On 6/22/26 18:50, Gary Guo wrote:
On Mon Jun 22, 2026 at 3:44 AM BST, Alvin Sun wrote:
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 <[email protected]>
---
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
}
Also, FWIW I think this should not put this in the crate root. Perhaps create a
modules.rs?
Makes sense. I'll create a new `module.rs` and move the module-related items
(`ModuleMetadata`, `ThisModule`, `this_module()`) there, then re-export from
`lib.rs`.
Best regards,
Alvin Sun
Best,
Gary
/// 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
