rust: module: move module types into `module.rs`

Move `Module`, `InPlaceModule`, `ModuleMetadata` and `ThisModule` from
`lib.rs` into a new `rust/kernel/module.rs`. Re-export them from `lib.rs`
to avoid tree-wide changes.

Switch six bus driver registrations from `module.0` to the public
`ThisModule::as_ptr()` accessor, since the field is no longer visible
outside the new `module` submodule.

No functional change.

Assisted-by: opencode:glm-5.2
Suggested-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/all/DJFIQPLOVO4T.1K8T0VZM30LDA@garyguo.net/
Reviewed-by: Gary Guo <gary@garyguo.net>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
Link: https://patch.msgid.link/20260811-fix-fops-owner-v10-1-7e71776f9dbe@linux.dev
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 7 insertions, 68 deletions

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 9512af7156df..2e175dcb145a 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -94,6 +94,7 @@ pub mod list;
 pub mod maple_tree;
 pub mod miscdevice;
 pub mod mm;
+pub mod module;
 pub mod module_param;
 #[cfg(CONFIG_NET)]
 pub mod net;
@@ -140,79 +141,17 @@ pub mod xarray;
 #[doc(hidden)]
 pub use bindings;
 pub use macros;
+pub use module::{
+    InPlaceModule,
+    Module,
+    ModuleMetadata,
+    ThisModule, //
+};
 pub use uapi;
 
 /// Prefix to appear before log messages printed from within the `kernel` crate.
 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
 
-/// The top level entrypoint to implementing a kernel module.
-///
-/// For any teardown or cleanup operations, your type may implement [`Drop`].
-pub trait Module: Sized + Sync + Send {
-    /// Called at module initialization time.
-    ///
-    /// Use this method to perform whatever setup or registration your module
-    /// should do.
-    ///
-    /// Equivalent to the `module_init` macro in the C API.
-    fn init(module: &'static ThisModule) -> error::Result<Self>;
-}
-
-/// A module that is pinned and initialised in-place.
-pub trait InPlaceModule: Sync + Send {
-    /// Creates an initialiser for the module.
-    ///
-    /// It is called when the module is loaded.
-    fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>;
-}
-
-impl<T: Module> InPlaceModule for T {
-    fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> {
-        let initer = move |slot: *mut Self| {
-            let m = <Self as Module>::init(module)?;
-
-            // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`.
-            unsafe { slot.write(m) };
-            Ok(())
-        };
-
-        // SAFETY: On success, `initer` always fully initialises an instance of `Self`.
-        unsafe { pin_init::pin_init_from_closure(initer) }
-    }
-}
-
-/// 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)
-pub struct ThisModule(*mut bindings::module);
-
-// SAFETY: `THIS_MODULE` may be used from all threads within a module.
-unsafe impl Sync for ThisModule {}
-
-impl ThisModule {
-    /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
-    ///
-    /// # Safety
-    ///
-    /// The pointer must be equal to the right `THIS_MODULE`.
-    pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
-        ThisModule(ptr)
-    }
-
-    /// Access the raw pointer for this module.
-    ///
-    /// It is up to the user to use it correctly.
-    pub const fn as_ptr(&self) -> *mut bindings::module {
-        self.0
-    }
-}
-
 #[cfg(not(testlib))]
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {