* Paolo Bonzini ([email protected]) wrote:
> The definition of _uatomic_cmpxchg is different in x86 and other 
> architectures.
> For x86 it is a 4-argument macro, for other architectures it is a 3-argument
> function.  The next patch will use uatomic_cmpxchg in uatomic_generic.h
> even on x86: adjust existing uses of the underscore-prefixed variant for
> consistency.

Nope. See 

#if ((BITS_PER_LONG != 64) && defined(CONFIG_RCU_COMPAT_ARCH))

#else

path in uatomic_arch_x86.h

to see why we use this trick.

We remove a dynamic test on these architectures where compatibility mode
is present.

Thanks,

Mathieu

> 
> Signed-off-by: Paolo Bonzini <[email protected]>
> ---
>  urcu/uatomic_generic.h |   24 ++++++++++++++++--------
>  1 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/urcu/uatomic_generic.h b/urcu/uatomic_generic.h
> index f65b398..383ddfa 100644
> --- a/urcu/uatomic_generic.h
> +++ b/urcu/uatomic_generic.h
> @@ -201,7 +201,8 @@ unsigned long _uatomic_add_return(void *addr, unsigned 
> long val, int len)
>               oldt = uatomic_read((unsigned char *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, old + val, 1);
> +                     oldt = uatomic_cmpxchg((unsigned char *)addr,
> +                                               old, old + val);
>               } while (oldt != old);
>  
>               return old + val;
> @@ -215,7 +216,8 @@ unsigned long _uatomic_add_return(void *addr, unsigned 
> long val, int len)
>               oldt = uatomic_read((unsigned short *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, old + val, 2);
> +                     oldt = uatomic_cmpxchg((unsigned short *)addr,
> +                                               old, old + val);
>               } while (oldt != old);
>  
>               return old + val;
> @@ -228,7 +230,8 @@ unsigned long _uatomic_add_return(void *addr, unsigned 
> long val, int len)
>               oldt = uatomic_read((unsigned int *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, old + val, 4);
> +                     oldt = uatomic_cmpxchg((unsigned int *)addr,
> +                                               old, old + val);
>               } while (oldt != old);
>  
>               return old + val;
> @@ -241,7 +244,8 @@ unsigned long _uatomic_add_return(void *addr, unsigned 
> long val, int len)
>               oldt = uatomic_read((unsigned long *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, old + val, 8);
> +                     oldt = uatomic_cmpxchg((unsigned long *)addr,
> +                                               old, old + val);
>               } while (oldt != old);
>  
>               return old + val;
> @@ -273,7 +277,8 @@ unsigned long _uatomic_exchange(void *addr, unsigned long 
> val, int len)
>               oldt = uatomic_read((unsigned char *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, val, 1);
> +                     oldt = uatomic_cmpxchg((unsigned char *)addr,
> +                                               old, val);
>               } while (oldt != old);
>  
>               return old;
> @@ -287,7 +292,8 @@ unsigned long _uatomic_exchange(void *addr, unsigned long 
> val, int len)
>               oldt = uatomic_read((unsigned short *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, val, 2);
> +                     oldt = uatomic_cmpxchg((unsigned short *)addr,
> +                                               old, val);
>               } while (oldt != old);
>  
>               return old;
> @@ -300,7 +306,8 @@ unsigned long _uatomic_exchange(void *addr, unsigned long 
> val, int len)
>               oldt = uatomic_read((unsigned int *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, val, 4);
> +                     oldt = uatomic_cmpxchg((unsigned int *)addr,
> +                                               old, val);
>               } while (oldt != old);
>  
>               return old;
> @@ -313,7 +320,8 @@ unsigned long _uatomic_exchange(void *addr, unsigned long 
> val, int len)
>               oldt = uatomic_read((unsigned long *)addr);
>               do {
>                       old = oldt;
> -                     oldt = _uatomic_cmpxchg(addr, old, val, 8);
> +                     oldt = uatomic_cmpxchg((unsigned long *)addr,
> +                                               old, val);
>               } while (oldt != old);
>  
>               return old;
> -- 
> 1.7.3.2
> 
> 
> 
> _______________________________________________
> ltt-dev mailing list
> [email protected]
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

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