Re: [PATCH 5/9] mips/gup: Replace ACCESS_ONCE with READ_ONCE

[Paul E. McKenney]

On Wed, Dec 03, 2014 at 11:30:17PM +0100, Christian Borntraeger wrote:
> ACCESS_ONCE does not work reliably on non-scalar types. For
> example gcc 4.6 and 4.7 might remove the volatile tag for such
> accesses during the SRA (scalar replacement of aggregates) step
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)
> 
> Change the gup code to replace ACCESS_ONCE with READ_ONCE.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>

Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>

> ---
>  arch/mips/mm/gup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c
> index 06ce17c..8aa50e3 100644
> --- a/arch/mips/mm/gup.c
> +++ b/arch/mips/mm/gup.c
> @@ -30,7 +30,7 @@ retry:
> 
>  	return pte;
>  #else
> -	return ACCESS_ONCE(*ptep);
> +	return READ_ONCE(*ptep);
>  #endif
>  }
> 
> -- 
> 1.9.3
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/