We used to have USERFAULTFD configs stored in init/. It makes sense as a
start because that's the default place for storing syscall related configs.
However userfaultfd evolved a bit in the past few years and some more
config options were added. They're no longer related to syscalls and start
to be not suitable to be kept in the init/ directory anymore, because
they're pure mm concepts.
But it's not ideal either to keep the userfaultfd configs separate from
each other. Hence this patch moves the userfaultfd configs under init/ to
be under mm/ so that we'll start to group all userfaultfd configs
together.
We do have quite a few examples of syscall related configs that are not put
under init/Kconfig: FTRACE_SYSCALLS, SWAP, FILE_LOCKING, MEMFD_CREATE..
They all reside in the dir where they're more suitable for the concept. So
it seems there's no restriction to keep the role of having syscall related
CONFIG_* under init/ only.
Suggested-by: Johannes Weiner <[email protected]>
Signed-off-by: Peter Xu <[email protected]>
---
NOTE: there's a light dependency to patch "mm/uffd: Hide PTE_MARKER option".
---
init/Kconfig | 17 -----------------
mm/Kconfig | 17 +++++++++++++++++
2 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 6a32b466dad1..0a358fc858cd 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1685,16 +1685,6 @@ config ADVISE_SYSCALLS
applications use these syscalls, you can disable this option to save
space.
-config HAVE_ARCH_USERFAULTFD_WP
- bool
- help
- Arch has userfaultfd write protection support
-
-config HAVE_ARCH_USERFAULTFD_MINOR
- bool
- help
- Arch has userfaultfd minor fault support
-
config MEMBARRIER
bool "Enable membarrier() system call" if EXPERT
default y
@@ -1759,13 +1749,6 @@ config KALLSYMS_BASE_RELATIVE
# syscall, maps, verifier
-config USERFAULTFD
- bool "Enable userfaultfd() system call"
- depends on MMU
- help
- Enable the userfaultfd() system call that allows to intercept and
- handle page faults in userland.
-
config ARCH_HAS_MEMBARRIER_CALLBACKS
bool
diff --git a/mm/Kconfig b/mm/Kconfig
index d740e1ff3b2f..f268ba545e02 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -909,6 +909,23 @@ config ANON_VMA_NAME
area from being merged with adjacent virtual memory areas due to the
difference in their name.
+config USERFAULTFD
+ bool "Enable userfaultfd() system call"
+ depends on MMU
+ help
+ Enable the userfaultfd() system call that allows to intercept and
+ handle page faults in userland.
+
+config HAVE_ARCH_USERFAULTFD_WP
+ bool
+ help
+ Arch has userfaultfd write protection support
+
+config HAVE_ARCH_USERFAULTFD_MINOR
+ bool
+ help
+ Arch has userfaultfd minor fault support
+
config PTE_MARKER
bool
--
2.32.0
Reviewed-by: Axel Rasmussen <[email protected]>
On Wed, Apr 20, 2022 at 8:31 AM Johannes Weiner <[email protected]> wrote:
>
> On Wed, Apr 20, 2022 at 10:48:23AM -0400, Peter Xu wrote:
> > We used to have USERFAULTFD configs stored in init/. It makes sense as a
> > start because that's the default place for storing syscall related configs.
> >
> > However userfaultfd evolved a bit in the past few years and some more
> > config options were added. They're no longer related to syscalls and start
> > to be not suitable to be kept in the init/ directory anymore, because
> > they're pure mm concepts.
> >
> > But it's not ideal either to keep the userfaultfd configs separate from
> > each other. Hence this patch moves the userfaultfd configs under init/ to
> > be under mm/ so that we'll start to group all userfaultfd configs
> > together.
> >
> > We do have quite a few examples of syscall related configs that are not put
> > under init/Kconfig: FTRACE_SYSCALLS, SWAP, FILE_LOCKING, MEMFD_CREATE..
> > They all reside in the dir where they're more suitable for the concept. So
> > it seems there's no restriction to keep the role of having syscall related
> > CONFIG_* under init/ only.
> >
> > Suggested-by: Johannes Weiner <[email protected]>
> > Signed-off-by: Peter Xu <[email protected]>
>
> Acked-by: Johannes Weiner <[email protected]>
On Wed, Apr 20, 2022 at 10:48:23AM -0400, Peter Xu wrote:
> We used to have USERFAULTFD configs stored in init/. It makes sense as a
> start because that's the default place for storing syscall related configs.
>
> However userfaultfd evolved a bit in the past few years and some more
> config options were added. They're no longer related to syscalls and start
> to be not suitable to be kept in the init/ directory anymore, because
> they're pure mm concepts.
>
> But it's not ideal either to keep the userfaultfd configs separate from
> each other. Hence this patch moves the userfaultfd configs under init/ to
> be under mm/ so that we'll start to group all userfaultfd configs
> together.
>
> We do have quite a few examples of syscall related configs that are not put
> under init/Kconfig: FTRACE_SYSCALLS, SWAP, FILE_LOCKING, MEMFD_CREATE..
> They all reside in the dir where they're more suitable for the concept. So
> it seems there's no restriction to keep the role of having syscall related
> CONFIG_* under init/ only.
>
> Suggested-by: Johannes Weiner <[email protected]>
> Signed-off-by: Peter Xu <[email protected]>
Acked-by: Johannes Weiner <[email protected]>