1#include <linux/fs.h>
 2#include <linux/init.h>
 3#include <linux/proc_fs.h>
 4#include <linux/seq_file.h>
 5
 6static int devinfo_show(struct seq_file *f, void *v)
 7{
 8	int i = *(loff_t *) v;
 9
10	if (i < CHRDEV_MAJOR_HASH_SIZE) {
11		if (i == 0)
12			seq_puts(f, "Character devices:\n");
13		chrdev_show(f, i);
14	}
15#ifdef CONFIG_BLOCK
16	else {
17		i -= CHRDEV_MAJOR_HASH_SIZE;
18		if (i == 0)
19			seq_puts(f, "\nBlock devices:\n");
20		blkdev_show(f, i);
21	}
22#endif
23	return 0;
24}
25
26static void *devinfo_start(struct seq_file *f, loff_t *pos)
27{
28	if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
29		return pos;
30	return NULL;
31}
32
33static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
34{
35	(*pos)++;
36	if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
37		return NULL;
38	return pos;
39}
40
41static void devinfo_stop(struct seq_file *f, void *v)
42{
43	/* Nothing to do */
44}
45
46static const struct seq_operations devinfo_ops = {
47	.start = devinfo_start,
48	.next  = devinfo_next,
49	.stop  = devinfo_stop,
50	.show  = devinfo_show
51};
52
53static int devinfo_open(struct inode *inode, struct file *filp)
54{
55	return seq_open(filp, &devinfo_ops);
56}
57
58static const struct file_operations proc_devinfo_operations = {
59	.open		= devinfo_open,
60	.read		= seq_read,
61	.llseek		= seq_lseek,
62	.release	= seq_release,
63};
64
65static int __init proc_devices_init(void)
66{
67	proc_create("devices", 0, NULL, &proc_devinfo_operations);
68	return 0;
69}
70module_init(proc_devices_init);

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/fs.h>
 3#include <linux/init.h>
 4#include <linux/proc_fs.h>
 5#include <linux/seq_file.h>
 6
 7static int devinfo_show(struct seq_file *f, void *v)
 8{
 9	int i = *(loff_t *) v;
10
11	if (i < CHRDEV_MAJOR_MAX) {
12		if (i == 0)
13			seq_puts(f, "Character devices:\n");
14		chrdev_show(f, i);
15	}
16#ifdef CONFIG_BLOCK
17	else {
18		i -= CHRDEV_MAJOR_MAX;
19		if (i == 0)
20			seq_puts(f, "\nBlock devices:\n");
21		blkdev_show(f, i);
22	}
23#endif
24	return 0;
25}
26
27static void *devinfo_start(struct seq_file *f, loff_t *pos)
28{
29	if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
30		return pos;
31	return NULL;
32}
33
34static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
35{
36	(*pos)++;
37	if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
38		return NULL;
39	return pos;
40}
41
42static void devinfo_stop(struct seq_file *f, void *v)
43{
44	/* Nothing to do */
45}
46
47static const struct seq_operations devinfo_ops = {
48	.start = devinfo_start,
49	.next  = devinfo_next,
50	.stop  = devinfo_stop,
51	.show  = devinfo_show
52};
53
54static int devinfo_open(struct inode *inode, struct file *filp)
55{
56	return seq_open(filp, &devinfo_ops);
57}
58
59static const struct file_operations proc_devinfo_operations = {
60	.open		= devinfo_open,
61	.read		= seq_read,
62	.llseek		= seq_lseek,
63	.release	= seq_release,
64};
65
66static int __init proc_devices_init(void)
67{
68	proc_create("devices", 0, NULL, &proc_devinfo_operations);
69	return 0;
70}
71fs_initcall(proc_devices_init);