On Mon, Jul 25, 2011 at 11:51 PM, Nicholas A. Bellinger
<nab@xxxxxxxxxxxxxxx> wrote:
>
> How about the following to add a new DIV_ROUND_UP_ULL macro
Hmm.
> #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
> +#define DIV_ROUND_UP_ULL(n,d) ( \
> +{ \
> + unsigned long long _tmp = n, _off; \
> + int _res; \
> + /* Round up using asm/div64.h:do_div */ \
> + _off = do_div(_tmp, d); \
> + if (_off != 0) \
> + _tmp++; \
> + _res = _tmp; \
> +} \
> +)
That looks buggy. Why the "_res = _tmp" there? All that does is to
truncate the result to "int", which looks bogus.
And it just looks unnecessarily complicated. Just a simple
#define DIV_ROUND_UP_ULL(ll,d) \
({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
looks like it would work and be simpler. Avoid the conditional, do the
same "add 'd-1' thing as the regular ROUND_UP().
Untested. And not much thinking involved.
Linus
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