From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6EDCA2D7DD4; Wed, 3 Jun 2026 01:10:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780449028; cv=none; b=OZzMKszVszP/tQ0Kt6wYfW43J2j9B3ooVNidfWhSJ+aWl9uNeS3PvngyfCCJ6k/xIz/hreo+vpfaICdStWA9Y8q/gjX/jaauT2+Fd3aq9OpSS3l3viLyPM2wtvjo3P5Mzq3U/BUK196kSWbgtZESRY2n80ain/8+TAdgcdZ3hwI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780449028; c=relaxed/simple; bh=VFJzEinoo/4V280HpZpXwl1kty1kGVWTjct7kNh18nc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dFzz0KIMviltWif40vAvQolCTbDzS13z2K4UiYboTygdcXcjni2VhpzAF/BgROQZw0OMqAx8OZ91/8hnmEJCMo4b9H834kUP+W9JJsGQN4VUIaMYJsqi9xXEm8uf4rKP7ipsfahXmvcmq/DwFyPQnEVOTI7qgpyFa+oC27O11uY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bK40Chfx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bK40Chfx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78B2A1F00893; Wed, 3 Jun 2026 01:10:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780449027; bh=vg4OT7qVOOfiZWFV5Vcsuizp9IDFD8+pqun6oZHSTcM=; h=From:To:Cc:Subject:Date; b=bK40Chfx+OYTbVFoho2VApu/zYarNWFjOtFjO7yjtr8tQILFmaHSzBTcATrsQ5lOt BzzDNGMelyIeLbDps5lE25YcnmL4lOYemVseUghlhimjykx9sBLUxO/LVIuSL5TfNs /WQnxYsAq1fscjQsNbEJcqZ0vTlc7b0aNghVgTWJLDxqJEOaw9TQDel7YZUsuO3J/U xsIDlEF8LylAtjBaClr+Snzq5QWNI8rrwO3FZocJauVvMtXjo/U1dOYTfN61eJf06J id3S68G+VgFIL2GjMBROGyqe855oW7lPLcRhPVROkwQt06aDl4mcPl/Df8zgTSm7Ry MwU62cK2I0z0Q== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, acourbot@nvidia.com, ecourtney@nvidia.com, m.wilczynski@samsung.com, david.m.ertman@intel.com, ira.weiny@intel.com, leon@kernel.org, daniel.almeida@collabora.com, bhelgaas@google.com, kwilczynski@kernel.org Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-pwm@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: [PATCH v2 0/7] ForLt/CovariantForLt split, auxiliary closure API and DevresLt Date: Wed, 3 Jun 2026 03:10:11 +0200 Message-ID: <20260603011020.2073650-1-dakr@kernel.org> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The ForLt trait currently guarantees covariance, which allows safe lifetime shortening via cast_ref(). However, some types (e.g. those containing Mutex<&'bound T>) are invariant over their lifetime parameter and cannot safely use cast_ref(). This series splits ForLt into two traits: - ForLt: base trait providing unsafe cast_ref_unchecked() for all lifetime-parameterized types. - CovariantForLt: unsafe subtrait that guarantees covariance, providing a safe cast_ref() method. For invariant types, a closure-based API (registration_data_with()) is added to the auxiliary subsystem. The closure's HRTB prevents the caller from choosing a concrete lifetime, which would be unsound for invariant types. On top of that, this series adds DevresLt, a thin wrapper around Devres> that shortens the stored 'static lifetime back to the caller's borrow scope. DevresLt provides both closure-based access (access_with/try_access_with for ForLt types) and direct reference access (access/try_access for CovariantForLt types). Also implement ForLt and CovariantForLt for Bar, IoMem and ExclusiveIoMem, and update their into_devres() methods to return DevresLt. Provide convenience type aliases DevresBar, DevresIoMem and DevresExclusiveIoMem. Changes in v2: - Fold the ForLt -> CovariantForLt rename and the new ForLt base trait into this series - Add closure-based registration_data_with() for auxiliary ForLt types - Add auxiliary sample demonstrating ForLt with an invariant Mutex type - DevresLt: add closure-based access_with()/try_access_with() for ForLt types alongside direct access()/try_access() for CovariantForLt types - Make DevresLt::new() unsafe; callers must guarantee the data outlives the device binding - Implement both ForLt and CovariantForLt (previously just ForLt) for Bar, IoMem, ExclusiveIoMem - Various safety comment and documentation improvements Danilo Krummrich (7): rust: types: rename ForLt to CovariantForLt rust: types: introduce ForLt base trait for CovariantForLt rust: auxiliary: add registration_data_with() for ForLt types rust: auxiliary: sample: demonstrate ForLt with invariant Mutex type rust: devres: add DevresLt for ForLt-aware device resource access rust: pci: return DevresLt from Bar::into_devres() rust: io: mem: return DevresLt from IoMem/ExclusiveIoMem::into_devres() drivers/gpu/nova-core/driver.rs | 4 +- drivers/pwm/pwm_th1520.rs | 5 +- rust/kernel/auxiliary.rs | 74 +++++++++++++--- rust/kernel/devres.rs | 110 +++++++++++++++++++++++ rust/kernel/io/mem.rs | 65 +++++++++----- rust/kernel/pci.rs | 1 + rust/kernel/pci/io.rs | 37 +++++--- rust/kernel/types.rs | 1 + rust/kernel/types/for_lt.rs | 122 ++++++++++++++++++++------ rust/macros/for_lt.rs | 52 ++++++++--- rust/macros/lib.rs | 18 +++- samples/rust/rust_driver_auxiliary.rs | 96 ++++++++++++++------ 12 files changed, 472 insertions(+), 113 deletions(-) base-commit: 0023a1e8d01a9d400257d30c851bd16a29568809 -- 2.54.0