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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21A29C02196 for ; Tue, 4 Feb 2025 22:50:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 58B0F280003; Tue, 4 Feb 2025 17:50:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 539E0280001; Tue, 4 Feb 2025 17:50:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 365C9280003; Tue, 4 Feb 2025 17:50:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 1778C280001 for ; Tue, 4 Feb 2025 17:50:30 -0500 (EST) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D641CC044C for ; Tue, 4 Feb 2025 22:50:29 +0000 (UTC) X-FDA: 83083757778.07.B9BC056 Received: from NAM02-SN1-obe.outbound.protection.outlook.com (mail-sn1nam02on2047.outbound.protection.outlook.com [40.107.96.47]) by imf12.hostedemail.com (Postfix) with ESMTP id 094AC40006 for ; Tue, 4 Feb 2025 22:50:26 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="LvMTO5G/"; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf12.hostedemail.com: domain of apopple@nvidia.com designates 40.107.96.47 as permitted sender) smtp.mailfrom=apopple@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738709427; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=+RK8HcctKWrWGjHAxyN8k6xlAbP24zFsv0TFbZlW19A=; b=7YEqLRCXZA5O4njYMRtKkbNWLITZjRPM6cxVD15orlReVZ3ADkV2RwNHPrzFZbGAR+mckL tF4sllo6DwMlxgvpIGGCc1vpp+S0gfNXy86EBZkUtl0Hwv3Xr6hXcIAsQxyrWcBqDHzLi2 mj5ldmV3yu5Qc2JsV057okHN8RP3DGM= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1738709427; a=rsa-sha256; cv=pass; b=mb22eg4CfK05vzlECBY+oULVCFvcwDT7mvoucATlbtBSWNnyTRo+8/VhuWH7cEBusHwmcC rTEsSqT/lVRpF47sBXSORNe+4KqEs+p2BabDBIHB+Z2FQjV8wlXm8UTsFkfjEdyudggaRR AlCMoxw2Xl70eNv8v8CnFe20/Y10JgI= ARC-Authentication-Results: i=2; imf12.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="LvMTO5G/"; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf12.hostedemail.com: domain of apopple@nvidia.com designates 40.107.96.47 as permitted sender) smtp.mailfrom=apopple@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=LWThh/AYziDVFX6FIPwZIDhCooJlt7qmuXaGQUYqeOCt8sKs+n/adKVcjXbYqB54LdRxX6WYr+0Di8d44qZAOoNdJdbVlrNr3WdEtjEOwfhXVPKU3SsIOz6KfChAno+9NlWrDkNO/V9pxoZH9YKOXPl6V5peNE94BfCY4CXiHowLidI/fFWTZ1DxDuJ1aOoII045vc5nZrjlpti2bvi233Twedbj/pvqM3nnL1lhf8tKT7zJsSIzmMIK0P/ceGHnAYc3YM3uvlGOzfPZhY0td6LhkbvDXvBYwTR//sHYl+8k615uh7xbKF6vj0paD2n8APruxGdg6pLyNzejaN/vNg== 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=+RK8HcctKWrWGjHAxyN8k6xlAbP24zFsv0TFbZlW19A=; b=cOtdm7AVIEAWwOgO4gb+K2i4B9td78Q0xBN6yIVqyplKZFXgS0SzhL2m0nMPo4L9wA3kSrQblMxKWhsvEJkLLrAYotshODg49g5HgcSXhaiANGdKubwYOqX6xRBaRpgwcUcpOcnzUGPU1yUjiUUMPpGnadY7T/2VfX1INOEFNa3Dk1Ts3BHHjdpKpKdXfak2PumVyUf9SWEeU6GBVSAmcTjtNyrPHhAB/wXEBKjd8gp/nBwsqoJ4LJqHaajiedsJ70TGELH95Hj73z/4nWKeg12+B7eRS2B7KFPPxvsPAhXHVCj68LS05fQ3DZvvsoMjLEYEsSSqq0a5UH/efNIl2g== 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=+RK8HcctKWrWGjHAxyN8k6xlAbP24zFsv0TFbZlW19A=; b=LvMTO5G/vq+G84KunIOt9dhCWlvhCf3GUs0jcFx7uCgP3sf4F6oTFl5y+jtQBtCXcgNT8XoYLkMt0eoj0+TscIUxYgevX6TnJ7wj18E8h+SAIXntI41wO3LEkny6Dx84XYBzhUxoVyvYzlvdPN9hgLJg5ouOlmy5ZrNfi+eqsAbTOVsPOylwGRJ4njs99ZtCC3Dk6lhgmhG9rkor4j31vcR69WsfTd/tSB9fMslQggts6GAXwUHxSN4BKPV/SLApKs9FlPgtWBn7odo7NXN7GktX9Ib48YOgQSx4jKiIdLdP3llSABBQuY2ZBflczDzc0yvso+oNyiPlho0Y03AJ3w== Received: from DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) by MN0PR12MB5978.namprd12.prod.outlook.com (2603:10b6:208:37d::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8398.25; Tue, 4 Feb 2025 22:50:19 +0000 Received: from DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe]) by DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe%7]) with mapi id 15.20.8398.025; Tue, 4 Feb 2025 22:50:18 +0000 From: Alistair Popple To: akpm@linux-foundation.org, dan.j.williams@intel.com, linux-mm@kvack.org Cc: Alistair Popple , Alison Schofield , lina@asahilina.net, zhang.lyra@gmail.com, gerald.schaefer@linux.ibm.com, vishal.l.verma@intel.com, dave.jiang@intel.com, logang@deltatee.com, bhelgaas@google.com, jack@suse.cz, jgg@ziepe.ca, catalin.marinas@arm.com, will@kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, dave.hansen@linux.intel.com, ira.weiny@intel.com, willy@infradead.org, djwong@kernel.org, tytso@mit.edu, linmiaohe@huawei.com, david@redhat.com, peterx@redhat.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de, david@fromorbit.com, chenhuacai@kernel.org, kernel@xen0n.name, loongarch@lists.linux.dev Subject: [PATCH v7 20/20] device/dax: Properly refcount device dax pages when mapping Date: Wed, 5 Feb 2025 09:48:17 +1100 Message-ID: <7d65e855fcdc5cee12b4500a557b2ad961bdc8f2.1738709036.git-series.apopple@nvidia.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: SY5P282CA0170.AUSP282.PROD.OUTLOOK.COM (2603:10c6:10:24a::25) To DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR12MB7726:EE_|MN0PR12MB5978:EE_ X-MS-Office365-Filtering-Correlation-Id: e8e5be72-8531-4596-0876-08dd456e4c34 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?lStfnsiSb+G8Iw91EnBGAJ0j2af9WK1uA3v+7TtIJTVBcQZ/D2NVAcMbCv++?= =?us-ascii?Q?ugeJX9KsrS7c5EhW2xHw26vrO3TVthtXSratgnjzkanfCNqVUK025wzgiQz3?= =?us-ascii?Q?A3V84KAoMHk+xNfj/LqvaDKS2r4mAAhu//ob16TlHHg60k0eEaUt1a9gxIrr?= =?us-ascii?Q?osNqqkT4qG3GVTBrXCFB5c7K/eJqYuJImcHhmXVa8cNYZxkKWoBpvJ72y7sh?= =?us-ascii?Q?HbcNuHwgJ0fObSyEDqwae++HpHQA4TGAlr9hiOPkDwH+mEqJfOYuhV9YSxky?= =?us-ascii?Q?2r0iw00w458ACvLnFDagvcrMUpmD3UbPxRVpGQXbSQcHScKyd3CY/e1XkuIP?= =?us-ascii?Q?eCDHxecCtQ/ks9I6tQtvswvEV3s2elVV9qHwNMex4zo9QuOeUuz7IKKFsm6w?= =?us-ascii?Q?4GJ6F7/5zpy8UzBgDxtNNWT1bkDIhCZzmsZ4FyaQCfLKpZR7mUWs0Ue6RxSZ?= =?us-ascii?Q?74SwSaY9VTrRvS3hgcmAr/1uUmKkXwfzvt2wf2rxq+t1pl0OjpIRxHqWU9bZ?= =?us-ascii?Q?TpSbU86nnm/jJnEl5GmuN1/9MA+j5EUaJMwVm3VhH8tooo4LcqKmb+ey6C9n?= =?us-ascii?Q?e3BHLTREkxw2Qgu9uWV30E/xva7btJpTk2sfTWswUqGEsbrXtsbNoxBrVdCA?= =?us-ascii?Q?3BSglWCkupdZjiC9X7NDJz6Yf4yKIErO1VkPeITEaZAHBQChjvh9yEX3mb1L?= =?us-ascii?Q?QuSfd9SLe41Fwp7aU4A54Wm62CNY9WJET1EtrVG71tmK7wH7JvR4HvQ8dOVW?= =?us-ascii?Q?SXLhdBdEn9FzsqWSGLL9ONLhlLQ7YT+nfZdKF9ABeZdfQAFu2IzLCBuDZiuo?= =?us-ascii?Q?FJq8C/r0n2JNlaDU+KZQGK6RRiZDY1tZDTG+2ZTWkcvsE03uRbOhQvnY7u+W?= =?us-ascii?Q?dbF4Abme7kbk99iurukxlV08Rc7qBBBXcASSiaWQ6D7JVpefkGFQvfuQ+013?= =?us-ascii?Q?p9iz4zxyo9zL2wmYObwPIujOD49Ivlr1ol94hc9bIRr0trxXJeiIP/PvN7bL?= =?us-ascii?Q?p0FvmxGZuMl9RBVF/cCvTnQOKXJptu/jIhLBqbyyxVgonuQk/DA97aELxGGI?= =?us-ascii?Q?HqkWNy6ic5OH9vhlxemWGumAdNtRX8jLg3TTJkqexhdfvmLa6L2qmKoxqxEn?= =?us-ascii?Q?Yar+uXRoynC6dn2s23oqxf30eA2ir4yhlRU2n80L9iaSsMufH43XEOdy53RP?= =?us-ascii?Q?Le8v3VPfsCAST1CmT+Od/XbPZjbfIg2NuCaTNdUG9JoyhrPdlO7XJB91U3uk?= =?us-ascii?Q?3Aqls7NPjyEU/ymtWT6peR41vd6ElLAKdlnbgh4EmsXpnUu7DnwHBhVJkuda?= =?us-ascii?Q?18QQkaq3R3Nas4Nf6B5ohAerWCM07SybHsPB0C4p3XMoel8ZSBju0GewOMkn?= =?us-ascii?Q?t/j0MRBDeal0qdqeKbouPVIDXkHV?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS0PR12MB7726.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?dqlNYgNXTk57smO1jyS5MHtYJGZx4MWUa+uIY098ykSR6WSxpGrbM/QEBT6W?= =?us-ascii?Q?zAcMoOmE1msxN7b5YV5FDSDW6fipOjyeXQsuxCXB/197UBv+SZHXrBabfe7G?= =?us-ascii?Q?gbSAJ2uu02Vp54FX5j2AD5ckOWBRYCBJMhfGtoqyqJ8zM7HwwZf3TfCf4N8V?= =?us-ascii?Q?+CH8dOw2Mqeo1OAforoKisS5PD9lOF+duGRvVpfnb7aV+Q5RriNG2W1wwh2G?= =?us-ascii?Q?aba3mjL100GvAFQF+moAfWQBM8x8IH9gKAmU/h5qG/Da8XZA4eENKV2t3/X/?= =?us-ascii?Q?muYfvbHcC9lpVeQIjk8Ba52Oawg6o50Cp0CTYMdQdhw9JWWMOSvVjn6EXUUq?= =?us-ascii?Q?pSX4O6jLVOBrzIgk4ve+YUq1R2DwxmLYooS8gUnpOUbLHjn60UgxYOB80wJm?= =?us-ascii?Q?gxWqge1PEce6GCQnzjcpFPgPZ5xtGuBh4uaaHJ4NusvmJIPTd2fWAfbNnPVP?= =?us-ascii?Q?dGpjeyqYUdOB9SVU+zzXDu4XPBgBaPXYMOIBAM/gMza+buEZ7lxyXd/tsgnJ?= =?us-ascii?Q?fg/YtemhjiyFiLI6GJAkdi83pAFX5mHuGmpmxM5Aofb8PXDrGmcBMTuhwsm3?= =?us-ascii?Q?I1/DWcQ/WCbVV41WjehADyxa+vbQFD+iOse0tCYZ2Dz87dMXbg67vlueMjJZ?= =?us-ascii?Q?4mplP17Ku6BA48Q5Pec9fh+lR7WSemDwMsYNeOzb9ycjjPZzwcHHUWJBjbwW?= =?us-ascii?Q?t+b03BYPahqJobWJgOoBjF0EtCeTrnsguq4mJBjO7ZMX/y23qCxdN7D9Mzmb?= =?us-ascii?Q?D0YiNOonh9myo7Fu3//FqNMCfF4D4PPwAF7Gj6f8ap/pcNfovtAVaf+p4Cpp?= =?us-ascii?Q?6P+8wpJxlpokxWPJOR1u691yAtiEUWZJk3NsP/2XF/lOPn/hyADvcOja7miO?= =?us-ascii?Q?5cExyphdIIPqRB07n1dkMkA4ImvEv1KWYV752ncRXIQBSwckpLpcSejXmC+7?= =?us-ascii?Q?/tAO2yAwZcgEHBAQWNBQL8Djiyv/0/RUsXC4Abh48wmvJlmDufVmjTFuctsk?= =?us-ascii?Q?61sXaeEKsZ5NkkGd+4o5B6naMVOJovffi6SGfagA58Bb4bHpINSgsEWhg/fn?= =?us-ascii?Q?vERpyJEDiYSQUjvGe/YduUUDDi7g9X+jsS1vdWNJSJZ/lDpQGMA16/Fqcdhv?= =?us-ascii?Q?L9X+qCmByCMzxgp4snyXv6ob15RChy8QeJvfMmR9g8z5tosDAgKqFNHUdVcO?= =?us-ascii?Q?19BFO2Fyh0GlfO7qFcmAccGWHPbDYWtCzS/IrBxQGOXI3GxVgZc54YaL8VgR?= =?us-ascii?Q?FR3Yc1fEylRquqnvOiH7HDBo2f43ZeR8cYPj4YIYpyzmfUBLKxrtorvS5anA?= =?us-ascii?Q?cRAa3nwUFPtJron59PR5xe0ysxireBcN5nlUXWNHTrsCH2CW/oOho/WXbOpB?= =?us-ascii?Q?yvvi5ojZUlAUEBuxwCfx8bvNThviWbDkkSQ7tbWM/vvSWPy5Rwlxm1NTXaRY?= =?us-ascii?Q?QxI4kwu+DoogCX0GQj0Tn6OAWEL3gZTMEGmw7gHxUIHVOTSb3E+UMTJipaeK?= =?us-ascii?Q?iD9ZOH1kKU+KROYCMZNhapfSTgN3+Yv6FQj2TkpJjYITEPcdEdgDmA1/P1SN?= =?us-ascii?Q?H1XAE7QqLRglOWPBCoH/J50efrKNIydiMTLoJRpE?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: e8e5be72-8531-4596-0876-08dd456e4c34 X-MS-Exchange-CrossTenant-AuthSource: DS0PR12MB7726.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Feb 2025 22:50:18.7040 (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: fSYMUkxbdq+ITdx/qthVTTj0IyujhXGyQAhbbbOtPDbjrjJZccO92ORw58EUaiF+1yq6tGysIw4gp/XEzM3MAg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB5978 X-Stat-Signature: odpi74ji8i1oohposcad9d1u13m9g3b7 X-Rspamd-Queue-Id: 094AC40006 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1738709426-574762 X-HE-Meta: U2FsdGVkX1/EFNGJRjkBpgSOtMZ4UanfqJVvYJSLpbAbK4ds7ctu7ldl6XCsTpDANlbhGPbYfuGhWurpQ1VmHh6uPmakvlgH4Qi54VN0Bbdq5hJnmIYdeQ2GV3Rhxd465pB/XpemY12VEk9HqmyTsxuUDqxiRW58bAG4zQh/SI+YdWS8v/GQp3yc+Gzlodjqirmb59N4Un/sUQMXPetoJvUJTbi7uEQySLpixR3kFQO8s/nU0cJiM34yvHv62ZZr/axddZn7AclSx4Rf2JqVyDsASGQe3XU3k8IPC/V0LJqyfANThiaw0orCaPEQOlQswQIo0XwMAmnYz0ZmD/IpseQIxQxThH06ogMHXO7I6jc8Y0e1wj6Mxx0yPf9rw4KwLP4chaNbyng23yqhFNQx4E1yO7WyqBXkHIEOutsydkMaWLvWRjPlTiZYjvR/kCRjreEcn3kmLCfA3BvEVDxPU5WGcnNNjZMHLgqDlxgbrbsUCtJgygXMViIvKrpD73MQSq8wQlJtRjOWIftFA2gwaG3pImGLypnGXz9JIUPWLc6KcEDwjG4NtkBN0ArzYJzH5pX6DM2p9rbhCjGRBgCZ2tzgSYbbwjrL2s9jY50jnuBxD1UtOJpWp28TuU4rINfheFbUz//KKHtHgs7VdgwJul24f51EMiYC4on3Pd8aw6/ymprMlFPBbGelwjkIVF+WC+4BBYDWf7PEhslLxftJj984ez6i/F0txn7kUzm+ZetWF9aS0sztKSO9ugoRJIruhjgM11952JfCej2IlW6I/X/BIpP53d3c/xqqHU8a3zf71z3w6LyDF541mI+IKAKrjGoMRG/YrjlH7eI+fPfJyp+Wx6tK7rW39gKR4NNeVRwsYo5d9hM479fSrgBcVzzbmbRjyaNVwUmKV3c1YxcTO1AqrmaeuorjzzCrUaqETJ1scuXDuG4GaWlr/mLSgWaRrqQmGyXggfO2QYrfcyp qIZXeGQk iLLfDrMFaRxSb1+jVZkpn0oJqveuSSQcQWAcq+v3SbcK8z+aVpLas1ZDR0+H35WnoqCA0urEIunqPJkQvt5rRMXjcgn5/DfommqSN3p+12Rvu2+toHJcNY+8SbiMMCoGv6eC5CRbEOoxdqtRy2ruDHK8uJo31kOMfXk8xamsMKj9oamfFnyCqeNBl49zlUetyVvN7/hot76jLnMRT3Cnwz8QzLxMRccId6Fkx6HQYsCYtj/lRzUFdKvt299RXt/WBidSSp889oWPqmQP2ijmDjyHhLiuDa7U32TSkdW/Bhl3lzolbSzc2pVvRtoUSWcd3Le9zjeM0klPdX7wlRmJxTg+kmLH82dnfth8Dof/DsuId9mj/wOhu6YJ7nDR3a1JspqBqPzrKNWAw15ji7JE2HlNJgzlTa18066e6 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Device DAX pages are currently not reference counted when mapped, instead relying on the devmap PTE bit to ensure mapping code will not get/put references. This requires special handling in various page table walkers, particularly GUP, to manage references on the underlying pgmap to ensure the pages remain valid. However there is no reason these pages can't be refcounted properly at map time. Doning so eliminates the need for the devmap PTE bit, freeing up a precious PTE bit. It also simplifies GUP as it no longer needs to manage the special pgmap references and can instead just treat the pages normally as defined by vm_normal_page(). Signed-off-by: Alistair Popple --- drivers/dax/device.c | 15 +++++++++------ mm/memremap.c | 13 ++++++------- 2 files changed, 15 insertions(+), 13 deletions(-) diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 6d74e62..fd22dbf 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -126,11 +126,12 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP); + pfn = phys_to_pfn_t(phys, 0); dax_set_mapping(vmf, pfn, fault_size); - return vmf_insert_mixed(vmf->vma, vmf->address, pfn); + return vmf_insert_page_mkwrite(vmf, pfn_t_to_page(pfn), + vmf->flags & FAULT_FLAG_WRITE); } static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, @@ -169,11 +170,12 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP); + pfn = phys_to_pfn_t(phys, 0); dax_set_mapping(vmf, pfn, fault_size); - return vmf_insert_pfn_pmd(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE); + return vmf_insert_folio_pmd(vmf, page_folio(pfn_t_to_page(pfn)), + vmf->flags & FAULT_FLAG_WRITE); } #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD @@ -214,11 +216,12 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP); + pfn = phys_to_pfn_t(phys, 0); dax_set_mapping(vmf, pfn, fault_size); - return vmf_insert_pfn_pud(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE); + return vmf_insert_folio_pud(vmf, page_folio(pfn_t_to_page(pfn)), + vmf->flags & FAULT_FLAG_WRITE); } #else static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, diff --git a/mm/memremap.c b/mm/memremap.c index 9a8879b..532a52a 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -460,11 +460,10 @@ void free_zone_device_folio(struct folio *folio) { struct dev_pagemap *pgmap = folio->pgmap; - if (WARN_ON_ONCE(!pgmap->ops)) - return; - - if (WARN_ON_ONCE(pgmap->type != MEMORY_DEVICE_FS_DAX && - !pgmap->ops->page_free)) + if (WARN_ON_ONCE((!pgmap->ops && + pgmap->type != MEMORY_DEVICE_GENERIC) || + (pgmap->ops && !pgmap->ops->page_free && + pgmap->type != MEMORY_DEVICE_FS_DAX))) return; mem_cgroup_uncharge(folio); @@ -494,7 +493,8 @@ void free_zone_device_folio(struct folio *folio) * zero which indicating the page has been removed from the file * system mapping. */ - if (pgmap->type != MEMORY_DEVICE_FS_DAX) + if (pgmap->type != MEMORY_DEVICE_FS_DAX && + pgmap->type != MEMORY_DEVICE_GENERIC) folio->mapping = NULL; switch (pgmap->type) { @@ -509,7 +509,6 @@ void free_zone_device_folio(struct folio *folio) * Reset the refcount to 1 to prepare for handing out the page * again. */ - pgmap->ops->page_free(folio_page(folio, 0)); folio_set_count(folio, 1); break; -- git-series 0.9.1