2015-07-21 04:50:13

by Sowmini Varadhan

Subject: [PATCH v2] iommu-common: Do not use 64 bit constant 0xffffffffffffffffl for computing align_mask

Using a 64 bit constant generates "warning: integer constant is too
large for 'long' type" on 32 bit platforms. Instead use ~0ul and
BITS_PER_LONG.

Detected by Andrew Morton on ARMD.

Signed-off-by: Sowmini Varadhan <[email protected]>
---
v2: use BITS_PER_LONG and ulong as discussed on mailing list.

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..ff19f66 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 = ~0ul >> (BITS_PER_LONG - align_order);

/* Sanity check */
if (unlikely(npages == 0)) {
--
1.7.1

2015-07-21 20:03:14

by Guenter Roeck

Subject: Re: [PATCH v2] iommu-common: Do not use 64 bit constant 0xffffffffffffffffl for computing align_mask

On Tue, Jul 21, 2015 at 06:49:41AM +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 ~0ul and
> BITS_PER_LONG.
>
> Detected by Andrew Morton on ARMD.
>
> Signed-off-by: Sowmini Varadhan <[email protected]>

Looks ok afaics.

Reviewed-by: Guenter Roeck <[email protected]>

> ---
> v2: use BITS_PER_LONG and ulong as discussed on mailing list.
>
> 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..ff19f66 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 = ~0ul >> (BITS_PER_LONG - align_order);
>
> /* Sanity check */
> if (unlikely(npages == 0)) {
> --
> 1.7.1
>