Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro

Andy Shevchenko
2019-03-26T13:19:03Z

On Tue, Mar 26, 2019 at 02:03:19PM +0100, Lukas Wunner wrote:
> On Tue, Mar 26, 2019 at 07:08:18PM +0900, William Breathitt Gray wrote:
> > On Tue, Mar 26, 2019 at 10:43:45AM +0100, Lukas Wunner wrote:

> > In this case, bitmap_get_value8 could be simplified to something like
> > this:
> >
> > index = BIT_WORD(start);
> > offset = start % BITS_PER_LONG;
> > return (bitmap[index] >> offset) & 0xFF;
>

> Hm, shouldn't that be "offset = round_down(start, 8)" ?

No, the index points to the word, the offset points to the offset inside word.

> (I prefer the multi-line version FWIW.)

+1 here.

> > Would it be better to define bitmap_get_value8 as a macro then?
>
> Or a static inline.

Please, no macro. It disadvantages in terms of type checking.

--
With Best Regards,
Andy Shevchenko