Re: [PATCH 3/8] mm: remove clear_page_dirty_for_io()

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Mon, Nov 02, 2026 at 05:54:08PM -0500, Tal Zussman wrote:
> There are no callers left. Point the comments that named it at
> folio_clear_dirty_for_io() instead.
>
> Signed-off-by: Tal Zussman <tz2294@columbia.edu>

LGTM!

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

> ---
>  include/linux/pagemap.h | 1 -
>  mm/folio-compat.c       | 6 ------
>  mm/gup.c                | 6 +++---
>  mm/page-writeback.c     | 2 +-
>  4 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 692ce3867a1d..9adfeae2153c 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -1315,7 +1315,6 @@ static inline void folio_cancel_dirty(struct folio *folio)
>  		__folio_cancel_dirty(folio);
>  }
>  bool folio_clear_dirty_for_io(struct folio *folio);
> -bool clear_page_dirty_for_io(struct page *page);
>  void folio_invalidate(struct folio *folio, size_t offset, size_t length);
>  bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
>
> diff --git a/mm/folio-compat.c b/mm/folio-compat.c
> index 9f2cd0ebfbbd..13d4d39e1896 100644
> --- a/mm/folio-compat.c
> +++ b/mm/folio-compat.c
> @@ -42,12 +42,6 @@ int set_page_dirty_lock(struct page *page)
>  }
>  EXPORT_SYMBOL(set_page_dirty_lock);
>
> -bool clear_page_dirty_for_io(struct page *page)
> -{
> -	return folio_clear_dirty_for_io(page_folio(page));
> -}
> -EXPORT_SYMBOL(clear_page_dirty_for_io);
> -
>  bool redirty_page_for_writepage(struct writeback_control *wbc,
>  		struct page *page)
>  {
> diff --git a/mm/gup.c b/mm/gup.c
> index 7d43ce717b24..335dcb3a5c17 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -298,16 +298,16 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
>  		folio = gup_folio_next(pages, npages, i, &nr);
>  		/*
>  		 * Checking PageDirty at this point may race with
> -		 * clear_page_dirty_for_io(), but that's OK. Two key
> +		 * folio_clear_dirty_for_io(), but that's OK. Two key
>  		 * cases:
>  		 *
>  		 * 1) This code sees the page as already dirty, so it
>  		 * skips the call to set_page_dirty(). That could happen
> -		 * because clear_page_dirty_for_io() called
> +		 * because folio_clear_dirty_for_io() called
>  		 * folio_mkclean(), followed by set_page_dirty().
>  		 * However, now the page is going to get written back,
>  		 * which meets the original intention of setting it
> -		 * dirty, so all is well: clear_page_dirty_for_io() goes
> +		 * dirty, so all is well: folio_clear_dirty_for_io() goes
>  		 * on to call TestClearPageDirty(), and write the page
>  		 * back.
>  		 *
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 0694ec4098f6..b56f2c91b0f2 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2821,7 +2821,7 @@ EXPORT_SYMBOL(folio_mark_dirty_lock);
>   * This cancels just the dirty bit on the kernel page itself, it does NOT
>   * actually remove dirty bits on any mmap's that may be around. It also
>   * leaves the page tagged dirty, so any sync activity will still find it on
> - * the dirty lists, and in particular, clear_page_dirty_for_io() will still
> + * the dirty lists, and in particular, folio_clear_dirty_for_io() will still
>   * look at the dirty bits in the VM.
>   *
>   * Doing this should *normally* only ever be done when a page is truncated,
>
> --
> 2.39.5
>

--
Cheers, Lorenzo