[PATCH] driver core: add helper device_is_registered()

add the helper and use it instead of open coding the klist_node_attached() check
(which is a layering violation IMHO)

idea by Alan Stern.

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/device.h b/include/linux/device.h
index 06e5d42..95d607a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -317,6 +317,11 @@
 	dev->driver_data = data;
 }
 
+static inline int device_is_registered(struct device *dev)
+{
+	return klist_node_attached(&dev->knode_bus);
+}
+
 /*
  * High level routines for use by the bus drivers
  */