From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A8B71FB3; Sun, 9 Mar 2025 09:48:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741513721; cv=none; b=n79lIERkV04OW1bcU6BUZhtXLeyq4B9rkB4/oMbNJCzXUnXoS9/EqNG4uGvkszZ5EojaaIMzWBJX1aAeo92BJysd+Z7ekPZaRvxZdj9qm0fJsaf6/BO18dbo/1AVeRSGPwBMdS0HheUXS49LMX3aP/kcIaZGiE/tS8Iu1eV99yQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741513721; c=relaxed/simple; bh=Z49LUML22w8acm4D99U7000XO615tLvxngC+pTm1xN4=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=DQBXKby6xUNM/bw0hP5l+3GPyc6yQNnjhzo3OfY7xrfI5U8F/5fTwsfOkLDVAux8dSwF0P7ZJYYwwOPS74+59yEQ6Mt7ku00D+bBV7yZ92a1YW5Y6zc3yKnuTzYuyOMvhQ3TOM2p/deeP3mPehi6G0Cb1Beg28wEU327PtDXKv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=m8FT/kSU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="m8FT/kSU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E258C4CEE5; Sun, 9 Mar 2025 09:48:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741513720; bh=Z49LUML22w8acm4D99U7000XO615tLvxngC+pTm1xN4=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=m8FT/kSUQbrkrIfDKs38CZ543w9xATbyGW97UBDggrZ5QytHnRxqh20cKCLhu/UNV PeVW0Imorf6W7pVfqky/UNodTf9XiaejnFvB3ep6bXiO+eWYtDsChaOPAbOoLoBCeg zBEAoTh8PT74NQGgvwEZ6H9vOc80uZlA1szVNTQ4= Subject: Patch "rust: alloc: add `Allocator` trait" has been added to the 6.12-stable tree To: aliceryhl@google.com,benno.lossin@proton.me,dakr@kernel.org,gary@garyguo.net,gregkh@linuxfoundation.org,hi@alyssa.is,noisycoil@disroot.org,ojeda@kernel.org,patches@lists.linux.dev,sashal@kernel.org Cc: From: Date: Sun, 09 Mar 2025 10:46:48 +0100 In-Reply-To: <20250307225008.779961-21-ojeda@kernel.org> Message-ID: <2025030948-daytime-trillion-a00d@gregkh> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore This is a note to let you know that I've just added the patch titled rust: alloc: add `Allocator` trait 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-add-allocator-trait.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 know about it. >From stable+bounces-121475-greg=kroah.com@vger.kernel.org Fri Mar 7 23:51:36 2025 From: Miguel Ojeda Date: Fri, 7 Mar 2025 23:49:27 +0100 Subject: rust: alloc: add `Allocator` trait To: Greg Kroah-Hartman , Sasha Levin , stable@vger.kernel.org Cc: Danilo Krummrich , Alice Ryhl , Alyssa Ross , NoisyCoil , patches@lists.linux.dev, Miguel Ojeda Message-ID: <20250307225008.779961-21-ojeda@kernel.org> From: Danilo Krummrich commit b7a084ba4fbb8f416ce8d19c93a3a2bee63c9c89 upstream. Add a kernel specific `Allocator` trait, that in contrast to the one in Rust's core library doesn't require unstable features and supports GFP flags. Subsequent patches add the following trait implementors: `Kmalloc`, `Vmalloc` and `KVmalloc`. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-2-dakr@kernel.org [ Fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman --- rust/kernel/alloc.rs | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) --- a/rust/kernel/alloc.rs +++ b/rust/kernel/alloc.rs @@ -11,6 +11,7 @@ pub mod vec_ext; /// Indicates an allocation error. #[derive(Copy, Clone, PartialEq, Eq, Debug)] pub struct AllocError; +use core::{alloc::Layout, ptr::NonNull}; /// Flags to be used when allocating memory. /// @@ -86,3 +87,103 @@ pub mod flags { /// small allocations. pub const GFP_NOWAIT: Flags = Flags(bindings::GFP_NOWAIT); } + +/// The kernel's [`Allocator`] trait. +/// +/// An implementation of [`Allocator`] can allocate, re-allocate and free memory buffers described +/// via [`Layout`]. +/// +/// [`Allocator`] is designed to be implemented as a ZST; [`Allocator`] functions do not operate on +/// an object instance. +/// +/// In order to be able to support `#[derive(SmartPointer)]` later on, we need to avoid a design +/// that requires an `Allocator` to be instantiated, hence its functions must not contain any kind +/// of `self` parameter. +/// +/// # Safety +/// +/// - A memory allocation returned from an allocator must remain valid until it is explicitly freed. +/// +/// - Any pointer to a valid memory allocation must be valid to be passed to any other [`Allocator`] +/// function of the same type. +/// +/// - Implementers must ensure that all trait functions abide by the guarantees documented in the +/// `# Guarantees` sections. +pub unsafe trait Allocator { + /// Allocate memory based on `layout` and `flags`. + /// + /// On success, returns a buffer represented as `NonNull<[u8]>` that satisfies the layout + /// constraints (i.e. minimum size and alignment as specified by `layout`). + /// + /// This function is equivalent to `realloc` when called with `None`. + /// + /// # Guarantees + /// + /// When the return value is `Ok(ptr)`, then `ptr` is + /// - valid for reads and writes for `layout.size()` bytes, until it is passed to + /// [`Allocator::free`] or [`Allocator::realloc`], + /// - aligned to `layout.align()`, + /// + /// Additionally, `Flags` are honored as documented in + /// . + fn alloc(layout: Layout, flags: Flags) -> Result, AllocError> { + // SAFETY: Passing `None` to `realloc` is valid by its safety requirements and asks for a + // new memory allocation. + unsafe { Self::realloc(None, layout, Layout::new::<()>(), flags) } + } + + /// Re-allocate an existing memory allocation to satisfy the requested `layout`. + /// + /// If the requested size is zero, `realloc` behaves equivalent to `free`. + /// + /// If the requested size is larger than the size of the existing allocation, a successful call + /// to `realloc` guarantees that the new or grown buffer has at least `Layout::size` bytes, but + /// may also be larger. + /// + /// If the requested size is smaller than the size of the existing allocation, `realloc` may or + /// may not shrink the buffer; this is implementation specific to the allocator. + /// + /// On allocation failure, the existing buffer, if any, remains valid. + /// + /// The buffer is represented as `NonNull<[u8]>`. + /// + /// # Safety + /// + /// - If `ptr == Some(p)`, then `p` must point to an existing and valid memory allocation + /// created by this [`Allocator`]; if `old_layout` is zero-sized `p` does not need to be a + /// pointer returned by this [`Allocator`]. + /// - `ptr` is allowed to be `None`; in this case a new memory allocation is created and + /// `old_layout` is ignored. + /// - `old_layout` must match the `Layout` the allocation has been created with. + /// + /// # Guarantees + /// + /// This function has the same guarantees as [`Allocator::alloc`]. When `ptr == Some(p)`, then + /// it additionally guarantees that: + /// - the contents of the memory pointed to by `p` are preserved up to the lesser of the new + /// and old size, i.e. `ret_ptr[0..min(layout.size(), old_layout.size())] == + /// p[0..min(layout.size(), old_layout.size())]`. + /// - when the return value is `Err(AllocError)`, then `ptr` is still valid. + unsafe fn realloc( + ptr: Option>, + layout: Layout, + old_layout: Layout, + flags: Flags, + ) -> Result, AllocError>; + + /// Free an existing memory allocation. + /// + /// # Safety + /// + /// - `ptr` must point to an existing and valid memory allocation created by this [`Allocator`]; + /// if `old_layout` is zero-sized `p` does not need to be a pointer returned by this + /// [`Allocator`]. + /// - `layout` must match the `Layout` the allocation has been created with. + /// - The memory allocation at `ptr` must never again be read from or written to. + unsafe fn free(ptr: NonNull, layout: Layout) { + // SAFETY: The caller guarantees that `ptr` points at a valid allocation created by this + // allocator. We are passing a `Layout` with the smallest possible alignment, so it is + // smaller than or equal to the alignment previously used with this allocation. + let _ = unsafe { Self::realloc(Some(ptr), Layout::new::<()>(), layout, Flags(0)) }; + } +} 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