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

Alistair Popple
2024-04-12T01:38:09Z

David Hildenbrand <david@redhat.com> writes:

> 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 :)

Thanks. Rebasing was the other thing I meant to add as a TODO in the
cover letter :)

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