[PATCH] Driver Core: Make dev_info and friends print the bus name if there is no driver

This patch (as721) makes dev_info and related macros print the device's
bus name if the device doesn't have a driver, instead of printing just a
blank.  If the device isn't on a bus either... well, then it does leave
a blank space.  But it will be easier for someone else to change if they
want.

Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/device.h b/include/linux/device.h
index b473f42..1e5f30d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -416,8 +416,9 @@
 extern void firmware_unregister(struct subsystem *);
 
 /* debugging and troubleshooting/diagnostic helpers. */
+extern const char *dev_driver_string(struct device *dev);
 #define dev_printk(level, dev, format, arg...)	\
-	printk(level "%s %s: " format , (dev)->driver ? (dev)->driver->name : "" , (dev)->bus_id , ## arg)
+	printk(level "%s %s: " format , dev_driver_string(dev) , (dev)->bus_id , ## arg)
 
 #ifdef DEBUG
 #define dev_dbg(dev, format, arg...)		\