Re: [PATCH 09/14] bitmap: extend bitmap_{get,set}_value8() to bitmap_{get,set}_bits()

From: Andy Shevchenko
Date: Wed Oct 11 2023 - 06:37:01 EST


On Wed, Oct 11, 2023 at 11:33:25AM +0200, Alexander Lobakin wrote:
> From: Yury Norov <yury.norov@xxxxxxxxx>
> Date: Mon, 9 Oct 2023 09:31:15 -0700
>
> > + Alexander Potapenko <glider@xxxxxxxxxx>
> >
> > On Mon, Oct 09, 2023 at 05:10:21PM +0200, Alexander Lobakin wrote:
> >> Sometimes there's need to get a 8/16/...-bit piece of a bitmap at a
> >> particular offset. Currently, there are only bitmap_{get,set}_value8()
> >> to do that for 8 bits and that's it.
> >
> > And also a series from Alexander Potapenko, which I really hope will
> > get into the -next really soon. It introduces bitmap_read/write which
> > can set up to BITS_PER_LONG at once, with no limitations on alignment
> > of position and length:
> >
> > https://lore.kernel.org/linux-arm-kernel/ZRXbOoKHHafCWQCW@yury-ThinkPad/T/#mc311037494229647088b3a84b9f0d9b50bf227cb
> >
> > Can you consider building your series on top of it?
>
> Yeah, I mentioned in the cover letter that I'm aware of it and in fact
> it doesn't conflict much, as the functions I'm adding here get optimized
> as much as the original bitmap_{get,set}_value8(), while Alexander's
> generic helpers are heavier.
> I realize lots of calls will be optimized as well due to the offset and
> the width being compile-time constants, but not all of them. The idea of
> keeping two pairs of helpers initially came from Andy if I understood
> him correctly.

Just a disclaimer: The idea came before I saw the series by Alexander Potapenko.

> What do you think? I can provide some bloat-o-meter stats after
> rebasing. And either way, I see no issue in basing this series on top of
> Alex' one.

--
With Best Regards,
Andy Shevchenko