rust: pin-init: miscellaneous synchronization with the user-space version

Remove the last differences between the kernel version and the
user-space version.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Tested-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Fiona Behrens <me@kloenk.dev>
Link: https://lore.kernel.org/r/20250308110339.2997091-20-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

rust/pin-init/internal/src/lib.rs

@@ -14,6 +14,8 @@
 //
 // Remove once we have `proc_macro2` in the kernel.
 #![allow(clippy::useless_conversion)]
+// Documentation is done in the pin-init crate instead.
+#![allow(missing_docs)]
 
 use proc_macro::TokenStream;
 
@@ -30,19 +32,16 @@ mod pin_data;
 mod pinned_drop;
 mod zeroable;
 
-#[allow(missing_docs)]
 #[proc_macro_attribute]
 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
     pin_data::pin_data(inner.into(), item.into()).into()
 }
 
-#[allow(missing_docs)]
 #[proc_macro_attribute]
 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
     pinned_drop::pinned_drop(args.into(), input.into()).into()
 }
 
-#[allow(missing_docs)]
 #[proc_macro_derive(Zeroable)]
 pub fn derive_zeroable(input: TokenStream) -> TokenStream {
     zeroable::derive(input.into()).into()

rust/pin-init/src/__internal.rs

@@ -14,7 +14,7 @@ use super::*;
 ///
 /// [nomicon]: https://doc.rust-lang.org/nomicon/subtyping.html
 /// [this table]: https://doc.rust-lang.org/nomicon/phantom-data.html#table-of-phantomdata-patterns
-pub(super) type Invariant<T> = PhantomData<fn(*mut T) -> *mut T>;
+pub(crate) type Invariant<T> = PhantomData<fn(*mut T) -> *mut T>;
 
 /// Module-internal type implementing `PinInit` and `Init`.
 ///

rust/pin-init/src/lib.rs

@@ -349,8 +349,6 @@ pub use alloc::InPlaceInit;
 ///     }
 /// }
 /// ```
-///
-/// [`pin_init!`]: crate::pin_init
 pub use ::pin_init_internal::pin_data;
 
 /// Used to implement `PinnedDrop` safely.