kernel26-2.6.12-alx-r9/fs/char_dev.c

/*
 *  linux/fs/char_dev.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/config.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <linux/major.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>

#include <linux/kobject.h>
#include <linux/kobj_map.h>
#include <linux/cdev.h>

#ifdef CONFIG_KMOD
#include <linux/kmod.h>
#endif

static struct kobj_map *cdev_map;

#define MAX_PROBE_HASH 255	/* random */

static DECLARE_MUTEX(chrdevs_lock);

static struct char_device_struct {
	struct char_device_struct *next;
	unsigned int major;
	unsigned int baseminor;
	int minorct;
	const char *name;
	struct file_operations *fops;
	struct cdev *cdev;		/* will die */
} *chrdevs[MAX_PROBE_HASH];

/* index in the above */
static inline int major_to_index(int major)
{
	return major % MAX_PROBE_HASH;
}

/* get char device names in somewhat random order */
int get_chrdev_list(char *page)
{
	struct char_device_struct *cd;
	int i, len;

	len = sprintf(page, "Character devices:\n");

	down(&chrdevs_lock);
	for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) {
		for (cd = chrdevs[i]; cd; cd = cd->next)
			len += sprintf(page+len, "%3d %s\n",
				       cd->major, cd->name);
	}
	up(&chrdevs_lock);

	return len;
}

/*
 * Register a single major with a specified minor range.
 *
 * If major == 0 this functions will dynamically allocate a major and return
 * its number.
 *
 * If major > 0 this function will attempt to reserve the passed range of
 * minors and will return zero on success.
 *
 * Returns a -ve errno on failure.
 */
static struct char_device_struct *
__register_chrdev_region(unsigned int major, unsigned int baseminor,
			   int minorct, const char *name)
{
	struct char_device_struct *cd, **cp;
	int ret = 0;
	int i;

	cd = kmalloc(sizeof(struct char_device_struct), GFP_KERNEL);
	if (cd == NULL)
		return ERR_PTR(-ENOMEM);

	memset(cd, 0, sizeof(struct char_device_struct));

	down(&chrdevs_lock);

	/* temporary */
	if (major == 0) {
		for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) {
			if (chrdevs[i] == NULL)
				break;
		}

		if (i == 0) {
			ret = -EBUSY;
			goto out;
		}
		major = i;
		ret = major;
	}

	cd->major = major;
	cd->baseminor = baseminor;
	cd->minorct = minorct;
	cd->name = name;

	i = major_to_index(major);

	for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
		if ((*cp)->major > major ||
		    ((*cp)->major == major && (*cp)->baseminor >= baseminor))
			break;
	if (*cp && (*cp)->major == major &&
	    (*cp)->baseminor < baseminor + minorct) {
		ret = -EBUSY;
		goto out;
	}
	cd->next = *cp;
	*cp = cd;
	up(&chrdevs_lock);
	return cd;
out:
	up(&chrdevs_lock);
	kfree(cd);
	return ERR_PTR(ret);
}

static struct char_device_struct *
__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
{
	struct char_device_struct *cd = NULL, **cp;
	int i = major_to_index(major);

	down(&chrdevs_lock);
	for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
		if ((*cp)->major == major &&
		    (*cp)->baseminor == baseminor &&
		    (*cp)->minorct == minorct)
			break;
	if (*cp) {
		cd = *cp;
		*cp = cd->next;
	}
	up(&chrdevs_lock);
	return cd;
}

int register_chrdev_region(dev_t from, unsigned count, const char *name)
{
	struct char_device_struct *cd;
	dev_t to = from + count;
	dev_t n, next;

	for (n = from; n < to; n = next) {
		next = MKDEV(MAJOR(n)+1, 0);
		if (next > to)
			next = to;
		cd = __register_chrdev_region(MAJOR(n), MINOR(n),
			       next - n, name);
		if (IS_ERR(cd))
			goto fail;
	}
	return 0;
fail:
	to = n;
	for (n = from; n < to; n = next) {
		next = MKDEV(MAJOR(n)+1, 0);
		kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
	}
	return PTR_ERR(cd);
}

int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
			const char *name)
{
	struct char_device_struct *cd;
	cd = __register_chrdev_region(0, baseminor, count, name);
	if (IS_ERR(cd))
		return PTR_ERR(cd);
	*dev = MKDEV(cd->major, cd->baseminor);
	return 0;
}

int register_chrdev(unsigned int major, const char *name,
		    struct file_operations *fops)
{
	struct char_device_struct *cd;
	struct cdev *cdev;
	char *s;
	int err = -ENOMEM;

	cd = __register_chrdev_region(major, 0, 256, name);
	if (IS_ERR(cd))
		return PTR_ERR(cd);
	
	cdev = cdev_alloc();
	if (!cdev)
		goto out2;

	cdev->owner = fops->owner;
	cdev->ops = fops;
	kobject_set_name(&cdev->kobj, "%s", name);
	for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/'))
		*s = '!';
		
	err = cdev_add(cdev, MKDEV(cd->major, 0), 256);
	if (err)
		goto out;

	cd->cdev = cdev;

	return major ? 0 : cd->major;
out:
	kobject_put(&cdev->kobj);
out2:
	kfree(__unregister_chrdev_region(cd->major, 0, 256));
	return err;
}

void unregister_chrdev_region(dev_t from, unsigned count)
{
	dev_t to = from + count;
	dev_t n, next;

	for (n = from; n < to; n = next) {
		next = MKDEV(MAJOR(n)+1, 0);
		if (next > to)
			next = to;
		kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
	}
}

int unregister_chrdev(unsigned int major, const char *name)
{
	struct char_device_struct *cd;
	cd = __unregister_chrdev_region(major, 0, 256);
	if (cd && cd->cdev)
		cdev_del(cd->cdev);
	kfree(cd);
	return 0;
}

static DEFINE_SPINLOCK(cdev_lock);

static struct kobject *cdev_get(struct cdev *p)
{
	struct module *owner = p->owner;
	struct kobject *kobj;

	if (owner && !try_module_get(owner))
		return NULL;
	kobj = kobject_get(&p->kobj);
	if (!kobj)
		module_put(owner);
	return kobj;
}

void cdev_put(struct cdev *p)
{
	if (p) {
		kobject_put(&p->kobj);
		module_put(p->owner);
	}
}

/*
 * Called every time a character special file is opened
 */
int chrdev_open(struct inode * inode, struct file * filp)
{
	struct cdev *p;
	struct cdev *new = NULL;
	int ret = 0;

	spin_lock(&cdev_lock);
	p = inode->i_cdev;
	if (!p) {
		struct kobject *kobj;
		int idx;
		spin_unlock(&cdev_lock);
		kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
		if (!kobj)
			return -ENXIO;
		new = container_of(kobj, struct cdev, kobj);
		spin_lock(&cdev_lock);
		p = inode->i_cdev;
		if (!p) {
			inode->i_cdev = p = new;
			inode->i_cindex = idx;
			list_add(&inode->i_devices, &p->list);
			new = NULL;
		} else if (!cdev_get(p))
			ret = -ENXIO;
	} else if (!cdev_get(p))
		ret = -ENXIO;
	spin_unlock(&cdev_lock);
	cdev_put(new);
	if (ret)
		return ret;
	filp->f_op = fops_get(p->ops);
	if (!filp->f_op) {
		cdev_put(p);
		return -ENXIO;
	}
	if (filp->f_op->open) {
		lock_kernel();
		ret = filp->f_op->open(inode,filp);
		unlock_kernel();
	}
	if (ret)
		cdev_put(p);
	return ret;
}

void cd_forget(struct inode *inode)
{
	spin_lock(&cdev_lock);
	list_del_init(&inode->i_devices);
	inode->i_cdev = NULL;
	spin_unlock(&cdev_lock);
}

static void cdev_purge(struct cdev *cdev)
{
	spin_lock(&cdev_lock);
	while (!list_empty(&cdev->list)) {
		struct inode *inode;
		inode = container_of(cdev->list.next, struct inode, i_devices);
		list_del_init(&inode->i_devices);
		inode->i_cdev = NULL;
	}
	spin_unlock(&cdev_lock);
}

/*
 * Dummy default file-operations: the only thing this does
 * is contain the open that then fills in the correct operations
 * depending on the special file...
 */
struct file_operations def_chr_fops = {
	.open = chrdev_open,
};

static struct kobject *exact_match(dev_t dev, int *part, void *data)
{
	struct cdev *p = data;
	return &p->kobj;
}

static int exact_lock(dev_t dev, void *data)
{
	struct cdev *p = data;
	return cdev_get(p) ? 0 : -1;
}

int cdev_add(struct cdev *p, dev_t dev, unsigned count)
{
	p->dev = dev;
	p->count = count;
	return kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p);
}

static void cdev_unmap(dev_t dev, unsigned count)
{
	kobj_unmap(cdev_map, dev, count);
}

void cdev_del(struct cdev *p)
{
	cdev_unmap(p->dev, p->count);
	kobject_put(&p->kobj);
}


static void cdev_default_release(struct kobject *kobj)
{
	struct cdev *p = container_of(kobj, struct cdev, kobj);
	cdev_purge(p);
}

static void cdev_dynamic_release(struct kobject *kobj)
{
	struct cdev *p = container_of(kobj, struct cdev, kobj);
	cdev_purge(p);
	kfree(p);
}

static struct kobj_type ktype_cdev_default = {
	.release	= cdev_default_release,
};

static struct kobj_type ktype_cdev_dynamic = {
	.release	= cdev_dynamic_release,
};

struct cdev *cdev_alloc(void)
{
	struct cdev *p = kmalloc(sizeof(struct cdev), GFP_KERNEL);
	if (p) {
		memset(p, 0, sizeof(struct cdev));
		p->kobj.ktype = &ktype_cdev_dynamic;
		INIT_LIST_HEAD(&p->list);
		kobject_init(&p->kobj);
	}
	return p;
}

void cdev_init(struct cdev *cdev, struct file_operations *fops)
{
	memset(cdev, 0, sizeof *cdev);
	INIT_LIST_HEAD(&cdev->list);
	cdev->kobj.ktype = &ktype_cdev_default;
	kobject_init(&cdev->kobj);
	cdev->ops = fops;
}

static struct kobject *base_probe(dev_t dev, int *part, void *data)
{
	if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
		/* Make old-style 2.4 aliases work */
		request_module("char-major-%d", MAJOR(dev));
	return NULL;
}

void __init chrdev_init(void)
{
	cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
}


/* Let modules do char dev stuff */
EXPORT_SYMBOL(register_chrdev_region);
EXPORT_SYMBOL(unregister_chrdev_region);
EXPORT_SYMBOL(alloc_chrdev_region);
EXPORT_SYMBOL(cdev_init);
EXPORT_SYMBOL(cdev_alloc);
EXPORT_SYMBOL(cdev_del);
EXPORT_SYMBOL(cdev_add);
EXPORT_SYMBOL(register_chrdev);
EXPORT_SYMBOL(unregister_chrdev);
1	/*
2	* linux/fs/char_dev.c
3	*
4	* Copyright (C) 1991, 1992 Linus Torvalds
5	*/
6
7	#include <linux/config.h>
8	#include <linux/init.h>
9	#include <linux/fs.h>
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>
16	#include <linux/smp_lock.h>
17	#include <linux/devfs_fs_kernel.h>
18
19	#include <linux/kobject.h>
20	#include <linux/kobj_map.h>
21	#include <linux/cdev.h>
22
23	#ifdef CONFIG_KMOD
24	#include <linux/kmod.h>
25	#endif
26
27	static struct kobj_map *cdev_map;
28
29	#define MAX_PROBE_HASH 255 /* random */
30
31	static DECLARE_MUTEX(chrdevs_lock);
32
33	static struct char_device_struct {
34	struct char_device_struct *next;
35	unsigned int major;
36	unsigned int baseminor;
37	int minorct;
38	const char *name;
39	struct file_operations *fops;
40	struct cdev cdev; / will die */
41	} *chrdevs[MAX_PROBE_HASH];
42
43	/* index in the above */
44	static inline int major_to_index(int major)
45	{
46	return major % MAX_PROBE_HASH;
47	}
48
49	/* get char device names in somewhat random order */
50	int get_chrdev_list(char *page)
51	{
52	struct char_device_struct *cd;
53	int i, len;
54
55	len = sprintf(page, "Character devices:\n");
56
57	down(&chrdevs_lock);
58	for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) {
59	for (cd = chrdevs[i]; cd; cd = cd->next)
60	len += sprintf(page+len, "%3d %s\n",
61	cd->major, cd->name);
62	}
63	up(&chrdevs_lock);
64
65	return len;
66	}
67
68	/*
69	* Register a single major with a specified minor range.
70	*
71	* If major == 0 this functions will dynamically allocate a major and return
72	* its number.
73	*
74	* If major > 0 this function will attempt to reserve the passed range of
75	* minors and will return zero on success.
76	*
77	* Returns a -ve errno on failure.
78	*/
79	static struct char_device_struct *
80	__register_chrdev_region(unsigned int major, unsigned int baseminor,
81	int minorct, const char *name)
82	{
83	struct char_device_struct cd, *cp;
84	int ret = 0;
85	int i;
86
87	cd = kmalloc(sizeof(struct char_device_struct), GFP_KERNEL);
88	if (cd == NULL)
89	return ERR_PTR(-ENOMEM);
90
91	memset(cd, 0, sizeof(struct char_device_struct));
92
93	down(&chrdevs_lock);
94
95	/* temporary */
96	if (major == 0) {
97	for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) {
98	if (chrdevs[i] == NULL)
99	break;
100	}
101
102	if (i == 0) {
103	ret = -EBUSY;
104	goto out;
105	}
106	major = i;
107	ret = major;
108	}
109
110	cd->major = major;
111	cd->baseminor = baseminor;
112	cd->minorct = minorct;
113	cd->name = name;
114
115	i = major_to_index(major);
116
117	for (cp = &chrdevs[i]; cp; cp = &(cp)->next)
118	if ((*cp)->major > major \|\|
119	((cp)->major == major && (cp)->baseminor >= baseminor))
120	break;
121	if (cp && (cp)->major == major &&
122	(*cp)->baseminor < baseminor + minorct) {
123	ret = -EBUSY;
124	goto out;
125	}
126	cd->next = *cp;
127	*cp = cd;
128	up(&chrdevs_lock);
129	return cd;
130	out:
131	up(&chrdevs_lock);
132	kfree(cd);
133	return ERR_PTR(ret);
134	}
135
136	static struct char_device_struct *
137	__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
138	{
139	struct char_device_struct cd = NULL, *cp;
140	int i = major_to_index(major);
141
142	down(&chrdevs_lock);
143	for (cp = &chrdevs[i]; cp; cp = &(cp)->next)
144	if ((*cp)->major == major &&
145	(*cp)->baseminor == baseminor &&
146	(*cp)->minorct == minorct)
147	break;
148	if (*cp) {
149	cd = *cp;
150	*cp = cd->next;
151	}
152	up(&chrdevs_lock);
153	return cd;
154	}
155
156	int register_chrdev_region(dev_t from, unsigned count, const char *name)
157	{
158	struct char_device_struct *cd;
159	dev_t to = from + count;
160	dev_t n, next;
161
162	for (n = from; n < to; n = next) {
163	next = MKDEV(MAJOR(n)+1, 0);
164	if (next > to)
165	next = to;
166	cd = __register_chrdev_region(MAJOR(n), MINOR(n),
167	next - n, name);
168	if (IS_ERR(cd))
169	goto fail;
170	}
171	return 0;
172	fail:
173	to = n;
174	for (n = from; n < to; n = next) {
175	next = MKDEV(MAJOR(n)+1, 0);
176	kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
177	}
178	return PTR_ERR(cd);
179	}
180
181	int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
182	const char *name)
183	{
184	struct char_device_struct *cd;
185	cd = __register_chrdev_region(0, baseminor, count, name);
186	if (IS_ERR(cd))
187	return PTR_ERR(cd);
188	*dev = MKDEV(cd->major, cd->baseminor);
189	return 0;
190	}
191
192	int register_chrdev(unsigned int major, const char *name,
193	struct file_operations *fops)
194	{
195	struct char_device_struct *cd;
196	struct cdev *cdev;
197	char *s;
198	int err = -ENOMEM;
199
200	cd = __register_chrdev_region(major, 0, 256, name);
201	if (IS_ERR(cd))
202	return PTR_ERR(cd);
203
204	cdev = cdev_alloc();
205	if (!cdev)
206	goto out2;
207
208	cdev->owner = fops->owner;
209	cdev->ops = fops;
210	kobject_set_name(&cdev->kobj, "%s", name);
211	for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/'))
212	*s = '!';
213
214	err = cdev_add(cdev, MKDEV(cd->major, 0), 256);
215	if (err)
216	goto out;
217
218	cd->cdev = cdev;
219
220	return major ? 0 : cd->major;
221	out:
222	kobject_put(&cdev->kobj);
223	out2:
224	kfree(__unregister_chrdev_region(cd->major, 0, 256));
225	return err;
226	}
227
228	void unregister_chrdev_region(dev_t from, unsigned count)
229	{
230	dev_t to = from + count;
231	dev_t n, next;
232
233	for (n = from; n < to; n = next) {
234	next = MKDEV(MAJOR(n)+1, 0);
235	if (next > to)
236	next = to;
237	kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
238	}
239	}
240
241	int unregister_chrdev(unsigned int major, const char *name)
242	{
243	struct char_device_struct *cd;
244	cd = __unregister_chrdev_region(major, 0, 256);
245	if (cd && cd->cdev)
246	cdev_del(cd->cdev);
247	kfree(cd);
248	return 0;
249	}
250
251	static DEFINE_SPINLOCK(cdev_lock);
252
253	static struct kobject cdev_get(struct cdev p)
254	{
255	struct module *owner = p->owner;
256	struct kobject *kobj;
257
258	if (owner && !try_module_get(owner))
259	return NULL;
260	kobj = kobject_get(&p->kobj);
261	if (!kobj)
262	module_put(owner);
263	return kobj;
264	}
265
266	void cdev_put(struct cdev *p)
267	{
268	if (p) {
269	kobject_put(&p->kobj);
270	module_put(p->owner);
271	}
272	}
273
274	/*
275	* Called every time a character special file is opened
276	*/
277	int chrdev_open(struct inode * inode, struct file * filp)
278	{
279	struct cdev *p;
280	struct cdev *new = NULL;
281	int ret = 0;
282
283	spin_lock(&cdev_lock);
284	p = inode->i_cdev;
285	if (!p) {
286	struct kobject *kobj;
287	int idx;
288	spin_unlock(&cdev_lock);
289	kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
290	if (!kobj)
291	return -ENXIO;
292	new = container_of(kobj, struct cdev, kobj);
293	spin_lock(&cdev_lock);
294	p = inode->i_cdev;
295	if (!p) {
296	inode->i_cdev = p = new;
297	inode->i_cindex = idx;
298	list_add(&inode->i_devices, &p->list);
299	new = NULL;
300	} else if (!cdev_get(p))
301	ret = -ENXIO;
302	} else if (!cdev_get(p))
303	ret = -ENXIO;
304	spin_unlock(&cdev_lock);
305	cdev_put(new);
306	if (ret)
307	return ret;
308	filp->f_op = fops_get(p->ops);
309	if (!filp->f_op) {
310	cdev_put(p);
311	return -ENXIO;
312	}
313	if (filp->f_op->open) {
314	lock_kernel();
315	ret = filp->f_op->open(inode,filp);
316	unlock_kernel();
317	}
318	if (ret)
319	cdev_put(p);
320	return ret;
321	}
322
323	void cd_forget(struct inode *inode)
324	{
325	spin_lock(&cdev_lock);
326	list_del_init(&inode->i_devices);
327	inode->i_cdev = NULL;
328	spin_unlock(&cdev_lock);
329	}
330
331	static void cdev_purge(struct cdev *cdev)
332	{
333	spin_lock(&cdev_lock);
334	while (!list_empty(&cdev->list)) {
335	struct inode *inode;
336	inode = container_of(cdev->list.next, struct inode, i_devices);
337	list_del_init(&inode->i_devices);
338	inode->i_cdev = NULL;
339	}
340	spin_unlock(&cdev_lock);
341	}
342
343	/*
344	* Dummy default file-operations: the only thing this does
345	* is contain the open that then fills in the correct operations
346	* depending on the special file...
347	*/
348	struct file_operations def_chr_fops = {
349	.open = chrdev_open,
350	};
351
352	static struct kobject exact_match(dev_t dev, int part, void *data)
353	{
354	struct cdev *p = data;
355	return &p->kobj;
356	}
357
358	static int exact_lock(dev_t dev, void *data)
359	{
360	struct cdev *p = data;
361	return cdev_get(p) ? 0 : -1;
362	}
363
364	int cdev_add(struct cdev *p, dev_t dev, unsigned count)
365	{
366	p->dev = dev;
367	p->count = count;
368	return kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p);
369	}
370
371	static void cdev_unmap(dev_t dev, unsigned count)
372	{
373	kobj_unmap(cdev_map, dev, count);
374	}
375
376	void cdev_del(struct cdev *p)
377	{
378	cdev_unmap(p->dev, p->count);
379	kobject_put(&p->kobj);
380	}
381
382
383	static void cdev_default_release(struct kobject *kobj)
384	{
385	struct cdev *p = container_of(kobj, struct cdev, kobj);
386	cdev_purge(p);
387	}
388
389	static void cdev_dynamic_release(struct kobject *kobj)
390	{
391	struct cdev *p = container_of(kobj, struct cdev, kobj);
392	cdev_purge(p);
393	kfree(p);
394	}
395
396	static struct kobj_type ktype_cdev_default = {
397	.release = cdev_default_release,
398	};
399
400	static struct kobj_type ktype_cdev_dynamic = {
401	.release = cdev_dynamic_release,
402	};
403
404	struct cdev *cdev_alloc(void)
405	{
406	struct cdev *p = kmalloc(sizeof(struct cdev), GFP_KERNEL);
407	if (p) {
408	memset(p, 0, sizeof(struct cdev));
409	p->kobj.ktype = &ktype_cdev_dynamic;
410	INIT_LIST_HEAD(&p->list);
411	kobject_init(&p->kobj);
412	}
413	return p;
414	}
415
416	void cdev_init(struct cdev cdev, struct file_operations fops)
417	{
418	memset(cdev, 0, sizeof *cdev);
419	INIT_LIST_HEAD(&cdev->list);
420	cdev->kobj.ktype = &ktype_cdev_default;
421	kobject_init(&cdev->kobj);
422	cdev->ops = fops;
423	}
424
425	static struct kobject base_probe(dev_t dev, int part, void *data)
426	{
427	if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
428	/* Make old-style 2.4 aliases work */
429	request_module("char-major-%d", MAJOR(dev));
430	return NULL;
431	}
432
433	void __init chrdev_init(void)
434	{
435	cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
436	}
437
438
439	/* Let modules do char dev stuff */
440	EXPORT_SYMBOL(register_chrdev_region);
441	EXPORT_SYMBOL(unregister_chrdev_region);
442	EXPORT_SYMBOL(alloc_chrdev_region);
443	EXPORT_SYMBOL(cdev_init);
444	EXPORT_SYMBOL(cdev_alloc);
445	EXPORT_SYMBOL(cdev_del);
446	EXPORT_SYMBOL(cdev_add);
447	EXPORT_SYMBOL(register_chrdev);
448	EXPORT_SYMBOL(unregister_chrdev);