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 67B08D58B1C for ; Sun, 15 Mar 2026 11:21:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6CDA610E566; Sun, 15 Mar 2026 11:21:31 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=posteo.de header.i=@posteo.de header.b="eVny/CGI"; dkim-atps=neutral Received: from mout01.posteo.de (mout01.posteo.de [185.67.36.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9CDF610E086 for ; Sat, 14 Mar 2026 11:42:05 +0000 (UTC) Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 6BDFD240029 for ; Sat, 14 Mar 2026 12:42:03 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1773488523; bh=wuP7aGFXaCoi0Qj9e0TOENROxQfNcb8qbW4/sLW+2MA=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=eVny/CGIImF8jH8O0FIZKcN4zAb274dFEU7yPs677sQjMepqSt/RUW83YjX+qB7Qr H5/XMYTx9dp1t51PclxmWw1tn/Tr3yV1pJX/AJC4G32q5/iqEthVYjiIvB3SfEzlhG 6Fl4NNkKQqC6w8NEpVTB/N+x7TNODppf+nzOreinRB+JvxSLIxxYbVjsUhq5+jIdeV ADYAPMYTRKaPT9fXDbIntJXEUTsStWos57nrbS+VayXpXM+sdJjuZ+cnL8lvlKPYl9 FLhxEx3aH5ty0NZ3c6nNLtplG1VRKHQzKwzzPYPgnwKJONXgYX8LxhsaEaarRHCcxE wbQOvj4X8CBFg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4fXzwR5X5Nz6tvm; Sat, 14 Mar 2026 12:41:59 +0100 (CET) Message-ID: Subject: Re: [PATCH v3 2/4] serdev: add rust private data to serdev_device From: Markus Probst To: Greg Kroah-Hartman Cc: Rob Herring , Jiri Slaby , Miguel Ojeda , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Kari Argillander , "Rafael J. Wysocki" , Viresh Kumar , Boqun Feng , David Airlie , Simona Vetter , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-pm@vger.kernel.org, driver-core@lists.linux.dev, dri-devel@lists.freedesktop.org Date: Sat, 14 Mar 2026 11:42:02 +0000 In-Reply-To: <2026031402-absence-graph-af5d@gregkh> References: <20260313-rust_serdev-v3-0-c9a3af214f7f@posteo.de> <20260313-rust_serdev-v3-2-c9a3af214f7f@posteo.de> <2026031402-absence-graph-af5d@gregkh> Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=mQINBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93 qReNLkOWguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVA m76Ww+/pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt 9k5JARhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbm fAjaoT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwT jRQxBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1 J+FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN 6OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJCX CeMe4BO4iaxUQARAQABtCdNYXJrdXMgUHJvYnN0IDxtYXJrdXMucHJvYnN0QHBvc3Rlby5kZT6JAl QEEwEIAD4CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AWIQSCdBjE9KxY53IwxHM0dh/4561 D0gUCaIZ9HQIZAQAKCRA0dh/4561D0pKmD/92zsCfbD+SrvBpNWtbit7J9wFBNr9qSFFm2n/65qen NNWKDrCzDsjRbALMHSO8nigMWzjofbVjj8Nf7SDcdapRjrMCnidS0DuW3pZBo6W0sZqV/fLx+AzgQ 7PAr6jtBbUoKW/GCGHLLtb6Hv+zjL17KGVO0DdQeoHEXMa48mJh8rS7VlUzVtpbxsWbb1wRZJTD88 ALDOLTWGqMbCTFDKFfGcqBLdUT13vx706Q29wrDiogmQhLGYKc6fQzpHhCLNhHTl8ZVLuKVY3wTT+ f9TzW1BDzFTAe3ZXsKhrzF+ud7vr6ff9p1Zl+Nujz94EDYHi/5Yrtp//+N/ZjDGDmqZOEA86/Gybu 6XE/v4S85ls0cAe37WTqsMCJjVRMP52r7Y1AuOONJDe3sIsDge++XFhwfGPbZwBnwd4gEVcdrKhnO ntuP9TvBMFWeTvtLqlWJUt7n8f/ELCcGoO5acai1iZ59GC81GLl2izObOLNjyv3G6hia/w50Mw9MU dAdZQ2MxM6k+x4L5XeysdcR/2AydVLtu2LGFOrKyEe0M9XmlE6OvziWXvVVwomvTN3LaNUmaINhr7 pHTFwDiZCSWKnwnvD2+jA1trKq1xKUQY1uGW9XgSj98pKyixHWoeEpydr+alSTB43c3m0351/9rYT TTi4KSk73wtapPKtaoIR3rOFHLQXbWFya3VzLnByb2JzdEBwb3N0ZW8uZGWJAlEEEwEIADsWIQSCd BjE9KxY53IwxHM0dh/4561D0gUCaIO9eAIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCR A0dh/4561D0oHZEACEmk5Ng9+OXoVxJJ+c9slBI2lYxyBO84qkWjoJ/0GpwoHk1IpyL+i+kF1Bb7y Hx9Tiz8ENYX7xIPTZzS8hXs1ksuo76FQUyD6onA/69xZIrYZ0NSA5HUo62qzzMSZL7od5e12R6OPR lR0PIuc4ecOGCEq3BLRPfZSYrL54tiase8HubXsvb6EBQ8jPI8ZUlr96ZqFEwrQZF/3ihyV6LILLk geExgwlTzo5Wv3piOXPTITBuzuFhBJqEnT25q2j8OumGQ+ri8oVeAzx24g1kc11pwpR0sowfa5MvZ WrrBcaIL7uJfR/ig7FyGnTQ1nS3btf3p0v8A3fc4eUu/K2No3l2huJp3+LHhCmpmeykOhSB63Mj3s 3Q87LD0HE0HBkTEMwp+sD97ZRpO67H5shzJRanUaDTb/mREfzpJmRT1uuec0X2zItL7a6itgMJvYI KG29aJLX3fTzzVzFGPgzVZYEdhu4y53p0qEGrrC1JtKR6DRPE1hb/OdWOkjmJ75+PPLD9U5IuRd6y sHJWsEBR1F0wkMPkEofWsvMYJzWXx/rvTWO8N4D6HigTgBXAXNgbc3IHpHlkvKoBJptv6DRVRtIrz 0G0cfBY0Sm7he4N2IYDWWdGnPBZ3rlLSdj5EiBU2YWgIgtLrb8ZNJ3ZlhYluGnBJDGRqy2jC9s1jY 66sLA9rQZMHhJTzMyIDwweGlvMzJAcG9zdGVvLmV1PokCbQQTAQgAVxYhBIJ0GMT0rFjncjDEczR2 H/jnrUPSBQJpa71VGxSAAAAAAAQADm1hbnUyLDIuNSsxLjExLDIsMgIbAwULCQgHAgIiAgYVCgkIC wIEFgIDAQIeBwIXgAAKCRA0dh/4561D0gKJD/9uOQKYlsDoQX65Gd0LiMT0C+5vXgr3VI0PHDOwcv 51fJ3A1vNyPZRFPGrz8+mDEXUQOF/INfnz5Tu1QHwf+iYcWcTGAN/FHgVR6ET6VBNU2hJaKhu+Ggo kjYyJTOvyX+3yNRUfSny0GjTjIPuPTErjqmHF+BtjXslpgwqnNMznf3lRIuUjRORupos6p3k1DndE 5vzUTmXSvMyXyOD2KhBl/kL76k0bHYyAQytZPag12pltrtFbA/r2phDGN2si8PooDT99bSTJjaM45 MTAAHbHKJfvgfK41bNFD5mMtpWpL195XRtS0Nrxdg3PaYBxN5gtTG0RyZfpYRlkdEhm+jj/8RxuSG i/qdhRdbiI7K2IELWeQVHSNDi9JabR/UzlR4NSnhfAjRIVlRM+eFbUl8XwxwVrAkojF5IraH2qRvg VCmuFsHUW07FUlrDrzpjXsD73cKppoFGDCdDR0BHJepXbFLS9+AqkT+guRJlnCTg2p+TQtnbwPgKp Vj98JixovCl99zRYTsL2bRNU5+q8iET65VMJ1ydyNanvLd5vI/NqDkXhlXLsGmdaDTtu4R21PkToX dQNGrZ91M9nlIBKw8Y7c7xZ4098qX2b8JX/CxD+gC1r4C8vuA3GkhFLx+KlkON7LyiJPkrePp6Qky jfGillcaQOqFZ3WwVqyzG1BUfTow== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-I1iRCfX0MpbeR/VGtPiF" MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt X-Mailman-Approved-At: Sun, 15 Mar 2026 11:20:58 +0000 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" --=-I1iRCfX0MpbeR/VGtPiF Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2026-03-14 at 09:07 +0100, Greg Kroah-Hartman wrote: > On Fri, Mar 13, 2026 at 06:12:31PM +0000, Markus Probst wrote: > > Add rust private data to `struct serdev_device`, as it is required by t= he > > rust abstraction added in the following commit > > (rust: add basic serial device bus abstractions). >=20 > why is rust "special" here? What's wrong with the existing private > pointer in this structure? Why must we add another one? Because in rust, the device drvdata will be set after probe has run. In serdev, once the device has been opened, it can receive data. It must be opened either inside probe or before probe, because it can only be configured (baudrate, flow control etc.) and data written to after it has been opened. Because it can receive data before drvdata has been set yet, we need to ensure it waits on data receival for the probe to be finished. Otherwise this would be a null pointer dereference. To do this, we need to store a `Completion` for it to wait and a `bool` in case the probe exits with an error. We cannot store this data in the device drvdata, because this is where the drivers drvdata goes. We also cannot create a wrapper of the drivers drvdata, because `Device::drvdata::()` would always fail in that case. That is why we need a "rust_private_data" for this abstraction to store the `Completion` and `bool`. Thanks - Markus Probst >=20 > thanks, >=20 > greg k-h --=-I1iRCfX0MpbeR/VGtPiF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmm1SXgbFIAAAAAABAAO bWFudTIsMi41KzEuMTEsMiwyAAoJEDR2H/jnrUPS9jAP/3JGU2gk+hFkYnBUk8UU iP1lJJDruz2fV0dXxGHCh3svfkHvcKFTtozb6FSQ7hZ9wNU8tsxTfnqMhycvmf6S J3NpCtL/ifnjtIWpy6qq0xk89BLrEU0EglsQ5tLN+BAY0Nkxsa1e7bvw461ZFEPF xzVwh8hAucFdEZuVt7O6ouZ0CIryYmM6MK2BSnjA5yo+vMlS560JtDh2rQFuilrd zzbOBhpbxlIxRGVHg5WdiTT07kgm6zr+uHehF4GQmyYH6Z7KvNOHRRFA8FUYUes0 cRZjsxmeMzE/7EU4lshWDN6AYprhE8CHDNxEJd05aFMATuWpOKB82SCyC1qKQdE+ EGdLS2lcUUl5yRXXRFl6+VjfrvaZo7IrwhE8i1Akbp2kXqZbn5R2kADaQ1RIDt/Z AvDz9Af8HhqJF3wwUrtlameo6UyKl/AOAWK6QQzjTyk9/8LXmA1lfHiSZr7waTxf 6zE39ALkP5vaBNjDbljj01OkoPR9NNjbaZZ3O2WKy9656HWDVofGnISWq9L++lXO FtGVAQGxPETFtqjA81aFVchaYtskooLtA2VuAnnuoEJok6hqYTUCgSdijOi/rEJW k6THWQDqZ9kM5F/oxvn1a3h2jAosCbISp/lXkKGlUiOcGrlc0D3UjVC641JaOHYD 9U2DU5EH/6+xscOpnN2O1gvc =2BtH -----END PGP SIGNATURE----- --=-I1iRCfX0MpbeR/VGtPiF--