Merge tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

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

   - Extract the 'pin-init' API from the 'kernel' crate and make it into
     a standalone crate.

     In order to do this, the contents are rearranged so that they can
     easily be kept in sync with the version maintained out-of-tree that
     other projects have started to use too (or plan to, like QEMU).

     This will reduce the maintenance burden for Benno, who will now
     have his own sub-tree, and will simplify future expected changes
     like the move to use 'syn' to simplify the implementation.

   - Add '#[test]'-like support based on KUnit.

     We already had doctests support based on KUnit, which takes the
     examples in our Rust documentation and runs them under KUnit.

     Now, we are adding the beginning of the support for "normal" tests,
     similar to those the '#[test]' tests in userspace Rust. For
     instance:

         #[kunit_tests(my_suite)]
         mod tests {
             #[test]
             fn my_test() {
                 assert_eq!(1 + 1, 2);
             }
         }

     Unlike with doctests, the 'assert*!'s do not map to the KUnit
     assertion APIs yet.

   - Check Rust signatures at compile time for functions called from C
     by name.

     In particular, introduce a new '#[export]' macro that can be placed
     in the Rust function definition. It will ensure that the function
     declaration on the C side matches the signature on the Rust
     function:

         #[export]
         pub unsafe extern "C" fn my_function(a: u8, b: i32) -> usize {
             // ...
         }

     The macro essentially forces the compiler to compare the types of
     the actual Rust function and the 'bindgen'-processed C signature.

     These cases are rare so far. In the future, we may consider
     introducing another tool, 'cbindgen', to generate C headers
     automatically. Even then, having these functions explicitly marked
     may be a good idea anyway.

   - Enable the 'raw_ref_op' Rust feature: it is already stable, and
     allows us to use the new '&raw' syntax, avoiding a couple macros.
     After everyone has migrated, we will disallow the macros.

   - Pass the correct target to 'bindgen' on Usermode Linux.

   - Fix 'rusttest' build in macOS.

  'kernel' crate:

   - New 'hrtimer' module: add support for setting up intrusive timers
     without allocating when starting the timer. Add support for
     'Pin<Box<_>>', 'Arc<_>', 'Pin<&_>' and 'Pin<&mut _>' as pointer
     types for use with timer callbacks. Add support for setting clock
     source and timer mode.

   - New 'dma' module: add a simple DMA coherent allocator abstraction
     and a test sample driver.

   - 'list' module: make the linked list 'Cursor' point between
     elements, rather than at an element, which is more convenient to us
     and allows for cursors to empty lists; and document it with
     examples of how to perform common operations with the provided
     methods.

   - 'str' module: implement a few traits for 'BStr' as well as the
     'strip_prefix()' method.

   - 'sync' module: add 'Arc::as_ptr'.

   - 'alloc' module: add 'Box::into_pin'.

   - 'error' module: extend the 'Result' documentation, including a few
     examples on different ways of handling errors, a warning about
     using methods that may panic, and links to external documentation.

  'macros' crate:

   - 'module' macro: add the 'authors' key to support multiple authors.
     The original key will be kept until everyone has migrated.

  Documentation:

   - Add error handling sections.

  MAINTAINERS:

   - Add Danilo Krummrich as reviewer of the Rust "subsystem".

   - Add 'RUST [PIN-INIT]' entry with Benno Lossin as maintainer. It has
     its own sub-tree.

   - Add sub-tree for 'RUST [ALLOC]'.

   - Add 'DMA MAPPING HELPERS DEVICE DRIVER API [RUST]' entry with
     Abdiel Janulgue as primary maintainer. It will go through the
     sub-tree of the 'RUST [ALLOC]' entry.

   - Add 'HIGH-RESOLUTION TIMERS [RUST]' entry with Andreas Hindborg as
     maintainer. It has its own sub-tree.

  And a few other cleanups and improvements"

* tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (71 commits)
  rust: dma: add `Send` implementation for `CoherentAllocation`
  rust: macros: fix `make rusttest` build on macOS
  rust: block: refactor to use `&raw mut`
  rust: enable `raw_ref_op` feature
  rust: uaccess: name the correct function
  rust: rbtree: fix comments referring to Box instead of KBox
  rust: hrtimer: add maintainer entry
  rust: hrtimer: add clocksource selection through `ClockId`
  rust: hrtimer: add `HrTimerMode`
  rust: hrtimer: implement `HrTimerPointer` for `Pin<Box<T>>`
  rust: alloc: add `Box::into_pin`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>`
  rust: hrtimer: add `hrtimer::ScopedHrTimerPointer`
  rust: hrtimer: add `UnsafeHrTimerPointer`
  rust: hrtimer: allow timer restart from timer handler
  rust: str: implement `strip_prefix` for `BStr`
  rust: str: implement `AsRef<BStr>` for `[u8]` and `BStr`
  rust: str: implement `Index` for `BStr`
  rust: str: implement `PartialEq` for `BStr`
  ...

1 files changed, 14 insertions, 9 deletions

diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 2bbaab83b9d6..9d0471afc964 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -2,7 +2,6 @@
 
 //! Kernel types.
 
-use crate::init::{self, PinInit};
 use core::{
     cell::UnsafeCell,
     marker::{PhantomData, PhantomPinned},
@@ -10,6 +9,7 @@ use core::{
     ops::{Deref, DerefMut},
     ptr::NonNull,
 };
+use pin_init::{PinInit, Zeroable};
 
 /// Used to transfer ownership to and from foreign (non-Rust) languages.
 ///
@@ -77,7 +77,7 @@ pub trait ForeignOwnable: Sized {
     ///
     /// The provided pointer must have been returned by a previous call to [`into_foreign`], and if
     /// the pointer is ever passed to [`from_foreign`], then that call must happen after the end of
-    /// the lifetime 'a.
+    /// the lifetime `'a`.
     ///
     /// [`into_foreign`]: Self::into_foreign
     /// [`from_foreign`]: Self::from_foreign
@@ -100,9 +100,9 @@ pub trait ForeignOwnable: Sized {
     ///
     /// The provided pointer must have been returned by a previous call to [`into_foreign`], and if
     /// the pointer is ever passed to [`from_foreign`], then that call must happen after the end of
-    /// the lifetime 'a.
+    /// the lifetime `'a`.
     ///
-    /// The lifetime 'a must not overlap with the lifetime of any other call to [`borrow`] or
+    /// The lifetime `'a` must not overlap with the lifetime of any other call to [`borrow`] or
     /// `borrow_mut` on the same object.
     ///
     /// [`into_foreign`]: Self::into_foreign
@@ -251,7 +251,7 @@ impl<T, F: FnOnce(T)> Drop for ScopeGuard<T, F> {
 
 /// Stores an opaque value.
 ///
-/// `Opaque<T>` is meant to be used with FFI objects that are never interpreted by Rust code.
+/// [`Opaque<T>`] is meant to be used with FFI objects that are never interpreted by Rust code.
 ///
 /// It is used to wrap structs from the C side, like for example `Opaque<bindings::mutex>`.
 /// It gets rid of all the usual assumptions that Rust has for a value:
@@ -266,7 +266,7 @@ impl<T, F: FnOnce(T)> Drop for ScopeGuard<T, F> {
 /// This has to be used for all values that the C side has access to, because it can't be ensured
 /// that the C side is adhering to the usual constraints that Rust needs.
 ///
-/// Using `Opaque<T>` allows to continue to use references on the Rust side even for values shared
+/// Using [`Opaque<T>`] allows to continue to use references on the Rust side even for values shared
 /// with C.
 ///
 /// # Examples
@@ -309,6 +309,9 @@ pub struct Opaque<T> {
     _pin: PhantomPinned,
 }
 
+// SAFETY: `Opaque<T>` allows the inner value to be any bit pattern, including all zeros.
+unsafe impl<T> Zeroable for Opaque<T> {}
+
 impl<T> Opaque<T> {
     /// Creates a new opaque value.
     pub const fn new(value: T) -> Self {
@@ -333,7 +336,7 @@ impl<T> Opaque<T> {
             //   - `ptr` is a valid pointer to uninitialized memory,
             //   - `slot` is not accessed on error; the call is infallible,
             //   - `slot` is pinned in memory.
-            let _ = unsafe { init::PinInit::<T>::__pinned_init(slot, ptr) };
+            let _ = unsafe { PinInit::<T>::__pinned_init(slot, ptr) };
         })
     }
 
@@ -349,7 +352,7 @@ impl<T> Opaque<T> {
         // SAFETY: We contain a `MaybeUninit`, so it is OK for the `init_func` to not fully
         // initialize the `T`.
         unsafe {
-            init::pin_init_from_closure::<_, ::core::convert::Infallible>(move |slot| {
+            pin_init::pin_init_from_closure::<_, ::core::convert::Infallible>(move |slot| {
                 init_func(Self::raw_get(slot));
                 Ok(())
             })
@@ -369,7 +372,9 @@ impl<T> Opaque<T> {
     ) -> impl PinInit<Self, E> {
         // SAFETY: We contain a `MaybeUninit`, so it is OK for the `init_func` to not fully
         // initialize the `T`.
-        unsafe { init::pin_init_from_closure::<_, E>(move |slot| init_func(Self::raw_get(slot))) }
+        unsafe {
+            pin_init::pin_init_from_closure::<_, E>(move |slot| init_func(Self::raw_get(slot)))
+        }
     }
 
     /// Returns a raw pointer to the opaque data.