-static struct usb_class {
- struct kref kref;
- struct class *class;
-} *usb_class;
-
-static int init_usb_class(void)
-{
- int result = 0;
-
- 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;
- }
-
- 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");
- kfree(usb_class);
- usb_class = NULL;
- }
-
-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);
-}