From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A1F72CD3427 for ; Tue, 5 May 2026 15:24:13 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0996310EB24; Tue, 5 May 2026 15:24:13 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="SXJ30qcv"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5BF8F10EB24 for ; Tue, 5 May 2026 15:24:11 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 4300543BDC; Tue, 5 May 2026 15:24:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3752DC2BCF5; Tue, 5 May 2026 15:24:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777994651; bh=/fRYQ5zjyOWJ/pjwZIQGbTj2eLYzfvrx5wG1aPkJ0yk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SXJ30qcvZyrwl+5xqeEEOkQOYPEOuJoahNOTRVpjZWEZtRGtD+oA+gZn8TpWHKWBm GYYhJ13x8GubFYRcnUxl501mOCZHvRaMTcJV3u8hp0M4dIEHS/I8g60qqKfZwFQSzl 9A4jDC4V+x/sNS4OaC0oukadQ4UaMe9OcIvKgc3IGE7AGdt992KemwXAzEHHe2Xglc ad4wFuVYf/0nD1S/hmJgyQlcmf3IleEqNeFYMJIl012IlPjFoAdpH0uU76mpTtnFWS oemGjtz7Gh4M9NeBE46mWuutnWcefecejUYSwb3awnNqkNOH5rPEtVYSaE21VBfs8O nRHOS0RJ7fBhA== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, acourbot@nvidia.com, aliceryhl@google.com, david.m.ertman@intel.com, ira.weiny@intel.com, leon@kernel.org, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 1/3] rust: alloc: add Box::zeroed() Date: Tue, 5 May 2026 17:23:07 +0200 Message-ID: <20260505152400.3905096-2-dakr@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260505152400.3905096-1-dakr@kernel.org> References: <20260505152400.3905096-1-dakr@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add Box::zeroed() for T: Zeroable types. This allocates with __GFP_ZERO directly, letting the underlying allocator deal with zeroing out the memory compared to Box::new(T::zeroed(), flags). Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kbox.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index bd6da02c7ab8..c824ed6e1523 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -19,6 +19,7 @@ use crate::fmt; use crate::init::InPlaceInit; use crate::page::AsPageIter; +use crate::prelude::*; use crate::types::ForeignOwnable; use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption}; @@ -256,6 +257,27 @@ pub fn new_uninit(flags: Flags) -> Result, A>, AllocError> { Ok(Box(ptr.cast(), PhantomData)) } + /// Creates a new zero-initialized `Box`. + /// + /// New memory is allocated with `A` and the [`__GFP_ZERO`] flag. The allocation may fail, in + /// which case an error is returned. For ZSTs no memory is allocated. + /// + /// # Examples + /// + /// ``` + /// let b = KBox::<[u8; 128]>::zeroed(GFP_KERNEL)?; + /// assert_eq!(*b, [0; 128]); + /// # Ok::<(), Error>(()) + /// ``` + pub fn zeroed(flags: Flags) -> Result + where + T: Zeroable, + { + // SAFETY: `__GFP_ZERO` guarantees the memory is zeroed; `T: Zeroable` guarantees that + // all-zeroes is a valid bit pattern for `T`. + Ok(unsafe { Self::new_uninit(flags | __GFP_ZERO)?.assume_init() }) + } + /// Constructs a new `Pin>`. If `T` does not implement [`Unpin`], then `x` will be /// pinned in memory and can't be moved. #[inline] -- 2.54.0