[PATCH v2 3/7] rust: doctest: add LocalModule fallback for #[vtable] ThisModule

[Alvin Sun]

Add a `LocalModule` struct with a null-pointer `ModuleMetadata` impl
in the doctest harness, so that `crate::LocalModule` (auto-inserted
by `#[vtable]`) resolves correctly when there is no `module!` macro.

Signed-off-by: Alvin Sun <alvi...@linux.dev>
---
scripts/rustdoc_test_gen.rs | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
index ee76e96b41eea..198af4e446c8c 100644
--- a/scripts/rustdoc_test_gen.rs
+++ b/scripts/rustdoc_test_gen.rs
@@ -239,6 +239,22 @@ macro_rules! assert_eq {{

const __LOG_PREFIX: &[u8] = b"rust_doctests_kernel\0";

+/// Dummy module type for doctest context.
+struct LocalModule;
+
+use kernel::{{
+ str::CStr,
+ ModuleMetadata,
+ ThisModule, //
+}};
+use core::ptr::null_mut;
+
+impl ModuleMetadata for LocalModule {{
+ const NAME: &'static CStr = c"rust_doctests_kernel";
+ // SAFETY: `try_module_get`/`module_put` handle null module pointers gracefully.
+ const THIS_MODULE: ThisModule = unsafe {{ ThisModule::from_ptr(null_mut()) }};
+}}
+
{rust_tests}
"#
)

--
2.43.0

[Andreas Hindborg]

Alvin Sun <alvi...@linux.dev> writes:

> Add a `LocalModule` struct with a null-pointer `ModuleMetadata` impl
> in the doctest harness, so that `crate::LocalModule` (auto-inserted
> by `#[vtable]`) resolves correctly when there is no `module!` macro.
>
> Signed-off-by: Alvin Sun <alvi...@linux.dev>

Reviewed-by: Andreas Hindborg <a.hin...@kernel.org>

Does this need to be ordered before the vtable auto insert in the patch series?

Best regards,
Andreas Hindborg

[Alvin Sun]

Yes, you're right — this patch would be better placed before the vtable
auto-insert patch to avoid a temporary state where the doctest harness
doesn't provide the LocalModule fallback that #[vtable] expects.

Thanks for the suggestions from you and Gary. v3 has been sent to the
list:

https://lore.kernel.org/rust-for-linux/20260622-fix-fops-ow...@linux.dev

Best regards,
Alvin Sun

>
> Best regards,
> Andreas Hindborg
>
>