#include <linux/fs.h>
  #include <linux/init.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  
  static int devinfo_show(struct seq_file *f, void *v)
  {
  	int i = *(loff_t *) v;
  
  	if (i < CHRDEV_MAJOR_HASH_SIZE) {
  		if (i == 0)

  			seq_puts(f, "Character devices:
  ");

  		chrdev_show(f, i);
  	}
  #ifdef CONFIG_BLOCK
  	else {
  		i -= CHRDEV_MAJOR_HASH_SIZE;
  		if (i == 0)

  			seq_puts(f, "
  Block devices:
  ");

  		blkdev_show(f, i);
  	}
  #endif
  	return 0;
  }
  
  static void *devinfo_start(struct seq_file *f, loff_t *pos)
  {
  	if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
  		return pos;
  	return NULL;
  }
  
  static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
  {
  	(*pos)++;
  	if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
  		return NULL;
  	return pos;
  }
  
  static void devinfo_stop(struct seq_file *f, void *v)
  {
  	/* Nothing to do */
  }
  
  static const struct seq_operations devinfo_ops = {
  	.start = devinfo_start,
  	.next  = devinfo_next,
  	.stop  = devinfo_stop,
  	.show  = devinfo_show
  };
  
  static int devinfo_open(struct inode *inode, struct file *filp)
  {
  	return seq_open(filp, &devinfo_ops);
  }
  
  static const struct file_operations proc_devinfo_operations = {
  	.open		= devinfo_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  
  static int __init proc_devices_init(void)
  {
  	proc_create("devices", 0, NULL, &proc_devinfo_operations);
  	return 0;
  }
  module_init(proc_devices_init);