[PATCH 2/2] rust: kunit: move test configuration gating into macro

[Yury Norov <ynorov@nvidia.com>]

KUnit test modules currently need a separate cfg attribute in addition to
the kunit_tests attribute. This makes every test suite repeat the same
two-attribute pattern.

Declaring a KUnit test without a preceding `#[cfg]` attribute is also
possible, causing it to be built whenever KUnit and its containing code are
enabled.

Require the controlling Kconfig symbol as the second kunit_tests argument
and have the macro emit the cfg attribute itself. Update all existing users
to the new form.

Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Yury Norov <ynorov@nvidia.com>
---
 Documentation/rust/testing.rst                | 11 ++++---
 .../gpu/nova-core/gsp/cmdq/continuation.rs    |  3 +-
 rust/kernel/alloc/allocator.rs                |  3 +-
 rust/kernel/alloc/kvec.rs                     |  3 +-
 rust/kernel/bitfield.rs                       |  3 +-
 rust/kernel/bitmap.rs                         |  3 +-
 rust/kernel/kunit.rs                          |  3 +-
 rust/kernel/str.rs                            |  3 +-
 rust/kernel/sync/atomic/predefine.rs          |  3 +-
 rust/macros/kunit.rs                          | 30 +++++++++++++++++--
 rust/macros/lib.rs                            |  6 ++--
 11 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/Documentation/rust/testing.rst b/Documentation/rust/testing.rst
index e3943aceceb9..767b111afd41 100644
--- a/Documentation/rust/testing.rst
+++ b/Documentation/rust/testing.rst
@@ -138,9 +138,10 @@ these are also fairly similar to what you would expect from userspace, and they
 are also mapped to KUnit.
 
 These tests are introduced by the ``kunit_tests`` procedural macro, which takes
-the name of the test suite as an argument.
+the name of the test suite and its controlling Kconfig option as arguments. The
+Kconfig option is required, and the macro uses it to guard the test suite.
 
-Each test suite should be guarded by a Kconfig option in
+Each test suite should have a Kconfig option, typically in
 ``rust/kernel/Kconfig.test``.
 
 For instance, assume we want to test the function ``f`` from the documentation
@@ -148,8 +149,7 @@ tests section. We could write, in the same file where we have our function:
 
 .. code-block:: rust
 
-	#[cfg(CONFIG_RUST_MYMOD_KUNIT_TEST)]
-	#[kunit_tests(rust_kernel_mymod)]
+	#[kunit_tests(rust_kernel_mymod, CONFIG_RUST_MYMOD_KUNIT_TEST)]
 	mod tests {
 	    use super::*;
 
@@ -177,8 +177,7 @@ the unit type ``()``) or ``Result`` (i.e. any ``Result<T, E>``). For instance:
 
 .. code-block:: rust
 
-	#[cfg(CONFIG_RUST_MYMOD_KUNIT_TEST)]
-	#[kunit_tests(rust_kernel_mymod)]
+	#[kunit_tests(rust_kernel_mymod, CONFIG_RUST_MYMOD_KUNIT_TEST)]
 	mod tests {
 	    use super::*;
 
diff --git a/drivers/gpu/nova-core/gsp/cmdq/continuation.rs b/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
index c0aa16c8fbf4..2e4b21f2002f 100644
--- a/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq/continuation.rs
@@ -167,8 +167,7 @@ fn init_variable_payload(
     }
 }
 
-#[cfg(CONFIG_NOVA_CORE_KUNIT_TEST)]
-#[kunit_tests(nova_core_gsp_continuation)]
+#[kunit_tests(nova_core_gsp_continuation, CONFIG_NOVA_CORE_KUNIT_TEST)]
 mod tests {
     use super::*;
 
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index cd4203f27aed..b2c235801a3f 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -265,8 +265,7 @@ unsafe fn realloc(
     }
 }
 
-#[cfg(CONFIG_RUST_ALLOCATOR_KUNIT_TEST)]
-#[macros::kunit_tests(rust_allocator)]
+#[macros::kunit_tests(rust_allocator, CONFIG_RUST_ALLOCATOR_KUNIT_TEST)]
 mod tests {
     use super::*;
     use core::mem::MaybeUninit;
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index f7af62835aa8..4b77425950d3 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -1508,8 +1508,7 @@ fn drop(&mut self) {
     }
 }
 
-#[cfg(CONFIG_RUST_KVEC_KUNIT_TEST)]
-#[macros::kunit_tests(rust_kvec)]
+#[macros::kunit_tests(rust_kvec, CONFIG_RUST_KVEC_KUNIT_TEST)]
 mod tests {
     use super::*;
     use crate::prelude::*;
diff --git a/rust/kernel/bitfield.rs b/rust/kernel/bitfield.rs
index 35ede53f2b8e..8b329b6e4f8d 100644
--- a/rust/kernel/bitfield.rs
+++ b/rust/kernel/bitfield.rs
@@ -548,8 +548,7 @@ fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
     };
 }
 
-#[cfg(CONFIG_RUST_BITFIELD_KUNIT_TEST)]
-#[::kernel::macros::kunit_tests(rust_kernel_bitfield)]
+#[::kernel::macros::kunit_tests(rust_kernel_bitfield, CONFIG_RUST_BITFIELD_KUNIT_TEST)]
 mod tests {
     use core::convert::TryFrom;
 
diff --git a/rust/kernel/bitmap.rs b/rust/kernel/bitmap.rs
index b27e0ec80d64..c4195e00d895 100644
--- a/rust/kernel/bitmap.rs
+++ b/rust/kernel/bitmap.rs
@@ -499,8 +499,7 @@ pub fn next_zero_bit(&self, start: usize) -> Option<usize> {
     }
 }
 
-#[cfg(CONFIG_RUST_BITMAP_KUNIT_TEST)]
-#[macros::kunit_tests(rust_kernel_bitmap)]
+#[macros::kunit_tests(rust_kernel_bitmap, CONFIG_RUST_BITMAP_KUNIT_TEST)]
 mod tests {
     use super::*;
     use kernel::alloc::flags::GFP_KERNEL;
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 91eaff8c186a..52f2ccbfba49 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -330,8 +330,7 @@ pub fn in_kunit_test() -> bool {
     !unsafe { bindings::kunit_get_current_test() }.is_null()
 }
 
-#[cfg(CONFIG_RUST_KUNIT_SELFTEST)]
-#[kunit_tests(rust_kernel_kunit)]
+#[kunit_tests(rust_kernel_kunit, CONFIG_RUST_KUNIT_SELFTEST)]
 mod tests {
     use super::*;
 
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index b3caa9a1c898..404418504c13 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -428,8 +428,7 @@ macro_rules! c_str {
     }};
 }
 
-#[cfg(CONFIG_RUST_STR_KUNIT_TEST)]
-#[kunit_tests(rust_kernel_str)]
+#[kunit_tests(rust_kernel_str, CONFIG_RUST_STR_KUNIT_TEST)]
 mod tests {
     use super::*;
 
diff --git a/rust/kernel/sync/atomic/predefine.rs b/rust/kernel/sync/atomic/predefine.rs
index 3d63f40791fa..e92194b37de8 100644
--- a/rust/kernel/sync/atomic/predefine.rs
+++ b/rust/kernel/sync/atomic/predefine.rs
@@ -152,8 +152,7 @@ fn rhs_into_delta(rhs: usize) -> isize_atomic_repr {
     }
 }
 
-#[cfg(CONFIG_RUST_ATOMICS_KUNIT_TEST)]
-#[macros::kunit_tests(rust_atomics)]
+#[macros::kunit_tests(rust_atomics, CONFIG_RUST_ATOMICS_KUNIT_TEST)]
 mod tests {
     use super::super::*;
 
diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs
index ae20ed6768f1..7c7ba30f58c0 100644
--- a/rust/macros/kunit.rs
+++ b/rust/macros/kunit.rs
@@ -13,6 +13,10 @@
     ToTokens, //
 };
 use syn::{
+    parse::{
+        Parse,
+        ParseStream, //
+    },
     parse_quote,
     Error,
     Ident,
@@ -20,9 +24,28 @@
     ItemMod,
     LitCStr,
     Result, //
+    Token,
 };
 
-pub(crate) fn kunit_tests(test_suite: Ident, mut module: ItemMod) -> Result<TokenStream> {
+pub(crate) struct KunitTestArgs {
+    test_suite: Ident,
+    config: Ident,
+}
+
+impl Parse for KunitTestArgs {
+    fn parse(input: ParseStream<'_>) -> Result<Self> {
+        let test_suite = input.parse()?;
+        input.parse::<Token![,]>()?;
+        let config = input.parse()?;
+
+        Ok(Self { test_suite, config })
+    }
+}
+
+pub(crate) fn kunit_tests(
+    KunitTestArgs { test_suite, config }: KunitTestArgs,
+    mut module: ItemMod,
+) -> Result<TokenStream> {
     if test_suite.to_string().len() > 255 {
         return Err(Error::new_spanned(
             test_suite,
@@ -34,7 +57,7 @@ pub(crate) fn kunit_tests(test_suite: Ident, mut module: ItemMod) -> Result<Toke
     let Some((module_brace, module_items)) = module.content.take() else {
         Err(Error::new_spanned(
             module,
-            "`#[kunit_tests(test_name)]` attribute should only be applied to inline modules",
+            "`#[kunit_tests(test_name, CONFIG_KUNIT_TEST)]` attribute should only be applied to inline modules",
         ))?
     };
 
@@ -42,6 +65,7 @@ pub(crate) fn kunit_tests(test_suite: Ident, mut module: ItemMod) -> Result<Toke
     module
         .attrs
         .insert(0, parse_quote!(#[cfg(CONFIG_KUNIT="y")]));
+    module.attrs.insert(0, parse_quote!(#[cfg(#config)]));
 
     let mut processed_items = Vec::new();
     let mut test_cases = Vec::new();
@@ -51,7 +75,7 @@ pub(crate) fn kunit_tests(test_suite: Ident, mut module: ItemMod) -> Result<Toke
     // The code generated for the following test module:
     //
     // ```
-    // #[kunit_tests(kunit_test_suit_name)]
+    // #[kunit_tests(kunit_test_suite_name, CONFIG_KUNIT_TEST)]
     // mod tests {
     //     #[test]
     //     fn foo() {
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
index 4a48fabbc268..a660296d5dbd 100644
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -464,14 +464,14 @@ pub fn paste(input: TokenStream) -> TokenStream {
 
 /// Registers a KUnit test suite and its test cases using a user-space like syntax.
 ///
-/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
-/// is ignored.
+/// This macro should be used on modules. The second argument is the Kconfig symbol that controls
+/// the test suite. If it or `CONFIG_KUNIT` (in `.config`) is `n`, the target module is ignored.
 ///
 /// # Examples
 ///
 /// ```ignore
 /// # use kernel::prelude::*;
-/// #[kunit_tests(kunit_test_suit_name)]
+/// #[kunit_tests(kunit_test_suite_name, CONFIG_KUNIT_TEST)]
 /// mod tests {
 ///     #[test]
 ///     fn foo() {
-- 
2.53.0