arm64: cmpxchg: update macros to prevent warnings

Make sure the value we are going to return is referenced in order to
avoid warnings from newer GCCs such as:

arch/arm64/include/asm/cmpxchg.h:162:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__cmpxchg_mb((ptr),   \
   ^
net/netfilter/nf_conntrack_core.c:674:2: note: in expansion of macro ‘cmpxchg’
  cmpxchg(&nf_conntrack_hash_rnd, 0, rand);

[Modified to use the current underlying implementation as current
mainline for both cmpxchg() and cmpxchg_local() does -- broonie]

Signed-off-by: Mark Hambleton <mahamble@broadcom.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
index 3914c0dcd09cf0d9ed3ceff35f3b5716762acc5a..56166d7f4a258867d817804c4c17145952895a20 100644 (file)
--- a/arch/arm64/include/asm/cmpxchg.h
+++ b/arch/arm64/include/asm/cmpxchg.h
@@ -158,17 +158,23 @@ static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
        return ret;
 }
 
-#define cmpxchg(ptr,o,n)                                               \
-       ((__typeof__(*(ptr)))__cmpxchg_mb((ptr),                        \
-                                         (unsigned long)(o),           \
-                                         (unsigned long)(n),           \
-                                         sizeof(*(ptr))))
-
-#define cmpxchg_local(ptr,o,n)                                         \
-       ((__typeof__(*(ptr)))__cmpxchg((ptr),                           \
-                                      (unsigned long)(o),              \
-                                      (unsigned long)(n),              \
-                                      sizeof(*(ptr))))
+#define cmpxchg(ptr, o, n) \
+({ \
+       __typeof__(*(ptr)) __ret; \
+       __ret = (__typeof__(*(ptr))) \
+               __cmpxchg_mb((ptr), (unsigned long)(o), (unsigned long)(n), \
+                            sizeof(*(ptr))); \
+       __ret; \
+})
+
+#define cmpxchg_local(ptr, o, n) \
+({ \
+       __typeof__(*(ptr)) __ret; \
+       __ret = (__typeof__(*(ptr))) \
+               __cmpxchg((ptr), (unsigned long)(o), \
+                         (unsigned long)(n), sizeof(*(ptr))); \
+       __ret; \
+})
 
 #define cmpxchg64(ptr,o,n)             cmpxchg((ptr),(o),(n))
 #define cmpxchg64_local(ptr,o,n)       cmpxchg_local((ptr),(o),(n))