atomic.h: i386 type safety fix

Remove an explicit cast to an integer type for the result returned by cmpxchg.
 It is not per se a problem on the i386 architecture, because sizeof(int) ==
sizeof(long), but whenever this code is cut'n'pasted to a accept passing an
atomic64_t value as parameter to cmpxchg, xchg and add_unless, having 64 bits
inputs casted to 32 bits.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-i386/atomic.h

@@ -207,8 +207,8 @@ static __inline__ int atomic_sub_return(int i, atomic_t *v)
 	return atomic_add_return(-i,v);
 }
 
-#define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
-#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
+#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
+#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
 
 /**
  * atomic_add_unless - add unless the number is already a given value
@@ -221,7 +221,7 @@ static __inline__ int atomic_sub_return(int i, atomic_t *v)
  */
 #define atomic_add_unless(v, a, u)				\
 ({								\
-	int c, old;						\
+	__typeof__((v)->counter) c, old;			\
 	c = atomic_read(v);					\
 	for (;;) {						\
 		if (unlikely(c == (u)))				\