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Commit 1905b1bf authored by Tejun Heo's avatar Tejun Heo Committed by Takashi Iwai
Browse files

chrdev: implement __[un]register_chrdev() 



[un]register_chrdev() assume minor range 0-255.  This patch adds __
prefixed versions which take @minorbase and @count explicitly.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent ed680c4a

fs/char_dev.c

+26 −13
Original line number Diff line number Diff line
@@ -237,8 +237,10 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, 
}



/**

 * register_chrdev() - Register a major number for character devices.

 * __register_chrdev() - create and register a cdev occupying a range of minors

 * @major: major device number or 0 for dynamic allocation

 * @baseminor: first of the requested range of minor numbers

 * @count: the number of minor numbers required

 * @name: name of this range of devices

 * @fops: file operations associated with this devices

 *
@@ -254,11 +256,9 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, 
 * /dev. It only helps to keep track of the different owners of devices. If

 * your module name has only one type of devices it's ok to use e.g. the name

 * of the module here.

 *

 * This function registers a range of 256 minor numbers. The first minor number

 * is 0.

 */

int register_chrdev(unsigned int major, const char *name,

int __register_chrdev(unsigned int major, unsigned int baseminor,

		      unsigned int count, const char *name,

		      const struct file_operations *fops)

{

	struct char_device_struct *cd;
@@ -266,7 +266,7 @@ int register_chrdev(unsigned int major, const char *name, 
	char *s;

	int err = -ENOMEM;



	cd = __register_chrdev_region(major, 0, 256, name);

	cd = __register_chrdev_region(major, baseminor, count, name);

	if (IS_ERR(cd))

		return PTR_ERR(cd);
@@ -280,7 +280,7 @@ int register_chrdev(unsigned int major, const char *name, 
	for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/'))

		*s = '!';

		

	err = cdev_add(cdev, MKDEV(cd->major, 0), 256);

	err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);

	if (err)

		goto out;
@@ -290,7 +290,7 @@ int register_chrdev(unsigned int major, const char *name, 
out:

	kobject_put(&cdev->kobj);

out2:

	kfree(__unregister_chrdev_region(cd->major, 0, 256));

	kfree(__unregister_chrdev_region(cd->major, baseminor, count));

	return err;

}
@@ -316,10 +316,23 @@ void unregister_chrdev_region(dev_t from, unsigned count) 
	}

}



void unregister_chrdev(unsigned int major, const char *name)

/**

 * __unregister_chrdev - unregister and destroy a cdev

 * @major: major device number

 * @baseminor: first of the range of minor numbers

 * @count: the number of minor numbers this cdev is occupying

 * @name: name of this range of devices

 *

 * Unregister and destroy the cdev occupying the region described by

 * @major, @baseminor and @count.  This function undoes what

 * __register_chrdev() did.

 */

void __unregister_chrdev(unsigned int major, unsigned int baseminor,

			 unsigned int count, const char *name)

{

	struct char_device_struct *cd;

	cd = __unregister_chrdev_region(major, 0, 256);



	cd = __unregister_chrdev_region(major, baseminor, count);

	if (cd && cd->cdev)

		cdev_del(cd->cdev);

	kfree(cd);
@@ -568,6 +581,6 @@ EXPORT_SYMBOL(cdev_alloc); 
EXPORT_SYMBOL(cdev_del);

EXPORT_SYMBOL(cdev_add);

EXPORT_SYMBOL(cdev_index);

EXPORT_SYMBOL(register_chrdev);

EXPORT_SYMBOL(unregister_chrdev);

EXPORT_SYMBOL(__register_chrdev);

EXPORT_SYMBOL(__unregister_chrdev);

EXPORT_SYMBOL(directly_mappable_cdev_bdi);

include/linux/fs.h

+16 −3
Original line number Diff line number Diff line
@@ -1998,12 +1998,25 @@ extern void bd_release_from_disk(struct block_device *, struct gendisk *); 
#define CHRDEV_MAJOR_HASH_SIZE	255

extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);

extern int register_chrdev_region(dev_t, unsigned, const char *);

extern int register_chrdev(unsigned int, const char *,

			   const struct file_operations *);

extern void unregister_chrdev(unsigned int, const char *);

extern int __register_chrdev(unsigned int major, unsigned int baseminor,

			     unsigned int count, const char *name,

			     const struct file_operations *fops);

extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,

				unsigned int count, const char *name);

extern void unregister_chrdev_region(dev_t, unsigned);

extern void chrdev_show(struct seq_file *,off_t);



static inline int register_chrdev(unsigned int major, const char *name,

				  const struct file_operations *fops)

{

	return __register_chrdev(major, 0, 256, name, fops);

}



static inline void unregister_chrdev(unsigned int major, const char *name)

{

	__unregister_chrdev(major, 0, 256, name);

}



/* fs/block_dev.c */

#define BDEVNAME_SIZE	32	/* Largest string for a blockdev identifier */

#define BDEVT_SIZE	10	/* Largest string for MAJ:MIN for blkdev */