |
233 | { | |
234 | struct char_device_struct *cd; | |
235 | cd = __register_chrdev_region(0, baseminor, count, name); | |
236 | if (IS_ERR(cd)) | |
237 | return PTR_ERR(cd); | |
238 | *dev = MKDEV(cd->major, cd->baseminor); | |
239 | return 0; | |
240 | } | |
241 | ||
d247e2c6 | 242 | /** |
1905b1bf | 243 | * __register_chrdev() - create and register a cdev occupying a range of minors |
d247e2c6 | 244 | * @major: major device number or 0 for dynamic allocation |
1905b1bf TH |
245 | * @baseminor: first of the requested range of minor numbers |
246 | * @count: the number of minor numbers required | |
d247e2c6 REB |
247 | * @name: name of this range of devices |
248 | * @fops: file operations associated with this devices | |
249 | * | |
250 | * If @major == 0 this functions will dynamically allocate a major and return | |
251 | * its number. | |
252 | * | |
253 | * If @major > 0 this function will attempt to reserve a device with the given | |
254 | * major number and will return zero on success. | |
255 | * | |
256 | * Returns a -ve errno on failure. | |
257 | * | |
258 | * The name of this device has nothing to do with the name of the device in | |
259 | * /dev. It only helps to keep track of the different owners of devices. If | |
260 | * your module name has only one type of devices it's ok to use e.g. the name | |
261 | * of the module here. | |
d247e2c6 | 262 | */ |
1905b1bf TH |
263 | int __register_chrdev(unsigned int major, unsigned int baseminor, |
264 | unsigned int count, const char *name, | |
265 | const struct file_operations *fops) | |
1da177e4 LT |
266 | { |
267 | struct char_device_struct *cd; | |
268 | struct cdev *cdev; | |
1da177e4 LT |
269 | int err = -ENOMEM; |
270 | ||
1905b1bf | 271 | cd = __register_chrdev_region(major, baseminor, count, name); |
1da177e4 LT |
272 | if (IS_ERR(cd)) |
273 | return PTR_ERR(cd); | |
1ff97647 | 274 | |
1da177e4 LT |
275 | cdev = cdev_alloc(); |
276 | if (!cdev) | |
277 | goto out2; | |
278 | ||
279 | cdev->owner = fops->owner; | |
280 | cdev->ops = fops; | |
281 | kobject_set_name(&cdev->kobj, "%s", name); | |
1ff97647 | 282 | |
1905b1bf | 283 | err = cdev_add(cdev, MKDEV(cd->major, baseminor), count); |
1da177e4 LT |
284 | if (err) |
285 | goto out; | |
286 | ||
287 | cd->cdev = cdev; | |
288 | ||
289 | return major ? 0 : cd->major; | |
290 | out: | |
291 | kobject_put(&cdev->kobj); | |
292 | out2: | |
1905b1bf | 293 | kfree(__unregister_chrdev_region(cd->major, baseminor, count)); |
1da177e4 LT |
294 | return err; |
295 | } | |
296 | ||
cf3e43db JC |
297 | /** |
298 | * unregister_chrdev_region() - return a range of device numbers | |
299 | * @from: the first in the range of numbers to unregister | |
300 | * @count: the number of device numbers to unregister | |
301 | * | |
302 | * This function will unregister a range of @count device numbers, | |
303 | * starting with @from. The caller should normally be the one who | |
304 | * allocated those numbers in the first place... | |
305 | */ | |
1da177e4 LT |
306 | void unregister_chrdev_region(dev_t from, unsigned count) |
307 | { | |
308 | dev_t to = from + count; | |
309 | dev_t n, next; | |
310 | ||
311 | for (n = from; n < to; n = next) { | |
312 | next = MKDEV(MAJOR(n)+1, 0); | |
313 | if (next > to) | |
314 | next = to; | |
315 | kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); | |
316 | } | |
317 | } | |
318 | ||
1905b1bf TH |
319 | /** |
320 | * __unregister_chrdev - unregister and destroy a cdev | |
321 | * @major: major device number | |
322 | * @baseminor: first of the range of minor numbers | |
323 | * @count: the number of minor numbers this cdev is occupying | |
324 | * @name: name of this range of devices | |
325 | * | |
326 | * Unregister and destroy the cdev occupying the region described by | |
327 | * @major, @baseminor and @count. This function undoes what | |
328 | * __register_chrdev() did. | |
329 | */ | |
330 | void __unregister_chrdev(unsigned int major, unsigned int baseminor, | |
331 | unsigned int count, const char *name) | |
1da177e4 LT |
332 | { |
333 | struct char_device_struct *cd; | |
1905b1bf TH |
334 | |
335 | cd = __unregister_chrdev_region(major, baseminor, count); | |
1da177e4 LT |
336 | if (cd && cd->cdev) |
337 | cdev_del(cd->cdev); | |
338 | kfree(cd); | |
1da177e4 LT |
339 | } |
340 | ||
341 | static DEFINE_SPINLOCK(cdev_lock); | |
342 | ||
343 | static struct kobject *cdev_get(struct cdev *p) | |
344 | { | |
345 | struct module *owner = p->owner; | |
346 | struct kobject *kobj; | |
347 | ||
348 | if (owner && !try_module_get(owner)) | |
349 | return NULL; | |
350 | kobj = kobject_get(&p->kobj); | |
351 | if (!kobj) | |
352 | module_put(owner); | |
353 | return kobj; | |
354 | } | |
355 | ||
356 | void cdev_put(struct cdev *p) | |
357 | { | |
358 | if (p) { | |
7da6844c | 359 | struct module *owner = p->owner; |
1da177e4 | 360 | kobject_put(&p->kobj); |
7da6844c | 361 | module_put(owner); |
1da177e4 LT |
362 | } |
363 | } | |
364 | ||
365 | /* | |
366 | * Called every time a character special file is opened | |
367 | */ | |
922f9cfa | 368 | static int chrdev_open(struct inode *inode, struct file *filp) |
1da177e4 | 369 | { |
e84f9e57 | 370 | const struct file_operations *fops; |
1da177e4 LT |
371 | struct cdev *p; |
372 | struct cdev *new = NULL; | |
373 | int ret = 0; | |
374 | ||
375 | spin_lock(&cdev_lock); | |
376 | p = inode->i_cdev; | |
377 | if (!p) { | |
378 | struct kobject *kobj; | |
379 | int idx; | |
380 | spin_unlock(&cdev_lock); | |
381 | kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx); | |
382 | if (!kobj) | |
383 | return -ENXIO; | |
384 | new = container_of(kobj, struct cdev, kobj); | |
385 | spin_lock(&cdev_lock); | |
a30427d9 JC |
386 | /* Check i_cdev again in case somebody beat us to it while |
387 | we dropped the lock. */ | |
1da177e4 LT |
388 | p = inode->i_cdev; |
389 | if (!p) { | |
390 | inode->i_cdev = p = new; | |
1da177e4 LT |
391 | list_add(&inode->i_devices, &p->list); |
392 | new = NULL; | |
393 | } else if (!cdev_get(p)) | |
394 | ret = -ENXIO; | |
395 | } else if (!cdev_get(p)) | |
396 | ret = -ENXIO; | |
397 | spin_unlock(&cdev_lock); | |
398 | cdev_put(new); | |
399 | if (ret) | |
400 | return ret; | |
a518ab93 CH |
401 | |
402 | ret = -ENXIO; | |
e84f9e57 AV |
403 | fops = fops_get(p->ops); |
404 | if (!fops) | |
a518ab93 CH |
405 | goto out_cdev_put; |
406 | ||
e84f9e57 | 407 | replace_fops(filp, fops); |
a518ab93 | 408 | if (filp->f_op->open) { |
1ff97647 | 409 | ret = filp->f_op->open(inode, filp); |
a518ab93 CH |
410 | if (ret) |
411 | goto out_cdev_put; | |
412 | } | |
413 | ||
414 | return 0; | |
415 | ||
416 | out_cdev_put: | |
417 | cdev_put(p); | |
1da177e4 LT |
418 | return ret; |
419 | } | |
420 | ||
421 | void cd_forget(struct inode *inode) | |
422 | { | |
423 | spin_lock(&cdev_lock); | |
424 | list_del_init(&inode->i_devices); | |
425 | inode->i_cdev = NULL; | |
426 | spin_unlock(&cdev_lock); | |
427 | } | |
428 | ||
75c96f85 | 429 | static void cdev_purge(struct cdev *cdev) |
1da177e4 LT |
430 | { |
431 | spin_lock(&cdev_lock); | |
432 | while (!list_empty(&cdev->list)) { | |
433 | struct inode *inode; | |
434 | inode = container_of(cdev->list.next, struct inode, i_devices); | |
435 | list_del_init(&inode->i_devices); | |
436 | inode->i_cdev = NULL; | |
437 | } | |
438 | spin_unlock(&cdev_lock); | |
439 | } | |
440 | ||
441 | /* | |
442 | * Dummy default file-operations: the only thing this does | |
443 | * is contain the open that then fills in the correct operations | |
444 | * depending on the special file... | |
445 | */ | |
4b6f5d20 | 446 | const struct file_operations def_chr_fops = { |
1da177e4 | 447 | .open = chrdev_open, |
6038f373 | 448 | .llseek = noop_llseek, |
1da177e4 LT |
449 | }; |
450 | ||
451 | static struct kobject *exact_match(dev_t dev, int *part, void *data) | |
452 | { | |
453 | struct cdev *p = data; | |
454 | return &p->kobj; | |
455 | } | |
456 | ||
457 | static int exact_lock(dev_t dev, void *data) | |
458 | { | |
459 | struct cdev *p = data; | |
460 | return cdev_get(p) ? 0 : -1; | |
461 | } | |
462 | ||
cf3e43db JC |
463 | /** |
464 | * cdev_add() - add a char device to the system | |
465 | * @p: the cdev structure for the device | |
466 | * @dev: the first device number for which this device is responsible | |
467 | * @count: the number of consecutive minor numbers corresponding to this | |
468 | * device | |
469 | * | |
470 | * cdev_add() adds the device represented by @p to the system, making it | |
471 | * live immediately. A negative error code is returned on failure. | |
472 | */ | |
1da177e4 LT |
473 | int cdev_add(struct cdev *p, dev_t dev, unsigned count) |
474 | { | |
2f0157f1 DT |
475 | int error; |
476 | ||
1da177e4 LT |
477 | p->dev = dev; |
478 | p->count = count; | |
2f0157f1 DT |
479 | |
480 | error = kobj_map(cdev_map, dev, count, NULL, | |
481 | exact_match, exact_lock, p); | |
482 | if (error) | |
483 | return error; | |
484 | ||
485 | kobject_get(p->kobj.parent); | |
486 | ||
487 | return 0; | |
1da177e4 LT |
488 | } |
489 | ||
490 | static void cdev_unmap(dev_t dev, unsigned count) | |
491 | { | |
492 | kobj_unmap(cdev_map, dev, count); | |
493 | } | |
494 | ||
cf3e43db JC |
495 | /** |
496 | * cdev_del() - remove a cdev from the system | |
497 | * @p: the cdev structure to be removed | |
498 | * | |
499 | * cdev_del() removes @p from the system, possibly freeing the structure | |
500 | * itself. | |
501 | */ | |
1da177e4 LT |
502 | void cdev_del(struct cdev *p) |
503 | { | |
504 | cdev_unmap(p->dev, p->count); | |
505 | kobject_put(&p->kobj); | |
506 | } | |
507 | ||
508 | ||
509 | static void cdev_default_release(struct kobject *kobj) | |
510 | { | |
511 | struct cdev *p = container_of(kobj, struct cdev, kobj); | |
2f0157f1 DT |
512 | struct kobject *parent = kobj->parent; |
513 | ||
1da177e4 | 514 | cdev_purge(p); |
2f0157f1 | 515 | kobject_put(parent); |
1da177e4 LT |
516 | } |
517 | ||
518 | static void cdev_dynamic_release(struct kobject *kobj) | |
519 | { | |
520 | struct cdev *p = container_of(kobj, struct cdev, kobj); | |
2f0157f1 DT |
521 | struct kobject *parent = kobj->parent; |
522 | ||
1da177e4 LT |
523 | cdev_purge(p); |
524 | kfree(p); | |
2f0157f1 | 525 | kobject_put(parent); |
1da177e4 LT |
526 | } |
527 | ||
528 | static struct kobj_type ktype_cdev_default = { | |
529 | .release = cdev_default_release, | |
530 | }; | |
531 | ||
532 | static struct kobj_type ktype_cdev_dynamic = { | |
533 | .release = cdev_dynamic_release, | |
534 | }; | |
535 | ||
cf3e43db JC |
536 | /** |
537 | * cdev_alloc() - allocate a cdev structure | |
538 | * | |
539 | * Allocates and returns a cdev structure, or NULL on failure. | |
540 | */ | |
1da177e4 LT |
541 | struct cdev *cdev_alloc(void) |
542 | { | |
11b0b5ab | 543 | struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL); |
1da177e4 | 544 | if (p) { |
1da177e4 | 545 | INIT_LIST_HEAD(&p->list); |
f9cb074b | 546 | kobject_init(&p->kobj, &ktype_cdev_dynamic); |
1da177e4 LT |
547 | } |
548 | return p; | |
549 | } | |
550 | ||
cf3e43db JC |
551 | /** |
552 | * cdev_init() - initialize a cdev structure | |
553 | * @cdev: the structure to initialize | |
554 | * @fops: the file_operations for this device | |
555 | * | |
556 | * Initializes @cdev, remembering @fops, making it ready to add to the | |
557 | * system with cdev_add(). | |
558 | */ | |
99ac48f5 | 559 | void cdev_init(struct cdev *cdev, const struct file_operations *fops) |
1da177e4 LT |
560 | { |
561 | memset(cdev, 0, sizeof *cdev); | |
562 | INIT_LIST_HEAD(&cdev->list); | |
f9cb074b | 563 | kobject_init(&cdev->kobj, &ktype_cdev_default); |
1da177e4 LT |
564 | cdev->ops = fops; |
565 | } | |
566 | ||
567 | static struct kobject *base_probe(dev_t dev, int *part, void *data) | |
568 | { | |
569 | if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0) | |
570 | /* Make old-style 2.4 aliases work */ | |
571 | request_module("char-major-%d", MAJOR(dev)); | |
572 | return NULL; | |
573 | } | |
574 | ||
575 | void __init chrdev_init(void) | |
576 | { | |
577 | cdev_map = kobj_map_init(base_probe, &chrdevs_lock); | |
8077c0d9 MP |
578 | if (bdi_init(&directly_mappable_cdev_bdi)) |
579 | panic("Failed to init directly mappable cdev bdi"); | |
1da177e4 LT |
580 | } |
581 | ||
582 | ||
583 | /* Let modules do char dev stuff */ | |
584 | EXPORT_SYMBOL(register_chrdev_region); | |
585 | EXPORT_SYMBOL(unregister_chrdev_region); | |
586 | EXPORT_SYMBOL(alloc_chrdev_region); | |
587 | EXPORT_SYMBOL(cdev_init); | |
588 | EXPORT_SYMBOL(cdev_alloc); | |
589 | EXPORT_SYMBOL(cdev_del); | |
590 | EXPORT_SYMBOL(cdev_add); | |
1905b1bf TH |
591 | EXPORT_SYMBOL(__register_chrdev); |
592 | EXPORT_SYMBOL(__unregister_chrdev); | |
5da6185b | 593 | EXPORT_SYMBOL(directly_mappable_cdev_bdi); |