rust: module: add trait ModuleMetadata

In order to access static metadata of a Rust kernel module, add the
`ModuleMetadata` trait.

In particular, this trait provides the name of a Rust kernel module as
specified by the `module!` macro.

Signed-off-by: Danilo Krummrich <[email protected]>

Author: Danilo Krummrich

rust/kernel/lib.rs

@@ -115,6 +115,12 @@ impl<T: Module> InPlaceModule for T {
     }
 }
 
+/// Metadata attached to a [`Module`] or [`InPlaceModule`].
+pub trait ModuleMetadata {
+    /// The name of the module as specified in the `module!` macro.
+    const NAME: &'static crate::str::CStr;
+}
+
 /// Equivalent to `THIS_MODULE` in the C API.
 ///
 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h)

rust/macros/module.rs

@@ -228,6 +228,10 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                 kernel::ThisModule::from_ptr(core::ptr::null_mut())
             }};
 
+            impl kernel::ModuleMetadata for {type_} {{
+                const NAME: &'static kernel::str::CStr = kernel::c_str!(\"{name}\");
+            }}
+
             // Double nested modules, since then nobody can access the public items inside.
             mod __module_init {{
                 mod __module_init {{