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54f846db7b
Since `const_refs_to_static` has been stable as of the MSRV bump, a `ThisModule` pointer can now be used in const contexts. Add a `THIS_MODULE` const to the `ModuleMetadata` trait so that modules can provide their `ThisModule` pointer in const contexts such as static `file_operations`. Add a `this_module()` helper to retrieve the `THIS_MODULE` pointer of a given module type, and update `__init` to use it instead of the `THIS_MODULE` static generated by the `module!` macro. The `static THIS_MODULE` generated by the `module!` macro is retained for backwards compatibility with existing users and removed in a later patch once all references have been migrated. Assisted-by: opencode:glm-5.2 Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> 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-v10-2-7e71776f9dbe@linux.dev Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
81 lines
2.6 KiB
Rust
81 lines
2.6 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Module-related types and helpers.
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/// The entrypoint to implementing a kernel module.
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///
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/// For any teardown or cleanup operations, your type may implement [`Drop`].
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pub trait Module: Sized + Sync + Send {
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/// Called at module initialization time.
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///
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/// Use this method to perform whatever setup or registration your module
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/// should do.
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///
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/// Equivalent to the `module_init` macro in the C API.
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fn init(module: &'static ThisModule) -> crate::error::Result<Self>;
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}
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/// A module that is pinned and initialised in-place.
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pub trait InPlaceModule: Sync + Send {
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/// Creates an initialiser for the module.
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///
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/// It is called when the module is loaded.
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fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, crate::error::Error>;
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}
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impl<T: Module> InPlaceModule for T {
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fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, crate::error::Error> {
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let initer = move |slot: *mut Self| {
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let m = <Self as Module>::init(module)?;
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// SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`.
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unsafe { slot.write(m) };
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Ok(())
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};
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// SAFETY: On success, `initer` always fully initialises an instance of `Self`.
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unsafe { pin_init::pin_init_from_closure(initer) }
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}
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}
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/// Metadata attached to a [`Module`] or [`InPlaceModule`].
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pub trait ModuleMetadata {
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/// The name of the module as specified in the `module!` macro.
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const NAME: &'static crate::str::CStr;
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/// The module's `THIS_MODULE` pointer.
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const THIS_MODULE: ThisModule;
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}
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/// Returns a reference to the `THIS_MODULE` of the given module type.
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#[inline]
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pub const fn this_module<M: ModuleMetadata>() -> &'static ThisModule {
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&M::THIS_MODULE
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}
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/// Equivalent to `THIS_MODULE` in the C API.
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///
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/// C header: [`include/linux/init.h`](srctree/include/linux/init.h)
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pub struct ThisModule(*mut crate::bindings::module);
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// SAFETY: `THIS_MODULE` may be used from all threads within a module.
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unsafe impl Sync for ThisModule {}
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impl ThisModule {
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/// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
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///
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/// # Safety
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///
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/// The pointer must be equal to the right `THIS_MODULE`.
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pub const unsafe fn from_ptr(ptr: *mut crate::bindings::module) -> ThisModule {
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ThisModule(ptr)
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}
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/// Access the raw pointer for this module.
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///
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/// It is up to the user to use it correctly.
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pub const fn as_ptr(&self) -> *mut crate::bindings::module {
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self.0
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}
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}
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