Merge tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Enable a series of lints, including safety-related ones, e.g. the
     compiler will now warn about missing safety comments, as well as
     unnecessary ones. How safety documentation is organized is a
     frequent source of review comments, thus having the compiler guide
     new developers on where they are expected (and where not) is very
     nice.

   - Start using '#[expect]': an interesting feature in Rust (stabilized
     in 1.81.0) that makes the compiler warn if an expected warning was
     _not_ emitted. This is useful to avoid forgetting cleaning up
     locally ignored diagnostics ('#[allow]'s).

   - Introduce '.clippy.toml' configuration file for Clippy, the Rust
     linter, which will allow us to tweak its behaviour. For instance,
     our first use cases are declaring a disallowed macro and, more
     importantly, enabling the checking of private items.

   - Lints-related fixes and cleanups related to the items above.

   - Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the
     kernel into stable Rust, one of the major pieces of the puzzle is
     the support to write custom types that can be used as 'self', i.e.
     as receivers, since the kernel needs to write types such as 'Arc'
     that common userspace Rust would not. 'arbitrary_self_types' has
     been accepted to become stable, and this is one of the steps
     required to get there.

   - Remove usage of the 'new_uninit' unstable feature.

   - Use custom C FFI types. Includes a new 'ffi' crate to contain our
     custom mapping, instead of using the standard library 'core::ffi'
     one. The actual remapping will be introduced in a later cycle.

   - Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize'
     instead of 32/64-bit integers.

   - Fix 'size_t' in bindgen generated prototypes of C builtins.

   - Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue
     in the projects, which we managed to trigger with the upcoming
     tracepoint support. It includes a build test since some
     distributions backported the fix (e.g. Debian -- thanks!). All
     major distributions we list should be now OK except Ubuntu non-LTS.

  'macros' crate:

   - Adapt the build system to be able run the doctests there too; and
     clean up and enable the corresponding doctests.

  'kernel' crate:

   - Add 'alloc' module with generic kernel allocator support and remove
     the dependency on the Rust standard library 'alloc' and the
     extension traits we used to provide fallible methods with flags.

     Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'.
     Add the 'Box' type (a heap allocation for a single value of type
     'T' that is also generic over an allocator and considers the
     kernel's GFP flags) and its shorthand aliases '{K,V,KV}Box'. Add
     'ArrayLayout' type. Add 'Vec' (a contiguous growable array type)
     and its shorthand aliases '{K,V,KV}Vec', including iterator
     support.

     For instance, now we may write code such as:

         let mut v = KVec::new();
         v.push(1, GFP_KERNEL)?;
         assert_eq!(&v, &[1]);

     Treewide, move as well old users to these new types.

   - 'sync' module: add global lock support, including the
     'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types
     and the 'global_lock!' macro. Add the 'Lock::try_lock' method.

   - 'error' module: optimize 'Error' type to use 'NonZeroI32' and make
     conversion functions public.

   - 'page' module: add 'page_align' function.

   - Add 'transmute' module with the existing 'FromBytes' and 'AsBytes'
     traits.

   - 'block::mq::request' module: improve rendered documentation.

   - 'types' module: extend 'Opaque' type documentation and add simple
     examples for the 'Either' types.

  drm/panic:

   - Clean up a series of Clippy warnings.

  Documentation:

   - Add coding guidelines for lints and the '#[expect]' feature.

   - Add Ubuntu to the list of distributions in the Quick Start guide.

  MAINTAINERS:

   - Add Danilo Krummrich as maintainer of the new 'alloc' module.

  And a few other small cleanups and fixes"

* tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux: (82 commits)
  rust: alloc: Fix `ArrayLayout` allocations
  docs: rust: remove spurious item in `expect` list
  rust: allow `clippy::needless_lifetimes`
  rust: warn on bindgen < 0.69.5 and libclang >= 19.1
  rust: use custom FFI integer types
  rust: map `__kernel_size_t` and friends also to usize/isize
  rust: fix size_t in bindgen prototypes of C builtins
  rust: sync: add global lock support
  rust: macros: enable the rest of the tests
  rust: macros: enable paste! use from macro_rules!
  rust: enable macros::module! tests
  rust: kbuild: expand rusttest target for macros
  rust: types: extend `Opaque` documentation
  rust: block: fix formatting of `kernel::block::mq::request` module
  rust: macros: fix documentation of the paste! macro
  rust: kernel: fix THIS_MODULE header path in ThisModule doc comment
  rust: page: add Rust version of PAGE_ALIGN
  rust: helpers: remove unnecessary header includes
  rust: exports: improve grammar in commentary
  drm/panic: allow verbose version check
  ...

1 files changed, 14 insertions, 4 deletions

diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs
index 9a0c4650ef67..1fd146a83241 100644
--- a/rust/kernel/init/macros.rs
+++ b/rust/kernel/init/macros.rs
@@ -182,13 +182,13 @@
 //!     // Normally `Drop` bounds do not have the correct semantics, but for this purpose they do
 //!     // (normally people want to know if a type has any kind of drop glue at all, here we want
 //!     // to know if it has any kind of custom drop glue, which is exactly what this bound does).
-//!     #[allow(drop_bounds)]
+//!     #[expect(drop_bounds)]
 //!     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
 //!     impl<T> MustNotImplDrop for Bar<T> {}
 //!     // Here comes a convenience check, if one implemented `PinnedDrop`, but forgot to add it to
 //!     // `#[pin_data]`, then this will error with the same mechanic as above, this is not needed
 //!     // for safety, but a good sanity check, since no normal code calls `PinnedDrop::drop`.
-//!     #[allow(non_camel_case_types)]
+//!     #[expect(non_camel_case_types)]
 //!     trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
 //!     impl<
 //!         T: ::kernel::init::PinnedDrop,
@@ -513,6 +513,7 @@ macro_rules! __pinned_drop {
             }
         ),
     ) => {
+        // SAFETY: TODO.
         unsafe $($impl_sig)* {
             // Inherit all attributes and the type/ident tokens for the signature.
             $(#[$($attr)*])*
@@ -872,6 +873,7 @@ macro_rules! __pin_data {
                 }
             }
 
+            // SAFETY: TODO.
             unsafe impl<$($impl_generics)*>
                 $crate::init::__internal::PinData for __ThePinData<$($ty_generics)*>
             where $($whr)*
@@ -923,14 +925,14 @@ macro_rules! __pin_data {
         // `Drop`. Additionally we will implement this trait for the struct leading to a conflict,
         // if it also implements `Drop`
         trait MustNotImplDrop {}
-        #[allow(drop_bounds)]
+        #[expect(drop_bounds)]
         impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
         impl<$($impl_generics)*> MustNotImplDrop for $name<$($ty_generics)*>
         where $($whr)* {}
         // We also take care to prevent users from writing a useless `PinnedDrop` implementation.
         // They might implement `PinnedDrop` correctly for the struct, but forget to give
         // `PinnedDrop` as the parameter to `#[pin_data]`.
-        #[allow(non_camel_case_types)]
+        #[expect(non_camel_case_types)]
         trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
         impl<T: $crate::init::PinnedDrop>
             UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}
@@ -987,6 +989,7 @@ macro_rules! __pin_data {
         //
         // The functions are `unsafe` to prevent accidentally calling them.
         #[allow(dead_code)]
+        #[expect(clippy::missing_safety_doc)]
         impl<$($impl_generics)*> $pin_data<$($ty_generics)*>
         where $($whr)*
         {
@@ -997,6 +1000,7 @@ macro_rules! __pin_data {
                     slot: *mut $p_type,
                     init: impl $crate::init::PinInit<$p_type, E>,
                 ) -> ::core::result::Result<(), E> {
+                    // SAFETY: TODO.
                     unsafe { $crate::init::PinInit::__pinned_init(init, slot) }
                 }
             )*
@@ -1007,6 +1011,7 @@ macro_rules! __pin_data {
                     slot: *mut $type,
                     init: impl $crate::init::Init<$type, E>,
                 ) -> ::core::result::Result<(), E> {
+                    // SAFETY: TODO.
                     unsafe { $crate::init::Init::__init(init, slot) }
                 }
             )*
@@ -1121,6 +1126,8 @@ macro_rules! __init_internal {
         // no possibility of returning without `unsafe`.
         struct __InitOk;
         // Get the data about fields from the supplied type.
+        //
+        // SAFETY: TODO.
         let data = unsafe {
             use $crate::init::__internal::$has_data;
             // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
@@ -1176,6 +1183,7 @@ macro_rules! __init_internal {
         let init = move |slot| -> ::core::result::Result<(), $err> {
             init(slot).map(|__InitOk| ())
         };
+        // SAFETY: TODO.
         let init = unsafe { $crate::init::$construct_closure::<_, $err>(init) };
         init
     }};
@@ -1324,6 +1332,8 @@ macro_rules! __init_internal {
         // Endpoint, nothing more to munch, create the initializer.
         // Since we are in the closure that is never called, this will never get executed.
         // We abuse `slot` to get the correct type inference here:
+        //
+        // SAFETY: TODO.
         unsafe {
             // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
             // information that is associated to already parsed fragments, so a path fragment