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 8DBD5635; Sun, 8 Jun 2025 11:49:58 +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=1749383398; cv=none; b=slyiielvLoO259mkxhE/PFwcWjIsEiFGoMZQc+oT1KrDiXQ9WveB518DbhtR70nMVLUzV/U9qYgN5TPWZiVK367fl58Sks4Vsfb/H9XmXUeffn94Rx2rusSMPOUFvxFBq7NEQaeqf0n4lg+rAluHh4Fy/LOn2jx5J1glMw0DW9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749383398; c=relaxed/simple; bh=k6pMNcwV0zxTMuLsmCGwWquM4fEvZLtbEk4eKhiRONQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GFqRsJkxGCHmQdKu5YQIWfKCuHd3lnHutIOX3SifyEzaB8sq/1fbNAlN1AeS3yR6j5jFLumpFOEZwC5imWT0FQOTjSRGiol7S1akZVh+Y8vx7Qnqg2sLYYxFreKy998rIdabMzewS0zYwwmTorn23GMYy4QNbmkYYX2ElpEwcXY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DsUeEJpp; 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="DsUeEJpp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24EE6C4CEEF; Sun, 8 Jun 2025 11:49:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749383398; bh=k6pMNcwV0zxTMuLsmCGwWquM4fEvZLtbEk4eKhiRONQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DsUeEJpporxG7D8uvJL18YxmvfWj5oqQQvnKklpFH9LArRfX3mFn9LiDoER1CM07+ zspwxAPN4jXk1ksVZxU2aRxpMw6aNOgZFMkedArITPji7C3rWSOKHKqSFzkp2pKi/a JtKfaSqdLFBslT/dhFAWGSgvcdIbsvyBLHssE1Kc3gvUTKVtz/7+1i0rhcllCZp/4s 4WWMeziGPgtP4ZnD1ePOhMEi9G2Li2yX3drm72nYqxC0R3NAyPlVDeZAJDkbep7shP Lds+5op+ZqjojKQA0BTErTvWzlOkFG3t0kVaE2FG7wVJX2B4HMnbik/TLFxNTfae+/ vfVXbjF8sR4gg== Date: Sun, 8 Jun 2025 13:49:51 +0200 From: Danilo Krummrich To: Benno Lossin Cc: Igor Korotin , ojeda@kernel.org, alex.gaynor@gmail.com, rafael@kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-acpi@vger.kernel.org, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, lenb@kernel.org, wedsonaf@gmail.com, viresh.kumar@linaro.org, alex.hung@amd.com, dingxiangfei2009@gmail.com, Igor Korotin Subject: Re: [PATCH v3 2/4] rust: driver: Add ACPI id table support to Adapter trait Message-ID: References: <20250606170341.3880941-1-igor.korotin.linux@gmail.com> <20250606170817.3881748-1-igor.korotin.linux@gmail.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sun, Jun 08, 2025 at 01:46:17PM +0200, Benno Lossin wrote: > On Sun Jun 8, 2025 at 12:48 PM CEST, Danilo Krummrich wrote: > > On Sun, Jun 08, 2025 at 09:54:30AM +0200, Benno Lossin wrote: > >> On Fri Jun 6, 2025 at 7:08 PM CEST, Igor Korotin wrote: > >> > @@ -141,6 +141,38 @@ pub trait Adapter { > >> > /// The type holding driver private data about each device id supported by the driver. > >> > type IdInfo: 'static; > >> > > >> > + /// The [`acpi::IdTable`] of the corresponding driver > >> > + fn acpi_id_table() -> Option>; > >> > + > >> > + /// Returns the driver's private data from the matching entry in the [`acpi::IdTable`], if any. > >> > + /// > >> > + /// If this returns `None`, it means there is no match with an entry in the [`acpi::IdTable`]. > >> > + #[cfg(CONFIG_ACPI)] > >> > + fn acpi_id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> { > >> > + let table = Self::acpi_id_table()?; > >> > + > >> > + // SAFETY: > >> > + // - `table` has static lifetime, hence it's valid for read, > >> > + // - `dev` is guaranteed to be valid while it's alive, and so is `pdev.as_ref().as_raw()`. > >> > + let raw_id = unsafe { bindings::acpi_match_device(table.as_ptr(), dev.as_raw()) }; > >> > + > >> > + if raw_id.is_null() { > >> > + None > >> > + } else { > >> > + // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and > >> > + // does not add additional invariants, so it's safe to transmute. > >> > + let id = unsafe { &*raw_id.cast::() }; > >> > + > >> > + Some(table.info(::index(id))) > >> > + } > >> > + } > >> > + > >> > + #[cfg(not(CONFIG_ACPI))] > >> > + #[allow(missing_docs)] > >> > >> I think we should change this to one single definition and do > >> > >> if cfg!(not(CONFIG_ACPI)) { > >> return None; > >> } > >> /* body from above */ > >> > >> In a single function instead. > > > > Generally, that's fine, but in this case I'd rather keep it as it is for > > consistency with the rest of the file. > > Then let's also change the OF bindings in this file to that style :) Fine for me. @Igor: If you do so, please do it in a seaparate patch. > >> > + fn acpi_id_info(_dev: &device::Device) -> Option<&'static Self::IdInfo> { > >> > + None > >> > + } > >> > + > >> > /// The [`of::IdTable`] of the corresponding driver. > >> > fn of_id_table() -> Option>; > >> > > >> > @@ -178,6 +210,11 @@ fn of_id_info(_dev: &device::Device) -> Option<&'static Self::IdInfo> { > >> > /// If this returns `None`, it means that there is no match in any of the ID tables directly > >> > /// associated with a [`device::Device`]. > >> > fn id_info(dev: &device::Device) -> Option<&'static Self::IdInfo> { > >> > + let id = Self::acpi_id_info(dev); > >> > + if id.is_some() { > >> > + return id; > >> > + } > >> > >> Is a driver only going to have one id_info? Or is there some kind of > >> precedence? > > > > A driver potentially has lots of them, but the device is only matching a single > > entry in one of the driver's ID tables and hence a single ID info. > > Ah so if `of_id_info` and `acpi_id_info` return `Some(_)`, then both > values are the same? No, if one of them returns Some(_), the other one will always return None. Or phrased differently, the first match will always be the only match.