Re: [PATCH v2] mm/sparse: keep mem_section_usage_size() internal

[Mike Rapoport <rppt@kernel.org>]

On Wed, Aug 05, 2026 at 10:25:36AM +0800, Muchun Song wrote:
> mem_section_usage_size() is only needed by sparsemem implementation code
> after commit ae751d567baa ("mm/bootmem_info: stop marking mem_section_usage
> as MIX_SECTION_INFO"), so keeping the declaration in mmzone.h now exposes
> the helper to all mmzone.h users for no reason.
> 
> Move the helper to sparse.h so sparse.c and sparse-vmemmap.c can share it
> through the internal header. While doing so, calculate the allocation size
> with struct_size_t(), which ties the expression to the pageblock_flags
> trailing array instead of open-coding the struct header plus bitmap size.
> 
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
> v2:
> - Mention that ae751d567baa removed the last external user (David)
> - Use struct_size_t() for the mem_section_usage size calculation (David)
> ---
>  include/linux/mmzone.h |  1 -
>  mm/sparse.c            | 10 ----------
>  mm/sparse.h            |  6 ++++++
>  3 files changed, 6 insertions(+), 11 deletions(-)

-- 
Sincerely yours,
Mike.