[PATCH] mm/uffd: Hide PTE_MARKER option

[PATCH] mm/uffd: Hide PTE_MARKER option

[Peter Xu]

The PTE_MARKER option should not need to be exposed to the kernel builder,
keep it internal and remove the prompt so it won't be seen.

Instead, make the PTE_MARKER_UFFD_WP option to explicitly choose PTE_MARKER
when necessary.

While PTE_MARKER_UFFD_WP will still prompt to user, change the wording so
that it'll not mention PTE_MARKER at all but renaming it to "Userfaultfd
write protection support for shmem/hugetlbfs".

Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
---

NOTE: IMHO this patch can either be standalone if easier, or be squashed
into patch "mm: Enable PTE markers by default" in -mm.

Please review, thanks.
---
 mm/Kconfig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/Kconfig b/mm/Kconfig
index 3eca34c864c5..d740e1ff3b2f 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -910,16 +910,16 @@ config ANON_VMA_NAME
 	  difference in their name.
 
 config PTE_MARKER
-	bool "Marker PTEs support"
-	default y
+	bool
 
 	help
 	  Allows to create marker PTEs for file-backed memory.
 
 config PTE_MARKER_UFFD_WP
-	bool "Marker PTEs support for userfaultfd write protection"
+	bool "Userfaultfd write protection support for shmem/hugetlbfs"
 	default y
-	depends on PTE_MARKER && HAVE_ARCH_USERFAULTFD_WP
+	depends on HAVE_ARCH_USERFAULTFD_WP
+	select PTE_MARKER
 
 	help
 	  Allows to create marker PTEs for userfaultfd write protection
-- 
2.32.0

Re: [PATCH] mm/uffd: Hide PTE_MARKER option

[Johannes Weiner]

On Tue, Apr 19, 2022 at 04:25:31PM -0400, Peter Xu wrote:
> The PTE_MARKER option should not need to be exposed to the kernel builder,
> keep it internal and remove the prompt so it won't be seen.
> 
> Instead, make the PTE_MARKER_UFFD_WP option to explicitly choose PTE_MARKER
> when necessary.
> 
> While PTE_MARKER_UFFD_WP will still prompt to user, change the wording so
> that it'll not mention PTE_MARKER at all but renaming it to "Userfaultfd
> write protection support for shmem/hugetlbfs".
> 
> Reported-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Thank you Peter