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: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/fs/char_dev.c b/fs/char_dev.c
index a173551..2f18c1e 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -237,8 +237,10 @@
}
/**
- * 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
*
@@ -254,19 +256,17 @@
* /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,
- const struct file_operations *fops)
+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;
struct cdev *cdev;
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 @@
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 @@
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(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_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);