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SubjectRe: [PATCH 1/2] kernel.h: Add DIV_ROUND_UP_ULL usage
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On Tue, 2011-07-26 at 00:53 -0700, Joe Perches wrote:
> On Tue, 2011-07-26 at 07:10 +0000, Nicholas A. Bellinger wrote:
> > Add new DIV_ROUND_UP_ULL macro usage for 32-bit architectures requiring
> > unsigned long long division of sectors * dev_max_sectors.
> []
> > diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> []
> > +#define DIV_ROUND_UP_ULL(ll,d) \
> > + ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
>
> Maybe use uint64_t and a temporary for d?
>
> #define DIV_ROUND_UP_ULL(ll, d) \
> ({ \
> typeof(d) _d = d; \
> uint64_t _tmp = (uint64_t)(ll) + _d - 1; \
> do_div(_tmp, _d); \
> _tmp; \
> })
>
>

Hi Joe,

Not sure on this one myself.. Would this case ever be strictly required
for proper 32-bit operation with unsigned long long division with
sector_t..?

--nab




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