On Fri, 25 Nov 2011 13:12:04 +0100 Przemyslaw Czarnowski
<przemyslaw.hawrylewicz.czarnowski@xxxxxxxxx> wrote:
> Only least significant bit of chunk size provided by user has been used
> in test with OROM capabilities. This way user could pass value which is
> not a power of 2.
>
> Signed-off-by: Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@xxxxxxxxx>
> ---
> platform-intel.h | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/platform-intel.h b/platform-intel.h
> index 6c094d7..99450ba 100644
> --- a/platform-intel.h
> +++ b/platform-intel.h
> @@ -124,11 +124,13 @@ static inline int imsm_orom_has_raid5(const struct imsm_orom *orom)
> static inline int imsm_orom_has_chunk(const struct imsm_orom *orom, int chunk)
> {
> int fs = ffs(chunk);
> + int orom_chunk_bit;
>
> if (!fs)
> return 0;
> fs--; /* bit num to bit index */
> - return !!(orom->sss & (1 << (fs - 1)));
> + orom_chunk_bit = (orom->sss & (1 << (fs - 1)));
> + return orom_chunk_bit && 1 << orom_chunk_bit == chunk;
> }
>
>
applied, thanks.
However it feels a bit clumsy, though maybe that is just me.
I would use a separate explicit test for "is a power of 2".
ie.
if (chunk & (chunk-1))
return 0; /* not a power of 2 */
fs = ffs(chunk);
return !!(orom->sss & (1 << (fs-2)));
or something like that.
NeilBrown
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