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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775433320; bh=HV0bL0gHeo5ytVraoqeUk7gpt273iWarFnhuW3AZrCI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gCHzAlM6VUIfeMuR3tiYiw4x52ObAlTAx9UnTip4jjUZVJ+sCfoUGSFvE9wPi7740 3QRK9w03A1z3Tiq5yMZhcKxEuaP5+x1h4JJYclMBu42+WH1zGRYSSJnyRXj0xz8xrv WlxPczxRkcp0lLRcjK9sorp63+5xChEEuulrugfJ6ET5VVvThzAtNxIfG4WG00VknT VdwbEkh/mOhhQJFQ0CiDoVyIB6OAVfcFk5XDu9QYRf/aMi7Zgkc5If449omeQ0BNT3 YtPI2fbmIXg2yzp3nTj1jj9b4E2kcYl6f6NENEgnXH14mkqjTi3gSF9ScvSlzg3pmV OfGyMkO6NzpJQ== From: Miguel Ojeda To: Miguel Ojeda , Nathan Chancellor , Nicolas Schier , Danilo Krummrich , Andreas Hindborg , Catalin Marinas , Will Deacon , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Courbot , David Airlie , Simona Vetter , Brendan Higgins , David Gow , Greg Kroah-Hartman , =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , Todd Kjos , Christian Brauner , Carlos Llamas , Alice Ryhl , Jonathan Corbet Subject: [PATCH v2 10/33] rust: remove `RUSTC_HAS_COERCE_POINTEE` and simplify code Date: Mon, 6 Apr 2026 01:52:46 +0200 Message-ID: <20260405235309.418950-11-ojeda@kernel.org> In-Reply-To: <20260405235309.418950-1-ojeda@kernel.org> References: <20260405235309.418950-1-ojeda@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: KG2LF7WLXOIZQI65ZZIW3P4DD6GNNMDT X-Message-ID-Hash: KG2LF7WLXOIZQI65ZZIW3P4DD6GNNMDT X-MailFrom: ojeda@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Trevor Gross , rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, Lorenzo Stoakes , Vlastimil Babka , "Liam R . Howlett" , Uladzislau Rezki , linux-block@vger.kernel.org, moderated for non-subscribers , Alexandre Ghiti , linux-riscv@lists.infradead.org, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Rae Moar , linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, Nick Desaulniers , Bill Wendling , Justin Stitt , llvm@lists.linux.dev, linux-kernel@vger.kernel.org, Shuah Khan , linux-doc@vger.kernel.org, Tamir Duberstein X-Mailman-Version: 3.3.8 Precedence: list List-Id: Nouveau development list Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: With the Rust version bump in place, the `RUSTC_HAS_COERCE_POINTEE` Kconfig (automatic) option is always true. Thus remove the option and simplify the code. In particular, this includes removing our use of the predecessor unstable features we used with Rust < 1.84.0 (`coerce_unsized`, `dispatch_from_dyn` and `unsize`). Reviewed-by: Tamir Duberstein Acked-by: Danilo Krummrich Reviewed-by: Gary Guo Signed-off-by: Miguel Ojeda --- init/Kconfig | 3 --- rust/kernel/alloc/kbox.rs | 29 ++--------------------------- rust/kernel/lib.rs | 8 +------- rust/kernel/list/arc.rs | 22 +--------------------- rust/kernel/sync/arc.rs | 21 ++------------------- 5 files changed, 6 insertions(+), 77 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index c38f49228157..f9fac458e4d4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -178,9 +178,6 @@ config LD_CAN_USE_KEEP_IN_OVERLAY # https://github.com/llvm/llvm-project/pull/130661 def_bool LD_IS_BFD || LLD_VERSION >= 210000 -config RUSTC_HAS_COERCE_POINTEE - def_bool RUSTC_VERSION >= 108400 - config RUSTC_HAS_SPAN_FILE def_bool RUSTC_VERSION >= 108800 diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index 622b3529edfc..bd6da02c7ab8 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -77,33 +77,8 @@ /// `self.0` is always properly aligned and either points to memory allocated with `A` or, for /// zero-sized types, is a dangling, well aligned pointer. #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] -pub struct Box<#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, pointee)] T: ?Sized, A: Allocator>( - NonNull, - PhantomData, -); - -// This is to allow coercion from `Box` to `Box` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::CoerceUnsized> for Box -where - T: ?Sized + core::marker::Unsize, - U: ?Sized, - A: Allocator, -{ -} - -// This is to allow `Box` to be dispatched on when `Box` can be coerced into `Box`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::DispatchFromDyn> for Box -where - T: ?Sized + core::marker::Unsize, - U: ?Sized, - A: Allocator, -{ -} +#[derive(core::marker::CoercePointee)] +pub struct Box<#[pointee] T: ?Sized, A: Allocator>(NonNull, PhantomData); /// Type alias for [`Box`] with a [`Kmalloc`] allocator. /// diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 621cae75030c..66a09d77a2c4 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -39,17 +39,11 @@ // // Expected to become stable. #![feature(arbitrary_self_types)] +#![feature(derive_coerce_pointee)] // // To be determined. #![feature(used_with_arg)] // -// `feature(derive_coerce_pointee)` is expected to become stable. Before Rust -// 1.84.0, it did not exist, so enable the predecessor features. -#![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] -#![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] -// // `feature(file_with_nul)` is expected to become stable. Before Rust 1.89.0, it did not exist, so // enable it conditionally. #![cfg_attr(CONFIG_RUSTC_HAS_FILE_WITH_NUL, feature(file_with_nul))] diff --git a/rust/kernel/list/arc.rs b/rust/kernel/list/arc.rs index e1082423909c..a9a2b0178f65 100644 --- a/rust/kernel/list/arc.rs +++ b/rust/kernel/list/arc.rs @@ -160,7 +160,7 @@ fn try_new_list_arc(&self) -> bool { /// /// [`List`]: crate::list::List #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct ListArc where T: ListArcSafe + ?Sized, @@ -443,26 +443,6 @@ fn as_ref(&self) -> &Arc { } } -// This is to allow coercion from `ListArc` to `ListArc` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::CoerceUnsized> for ListArc -where - T: ListArcSafe + core::marker::Unsize + ?Sized, - U: ListArcSafe + ?Sized, -{ -} - -// This is to allow `ListArc` to be dispatched on when `ListArc` can be coerced into -// `ListArc`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl core::ops::DispatchFromDyn> for ListArc -where - T: ListArcSafe + core::marker::Unsize + ?Sized, - U: ListArcSafe + ?Sized, -{ -} - /// A utility for tracking whether a [`ListArc`] exists using an atomic. /// /// # Invariants diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index 921e19333b89..18d6c0d62ce0 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -128,7 +128,7 @@ /// # Ok::<(), Error>(()) /// ``` #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct Arc { ptr: NonNull>, // NB: this informs dropck that objects of type `ArcInner` may be used in ` as @@ -182,15 +182,6 @@ unsafe fn container_of(ptr: *const T) -> NonNull> { } } -// This is to allow coercion from `Arc` to `Arc` if `T` can be converted to the -// dynamically-sized type (DST) `U`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::CoerceUnsized> for Arc {} - -// This is to allow `Arc` to be dispatched on when `Arc` can be coerced into `Arc`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::DispatchFromDyn> for Arc {} - // SAFETY: It is safe to send `Arc` to another thread when the underlying `T` is `Sync` because // it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs // `T` to be `Send` because any thread that has an `Arc` may ultimately access `T` using a @@ -547,20 +538,12 @@ fn from(item: Pin>) -> Self { /// # Ok::<(), Error>(()) /// ``` #[repr(transparent)] -#[cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, derive(core::marker::CoercePointee))] +#[derive(core::marker::CoercePointee)] pub struct ArcBorrow<'a, T: ?Sized + 'a> { inner: NonNull>, _p: PhantomData<&'a ()>, } -// This is to allow `ArcBorrow` to be dispatched on when `ArcBorrow` can be coerced into -// `ArcBorrow`. -#[cfg(not(CONFIG_RUSTC_HAS_COERCE_POINTEE))] -impl, U: ?Sized> core::ops::DispatchFromDyn> - for ArcBorrow<'_, T> -{ -} - impl Clone for ArcBorrow<'_, T> { fn clone(&self) -> Self { *self -- 2.53.0