Showcase the rust module parameter support by adding a module parameter to
the `rust_minimal` sample.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
 samples/rust/rust_minimal.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
index 1fc7a1be6b6d..8eb9583571d7 100644
--- a/samples/rust/rust_minimal.rs
+++ b/samples/rust/rust_minimal.rs
@@ -10,6 +10,12 @@
     authors: ["Rust for Linux Contributors"],
     description: "Rust minimal sample",
     license: "GPL",
+    params: {
+        test_parameter: i64 {
+            default: 1,
+            description: "This parameter has a default of 1",
+        },
+    },
 }
 
 struct RustMinimal {
@@ -20,6 +26,10 @@ impl kernel::Module for RustMinimal {
     fn init(_module: &'static ThisModule) -> Result<Self> {
         pr_info!("Rust minimal sample (init)\n");
         pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
+        pr_info!(
+            "test_parameter: {}\n",
+            *module_parameters::test_parameter.value()
+        );
 
         let mut numbers = KVec::new();
         numbers.push(72, GFP_KERNEL)?;

-- 
2.47.2

> Showcase the rust module parameter support by adding a module parameter to
> the `rust_minimal` sample.
> 
> Reviewed-by: Benno Lossin <lossin@kernel.org>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
>  samples/rust/rust_minimal.rs | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
> index 1fc7a1be6b6d..8eb9583571d7 100644
> --- a/samples/rust/rust_minimal.rs
> +++ b/samples/rust/rust_minimal.rs
> @@ -10,6 +10,12 @@
>      authors: ["Rust for Linux Contributors"],
>      description: "Rust minimal sample",
>      license: "GPL",
> +    params: {
> +        test_parameter: i64 {
> +            default: 1,
> +            description: "This parameter has a default of 1",
> +        },
> +    },

Thanks for the patches.

I've been using these in a new PCI device driver module and noticed
that the inclusion of `params:` in the rustdoc test here causes the
`rusttest` target to fail with a linker error (below) complaining about
undefined references for `rust_helper_atomic_try_cmpxchg_relaxed` and
`rust_helper_atomic_set_release`.

Building a real module and using the `params:` field seems to work
fine though so it must be something specific to the test configuration.

Any ideas how to fix this?

---

  RUSTDOC T rust/macros/lib.rs

running 10 tests
ii....... 9/10
rust/macros/lib.rs - module (line 61) --- FAILED

failures:

---- rust/macros/lib.rs - module (line 61) stdout ----
error: linking with `cc` failed: exit status: 1
  |
  = note:  "cc" "-m64" "/tmp/rustcVbJoqH/symbols.o" "<2 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "./rust/test/{libkernel.rlib,libuapi.rlib,libbindings.rlib,libbuild_error.rlib,libpin_init.rlib,libffi.rlib}.rlib" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib/{libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,libcfg_if-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-L" "/tmp/rustcVbJoqH/raw-dylibs" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "./rust/test" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/tmp/rustdoctestTFYhZ1/rust_out" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: /usr/bin/ld: ./rust/test/libkernel.rlib(kernel.kernel.a8a3768e1a8b2c2e-cgu.3.rcgu.o): in function `kernel::sync::set_once::SetOnce<T>::populate':
          kernel.a8a3768e1a8b2c2e-cgu.3:(.text._ZN6kernel4sync8set_once16SetOnce$LT$T$GT$8populate17hab8d57b99b7ebbcbE+0xd3): undefined reference to `rust_helper_atomic_try_cmpxchg_relaxed'
          /usr/bin/ld: kernel.a8a3768e1a8b2c2e-cgu.3:(.text._ZN6kernel4sync8set_once16SetOnce$LT$T$GT$8populate17hab8d57b99b7ebbcbE+0x2a8): undefined reference to `rust_helper_atomic_set_release'
          collect2: error: ld returned 1 exit status
          
  = note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link

"Darin Morrison" <darinmorrison@gmail.com> writes:

>> Showcase the rust module parameter support by adding a module parameter to
>> the `rust_minimal` sample.
>>
>> Reviewed-by: Benno Lossin <lossin@kernel.org>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>> ---
>>  samples/rust/rust_minimal.rs | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>> diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
>> index 1fc7a1be6b6d..8eb9583571d7 100644
>> --- a/samples/rust/rust_minimal.rs
>> +++ b/samples/rust/rust_minimal.rs
>> @@ -10,6 +10,12 @@
>>      authors: ["Rust for Linux Contributors"],
>>      description: "Rust minimal sample",
>>      license: "GPL",
>> +    params: {
>> +        test_parameter: i64 {
>> +            default: 1,
>> +            description: "This parameter has a default of 1",
>> +        },
>> +    },
>
> Thanks for the patches.
>
> I've been using these in a new PCI device driver module and noticed
> that the inclusion of `params:` in the rustdoc test here causes the
> `rusttest` target to fail with a linker error (below) complaining about
> undefined references for `rust_helper_atomic_try_cmpxchg_relaxed` and
> `rust_helper_atomic_set_release`.
>
> Building a real module and using the `params:` field seems to work
> fine though so it must be something specific to the test configuration.
>
> Any ideas how to fix this?

Thanks for reporting! I don't have that issue locally. Do you have a
tree and a config you can point me to, so I can try to reproduce?

Best regards,
Andreas Hindborg