Re: [PATCH 3/6] PCI/P2PDMA: create VMA without page_mkwrite() operator

Bjorn Helgaas
2024-06-05T21:45:02Z

On Wed, Jun 05, 2024 at 01:29:31PM -0600, Martin Oliveira wrote:
> The P2PDMA code does not need (or want) a page_mkwrite() operator on its
> VMA.
>
> Furthermore, having the page_mkwrite() operator causes
> writable_file_mapping_allowed() to fail due to
> vma_needs_dirty_tracking() on the gup flow, which is a pre-requisite for
> enabling P2PDMA with FOLL_LONGTERM use cases.
>
> Co-developed-by: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>

Fine with me, but please s/create/Create/ in the subject to match
history of the file.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
> drivers/pci/p2pdma.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index 4f47a13cb500..ac07053abfea 100644
> --- a/drivers/pci/p2pdma.c
> +++ b/drivers/pci/p2pdma.c
> @@ -171,6 +171,7 @@ static struct bin_attribute p2pmem_alloc_attr = {
> * to be very large.
> */
> .size = SZ_1T,
> + .mmap_allocates = true,
> };
>
> static struct attribute *p2pmem_attrs[] = {
> --
> 2.34.1
>