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 7E291CD6E5E for ; Sun, 31 May 2026 13:58:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A36EE112B62; Sun, 31 May 2026 13:58:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=posteo.de header.i=@posteo.de header.b="aFOrkf+6"; dkim-atps=neutral Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) by gabe.freedesktop.org (Postfix) with ESMTPS id 92F8D1128EB for ; Sat, 30 May 2026 16:30:09 +0000 (UTC) Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 751A7240106 for ; Sat, 30 May 2026 18:30:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1780158608; bh=IzWwiXoNDJJYymeauA4VceeTQ7BsvJ5+IlCouBR83fs=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=aFOrkf+6gVTszv4C85phxTXCt6KYLS5s6hYIUe3V4OFWYFygfLu8xrWbgMGDBg4JB mGYk5vrYthqxIUCBsu0mE8MVYIvUqY42OUxz6pdzqZtPISKh1BvmokAy72h6PH2Jmq Wb0GbGPGPZU9p/MCibM9ErBxYqHikey/f+V6iyKTiCtk7UcYlN6FfIh0ybTBXyiiZu nfmjtMIpw2IbT/la7toVaOBTfHNDarJ22pKvhUEi45CqcttEt1QNseMN+Gf41OUKcR /NBn25UIN8dOzNspF+UG0MtRASQ2qipuxlWgFJXmxUili3w5TG4BYD5lyAb90zemuh 0nUDbEXM3m6GA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4gSQgJ6hFKz6tsb; Sat, 30 May 2026 18:30:04 +0200 (CEST) Message-ID: Subject: Re: [PATCH v8 3/5] rust: add basic serial device bus abstractions From: Markus Probst To: Danilo Krummrich Cc: Markus Probst via B4 Relay , Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Miguel Ojeda , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , 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, 30 May 2026 16:30:07 +0000 In-Reply-To: References: <20260530-rust_serdev-v8-0-2a95f1da22a7@posteo.de> <20260530-rust_serdev-v8-3-2a95f1da22a7@posteo.de> <4638946fc49a38797b716ea173c93327eb751479.camel@posteo.de> <888dc39c52bb6ddac1a1eed7876c4573bdbef002.camel@posteo.de> <55eae11ea68f129508d0f7e30ac457ba919812b2.camel@posteo.de> <25dc9a4bbde0b542abf608be1b3305f1421a4502.camel@posteo.de> <6e5fd4275c2bbaeeac95a0ad4fe15bb8237d6a22.camel@posteo.de> 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="=-NdO1rLB0FIR+4lfpB0do" MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt X-Mailman-Approved-At: Sun, 31 May 2026 13:58:31 +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" --=-NdO1rLB0FIR+4lfpB0do Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2026-05-30 at 18:27 +0200, Danilo Krummrich wrote: > On Sat May 30, 2026 at 6:23 PM CEST, Markus Probst wrote: > > On Sat, 2026-05-30 at 18:14 +0200, Danilo Krummrich wrote: > > > On Sat May 30, 2026 at 4:51 PM CEST, Markus Probst wrote: > > > > On Sat, 2026-05-30 at 16:35 +0200, Danilo Krummrich wrote: > > > > > On Sat May 30, 2026 at 4:27 PM CEST, Markus Probst wrote: > > > > > > This would work, but I don't see how it would get rid of rust_p= rivate_data in > > > > > > this way. The device private data will but the private bus abst= raction data > > > > > > needs to outlive the devres callbacks (which is done by rust_pr= ivate_data). > > > > >=20 > > > > > Why? You only ever use it in the receive callback, which won't be= called after > > > > > device unbind anymore. > > > > Because the possibility exists that some classdev ops or Drop calls > > > > e.g. sdev.set_baudrate. This is a null pointer dereference after > > > > serdev_device_close has been called. I interpreted it to add a stat= e to > > > > the abstraction private data which would prevent those calls (early > > > > return with error) after serdev_device_close has been called, but t= his > > > > would only work if it outlives these calls. > > > >=20 > > > > But it seems you were refering to something else with the state? > > >=20 > > > Yes, but I just notice that I'm a step ahead. With the lifetime model= class > > > device registrations shouldn't be guarded with Devres anymore, but wi= th a > > > lifetime. > > >=20 > > > (This also entirely eliminates the need for having different devres s= tages to > > > prevent drivers from smuggling a newly created Devres object into an = existing > > > Devres>'s data, which would be unsound for obvious re= asons.) > > >=20 > > > With this there is no way there are still class device callbacks afte= r the bus > > > device private data has been dropped in the first place. > > There would still be Drop, which can access the device. > > Drop happens after remove_callback. >=20 > But you control drop(), so can order it such that first the driver's bus = device > private data drops and after this the private data of the bus wrapping it= (which > will also call serdev_device_close()). Yes. It seems I also have to rebase led then, as it currently uses Devres. Thanks - Markus Probst >=20 > > Might be simpler for now: I can use a mutex to prevent calls in > > receive_buf after remove_callback has been called. > >=20 > > Thanks > > - Markus Probst --=-NdO1rLB0FIR+4lfpB0do Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmobEIsbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMiwyAAoJEDR2H/jnrUPSwTUP/RtLybkJjeY75/6rR1z6 v8gVJLIWXafyklqhLr59QOolNHCHs91NmxiU2mFhpPG8XoanZWH623iTArP0Aq+c OXSbuZHZRVMW+5G0Sb9cVKllMFiR25QYcxhqGTkzE7jTThhwssN/8/3YrinlxBEm Tk54A1tEfW2SCB1yrAEKiPojAsdfw0IAdQJZTV80wzbaTl7LSIKobuH4bNrqIt0k fZ58XkOJMmeVzWPuRlh54kDfT9F8tuZkotA3GoaN/4nJDd6JuIZfhk6RFx+EnmAa DduvV1uNgUdQfAcrcdHkFbGUzkgLsecY4WHdC9+ZgZgdKUSbI/m4D+c8W/9vhtQ4 29AckBCjrtU03XNym2UhFbvnv6aMoRyWzeb1gz6Kw7zYgHOBrn5lQlxDjG/MV5Ux +OD8hgQLxNau/BZLgzGjuTaUTqeYUMiulI/MV/mcpotOxBYFR/zkfw3KunPIEKGN cY5kSG5406v7HomI6Pua/UwzzHS4i8tv9Tu9eWD6q49NAwLL/mI4vI5VHiZVWXK8 1DYwCuHIAB0KQRv9xjAi4f49ZOtUTOrQ0mg0lphFMipxfDQN8l9WG15J6tV35VH2 pipnKvEhDaAQzyVjlIfQU8g1N/PFS3HFnE/+NgBd4a23dK1svUYp5aiOeY5X7mru ZsERn7N+Q0bzGCMGor5YEpmQ =XatZ -----END PGP SIGNATURE----- --=-NdO1rLB0FIR+4lfpB0do--