sparc32: add __cmpxchg_u{8,16}() and teach __cmpxchg() to handle those sizes

trivial now
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

arch/sparc/include/asm/cmpxchg_32.h

@@ -38,21 +38,19 @@ static __always_inline unsigned long __arch_xchg(unsigned long x, __volatile__ v
 
 /* bug catcher for when unsupported size is used - won't link */
 void __cmpxchg_called_with_bad_pointer(void);
-/* we only need to support cmpxchg of a u32 on sparc */
+u8 __cmpxchg_u8(volatile u8 *m, u8 old, u8 new_);
+u16 __cmpxchg_u16(volatile u16 *m, u16 old, u16 new_);
 u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
 
 /* don't worry...optimizer will get rid of most of this */
 static inline unsigned long
 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
 {
-	switch (size) {
-	case 4:
-		return __cmpxchg_u32(ptr, old, new_);
-	default:
-		__cmpxchg_called_with_bad_pointer();
-		break;
-	}
-	return old;
+	return
+		size == 1 ? __cmpxchg_u8(ptr, old, new_) :
+		size == 2 ? __cmpxchg_u16(ptr, old, new_) :
+		size == 4 ? __cmpxchg_u32(ptr, old, new_) :
+			(__cmpxchg_called_with_bad_pointer(), old);
 }
 
 #define arch_cmpxchg(ptr, o, n)						\

arch/sparc/lib/atomic32.c

@@ -173,8 +173,12 @@ EXPORT_SYMBOL(sp32___change_bit);
 		return prev;					\
 	}
 
+CMPXCHG(u8)
+CMPXCHG(u16)
 CMPXCHG(u32)
 CMPXCHG(u64)
+EXPORT_SYMBOL(__cmpxchg_u8);
+EXPORT_SYMBOL(__cmpxchg_u16);
 EXPORT_SYMBOL(__cmpxchg_u32);
 EXPORT_SYMBOL(__cmpxchg_u64);