Re: [PATCH 3/4] bitmap: Introduce bitmap_size()

From: Andy Shevchenko
Date: Sun Jul 03 2022 - 11:21:06 EST


On Sun, Jul 03, 2022 at 08:50:19AM +0200, Christophe JAILLET wrote:
> Le 02/07/2022 à 23:09, Yury Norov a écrit :
> > On Sat, Jul 02, 2022 at 08:29:36PM +0200, Christophe JAILLET wrote:

...

> > This should be dropped, for sure, and kmalloc() at line 128 should be
> > replaced with bitmap_alloc().
>
> This kmalloc() is for a structure and a flexible array.
>
> You mean re-arranging the code to allocate the structure alone at first,
> then the bitmap?

It's one way, but it will increase fragmentation of memory. The other one
as it seems to me is to name a new API properly, i.e. bitmap_size_to_bytes().

In such case you won't need renames to begin with. And then would be able
to convert driver-by-driver in cases of duplicated code.

I think that's what confused Yuri and I kinda agree that bitmap_size() should
return bits, and not bytes. Also argument for pure bitmap_size() would be
bitmap itself, but we have no way to detect the length of bitmap because we
are using POD and not a specific data structure for it.

--
With Best Regards,
Andy Shevchenko