Re: [PATCH 3/23] make atomic_read() and atomic_set() behavior consistent on arm

[Russell King]

On Mon, Aug 13, 2007 at 08:46:52AM -0400, Chris Snook wrote:
> On Mon, Aug 13, 2007 at 01:19:31PM +0100, Russell King wrote:
> > On Mon, Aug 13, 2007 at 07:09:46AM -0400, Chris Snook wrote:
> > > By popular demand, I've redone the patchset to include volatile casts in
> > > atomic_set as well.  I've also converted the macros to inline functions, to
> > > help catch type mismatches at compile time.
> > 
> > and in the rest of include/asm-arm/atomic.h:
> > 
> > #else /* ARM_ARCH_6 */
> > 
> > #include <asm/system.h>
> > 
> > #ifdef CONFIG_SMP
> > #error SMP not supported on pre-ARMv6 CPUs
> > #endif
> > 
> > #define atomic_set(v,i) (((v)->counter) = (i))
> > 
> > Seems you missed that.  Grep is a wonderful tool.
> 
> D'oh!  Try this.

Thanks.

Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>

> --- linux-2.6.23-rc3-orig/include/asm-arm/atomic.h	2007-07-08 19:32:17.000000000 -0400
> +++ linux-2.6.23-rc3/include/asm-arm/atomic.h	2007-08-13 08:39:52.000000000 -0400
> @@ -14,13 +14,16 @@
>  #include <linux/compiler.h>
>  #include <asm/system.h>
>  
> -typedef struct { volatile int counter; } atomic_t;
> +typedef struct { int counter; } atomic_t;
>  
>  #define ATOMIC_INIT(i)	{ (i) }
>  
>  #ifdef __KERNEL__
>  
> -#define atomic_read(v)	((v)->counter)
> +static inline int atomic_read(atomic_t *v)
> +{
> +        return *(volatile int *)&v->counter;
> +}
>  
>  #if __LINUX_ARM_ARCH__ >= 6
>  
> @@ -122,7 +125,10 @@ static inline void atomic_clear_mask(uns
>  #error SMP not supported on pre-ARMv6 CPUs
>  #endif
>  
> -#define atomic_set(v,i)	(((v)->counter) = (i))
> +static inline void atomic_set(atomic_t *v, int i)
> +{
> +        *(volatile int *)&v->counter = i;
> +}
>  
>  static inline int atomic_add_return(int i, atomic_t *v)
>  {
> -
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-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:
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