Re: [PATCH 0/3] mm: treewide: make get_free_pages() and return void *

[Mike Rapoport <rppt@kernel.org>]

On Sun, Oct 19, 2025 at 01:30:47AM +0100, Matthew Wilcox wrote:
> On Sat, Oct 18, 2025 at 12:29:59PM +0300, Mike Rapoport wrote:
> > Vast majority of allocations that use get_free_pages() and its derivatives
> > cast the returned unsigned long to a pointer and then cast it back to
> > unsigned long when freeing the memory.
> > 
> > These castings are useless and only obfuscate the code.
> > 
> > Make get_free_pages() and friends return 'void *' and free_pages() accept
> > 'void *' as its address parameter.
> 
> No.  Linus has rejected this change before.  I can't find it now, it was
> a long time ago. 

If it was a long time ago, he might not object it now.

> Most of them shouldn't be using get_free_pages() at all, they should be
> using kmalloc().

Don't know if most but some of them could. Still, we'd have a bunch of
get_free_pages() users with needless castings.
And converting callers that should use kmalloc() is a long and tedious
process, while here we get an API improvement in a single automated change.

-- 
Sincerely yours,
Mike.