lkml.org 
[lkml]   [2015]   [Jul]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] iommu-common: Do not use 64 bit constant 0xffffffffffffffffl for computing align_mask
On Sun, Jul 19, 2015 at 02:20:14PM +0200, Sowmini Varadhan wrote:
>
> Using a 64 bit constant generates "warning: integer constant is too
> large for 'long' type" on 32 bit platforms. Instead use ~0l to get
> the desired effect.
>
> Detected by Andrew Morton who has confirmed that this patch
> fixes the warning on i386/gcc-4.4.3, i386/gcc-4.4.0 and arm/gcc-4.4.4.
>
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
> ---
> lib/iommu-common.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/lib/iommu-common.c b/lib/iommu-common.c
> index df30632..fd1297d 100644
> --- a/lib/iommu-common.c
> +++ b/lib/iommu-common.c
> @@ -119,7 +119,7 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
> unsigned long align_mask = 0;
>
> if (align_order > 0)
> - align_mask = 0xffffffffffffffffl >> (64 - align_order);
> + align_mask = ~0l >> (64 - align_order);
>
Wonder if this just hides the real problem. Unless align_order
is very large, the resulting mask on 32 bit systems may be 0.
Is this really the idea ?

Guenter


\
 
 \ /
  Last update: 2015-07-19 17:41    [from the cache]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and my Meterkast|Read the blog