Patch "rust: alloc: remove `VecExt` extension" has been added to the 6.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    rust: alloc: remove `VecExt` extension

to the 6.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rust-alloc-remove-vecext-extension.patch
and it can be found in the queue-6.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-121494-greg=kroah.com@vger.kernel.org Fri Mar  7 23:52:46 2025
From: Miguel Ojeda <ojeda@kernel.org>
Date: Fri,  7 Mar 2025 23:49:46 +0100
Subject: rust: alloc: remove `VecExt` extension
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Sasha Levin <sashal@kernel.org>, stable@vger.kernel.org
Cc: Danilo Krummrich <dakr@kernel.org>, Alice Ryhl <aliceryhl@google.com>, Alyssa Ross <hi@alyssa.is>, NoisyCoil <noisycoil@disroot.org>, patches@lists.linux.dev, Miguel Ojeda <ojeda@kernel.org>
Message-ID: <20250307225008.779961-40-ojeda@kernel.org>

From: Danilo Krummrich <dakr@kernel.org>

commit 405966efc789888c3e1a53cd09d2c2b338064438 upstream.

Now that all existing `Vec` users were moved to the kernel `Vec` type,
remove the `VecExt` extension.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-21-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 rust/kernel/alloc.rs         |    1 
 rust/kernel/alloc/vec_ext.rs |  185 -------------------------------------------
 rust/kernel/prelude.rs       |    5 -
 3 files changed, 1 insertion(+), 190 deletions(-)
 delete mode 100644 rust/kernel/alloc/vec_ext.rs

--- a/rust/kernel/alloc.rs
+++ b/rust/kernel/alloc.rs
@@ -7,7 +7,6 @@ pub mod allocator;
 pub mod kbox;
 pub mod kvec;
 pub mod layout;
-pub mod vec_ext;
 
 #[cfg(any(test, testlib))]
 pub mod allocator_test;
--- a/rust/kernel/alloc/vec_ext.rs
+++ /dev/null
@@ -1,185 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! Extensions to [`Vec`] for fallible allocations.
-
-use super::{AllocError, Flags};
-use alloc::vec::Vec;
-
-/// Extensions to [`Vec`].
-pub trait VecExt<T>: Sized {
-    /// Creates a new [`Vec`] instance with at least the given capacity.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let v = Vec::<u32>::with_capacity(20, GFP_KERNEL)?;
-    ///
-    /// assert!(v.capacity() >= 20);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError>;
-
-    /// Appends an element to the back of the [`Vec`] instance.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1]);
-    ///
-    /// v.push(2, GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 2]);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError>;
-
-    /// Pushes clones of the elements of slice into the [`Vec`] instance.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    ///
-    /// v.extend_from_slice(&[20, 30, 40], GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 20, 30, 40]);
-    ///
-    /// v.extend_from_slice(&[50, 60], GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 20, 30, 40, 50, 60]);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
-    where
-        T: Clone;
-
-    /// Ensures that the capacity exceeds the length by at least `additional` elements.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    ///
-    /// v.reserve(10, GFP_KERNEL)?;
-    /// let cap = v.capacity();
-    /// assert!(cap >= 10);
-    ///
-    /// v.reserve(10, GFP_KERNEL)?;
-    /// let new_cap = v.capacity();
-    /// assert_eq!(new_cap, cap);
-    ///
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError>;
-}
-
-impl<T> VecExt<T> for Vec<T> {
-    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError> {
-        let mut v = Vec::new();
-        <Self as VecExt<_>>::reserve(&mut v, capacity, flags)?;
-        Ok(v)
-    }
-
-    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError> {
-        <Self as VecExt<_>>::reserve(self, 1, flags)?;
-        let s = self.spare_capacity_mut();
-        s[0].write(v);
-
-        // SAFETY: We just initialised the first spare entry, so it is safe to increase the length
-        // by 1. We also know that the new length is <= capacity because of the previous call to
-        // `reserve` above.
-        unsafe { self.set_len(self.len() + 1) };
-        Ok(())
-    }
-
-    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
-    where
-        T: Clone,
-    {
-        <Self as VecExt<_>>::reserve(self, other.len(), flags)?;
-        for (slot, item) in core::iter::zip(self.spare_capacity_mut(), other) {
-            slot.write(item.clone());
-        }
-
-        // SAFETY: We just initialised the `other.len()` spare entries, so it is safe to increase
-        // the length by the same amount. We also know that the new length is <= capacity because
-        // of the previous call to `reserve` above.
-        unsafe { self.set_len(self.len() + other.len()) };
-        Ok(())
-    }
-
-    #[cfg(any(test, testlib))]
-    fn reserve(&mut self, additional: usize, _flags: Flags) -> Result<(), AllocError> {
-        Vec::reserve(self, additional);
-        Ok(())
-    }
-
-    #[cfg(not(any(test, testlib)))]
-    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError> {
-        let len = self.len();
-        let cap = self.capacity();
-
-        if cap - len >= additional {
-            return Ok(());
-        }
-
-        if core::mem::size_of::<T>() == 0 {
-            // The capacity is already `usize::MAX` for SZTs, we can't go higher.
-            return Err(AllocError);
-        }
-
-        // We know cap is <= `isize::MAX` because `Layout::array` fails if the resulting byte size
-        // is greater than `isize::MAX`. So the multiplication by two won't overflow.
-        let new_cap = core::cmp::max(cap * 2, len.checked_add(additional).ok_or(AllocError)?);
-        let layout = core::alloc::Layout::array::<T>(new_cap).map_err(|_| AllocError)?;
-
-        let (old_ptr, len, cap) = destructure(self);
-
-        // We need to make sure that `ptr` is either NULL or comes from a previous call to
-        // `krealloc_aligned`. A `Vec<T>`'s `ptr` value is not guaranteed to be NULL and might be
-        // dangling after being created with `Vec::new`. Instead, we can rely on `Vec<T>`'s capacity
-        // to be zero if no memory has been allocated yet.
-        let ptr = if cap == 0 {
-            core::ptr::null_mut()
-        } else {
-            old_ptr
-        };
-
-        // SAFETY: `ptr` is valid because it's either NULL or comes from a previous call to
-        // `krealloc_aligned`. We also verified that the type is not a ZST.
-        let new_ptr = unsafe { super::allocator::krealloc_aligned(ptr.cast(), layout, flags) };
-        if new_ptr.is_null() {
-            // SAFETY: We are just rebuilding the existing `Vec` with no changes.
-            unsafe { rebuild(self, old_ptr, len, cap) };
-            Err(AllocError)
-        } else {
-            // SAFETY: `ptr` has been reallocated with the layout for `new_cap` elements. New cap
-            // is greater than `cap`, so it continues to be >= `len`.
-            unsafe { rebuild(self, new_ptr.cast::<T>(), len, new_cap) };
-            Ok(())
-        }
-    }
-}
-
-#[cfg(not(any(test, testlib)))]
-fn destructure<T>(v: &mut Vec<T>) -> (*mut T, usize, usize) {
-    let mut tmp = Vec::new();
-    core::mem::swap(&mut tmp, v);
-    let mut tmp = core::mem::ManuallyDrop::new(tmp);
-    let len = tmp.len();
-    let cap = tmp.capacity();
-    (tmp.as_mut_ptr(), len, cap)
-}
-
-/// Rebuilds a `Vec` from a pointer, length, and capacity.
-///
-/// # Safety
-///
-/// The same as [`Vec::from_raw_parts`].
-#[cfg(not(any(test, testlib)))]
-unsafe fn rebuild<T>(v: &mut Vec<T>, ptr: *mut T, len: usize, cap: usize) {
-    // SAFETY: The safety requirements from this function satisfy those of `from_raw_parts`.
-    let mut tmp = unsafe { Vec::from_raw_parts(ptr, len, cap) };
-    core::mem::swap(&mut tmp, v);
-}
--- a/rust/kernel/prelude.rs
+++ b/rust/kernel/prelude.rs
@@ -14,10 +14,7 @@
 #[doc(no_inline)]
 pub use core::pin::Pin;
 
-pub use crate::alloc::{flags::*, vec_ext::VecExt, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
-
-#[doc(no_inline)]
-pub use alloc::vec::Vec;
+pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
 
 #[doc(no_inline)]
 pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable};


Patches currently in stable-queue which might be from ojeda@kernel.org are

queue-6.12/drm-panic-avoid-reimplementing-iterator-find.patch
queue-6.12/documentation-rust-add-coding-guidelines-on-lints.patch
queue-6.12/rust-provide-proper-code-documentation-titles.patch
queue-6.12/rust-alloc-make-allocator-module-public.patch
queue-6.12/rust-alloc-remove-vecext-extension.patch
queue-6.12/rust-alloc-implement-reallocfunc.patch
queue-6.12/rust-alloc-separate-aligned_size-from-krealloc_aligned.patch
queue-6.12/rust-enable-clippy-unnecessary_safety_comment-lint.patch
queue-6.12/rust-alloc-update-module-comment-of-alloc.rs.patch
queue-6.12/rust-kbuild-expand-rusttest-target-for-macros.patch
queue-6.12/rust-error-use-core-alloc-layouterror.patch
queue-6.12/rust-str-test-replace-alloc-format.patch
queue-6.12/loongarch-use-asm_reachable.patch
queue-6.12/rust-alloc-implement-allocator-for-kmalloc.patch
queue-6.12/rust-alloc-implement-collect-for-intoiter.patch
queue-6.12/rust-alloc-introduce-arraylayout.patch
queue-6.12/rust-alloc-implement-vmalloc-allocator.patch
queue-6.12/documentation-rust-discuss-in-the-guidelines.patch
queue-6.12/rust-error-check-for-config-test-in-error-name.patch
queue-6.12/rust-enable-clippy-ignored_unit_patterns-lint.patch
queue-6.12/rust-enable-clippy-unnecessary_safety_doc-lint.patch
queue-6.12/rust-alloc-add-box-to-prelude.patch
queue-6.12/kbuild-rust-remove-the-alloc-crate-and-globalalloc.patch
queue-6.12/rust-alloc-add-allocator-trait.patch
queue-6.12/rust-treewide-switch-to-our-kernel-box-type.patch
queue-6.12/rust-introduce-.clippy.toml.patch
queue-6.12/rust-alloc-rename-kernelallocator-to-kmalloc.patch
queue-6.12/rust-alloc-implement-cmalloc-in-module-allocator_test.patch
queue-6.12/drm-panic-allow-verbose-version-check.patch
queue-6.12/rust-map-__kernel_size_t-and-friends-also-to-usize-isize.patch
queue-6.12/rust-alloc-add-module-allocator_test.patch
queue-6.12/rust-replace-clippy-dbg_macro-with-disallowed_macros.patch
queue-6.12/rust-alloc-add-__gfp_nowarn-to-flags.patch
queue-6.12/rust-enable-clippy-s-check-private-items.patch
queue-6.12/rust-error-make-conversion-functions-public.patch
queue-6.12/rust-sort-global-rust-flags.patch
queue-6.12/rust-alloc-implement-contains-for-flags.patch
queue-6.12/rust-init-remove-unneeded.patch
queue-6.12/rust-use-custom-ffi-integer-types.patch
queue-6.12/rust-sync-remove-unneeded.patch
queue-6.12/rust-treewide-switch-to-the-kernel-vec-type.patch
queue-6.12/rust-alloc-implement-kvmalloc-allocator.patch
queue-6.12/drm-panic-correctly-indent-continuation-of-line-in-list-item.patch
queue-6.12/rust-alloc-implement-kernel-vec-type.patch
queue-6.12/rust-workqueue-remove-unneeded.patch
queue-6.12/rust-error-optimize-error-type-to-use-nonzero.patch
queue-6.12/drm-panic-remove-unnecessary-borrow-in-alignment_pattern.patch
queue-6.12/rust-alloc-remove-extension-of-std-s-box.patch
queue-6.12/rust-block-fix-formatting-in-gendisk-doc.patch
queue-6.12/rust-enable-rustdoc-unescaped_backticks-lint.patch
queue-6.12/rust-fix-size_t-in-bindgen-prototypes-of-c-builtins.patch
queue-6.12/rust-enable-clippy-undocumented_unsafe_blocks-lint.patch
queue-6.12/rust-alloc-add-vec-to-prelude.patch
queue-6.12/rust-alloc-implement-intoiterator-for-vec.patch
queue-6.12/rust-alloc-implement-kernel-box.patch
queue-6.12/drm-panic-remove-redundant-field-when-assigning-value.patch
queue-6.12/rust-types-avoid-repetition-in-as-from-bytes-impls.patch
queue-6.12/rust-start-using-the-attribute.patch
queue-6.12/drm-panic-allow-verbose-boolean-for-clarity.patch
queue-6.12/maintainers-add-entry-for-the-rust-alloc-module.patch
queue-6.12/rust-alloc-fix-arraylayout-allocations.patch
queue-6.12/drm-panic-prefer-eliding-lifetimes.patch