kdev_t.h old major/minor numbers

[Corey Richardson <kb1pkl@aim.com>]

While reading through some of the kernel stuff I noticed that the macros
at the end of include/linux/kdev_t.h were out-of-sync with the macros at
the top. I'm not certain when/if they would ever be defined and not the
other ones (I'm very new to the kernel), but I would assume that they
shouldn't be using the old 255-number system.

Was this just an oversight or is there something else going on?

Patch:

--- linux/include/linux/kdev_t.h	2011-05-19 00:06:34.000000000 -0400
+++ git/include/linux/kdev_t.h.	2011-08-10 03:19:10.228987057 -0400
@@ -93,8 +93,11 @@
 Some programs want their definitions of MAJOR and MINOR and MKDEV
 from the kernel sources. These must be the externally visible ones.
 */
-#define MAJOR(dev)	((dev)>>8)
-#define MINOR(dev)	((dev) & 0xff)
-#define MKDEV(ma,mi)	((ma)<<8 | (mi))
+#define MINORBITS	20
+#define MINORMASK	((1U << MINORBITS) - 1)
+
+#define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
+#define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
+#define MKDEV(ma,mi)	(((ma) << MINORBITS) | (mi))
 #endif /* __KERNEL__ */
 #endif
-- 
Corey Richardson
  "Those who deny freedom to others, deserve it not for themselves"
     -- Abraham Lincoln