Re: [PATCH] edac: Do alignment logic properly in edac_align_ptr()

[Chris Metcalf <cmetcalf@tilera.com>]

On 6/6/2012 1:24 PM, Chris Metcalf wrote:
> The logic was checking the sizeof the structure being allocated to
> determine whether an alignment fixup was required.  This isn't right;
> what we actually care about is the alignment of the actual pointer that's
> about to be returned.  This became an issue recently because struct
> edac_mc_layer has a size that is not zero modulo eight, so we were
> taking the correctly-aligned pointer and forcing it to be misaligned.
> On Tile this caused an alignment exception.
>
> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
> ---
> Mauro, I assume you will push this through your tree?  I am also happy
> to push it through the tile tree.  Let me know!

Ping - I see this didn't make it into 3.5-rc2.  I'm happy to push the change
through the tile tree if that's helpful (and someone wants to give their
Acked-by).

>
>  drivers/edac/edac_mc.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
> index 10f3750..de5ba86 100644
> --- a/drivers/edac/edac_mc.c
> +++ b/drivers/edac/edac_mc.c
> @@ -164,7 +164,7 @@ void *edac_align_ptr(void **p, unsigned size, int n_elems)
>  	else
>  		return (char *)ptr;
>  
> -	r = size % align;
> +	r = (unsigned long)p % align;
>  
>  	if (r == 0)
>  		return (char *)ptr;

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com