Merge tag 'alloc-next-v6.18-2025-09-04' of https://github.com/Rust-for-Linux/linux into rust-next

Pull alloc and DMA updates from Danilo Krummrich:

  Allocator:
   - Provide information about the minimum alignment guarantees of
     'Kmalloc', 'Vmalloc' and 'KVmalloc'.
   - Take minimum alignment guarantees of allocators for
     'ForeignOwnable' into account.
   - Remove the 'allocator_test' incl. 'Cmalloc'.

  Box:
   - Implement 'Box::pin_slice()', which constructs a pinned slice of
     elements.

  Vec:
   - Simplify KUnit test module name to 'rust_kvec'.
   - Add doc-test for 'Vec::as_slice()'.
   - Constify various methods.

  DMA:
   - Update 'ARef' and 'AlwaysRefCounted' imports.

  MISC:
   - Remove support for unused host '#[test]'s.
   - Constify 'ArrayLayout::new_unchecked()'.

* tag 'alloc-next-v6.18-2025-09-04' of https://github.com/Rust-for-Linux/linux:
  rust: alloc: remove `allocator_test`
  rust: kernel: remove support for unused host `#[test]`s
  rust: alloc: implement Box::pin_slice()
  rust: alloc: add ARCH_KMALLOC_MINALIGN to bindgen blocklist
  rust: dma: Update ARef and AlwaysRefCounted imports from sync::aref
  rust: alloc: take the allocator into account for FOREIGN_ALIGN
  rust: alloc: specify the minimum alignment of each allocator
  rust: make `kvec::Vec` functions `const fn`
  rust: make `ArrayLayout::new_unchecked` a `const fn`
  rust: alloc: kvec: simplify KUnit test module name to "rust_kvec"
  rust: alloc: kvec: add doc example for as_slice method

1 files changed, 0 insertions, 124 deletions

diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs
deleted file mode 100644
index 90dd987d40e4..000000000000
--- a/rust/kernel/alloc/allocator_test.rs
+++ /dev/null
@@ -1,124 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users
-//! of those types (e.g. `CString`) use kernel allocators for instantiation.
-//!
-//! In order to allow userspace test cases to make use of such types as well, implement the
-//! `Cmalloc` allocator within the `allocator_test` module and type alias all kernel allocators to
-//! `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend.
-
-#![allow(missing_docs)]
-
-use super::{flags::*, AllocError, Allocator, Flags};
-use core::alloc::Layout;
-use core::cmp;
-use core::ptr;
-use core::ptr::NonNull;
-
-/// The userspace allocator based on libc.
-pub struct Cmalloc;
-
-pub type Kmalloc = Cmalloc;
-pub type Vmalloc = Kmalloc;
-pub type KVmalloc = Kmalloc;
-
-impl Cmalloc {
-    /// Returns a [`Layout`] that makes [`Kmalloc`] fulfill the requested size and alignment of
-    /// `layout`.
-    pub fn aligned_layout(layout: Layout) -> Layout {
-        // Note that `layout.size()` (after padding) is guaranteed to be a multiple of
-        // `layout.align()` which together with the slab guarantees means that `Kmalloc` will return
-        // a properly aligned object (see comments in `kmalloc()` for more information).
-        layout.pad_to_align()
-    }
-}
-
-extern "C" {
-    #[link_name = "aligned_alloc"]
-    fn libc_aligned_alloc(align: usize, size: usize) -> *mut crate::ffi::c_void;
-
-    #[link_name = "free"]
-    fn libc_free(ptr: *mut crate::ffi::c_void);
-}
-
-// SAFETY:
-// - memory remains valid until it is explicitly freed,
-// - passing a pointer to a valid memory allocation created by this `Allocator` is always OK,
-// - `realloc` provides the guarantees as provided in the `# Guarantees` section.
-unsafe impl Allocator for Cmalloc {
-    unsafe fn realloc(
-        ptr: Option<NonNull<u8>>,
-        layout: Layout,
-        old_layout: Layout,
-        flags: Flags,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        let src = match ptr {
-            Some(src) => {
-                if old_layout.size() == 0 {
-                    ptr::null_mut()
-                } else {
-                    src.as_ptr()
-                }
-            }
-            None => ptr::null_mut(),
-        };
-
-        if layout.size() == 0 {
-            // SAFETY: `src` is either NULL or was previously allocated with this `Allocator`
-            unsafe { libc_free(src.cast()) };
-
-            return Ok(NonNull::slice_from_raw_parts(
-                crate::alloc::dangling_from_layout(layout),
-                0,
-            ));
-        }
-
-        // ISO C (ISO/IEC 9899:2011) defines `aligned_alloc`:
-        //
-        // > The value of alignment shall be a valid alignment supported by the implementation
-        // [...].
-        //
-        // As an example of the "supported by the implementation" requirement, POSIX.1-2001 (IEEE
-        // 1003.1-2001) defines `posix_memalign`:
-        //
-        // > The value of alignment shall be a power of two multiple of sizeof (void *).
-        //
-        // and POSIX-based implementations of `aligned_alloc` inherit this requirement. At the time
-        // of writing, this is known to be the case on macOS (but not in glibc).
-        //
-        // Satisfy the stricter requirement to avoid spurious test failures on some platforms.
-        let min_align = core::mem::size_of::<*const crate::ffi::c_void>();
-        let layout = layout.align_to(min_align).map_err(|_| AllocError)?;
-        let layout = layout.pad_to_align();
-
-        // SAFETY: Returns either NULL or a pointer to a memory allocation that satisfies or
-        // exceeds the given size and alignment requirements.
-        let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) }.cast::<u8>();
-        let dst = NonNull::new(dst).ok_or(AllocError)?;
-
-        if flags.contains(__GFP_ZERO) {
-            // SAFETY: The preceding calls to `libc_aligned_alloc` and `NonNull::new`
-            // guarantee that `dst` points to memory of at least `layout.size()` bytes.
-            unsafe { dst.as_ptr().write_bytes(0, layout.size()) };
-        }
-
-        if !src.is_null() {
-            // SAFETY:
-            // - `src` has previously been allocated with this `Allocator`; `dst` has just been
-            //   newly allocated, hence the memory regions do not overlap.
-            // - both` src` and `dst` are properly aligned and valid for reads and writes
-            unsafe {
-                ptr::copy_nonoverlapping(
-                    src,
-                    dst.as_ptr(),
-                    cmp::min(layout.size(), old_layout.size()),
-                )
-            };
-        }
-
-        // SAFETY: `src` is either NULL or was previously allocated with this `Allocator`
-        unsafe { libc_free(src.cast()) };
-
-        Ok(NonNull::slice_from_raw_parts(dst, layout.size()))
-    }
-}