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Mon, 4 Aug 2025 11:45:38 +0000 Received: from CH2PR12MB3990.namprd12.prod.outlook.com ([fe80::6e37:569f:82ee:3f99]) by CH2PR12MB3990.namprd12.prod.outlook.com ([fe80::6e37:569f:82ee:3f99%3]) with mapi id 15.20.8989.018; Mon, 4 Aug 2025 11:45:37 +0000 From: Alexandre Courbot Date: Mon, 04 Aug 2025 20:45:24 +0900 Subject: [PATCH v2 1/4] rust: add `CheckedAdd` trait Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250804-num-v2-1-a96b9ca6eb02@nvidia.com> References: <20250804-num-v2-0-a96b9ca6eb02@nvidia.com> In-Reply-To: <20250804-num-v2-0-a96b9ca6eb02@nvidia.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, nouveau@lists.freedesktop.org, Alexandre Courbot X-Mailer: b4 0.14.2 X-ClientProxiedBy: TYAPR01CA0097.jpnprd01.prod.outlook.com (2603:1096:404:2a::13) To CH2PR12MB3990.namprd12.prod.outlook.com (2603:10b6:610:28::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PR12MB3990:EE_|SA1PR12MB8841:EE_ X-MS-Office365-Filtering-Correlation-Id: a616c347-d5ea-44ed-22b9-08ddd34c6dee X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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The checked Rust arithmetic methods are unfortunately not behind a trait, which makes them unavailable to generic code. As a start, add the `CheckedAdd` trait providing the `checked_add` operation and implement it for all integer types. Its name and location are inspired by the user-space `num` crate. This trait is to be first used by the `Alignment` type. Signed-off-by: Alexandre Courbot --- rust/kernel/lib.rs | 1 + rust/kernel/num.rs | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 6b4774b2b1c37f4da1866e993be6230bc6715841..2955f65da1278dd4cba1e4272ff178b8211a892c 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -89,6 +89,7 @@ pub mod mm; #[cfg(CONFIG_NET)] pub mod net; +pub mod num; pub mod of; #[cfg(CONFIG_PM_OPP)] pub mod opp; diff --git a/rust/kernel/num.rs b/rust/kernel/num.rs new file mode 100644 index 0000000000000000000000000000000000000000..c81bb046078b70c321dd52aa9c2b5518be49d249 --- /dev/null +++ b/rust/kernel/num.rs @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Numerical and binary utilities for primitive types. + +use core::ops::Add; + +/// Trait for performing a checked addition that returns `None` if the operation would overflow. +/// +/// This trait exists in order to represent scalar types already having a `checked_add` method in +/// generic code. +pub trait CheckedAdd: Sized + Add { + /// Computes `self + rhs`, returning `None` if an overflow would occur. + fn checked_add(self, rhs: Self) -> Option; +} + +macro_rules! impl_checked_add { + ($($t:ty),*) => { + $( + impl CheckedAdd for $t { + fn checked_add(self, rhs: Self) -> Option { + self.checked_add(rhs) + } + } + )* + }; +} + +impl_checked_add!(u8, u16, u32, u64, usize, i8, i16, i32, i64, isize); -- 2.50.1