add dynamice usb class patch

1 files changed, 133 insertions, 0 deletions

diff --git a/usb/usb-dynamic-usb-class.patch b/usb/usb-dynamic-usb-class.patch
new file mode 100644
index 0000000000000..c80097a44f264
--- /dev/null
+++ b/usb/usb-dynamic-usb-class.patch
@@ -0,0 +1,133 @@
+From foo@baz Tue Apr  9 12:12:43 2002
+Date: Tue, 20 Jun 2006 15:14:07 -0700
+To: Greg KH <greg@kroah.com>
+From: Greg Kroah-Hartman <gregkh@suse.de>
+Subject: USB: only make /sys/class/usb show up when there is something in it
+
+Now /sys/class/usb is dynamically created when we have something to put
+in it, and removed when all devices go away.
+
+Just trying to cut down on the clutter in sysfs...
+
+
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ drivers/usb/core/file.c |   70 +++++++++++++++++++++++++++++++++++++-----------
+ 1 file changed, 54 insertions(+), 16 deletions(-)
+
+--- gregkh-2.6.orig/drivers/usb/core/file.c
++++ gregkh-2.6/drivers/usb/core/file.c
+@@ -61,33 +61,66 @@ static struct file_operations usb_fops =
+ 	.open =		usb_open,
+ };
+ 
+-static struct class *usb_class;
++static struct usb_class {
++	struct kref kref;
++	struct class *class;
++} *usb_class;
+ 
+-int usb_major_init(void)
++static int init_usb_class(void)
+ {
+-	int error;
++	int result = 0;
+ 
+-	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
+-	if (error) {
+-		err("unable to get major %d for usb devices", USB_MAJOR);
+-		goto out;
++	if (usb_class != NULL) {
++		kref_get(&usb_class->kref);
++		goto exit;
++	}
++
++	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
++	if (!usb_class) {
++		result = -ENOMEM;
++		goto exit;
+ 	}
+ 
+-	usb_class = class_create(THIS_MODULE, "usb");
+-	if (IS_ERR(usb_class)) {
+-		error = PTR_ERR(usb_class);
++	kref_init(&usb_class->kref);
++	usb_class->class = class_create(THIS_MODULE, "usb");
++	if (IS_ERR(usb_class->class)) {
++		result = IS_ERR(usb_class->class);
+ 		err("class_create failed for usb devices");
+-		unregister_chrdev(USB_MAJOR, "usb");
+-		goto out;
++		kfree(usb_class);
++		usb_class = NULL;
+ 	}
+ 
+-out:
++exit:
++	return result;
++}
++
++static void release_usb_class(struct kref *kref)
++{
++	/* Ok, we cheat as we know we only have one usb_class */
++	class_destroy(usb_class->class);
++	kfree(usb_class);
++	usb_class = NULL;
++}
++
++static void destroy_usb_class(void)
++{
++	if (usb_class)
++		kref_put(&usb_class->kref, release_usb_class);
++}
++
++int usb_major_init(void)
++{
++	int error;
++
++	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
++	if (error)
++		err("unable to get major %d for usb devices", USB_MAJOR);
++
+ 	return error;
+ }
+ 
+ void usb_major_cleanup(void)
+ {
+-	class_destroy(usb_class);
+ 	unregister_chrdev(USB_MAJOR, "usb");
+ }
+ 
+@@ -149,6 +182,10 @@ int usb_register_dev(struct usb_interfac
+ 	if (retval)
+ 		goto exit;
+ 
++	retval = init_usb_class();
++	if (retval)
++		goto exit;
++
+ 	intf->minor = minor;
+ 
+ 	/* create a usb class device for this usb interface */
+@@ -158,7 +195,7 @@ int usb_register_dev(struct usb_interfac
+ 		++temp;
+ 	else
+ 		temp = name;
+-	intf->usb_dev = device_create(usb_class, &intf->dev,
++	intf->usb_dev = device_create(usb_class->class, &intf->dev,
+ 				      MKDEV(USB_MAJOR, minor), "%s", temp);
+ 	if (IS_ERR(intf->usb_dev)) {
+ 		spin_lock (&minor_lock);
+@@ -205,9 +242,10 @@ void usb_deregister_dev(struct usb_inter
+ 	spin_unlock (&minor_lock);
+ 
+ 	snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
+-	device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor));
++	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
+ 	intf->usb_dev = NULL;
+ 	intf->minor = -1;
++	destroy_usb_class();
+ }
+ EXPORT_SYMBOL(usb_deregister_dev);
+