Re: [PATCH V10 2/5] mm: uffd_wp: Add pte_uffd_wp_available()

[David Hildenbrand]

On 09.09.25 11:56, Chunyan Zhang wrote:
> Some platforms can customize the PTE uffd_wp bit and make it unavailable
> even if the architecture allows providing the PTE resource.
> This patch adds a macro API which allows architectures to define
> their specific ones for checking if the PTE uffd_wp bit is available.
>
> Signed-off-by: Chunyan Zhang <zhangchunyan@xxxxxxxxxxx>
> ---
>   fs/userfaultfd.c                   | 25 +++++++++--------
>   include/asm-generic/pgtable_uffd.h | 12 ++++++++
>   include/linux/mm_inline.h          |  7 +++++
>   include/linux/userfaultfd_k.h      | 44 +++++++++++++++++++-----------
>   mm/memory.c                        |  6 ++--
>   5 files changed, 65 insertions(+), 29 deletions(-)
>
> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
> index 54c6cc7fe9c6..68e5006e5158 100644
> --- a/fs/userfaultfd.c
> +++ b/fs/userfaultfd.c
> @@ -1270,9 +1270,10 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
>   	if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
>   		vm_flags |= VM_UFFD_MISSING;
>   	if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) {
> -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
> -		goto out;
> -#endif
> +		if (!IS_ENABLED(CONFIG_HAVE_ARCH_USERFAULTFD_WP) ||
> +		    !pte_uffd_wp_available())
> +			goto out;
> +

Same comment as for the other patch: make the 
CONFIG_HAVE_ARCH_USERFAULTFD_WP part of the pte_uffd_wp_available() 
check and better call it "pgtable_uffd_wp_" ... available/supported.

--
Cheers

David / dhildenb