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 A58A6C87FD2 for ; Thu, 31 Jul 2025 15:49:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1873E10E7BA; Thu, 31 Jul 2025 15:49:53 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="N/X/JNrt"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 75B3410E7BA for ; Thu, 31 Jul 2025 15:49:52 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 6E7C06020C; Thu, 31 Jul 2025 15:49:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C20FCC4CEF7; Thu, 31 Jul 2025 15:49:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753976991; bh=TRPn+DgynwTBU4suc4xP+QjfUEO+i9ltjPYhmhrkr2A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N/X/JNrtyFakbTS/O9iOKZ67QuJWdk2GrjRdWBqwrDqXwaiu2XP315wrn0r0Z7bBY UUPrHbbI2WuDp6O0ej47Bxii1HSJW7FKIYKQTuB7tSmfB/SIwnRpAUb3zVam9ibvQ4 mQR02O6FWGqKnPce2tJPaxVy14al1kNBVFaP2f4O6gH8Sheg2zlVb8/p4j64G9Byqx BocWeAFMemBYxQ99Ju4Sq5UTSJg8deTAkU7kTr3tlEpKrte3IzPFD1XXcDI955jsTm 1l0+ifKC7nsak++M9SE0fkaRB7svvRG8+GXEchuaHrs7ASH7lhektT3SUjeftJQx6G Q9IUshOilxNaA== From: Danilo Krummrich To: lorenzo.stoakes@oracle.com, vbabka@suse.cz, Liam.Howlett@oracle.com, urezki@gmail.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch Cc: rust-for-linux@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH 4/4] rust: drm: don't pass the address of drm::Device to drm_dev_put() Date: Thu, 31 Jul 2025 17:48:09 +0200 Message-ID: <20250731154919.4132-5-dakr@kernel.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250731154919.4132-1-dakr@kernel.org> References: <20250731154919.4132-1-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" In drm_dev_put() call in AlwaysRefCounted::dec_ref() we rely on struct drm_device to be the first field in drm::Device, whereas everywhere else we correctly obtain the address of the actual struct drm_device. Analogous to the from_drm_device() helper, provide the into_drm_device() helper in order to address this. Fixes: 1e4b8896c0f3 ("rust: drm: add device abstraction") Signed-off-by: Danilo Krummrich --- rust/kernel/drm/device.rs | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index d0a9528121f1..d29c477e89a8 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -120,9 +120,13 @@ pub fn new(dev: &device::Device, data: impl PinInit) -> Result *mut Self { unsafe { crate::container_of!(Opaque::cast_from(ptr), Self, dev) }.cast_mut() } + /// # Safety + /// + /// `ptr` must be a valid pointer to `Self`. + unsafe fn into_drm_device(ptr: NonNull) -> *mut bindings::drm_device { + // SAFETY: By the safety requirements of this function, `ptr` is a valid pointer to `Self`. + unsafe { &raw mut (*ptr.as_ptr()).dev }.cast() + } + /// Not intended to be called externally, except via declare_drm_ioctls!() /// /// # Safety @@ -192,8 +204,11 @@ fn inc_ref(&self) { } unsafe fn dec_ref(obj: NonNull) { + // SAFETY: `obj` is a valid pointer to `Self`. + let drm_dev = unsafe { Self::into_drm_device(obj) }; + // SAFETY: The safety requirements guarantee that the refcount is non-zero. - unsafe { bindings::drm_dev_put(obj.cast().as_ptr()) }; + unsafe { bindings::drm_dev_put(drm_dev) }; } } -- 2.50.0