Re: [PATCH 07/10] powerpc/mm/slice: Switch to 3-operand slice bitops helpers

[Nicholas Piggin <npiggin@gmail.com>]

On Tue, 6 Mar 2018 15:44:46 +0100
Christophe LEROY <christophe.leroy@c-s.fr> wrote:

> Le 06/03/2018 à 14:25, Nicholas Piggin a écrit :
> > This converts the slice_mask bit operation helpers to be the usual
> > 3-operand kind, which is clearer to work with.  
> 
> What's the real benefit of doing that ?

One or two places where we want to combine 2 const input bitmaps
and can avoid the extra copy in the next patch.

E.g., slice_or_mask(&good_mask, maskp, compat_maskp);

> 
> It is helps for a subsequent patch, say it.

Fair point, I'll add to the changelog.

> > @@ -433,25 +433,33 @@ static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
> >   		return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
> >   }
> >   
> > -static inline void slice_or_mask(struct slice_mask *dst,
> > +static inline void slice_copy_mask(struct slice_mask *dst,
> >   					const struct slice_mask *src)  
> 
> This new function is not used, the compiler while probably not be happy.

I think it doesn't get so grumpy with inlines (otherwise we'd have a lot
of problems of headers). Usually I think the new function should go into
the patch where it's first used, but this being a self contained helper,
I thought it fit better to add here. Maybe I'm wrong, I can move it.