Make sure the value in abs() does not get truncated if it is greater than 2^32

abs() will truncate the input if is it outside the 2^32 range.  Fix that
by assuming `long' input.

This might generate worse code in the common case.
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/kernel.h

@@ -146,7 +146,7 @@ extern int _cond_resched(void);
 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 
 #define abs(x) ({				\
-		int __x = (x);			\
+		long __x = (x);			\
 		(__x < 0) ? -__x : __x;		\
 	})