From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DM5PR21CU001.outbound.protection.outlook.com (mail-centralusazon11011044.outbound.protection.outlook.com [52.101.62.44]) (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 7506E15B998; Wed, 31 Dec 2025 22:47:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.62.44 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767221267; cv=fail; b=MQ9L7pHG7EeIxJYykjXIJxDM0Jgw647cIskhAlEJSqHWbv4xXAqBl4EGDjEiNkPbYegEZq2AEstwMT+g+lxdaRzrFxWEnJlzwmKY8PsWvYBLTGjiQS3Gq0oDQ1B5LdEKT1Psd0nQGUFlJLYHVHwUeG5KK4OnKM/deiGsNCGAPlg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767221267; c=relaxed/simple; bh=MjiHakIG1tWzh5MHIG+jW/BhzvT8OEjQt11HbVbY6mE=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=lhKPVI+iw1Gx8TvUNYF9Ulxol6OprXS2hlxxLZxNGv6Hw82kyhLRku90IW3gPNyYY9eHRqyZDRH1h/qCUg2ktl+avWmXaHuY8lgxvccjTiMkLkJr98n9kk/tIeMRioeWBU7vSK6lN1/SXPzDtFe50/Aa9s2o949fgm2oRHO3Vu4= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=OipRIV/p; arc=fail smtp.client-ip=52.101.62.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="OipRIV/p" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=COH+rjCBw3AIRErK7OxiD1WqxIX5caztpOBVQtgfXpuzVS84rWckwbs182SmdgF1hBO6gC6LZrt49oySgib141ttYEujIVpqPc4it2+Mg0z1mcrzn6WSqWECF/3rqkqD/iI924wv4cB0s5DK4UqwMor+T6YRb5sBVWXc8Z40ZSvd53itigmHrQTD+LwtgC36FyFJ9orhthBIjvQvlUJvvtd1eraQjiW54TLUKfBYwDwYlZSMoF8x624bAYM3njlsimDOAv1LiNZkY0h8ZbOmPF/z0c8UrxzJsdqpIOHkiqTg9Tu8Pk1w7CMjWpgBNgS+CWpufr8vUfqjR1YTKyQ19A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=LmLvyhjS5HxtYkEa+IQJ3B/NTfrUW/fgj1p62V2gId8=; b=zNWBXezOW/w9TKqYHc+E/5/95OtrmgpvVQIZpN+PjlpIb5FzFKYZwseu5TJB1SYvLQB31ObjGDdJdTXLaoVkLLPrtFF2Y3owPj8qRx5c0Fk5muMIUbmoCrC65Y074ct9f1UuEv2H2BXhZ8PLFIH9pjUL8v5+JIDYrvi5yxZQ+i8QeAaswb8hDrqT/j4mzLcESk1G7iSdF7EeGziR1JLJJthBYRVL6lBnSdwk2cVdVbqH16lBXR8B88yQxJ3VUXN/c1U/BiQXwjzotTlhZw+XFhvWfGjt7bWeMAwYCarYWJPJdV3jKbpr4DS8Io2JTa6xCJOKBul87AC6uWiCc9ivHA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=LmLvyhjS5HxtYkEa+IQJ3B/NTfrUW/fgj1p62V2gId8=; b=OipRIV/pApkib/aC4sewQlGYLFbM3hhfoi9DT+p3UHtjpxLoM0/sTI7pZG+Q2GmsRgJvPOSLEgbTctJToA877imyx55I9Y1/AIThGYu7uA7JyJbzJzw31Z2AEtMpLYuylPxwxH7JB7oaj+kc6DhOh4+SrFNGO58A5zVm2SfH1LxniEEiH9LuOlh+I3A9N7mNRBb81Ni4jq3A4MkTcQwYDzCEG3INryq9xWZM2aBzrzDfM/ha2xMXuVow5pXyteRxcMUNuv0HV289Zdynrash3GIck0c7dqwJRv2rxCHE8ii6hk7TsdllxtEugIB4kjoCmvzxLa7x9XChp026KRX/mg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) by DM3PR12MB9413.namprd12.prod.outlook.com (2603:10b6:8:1af::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9456.14; Wed, 31 Dec 2025 22:47:41 +0000 Received: from DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8]) by DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8%7]) with mapi id 15.20.9478.004; Wed, 31 Dec 2025 22:47:40 +0000 Message-ID: Date: Wed, 31 Dec 2025 14:47:26 -0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] gpu: nova-core: bitfield: use &mut self setters instead of builder pattern To: Timur Tabi , "dakr@kernel.org" Cc: Alexandre Courbot , "lossin@kernel.org" , "a.hindborg@kernel.org" , "boqun.feng@gmail.com" , "aliceryhl@google.com" , Zhi Wang , "simona@ffwll.ch" , "alex.gaynor@gmail.com" , "ojeda@kernel.org" , "tmgross@umich.edu" , "nouveau@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "rust-for-linux@vger.kernel.org" , "bjorn3_gh@protonmail.com" , Edwin Peer , "airlied@gmail.com" , Joel Fernandes , "bhelgaas@google.com" , "gary@garyguo.net" , Alistair Popple References: <20251231214727.448776-1-jhubbard@nvidia.com> <9db27bd6015ccebaa20e51450d8c42eb2864cb2e.camel@nvidia.com> Content-Language: en-US From: John Hubbard In-Reply-To: <9db27bd6015ccebaa20e51450d8c42eb2864cb2e.camel@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: BYAPR07CA0069.namprd07.prod.outlook.com (2603:10b6:a03:60::46) To DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM3PR12MB9416:EE_|DM3PR12MB9413:EE_ X-MS-Office365-Filtering-Correlation-Id: aadc8aef-0b44-48cc-96db-08de48be9a7a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|366016|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?YWZ4Y0JLOHQ3MFFMdllDOVU1VEZ1WHdmYWpXU2ZNZ29FK0ZieGdOQWpFSlVH?= =?utf-8?B?WldKb3htY2lEaFBJS0I3S0psV09xbHVQWTZ5U2NrS2dLOWF0cHA4Wk1sT0ll?= =?utf-8?B?UU0yZVVWRXN5N3pvU3NqS09xN1VJWHhseWs3cDc1SFZ6QjlkZy9wRkhQZDMy?= =?utf-8?B?ZHhjTng1S2VSRkZwdnM4L2lBKzdkN1dwdXErSVRXUXUyaDlsSjQrMnpENHBO?= =?utf-8?B?SWdsY3Zsbm5oY3VISlZzbTVjQWprRWpnNFpLUnlxZjhkb0xGNVJZeEx0VVRH?= =?utf-8?B?VUxrQlNKWENHTEt6cGxESUtvVFFSdVZrblloSFA3dFpQQmh2QkxTOWV4a3ZZ?= =?utf-8?B?eGQ1a2ZibUlERU1EaWt1NjRadVp0SllLVUJJQTN1NHp5M2RRYWpmcWI2NzFF?= =?utf-8?B?ajNpZCtuVG1aQlBuMnRSNHNWQ3BMemRqNlo1Z2VzbFJ2UU0zdHdLZUhRSG9N?= =?utf-8?B?TGpsTG5VQkd5WjZPUmxTdnNrNDZ0dVRJYWVUTWxHbDBkUnpDTDF4d1NpaFA0?= =?utf-8?B?amtFbk1LUGd2dnRvVzNjM3UwNjdhSDJVbWpyNnVTZDA5VlFJSnhZc3phby9E?= =?utf-8?B?bUcxck51TExkQ3lnVEF0SS9wT2tsc0JKWGthSkRWMFhmM3BuajVZZ1U0Q1Ir?= =?utf-8?B?ZkhuUExiQnhjRWRZK2ZiZ0M1VWpNc093ZXEwSDk1VEV2VjMxNDdWZFdwMmNY?= =?utf-8?B?dkN5TVdOUHMzcXV4ZHdLd21BaFlXS3hQT2tQSTJCMnBPbGdzTmV4TFl0K1Zj?= =?utf-8?B?VUczRk1IUjQ2aWdQOVZNdmpiVEExUTZQN1dkZjYxZ2poaDNSRC9uOWpMelVL?= =?utf-8?B?ZStTclljUnB5TndFdC94RjZDdVh5Y1UwLzBMekFqTTBmUGs3L2xMaFhIWHcv?= =?utf-8?B?TTFhL013WGNhNlZjN25iVllaYXNZSmVXeVBNQ01CTXk5ZURuWUJjZnB1REZU?= =?utf-8?B?U01hZEtCMUtJb0ZDbGdtcXRicUxSTlhRRnZVVnZaYkxhaG9vT0N3VlBTVndG?= =?utf-8?B?QStFSkltdzI2eFgyZmpEb3VJQ2dYR2NuWWFkem9jVXN2dTdtelNBTktQaEk5?= =?utf-8?B?QjVKOEhWdDFsaEJtSE84bmVBaW9ydjRhekxEY3g4bUU5MExkbjBuaktUZXlJ?= =?utf-8?B?clNxREF2cmR0MElNVmdMTi9ZUG9vNm5TUE12RVN0Z1o3RWx0aFVodHlNRUJl?= =?utf-8?B?ZUtXays5OE1tZmxpZ3JrdnoyTTh6TjNMbEw5NWRvM1dxbVhaWmV4UG03dWRl?= =?utf-8?B?bDY3dUg1U3kxeDFQZFdrQTJ3dGJnNjBjRjdTRnlNMTBhUkdLL1ZPd0lvUkg0?= =?utf-8?B?RmxPbVlESE9Cd3VjaWFTU2dEUjJ6RmEycW5rN3RoK2NSNTdTak5xUFc2dkgx?= =?utf-8?B?NFB5TW1DZU5DS0U2RmNMWmlHTzJxZW43NDRoRnB1N2NnWGUyamk2SFR4cWFm?= =?utf-8?B?Qll2bWttUVE3alR5ZW52Q3I4WUhDdmR5NFNYL04reXEzRTE3Z1dRMEpzUE1W?= =?utf-8?B?WHpWcnBDOWNmaHhVdURibTYzSm9XUkdHbndqc3hXaXlWa2N1RmVkckNMSjl6?= =?utf-8?B?Q1JXSS9mWmlRc2pDWW1zc1dzUmx5amNCeGo3T0lZd2RudW5WRWdObVJFL1d5?= =?utf-8?B?cGsyUWtVRmJLZDJNZkEvMzFuYUx1TmFlaGk2anIzV2xnSWwvbm16MHVTSGow?= =?utf-8?B?MkpFWWFqN0ZTZTM1K2hneXIwWGpvbUR1bnRhNjI5blhKS3A2dHBoUHRPSXhp?= =?utf-8?B?MkdRY2s2aTFVOFNlSnl0TXFkb2I0TWdhcy9IWE9CaWFhaGFaY3BFZjZNdXZB?= =?utf-8?B?SlgxR0MwekFpUFZYUnZGT0RGb1poNzh0ZFhwZzR4QzZmWm1MVXJIMlJuTW1k?= =?utf-8?B?Q1JyWnpsWkJLTVZQK01xZHkwdEdYQjJnbXVjc2NmeWwybXpSbUE0SDFIR0FO?= =?utf-8?Q?cwIOsPHcQw+7hXk4hr+/TXEzH5z5ZLLC?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM3PR12MB9416.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(366016)(376014)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VHp6ZmowaW9OcU51UjJ2MDVGYVJ0MFVHVVVJbXQ4Y2FsVFVIQndUcjVweG42?= =?utf-8?B?ckVqcE9CQS95NDI4S0x3S2JoV0FzNTJ6RVozWERPZGcyZ0ZlRjJYUXlsSHVw?= =?utf-8?B?Y1lOK2hyMGdlWHljM0JUQXJmdlRyeDdJYmplNjFobkwzekFRVUZiZUFhVWhy?= =?utf-8?B?WUVnS3FESHhuUEdpelA4U0w0Wk5qS1E2R3RTU00xMHFGTWJBeG9lUnJ3R3p3?= =?utf-8?B?Y0dZMm5qNkhEYkd0Zno1N20wSmYvK2FPeW1rWkpwaFc3blFwY0NxQzlLRzVw?= =?utf-8?B?RHRoeG4wNHJNRExPMVZ1TFRrVmI2TzJ6N3VSd3JPQnZwVDFScTh5N0RQK1dO?= =?utf-8?B?WlB5c1o0U2JQUWwwbGkwVlRQQS9ROUhpVDBYaTVRV1ZrNlJIei9TU2E4cVl6?= =?utf-8?B?OG1vOHMwOUc5azBsdUJLUzlFOXBjRXpKbWt1d05sY0lMSy9BQkpVYVFTWElX?= =?utf-8?B?bzlrMk1PM05ENi9ycUpjaG8zVFBPNGxyUEdRb3Y1eTk5U3NKb1FkcWVpRWtQ?= =?utf-8?B?ak56U3ZGRTVnVVRnK2kvbXMvR0o2N2VDakwzOXhNWEwxN3doMVdaZFFYU1c0?= =?utf-8?B?ZzhhMzFLSVpKL0VDVGFhaVlyMGZoTXhieUdiQzVoWHBTbVpsYVFrblRtSFE0?= =?utf-8?B?VUFQbURJdzFFV2Q0d0hIM2RtbzkzREpLdVpnbWgvdnU4K012VHFFcmN2WmY0?= =?utf-8?B?aXcrRGtvVHNQelhEZllYNlVxMHduQlhrZTVpcm9TWEpReVpVVlUwTXNPY0Qz?= =?utf-8?B?T0habGNBZElSUFExRXJYVXR4djVOVmcrYmswRG10c2xENFNHRU1sa0E0czVu?= =?utf-8?B?dlR5MVlsYTNYSWlROXhud3NPclh6MHM3RG9OM2UyQ2NmemRMeG1hV3dxN0g5?= =?utf-8?B?WEpHZ3VqTmtRVm1uYktDeFRFSSt2MThBcmVkN0ZOR1ZPZFFqRStsQm5Dc3R4?= =?utf-8?B?YXlYSUNLQ0x2NndpU2N2OUQ1WUJaMEhEb25YNFBIRitIRW5CUm5hWnFNOU9M?= =?utf-8?B?MlozUWdKZEI4T0RwVmlwY0twNkViazEyR1VTN3FtbTlndG5lVzdtRU9zK255?= =?utf-8?B?cllheWp5S0Y0bjVRdmt5ZE5jSzlLWC80QzZmUFpkMXhYMjJtVnJnN0ovQjhP?= =?utf-8?B?K3pkT0ZnaTlQY2N4Z0tOalhsMWdseTJsbi9La0FoMEJvQU04WUh1aWtGeGE4?= =?utf-8?B?a3BZaWpjM29EbVJCOWtRcFk2VGtKekJRTFlqSXcwZkI1Yks4Ynd0c3gxc3pC?= =?utf-8?B?V1N2ODMySmVpZkJsQUR1cGdPU0hlNzlSUnEyUTRqM3poaTVzeXFvRE5qQmZY?= =?utf-8?B?Q0JwK0VxN1BsM0xWeUV4a1dxVmdLdmMzM3U1VVY2Zm8wakNUMHE3ZnJoU1RX?= =?utf-8?B?Q1dtcHdEQVVTanlCUkJRUmYrU1BBd3Z3cFJkbHNqNHUxc1I0ZzdlNDFZR3I4?= =?utf-8?B?Zy9WOTdQd3NRbnRoNzZyMUFuYU91VCtmbVhIZXFlTWFTck9wZk5rYlVzQVpO?= =?utf-8?B?K2VSb1hpMW9DbVlnRC81RzRvdnJzNitKVkwxRGlvSTNJV09VR2pFbktiYUxS?= =?utf-8?B?aDBuKzRuRzBKOVZOcHNhb2FJK3oybmk0YllOSzRlclBqU0VGak1rWW9uSjN4?= =?utf-8?B?SE9jQVFLVGliS2FvNjBTWFZKUzh5VmJWNlkraHBpaUZ3bnR4R0xpa2dEdlhW?= =?utf-8?B?TFhuVzRXQnZXWC9hcGZBWi9ISEhXbFNIeCtHUnQ1b01yWmRObmowTlFVSjUx?= =?utf-8?B?WUM2cEx1a20xTnFhSXRyb2JVRkRtVGx3a1dvMkVZRGQ4MUFFUmJiU3hrLy9v?= =?utf-8?B?UXJVeTdUck41U3kvbXEvbHdjcW1MVGl1QnRGODFBY3JEOVBXYzdJTExHOGdR?= =?utf-8?B?ZUVjNVRCUUUyeXdEUWEzVnAzMzBmVW5HSlVBaFZWMk5nK05yblhlUGVNMXpN?= =?utf-8?B?TEFjZit6K2V6Z1ZFSk1maG9VcllsSk5wT3VRcmlzMkJQcXh3ZWdhbS85RVhz?= =?utf-8?B?Y09idTlXamlIN3ArK2t2dXRCSGZEaGR3V0tnK0FCRkhHZFRrckZNc1ZHUXVn?= =?utf-8?B?N3VPNUJndXM0SGVHWVlteEk4SGJqZUZDS3pxWWFXcWVHU2pLRm1mTG1SdGMy?= =?utf-8?B?RGl5QkhCRytxQkpEMjdmb3d5elpFVCtNZGxNaTNaYStrV2JUYUJtTVZjbHpq?= =?utf-8?B?STNtQ2NsRDVQM1VaMTBsd3E4WEhrbzNLMjVqaGJpNHoyQVNSVGlTRkFodDZF?= =?utf-8?B?ZFA3VERmcHFJUkNHMGF5a3dtb1lwZlZmSG00bXFWeVVxTS8yUUM3NjJuVHY2?= =?utf-8?B?eXYrY0dGR2NSUVFheVhudTQ1Um01RmdPSjV0SEpWa2tiYjIzWElRdz09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: aadc8aef-0b44-48cc-96db-08de48be9a7a X-MS-Exchange-CrossTenant-AuthSource: DM3PR12MB9416.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Dec 2025 22:47:40.8062 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Xqw27NHZsn6DlUAcicxCL4HVKWZEe8mG5VVsH1g3PFqXZjaYYLUMA7GTFMgnNaoWQdzUpKQ+ZzRz9BFJmaPr/w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM3PR12MB9413 On 12/31/25 2:33 PM, Timur Tabi wrote: > On Wed, 2025-12-31 at 13:47 -0800, John Hubbard wrote: >> The builder-pattern setters (self -> Self) enabled method chaining like: >> >>     reg.set_foo(x).set_sec(y).write(bar); >> >> This made separate operations appear as a single expression, obscuring >> that each setter is a distinct mutation.  > > So you're concerned about the fact that the compiler is not merging the set_foo(x) and the > set_sec(y) into a single read-modify-write? No, I don't care about that aspect. > >> These setters are infallible, >> so the chaining provides no error-propagation benefit—it just obscures >> what are simple, independent assignments. >> >> Change the bitfield!() macro to generate `&mut self` setters, so each >> operation is a distinct statement: >> >>     reg.set_foo(x); >>     reg.set_sec(y); >>     reg.write(bar); > > Are you sure about this? It just seems like you're throwing out a neat little feature of Rust and > replacing it with something that's very C-like. This breaks compatible with all users of the regs > macros. Seems really disruptive for what seems to me like a cosmetic change. > It's only a neat feature if it *does* something. In this case, it *looks* like a neat Rust feature, but under the covers it really is just handing around copies unnecessarily, when really, it *is* doing the C-like thing in the end. I object to the fake Rust-ness that's being done here. It's like putting hubcabs on a car. thanks, -- John Hubbard