From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8ECFF1F30B2; Thu, 31 Jul 2025 15:49:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753976991; cv=none; b=M+tmv5WznujijSz0Cehmycy/olggA0A9Z/Jxzu7tG9B7u2SUByyx1S6AJUDIBBTYzbwUAoZ5zvi7Jkb5xFkKeyW1YNJoqI5oC0JA/r1AAE0jmfFo4/eV0z2KHhgP3JlaUB24k7CbA393aNNO9G3OrLRW4Z/6cY7rYFrfxSbm5h8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753976991; c=relaxed/simple; bh=TRPn+DgynwTBU4suc4xP+QjfUEO+i9ltjPYhmhrkr2A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fqhp6QRtSSNiPrKJPgumZJv+gOnp1Vy3tTqWpIoDbRxPo6ZD+HjnxvQ0T8eLghakBGnW4N7gcaxTvglnSNUMW7qXDQkrWyT5VidnduIbAe0hoIkDzR5GkWEAmhpsz4XDXLIIdOucUucflFZhneGlXNat9kqKTnej9EQ5DYP8SUI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N/X/JNrt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="N/X/JNrt" 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> 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 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