Re: [PATCH 07/14] mm/bootmem_info: avoid using sparse_decode_mem_map()

Mike Rapoport
2026-03-18T08:20:21Z

On Tue, Mar 17, 2026 at 05:56:45PM +0100, David Hildenbrand (Arm) wrote:
> With SPARSEMEM_VMEMMAP, we can just do a pfn_to_page(). It is not super
> clear whether the start_pfn is properly aligned ... so let's just make
> sure it is.
>
> We will soon might try to remove the bootmem info completely, for now,
> just keep it working as is.
>
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>

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

> ---
> mm/bootmem_info.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
> index e61e08e24924..3d7675a3ae04 100644
> --- a/mm/bootmem_info.c
> +++ b/mm/bootmem_info.c
> @@ -44,17 +44,16 @@ static void __init register_page_bootmem_info_section(unsigned long start_pfn)
> {
> unsigned long mapsize, section_nr, i;
> struct mem_section *ms;
> - struct page *page, *memmap;
> struct mem_section_usage *usage;
> + struct page *page;
>
> + start_pfn = SECTION_ALIGN_DOWN(start_pfn);
> section_nr = pfn_to_section_nr(start_pfn);
> ms = __nr_to_section(section_nr);
>
> - memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
> -
> if (!preinited_vmemmap_section(ms))
> - register_page_bootmem_memmap(section_nr, memmap,
> - PAGES_PER_SECTION);
> + register_page_bootmem_memmap(section_nr, pfn_to_page(start_pfn),
> + PAGES_PER_SECTION);
>
> usage = ms->usage;
> page = virt_to_page(usage);
> --
> 2.43.0
>

--
Sincerely yours,
Mike.