[PATCH] prepare device mapper for larger dev_t

From: Joe Thornber <thornber@sistina.com>

The only other thing that will need changing in dm to cope with 64bit
dev_t concerns the bitset I'm using to keep track of allocated minor
numbers.  A trivial patch like this would work for now:

drivers/md/dm.c

@@ -15,7 +15,7 @@
 #include <linux/slab.h>
 
 static const char *_name = DM_NAME;
-#define MAX_DEVICES (1 << KDEV_MINOR_BITS)
+#define MAX_DEVICES 1024
 
 static int major = 0;
 static int _major = 0;