Re: [PATCH v6 3/8] mm: add a set_page_section_from_pfn() helper

[Muchun Song <muchun.song@linux.dev>]

> On Jul 9, 2026, at 19:25, Li Zhe <lizhe.67@bytedance.com> wrote:
> 
> Callers that want to update section bits from a PFN currently need to
> open-code:
> 
> set_page_section(page, pfn_to_section_nr(pfn));
> 
> and guard that sequence with #ifdef SECTION_IN_PAGE_FLAGS.
> 
> Add set_page_section_from_pfn() to wrap that update in one place. When
> section bits are stored in page flags, the helper derives the section
> number from the PFN and updates the page flags. Otherwise keep it as a
> no-op so callers can use one helper without open-coding
> SECTION_IN_PAGE_FLAGS.
> 
> Convert set_page_links() to use the new helper so later ZONE_DEVICE
> fast-path patches can also update section bits without open-coding
> SECTION_IN_PAGE_FLAGS at each callsite.
> 
> This keeps the PFN-to-section translation local to the configurations
> that actually store section bits in struct page flags, and avoids
> exposing that detail to generic callers.
> 
> No functional change intended.
> 
> Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Acked-by: Muchun Song <muchun.song@linux.dev>