Re: [PATCH v1] mm: convert folio_page() back to a macro

From: Vishal Moola (Oracle)
Date: Wed Sep 24 2025 - 14:48:20 EST


On Tue, Sep 23, 2025 at 04:00:58PM +0200, David Hildenbrand wrote:
> In commit 73b3294b1152 ("mm: simplify folio_page() and folio_page_idx()")
> we converted folio_page() into a static inline function. However
> briefly afterwards in commit a847b17009ec ("mm: constify highmem related
> functions for improved const-correctness") we had to add some nasty
> const-away casting to make the compiler happy when checking const
> correctness.
>
> So let's just convert it back to a simple macro so the compiler can
> check const correctness properly. There is the alternative of
> using a _Generic() similar to page_folio(), but there is not a lot of
> benefit compared to just using a simple macro.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> Cc: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> ---

Reviewed-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>