[PATCH AUTOSEL 4.9 51/99] sparc64: Rework xchg() definition to avoid warnings.

[Sasha Levin]

From: "David S. Miller" <davem@xxxxxxxxxxxxx>

[ Upstream commit 6c2fc9cddc1ffdef8ada1dc8404e5affae849953 ]

Such as:

fs/ocfs2/file.c: In function âocfs2_file_write_iterâ:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

and

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c: In function âixgbevf_xdp_setupâ:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/sparc/include/asm/cmpxchg_64.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/sparc/include/asm/cmpxchg_64.h b/arch/sparc/include/asm/cmpxchg_64.h
index faa2f61058c27..92f0a46ace78e 100644
--- a/arch/sparc/include/asm/cmpxchg_64.h
+++ b/arch/sparc/include/asm/cmpxchg_64.h
@@ -40,7 +40,12 @@ static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long
 	return val;
 }
 
-#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
+#define xchg(ptr,x)							\
+({	__typeof__(*(ptr)) __ret;					\
+	__ret = (__typeof__(*(ptr)))					\
+		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)));	\
+	__ret;								\
+})
 
 void __xchg_called_with_bad_pointer(void);
 
-- 
2.20.1