Re: [PATCH 1/8] rust: module: add `MODULE_PTR` const to `ModuleMetadata` trait

[Gary Guo]

On Tue May 19, 2026 at 7:26 AM BST, Alvin Sun wrote:
> Add a `MODULE_PTR` const to the `ModuleMetadata` trait so that
> modules can provide a constant pointer to their `struct module`
> usable in const contexts such as static file_operations.

Please design a consistent API surface that integrates with the `THIS_MODULE`
that we have today, and avoid two ways of doing things.

Best,
Gary

>
> Signed-off-by: Alvin Sun <alvin.sun@xxxxxxxxx>
> ---
>  rust/kernel/lib.rs    |  3 +++
>  rust/macros/module.rs | 14 ++++++++++++++
>  2 files changed, 17 insertions(+)
>
> diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> index b72b2fbe046d6..c7e809636e1a9 100644
> --- a/rust/kernel/lib.rs
> +++ b/rust/kernel/lib.rs
> @@ -184,6 +184,9 @@ 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 pointer to the kernel `struct module` for this module.
> +    const MODULE_PTR: *mut bindings::module;
>  }
>  
>  /// Equivalent to `THIS_MODULE` in the C API.
> diff --git a/rust/macros/module.rs b/rust/macros/module.rs
> index 06c18e2075083..7204fe604f24a 100644
> --- a/rust/macros/module.rs
> +++ b/rust/macros/module.rs
> @@ -519,6 +519,20 @@ pub(crate) fn module(info: ModuleInfo) -> Result<TokenStream> {
>  
>          impl ::kernel::ModuleMetadata for #type_ {
>              const NAME: &'static ::kernel::str::CStr = #name_cstr;
> +
> +            #[cfg(MODULE)]
> +            const MODULE_PTR: *mut ::kernel::bindings::module = {
> +                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 { __this_module.get() }
> +            };
> +
> +            #[cfg(not(MODULE))]
> +            const MODULE_PTR: *mut ::kernel::bindings::module = ::core::ptr::null_mut();
>          }
>  
>          // Double nested modules, since then nobody can access the public items inside.