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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FDD4E784BA for ; Mon, 2 Oct 2023 19:36:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238893AbjJBTgV (ORCPT ); Mon, 2 Oct 2023 15:36:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229667AbjJBTgT (ORCPT ); Mon, 2 Oct 2023 15:36:19 -0400 Received: from NAM12-BN8-obe.outbound.protection.outlook.com (mail-bn8nam12on2065.outbound.protection.outlook.com [40.107.237.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DE95A9 for ; Mon, 2 Oct 2023 12:36:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=fRqRF+br3S4nQE48hv/JO6p3EM+SHr09ojY5D1JosuWDAWKNJ1bHrLA1XnIVmQT/uVSddGVTLY1wPS0q4L4jVQfvyZu8HYfMlA/SqHnPLUUk3celEUd5xq+mMFlSTI6x5i2uESDMb/8dk8XEDFHbZ9D0H81hnwMXSXzfDcjtowzuxlN7IyUhOTEU3gwd8NzENroJUKhbVWxtoQzNZdwKn8H0gussyTeKJgC6qMz/esXM3YlUYjSJyjWG0484b9kUVBYycMBKhIxFJ+rEpWpH0Ybag3bp9mD/MYxnxHcyocGKZofmzQFdg/RSibJROxtRecSw/qLeDW4pLxK4URfx/w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=c4mr54O4TnA1H0/uR+xUO2Hs8GCumrOGRb4t2eO7qvg=; b=hO4ipsTKBxyEWRf1cddwJv7XUFBuPMKyJP8nmisX5GnkExiXkz+bQBNaRQ+UorD8DPBMg5ajMxPLYEzwGU6v5PLsK8STrO4itjNl8WbFeBIRGeDRjPYQbp0J/O9jn2e5+vdPjFZfuZIZMMf5bHqtPTqlg+22o1nyLUuEBNYz59E7WBxnv8vHncX7Gm1tcu45tjGPhXCTyaoo9a6GgrcJCRCNjHGI9awtX+WS4yv+/LE9UvpZhxGivDJmt2lp4WQt6S1DMfS1eculfU072afSti2gmZrphUlCxVmk15NQC+8a9N7SO4J+/TuQS6eucVDWXfC1POq0FCXxy7ZS47ahTg== 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=c4mr54O4TnA1H0/uR+xUO2Hs8GCumrOGRb4t2eO7qvg=; b=bADBT6D43sCzLrDlTHswoqcmoibIiHHv736csPqPwUejYNuOzGjSQbkj3SwWmR9r/wc9NyEZWGgbXaU7vakSpT8kmfAoILwWlHen+1S91rfvyS75921lPPYh3/XE5KW4AVMvpvV3P6l6dwRxynnzAwWYMbu0+sZyAVU10bRCG4zFoJ3pM6jlg1Z6p6EJoJtKg+Bov6qgwYMDk6yHjjuyF0yf0HXTtwzssvShI/B+ESmYfuYNMDjd/8U9+Pl7+Yn1XlSqnepJcMTBrC+SpH0Ddk/H57BeGPWRscF+IxfzAavXcUvf3wh3dcGqEwSYVjsuoLSAvC0FziNXYNrY+pKx6w== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by LV2PR12MB5845.namprd12.prod.outlook.com (2603:10b6:408:176::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6813.23; Mon, 2 Oct 2023 19:36:14 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::3f66:c2b6:59eb:78c2]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::3f66:c2b6:59eb:78c2%6]) with mapi id 15.20.6838.030; Mon, 2 Oct 2023 19:36:14 +0000 Date: Mon, 2 Oct 2023 16:36:09 -0300 From: Jason Gunthorpe To: Robin Murphy Cc: joro@8bytes.org, will@kernel.org, iommu@lists.linux.dev, baolu.lu@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 4/7] iommu: Switch __iommu_domain_alloc() to device ops Message-ID: <20231002193609.GB650762@nvidia.com> References: <458dd0ed839541693a49da33239b33cf4c48b8ec.1696253096.git.robin.murphy@arm.com> <20231002141615.GA650249@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SJ2PR07CA0023.namprd07.prod.outlook.com (2603:10b6:a03:505::9) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|LV2PR12MB5845:EE_ X-MS-Office365-Filtering-Correlation-Id: b1d7bf02-f2c9-4741-ef33-08dbc37ed6f0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(346002)(366004)(376002)(396003)(39860400002)(136003)(230922051799003)(64100799003)(451199024)(1800799009)(186009)(38100700002)(41300700001)(4326008)(316002)(8936002)(478600001)(6916009)(33656002)(2616005)(26005)(2906002)(86362001)(8676002)(36756003)(5660300002)(1076003)(66946007)(53546011)(83380400001)(6506007)(6512007)(66476007)(66556008)(6486002)(6666004)(27376004);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MqCvCscCkf35hOTEMg20AWbBwz48AoopM4aATq3dH+RtkQhtNj6Ak3y1VA/D?= =?us-ascii?Q?heXGj063aXD5e7u3NyqpmTcLywHq4LNvzELIZnD0m1cDdVirkm9SrA18latd?= =?us-ascii?Q?sXZZTK9ADQtm4vCCrVE4YvH85KJ18s8ycxDgY39mxdsf08ZVh49Sj58qTt7M?= =?us-ascii?Q?39ElfVtOYq8nC8NbsuNetqpKw0O95QhpXFc8fHBTjMT5RkE6exX1mdE6ICwB?= =?us-ascii?Q?wwDUYP3HLRbNORU4PR93aznfvMU4vE86JU8ta2AYjQ4cZMaX55fdz0Ih62tq?= =?us-ascii?Q?u/qhr0EKKknzp7NiQZlpnEclaXHwMGj8FSwpfrZd92VjoJ8BwwPgEiZbXeRB?= =?us-ascii?Q?PcXasEW2aPdp3hqBmtFP9p2sX8ifRzlAIZKjErUnEUxhS2JvJEZ4BealHi45?= =?us-ascii?Q?gR6titAatoc7e0fWazodZ2dxQqp0SVwunBdkDSZgSVXTN40pxfEWBdstP9qN?= =?us-ascii?Q?gE+6/T56qMg06EZAPaZQ2Wrr4kYpOPedBxTR2IH0J4Z4p4wNyOeOHOgL34Yy?= =?us-ascii?Q?Q6w8DsRbT7AFusoFQ7U4jal6fG9ljKxln42cb/y/p/8jNPJlSOCh1wYVUo/f?= =?us-ascii?Q?yezGAuOJhZQirO7ANMY6TgZ2Np2otnfywugPqTUCQ+X2UWDz0rZHz/TXzXA0?= =?us-ascii?Q?h8FufPin1paWGM1vQrFLh3InmomUPt8Zx5DcifRyeR9czfrxjigC3624+/v3?= =?us-ascii?Q?MNTzTFJWqT0+W28Qqoa8A2VR+OE/bGhnFf5c+CPfueweKN5ijb5b+PiswpAB?= =?us-ascii?Q?35gR2q/FuhL4QAr9BD2kAgl4jUhwMnkN0CNhE2IsqRMgWhXEzfMgvJDjfSZf?= =?us-ascii?Q?F28rzzag9XVxbnPP17Ta3DdIWrxnDOQc/VsRWNhYWid4GqfC1k/YtvTIYB9Q?= =?us-ascii?Q?7vCKRAiYixYvX7DX151RIj1vA9Oy1pxraBGdqfzEu0v64MZwp5u5Z/PxouTe?= =?us-ascii?Q?ksB9oGVZWmjCvRaWies87dSoNTAl8Kt26KfndpiyPYtfehIlzAD9XaxpUTN4?= =?us-ascii?Q?LU/9rKQQGKifI7GVFUGuHYy0WFvZWIvwKpV57OdVsKIz1Rio8cEUTujOrKDr?= =?us-ascii?Q?GDwDzSwSAFx1pyDpANg8d/MR01PyoRiALVTYk0kzhRks6omlSk4itlytfPip?= =?us-ascii?Q?SQPemGbJYndSBk1b/C4Gb6GaXFVs1SqLmB5prpPk0TOZQoJ+UEnAtwrYhiIs?= =?us-ascii?Q?Z4vXSAdOkoyhEVH9bPeP4SqhhOwIjZhZ1XKmoYmbXRxQyIrix2s8Cn54k8BR?= =?us-ascii?Q?HXFMYd7JuPbxWbMNrnTXPD4YB3MKIgUwXtaALSk1jE5Ho1+5e6v5qCRe9VlP?= =?us-ascii?Q?17AY0e7fpjEzGxUH9FCY2PsodotNLAsy4/Nw2yStVUofhm2lwJRms2UeBKEl?= =?us-ascii?Q?OWRQ5s3diSVukAeEJkZ7CuoWqAxpGuUID1/Clvy1ZeL5Ni3NlN+AXNuhMdxy?= =?us-ascii?Q?20HtHJcCs2UjQkslJXqdFZN2vSLyyZa5BBa4HM4UeZ4ovbjX8tOO5pZwq/M7?= =?us-ascii?Q?/Lc5ZVOPPbxPfeo1MGQy3yZuCJID26nNhwGd9hWr/PoVpK8vvPu/HXcKRdSM?= =?us-ascii?Q?GJZBYaqIejGG9SS6J0p46wKay6knqewe0vRX/8WV?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b1d7bf02-f2c9-4741-ef33-08dbc37ed6f0 X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Oct 2023 19:36:14.4693 (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: taDoxQbX5iooRjChItFpkH7kr9mWwk8LK06bv00cHe3U1MfrhiN+o61OOQsgAjim X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV2PR12MB5845 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 02, 2023 at 08:02:23PM +0100, Robin Murphy wrote: > On 02/10/2023 3:16 pm, Jason Gunthorpe wrote: > > On Mon, Oct 02, 2023 at 02:49:12PM +0100, Robin Murphy wrote: > > > @@ -2120,20 +2120,30 @@ static struct iommu_domain *__iommu_domain_alloc(const struct iommu_ops *ops, > > > return domain; > > > } > > > -static struct iommu_domain * > > > -__iommu_group_domain_alloc(struct iommu_group *group, unsigned int type) > > > +static int __iommu_domain_alloc_dev(struct device *dev, void *data) > > > { > > > > Why? > > Because out of 3 callsites, two were in a context which now needed to > make the iommu_group_first_dev() call itself anyway, I don't see it. Why not just do this? static int __iommu_domain_alloc_dev(struct device *dev, void *data) { /* FIXME: This is not correctly locked */ struct iommu_group *group = iommu_group_get(dev); struct group **alloc_group = data; if (!group) return 0; mutex_lock(&group->mutex); /* Theoretically we could have raced against release */ if (list_empty(&group->devices)) { mutex_unlock(&group->mutex); iommu_group_put(group); return 0; } *alloc_group = group; return 1; } struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus) { struct iommu_group *alloc_group; struct iommu_domain *dom; /* Only one driver is supported with this interface */ if (WARN_ON(iommu_num_drivers > 1)) return NULL; bus_for_each_dev(bus, NULL, &alloc_group, __iommu_domain_alloc_dev); if (!alloc_group) return NULL; dom = __iommu_group_domain_alloc(alloc_group, IOMMU_DOMAIN_UNMANAGED); mutex_unlock(&alloc_group->mutex); iommu_group_put(alloc_group); return dom; } EXPORT_SYMBOL_GPL(iommu_domain_alloc); (and ++/-- iommu_num_drivers in iommu_device_register) One patch, it's pretty easy??? > Um... Good? I mean in 3/4 cases it's literally the exact same code just > factored out again, while the one I've added picks some arbitrary device > in a different way. Sure, but the whole point was to make it obvious that there was no direct linkage from the various dev parameters we have in places and what dev will be passed by the driver. Everything passes through __iommu_group_domain_alloc() and at the end of the day that should be the only allocation API. Jason