Re: [RFC 01/10] mm/gup.c: Remove redundant check for PCI P2PDMA page

David Hildenbrand
2024-04-11T13:47:22Z

On 11.04.24 02:57, Alistair Popple wrote:
> PCI P2PDMA pages are not mapped with pXX_devmap PTEs therefore the
> check in __gup_device_huge() is redundant. Remove it
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
> ---
> mm/gup.c | 5 -----
> 1 file changed, 5 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 2f8a2d8..a9c8a09 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2683,11 +2683,6 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr,
> break;
> }
>
> - if (!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)) {
> - undo_dev_pagemap(nr, nr_start, flags, pages);
> - break;
> - }
> -
> SetPageReferenced(page);
> pages[*nr] = page;
> if (unlikely(try_grab_page(page, flags))) {

Rebasing on mm-unstable, you'll notice some minor conflicts, but nothing
earth shattering :)

Acked-by: David Hildenbrand <david@redhat.com>

--
Cheers,

David / dhildenb