Re: [PATCH] mm/gup: remove no longer used gup_fast_undo_dev_pagemap

From: Alistair Popple

Date: Mon Dec 22 2025 - 21:58:13 EST


On 2025-12-20 at 01:27 +1100, "David Hildenbrand (Red Hat)" <david@xxxxxxxxxx> wrote...
> On 12/19/25 12:46, Kairui Song wrote:
> > From: Kairui Song <kasong@xxxxxxxxxxx>
> >
> > This helper is no longer used after commit fd2825b0760a ("mm/gup: remove
> > pXX_devmap usage from get_user_pages()").

Thanks for catching, we no longer have to treat the dev pagemap pages specially
so it makes sense this isn't needed.

Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>

> > Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> > ---
> > mm/gup.c | 11 -----------
> > 1 file changed, 11 deletions(-)
> >
> > diff --git a/mm/gup.c b/mm/gup.c
> > index 95d948c8e86c..8e7dc2c6ee73 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -2806,17 +2806,6 @@ static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags)
> > return !reject_file_backed || shmem_mapping(mapping);
> > }
> > -static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start,
> > - unsigned int flags, struct page **pages)
> > -{
> > - while ((*nr) - nr_start) {
> > - struct folio *folio = page_folio(pages[--(*nr)]);
> > -
> > - folio_clear_referenced(folio);
> > - gup_put_folio(folio, 1, flags);
> > - }
> > -}
> > -
>
> Thanks!
>
> Acked-by: David Hildenbrand (Red Hat) <david@xxxxxxxxxx>
>
> --
> Cheers
>
> David