[PATCH v3 1/6] rust: module: add `THIS_MODULE` const to `ModuleMetadata` trait
From: Alvin Sun <hidden>
Date: 2026-06-22 02:45:07
Also in:
b4-sent, dri-devel, driver-core, linux-block, linux-kselftest, lkml, nova-gpu, rust-for-linux
Subsystem:
module support, rust, the rest · Maintainers:
Luis Chamberlain, Petr Pavlu, Daniel Gomez, Sami Tolvanen, Miguel Ojeda, Linus Torvalds
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`. Move the `THIS_MODULE` static from the `module!` macro into the `ModuleMetadata` impl, add a `this_module()` helper, and update `__init` to use it. Signed-off-by: Alvin Sun <redacted> --- rust/kernel/lib.rs | 8 ++++++++ rust/macros/module.rs | 34 +++++++++++++++++----------------- 2 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index b72b2fbe046d6..50f5a7b5f028e 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs@@ -184,6 +184,14 @@ fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Erro pub trait ModuleMetadata { /// The name of the module as specified in the `module!` macro. const NAME: &'static crate::str::CStr; + + /// The module's `THIS_MODULE` pointer. + const THIS_MODULE: ThisModule; +} + +/// Returns a reference to the `THIS_MODULE` of the given module type. +pub const fn this_module<M: ModuleMetadata>() -> &'static ThisModule { + &M::THIS_MODULE } /// Equivalent to `THIS_MODULE` in the C API.
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 06c18e2075083..b9fdee2f2af47 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs@@ -497,28 +497,28 @@ pub(crate) fn module(info: ModuleInfo) -> Result<TokenStream> { /// Used by the printing macros, e.g. [`info!`]. const __LOG_PREFIX: &[u8] = #name_cstr.to_bytes_with_nul(); - // SAFETY: `__this_module` is constructed by the kernel at load time and will not be - // freed until the module is unloaded. - #[cfg(MODULE)] - static THIS_MODULE: ::kernel::ThisModule = unsafe { - extern "C" { - static __this_module: ::kernel::types::Opaque<::kernel::bindings::module>; - }; - - ::kernel::ThisModule::from_ptr(__this_module.get()) - }; - - #[cfg(not(MODULE))] - static THIS_MODULE: ::kernel::ThisModule = unsafe { - ::kernel::ThisModule::from_ptr(::core::ptr::null_mut()) - }; - /// The `LocalModule` type is the type of the module created by `module!`, /// `module_pci_driver!`, `module_platform_driver!`, etc. type LocalModule = #type_; impl ::kernel::ModuleMetadata for #type_ { const NAME: &'static ::kernel::str::CStr = #name_cstr; + + #[cfg(MODULE)] + const THIS_MODULE: ::kernel::ThisModule = { + extern "C" { + static __this_module: ::kernel::types::Opaque<::kernel::bindings::module>; + } + + // SAFETY: `__this_module` is constructed by the kernel at load time + // and lives until the module is unloaded. + unsafe { ::kernel::ThisModule::from_ptr(__this_module.get()) } + }; + + #[cfg(not(MODULE))] + const THIS_MODULE: ::kernel::ThisModule = unsafe { + ::kernel::ThisModule::from_ptr(::core::ptr::null_mut()) + }; } // Double nested modules, since then nobody can access the public items inside.
@@ -616,7 +616,7 @@ pub extern "C" fn #ident_exit() { /// This function must only be called once. unsafe fn __init() -> ::kernel::ffi::c_int { let initer = <super::super::LocalModule as ::kernel::InPlaceModule>::init( - &super::super::THIS_MODULE + ::kernel::this_module::<super::super::LocalModule>() ); // SAFETY: No data race, since `__MOD` can only be accessed by this module // and there only `__init` and `__exit` access it. These functions are only
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2.43.0