| Message ID | 1387543334-14036-1-git-send-email-broonie@kernel.org |
|---|---|
| State | New |
| Headers | show |
On Fri, Dec 20, 2013 at 12:42:14PM +0000, Mark Brown wrote: > From: Mark Hambleton <mahamble@broadcom.com> > > 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> I merged the previous one (should be in -next as of last night), I guess it's the same since the patch doesn't have a version number. But I wonder whether uses of cmpxchg without checking the return value are sane.
On Fri, Dec 20, 2013 at 02:10:02PM +0000, Catalin Marinas wrote: > I merged the previous one (should be in -next as of last night), I guess > it's the same since the patch doesn't have a version number. But I It's the same patch, I was resending it because it had been a while with no response. > wonder whether uses of cmpxchg without checking the return value are > sane. IIRC it was used as part of another macro which did have some reasonable uses without checking the return value.
diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h index 3914c0dcd09c..c558da59989e 100644 --- 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))