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 27760C48BC1 for ; Tue, 13 Feb 2024 03:33:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4330D6B0071; Mon, 12 Feb 2024 22:33:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E3166B0072; Mon, 12 Feb 2024 22:33:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 235056B0074; Mon, 12 Feb 2024 22:33:42 -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 130106B0071 for ; Mon, 12 Feb 2024 22:33:42 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id B007A403E9 for ; Tue, 13 Feb 2024 03:33:41 +0000 (UTC) X-FDA: 81785361042.15.6DDCC6E Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf18.hostedemail.com (Postfix) with ESMTP id 304B41C0009 for ; Tue, 13 Feb 2024 03:33:37 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=AZH3BuHl; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Rmll9OZe; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf18.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@oracle.com; dmarc=pass (policy=none) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707795218; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=goXbVLGn1Uls5GgCnwwxp7WAHrQQD4E1MfnT1U2nCeU=; b=nQQMYbV4o7maW/RAk0Jg/TNJ2sjPgapozt76HcYD6c6NfV1casAji5SiOXjULyF8fuQ8iJ VHoJmFJPVH+7KsIKhKNhHC1A+Lhi94QC97FDAvV+CB3XrpqEXCyh/SBIaEZjI/kqpDJA0r C7upPvzKHoJUiDJ8HKt95VEm+SAM2ew= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1707795218; a=rsa-sha256; cv=pass; b=p8I90ll/N7RGxzifKU7vp3kSCBav+L65J/v51tGJ0m2zvnpIunbNx5x3+7Jir9nETIxy2O csGs1vCx5NWmghu4Zi0Uib210KtzgIIvlDQREWBXW/5PxK22uaq7vlwFOOUdpQ2gvIxs+D PtNRCf8yt8fH/zsEQMAF6WElcu4RN0c= ARC-Authentication-Results: i=2; imf18.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=AZH3BuHl; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Rmll9OZe; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf18.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@oracle.com; dmarc=pass (policy=none) header.from=oracle.com Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 41D3KPBk006888; Tue, 13 Feb 2024 03:33:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : content-type : in-reply-to : mime-version; s=corp-2023-11-20; bh=goXbVLGn1Uls5GgCnwwxp7WAHrQQD4E1MfnT1U2nCeU=; b=AZH3BuHligli8YKiqIBQHuHKaXLiXAp1Q+D1BD3MI2OdKHvs/g3gIKt7DJvOYKSilJT8 08JVknu7t9WUfP/wDly7iPYissYgKE6GaTvZo3le+7dV6vQwgL3QHZuAYWWYoMP/IK3M P4whcly8+1zs+4Kw5fPA/TFC986lnxU/K2faf3bWREgNeA1Tn63tzr7LYGwyifVJa8P9 htusSErKNao8fXAm9bruqPxaI7RaUMttcVG3Z+ciKiXbjVb09iEpVhlMtECdFNTiSSw5 nMpJK6QBKKQIX06LQ82J/fF5/JI9DOX0mSle7l+tMEh6avMo6gTkd5tCRKcGO/Mmmp55 wg== Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.appoci.oracle.com [138.1.114.2]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3w80e100g3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Feb 2024 03:33:26 +0000 Received: from pps.filterd (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (8.17.1.19/8.17.1.19) with ESMTP id 41D3KSu2015207; Tue, 13 Feb 2024 03:33:25 GMT Received: from nam12-mw2-obe.outbound.protection.outlook.com (mail-mw2nam12lp2040.outbound.protection.outlook.com [104.47.66.40]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 3w5yk6qn5v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Feb 2024 03:33:25 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=FqPaN5/Eml9T+IuCRIdmiNUC4X6o1SnhAsuPDioADs0pAr3ovAW1Ao8GyR/4IVyWrNz3zPoFbDiV7P3pDOTlHQhaHu073n1ep2D+JR+LpiZKfeIDyHxywzRnFnpOF7VIWQaZBqUpzGc/1C0qBJN4y8NganOyM9Q99HBUoDeX+o+VbTavgkeAc6sDqumvYkiGkhxOo0I0EjiGREu4FK/IeVqzgID2i2ckjW6xLVxOoVa59aiXYfrKnxeRfYzlXd94WRoe3G3FgZqVECl2oMoYx9M2kyeHOqq2N2IUrql/PH/KXw1RA8S2/TEi8GnuuA758C5rm/tIVGE6FhmHOC8q1w== 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=goXbVLGn1Uls5GgCnwwxp7WAHrQQD4E1MfnT1U2nCeU=; b=SYVpMe+qzpUUfHurNOHYy+7ArZdM96GNGZLfjvMsGAIXCgDdoKavzweijnpYRaNuAXl1EDPgVRkESEREoUUHsqIp6pIgXuhojqvewu0JctpaCPJ4LUL7wl+Q9faFGyz/mwYEdvOXKWrSIteHPq0r8UDYWTaC1faiM9SrWy2qj8xmm1mEzI82ayx+MIT5Wqguo1VTj92xlOEuIQgHQPMY+W89j60Im+aBIlKYhv0YWqeQQFYDlloWNUoM3fBcXzKohzh1VojCv8nEKaxMjU3YKogdLDuhrbXZxIz7MF4HuNZhPn9vvuASRDORkUuPOMQ24gTm0ekTHmGpMUP96lQZpA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=goXbVLGn1Uls5GgCnwwxp7WAHrQQD4E1MfnT1U2nCeU=; b=Rmll9OZeaCPnPi4I9XSjF1bIui94lwGBS6etdbRGUpCpeg3CyO3qPAK6JL/l2Qwu/fMKJRileJu9jTP5gMD28kHRv6EGd8lGDGA16R67XviSfXekwhp/z9S3u+sqv+utk6aFs04IEio4kAPqIBdmkWASPysbhTaOO91EJ1IdsDE= Received: from DS0PR10MB7933.namprd10.prod.outlook.com (2603:10b6:8:1b8::15) by CH3PR10MB7356.namprd10.prod.outlook.com (2603:10b6:610:130::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7249.38; Tue, 13 Feb 2024 03:33:10 +0000 Received: from DS0PR10MB7933.namprd10.prod.outlook.com ([fe80::20c8:7efa:f9a8:7606]) by DS0PR10MB7933.namprd10.prod.outlook.com ([fe80::20c8:7efa:f9a8:7606%4]) with mapi id 15.20.7270.033; Tue, 13 Feb 2024 03:33:10 +0000 Date: Mon, 12 Feb 2024 22:33:07 -0500 From: "Liam R. Howlett" To: Lokesh Gidra Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, selinux@vger.kernel.org, surenb@google.com, kernel-team@android.com, aarcange@redhat.com, peterx@redhat.com, david@redhat.com, axelrasmussen@google.com, bgeffon@google.com, willy@infradead.org, jannh@google.com, kaleshsingh@google.com, ngeoffray@google.com, timmurray@google.com, rppt@kernel.org Subject: Re: [PATCH v5 3/3] userfaultfd: use per-vma locks in userfaultfd operations Message-ID: <20240213033307.zbhrpjigco7vl56z@revolver> Mail-Followup-To: "Liam R. Howlett" , Lokesh Gidra , akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, selinux@vger.kernel.org, surenb@google.com, kernel-team@android.com, aarcange@redhat.com, peterx@redhat.com, david@redhat.com, axelrasmussen@google.com, bgeffon@google.com, willy@infradead.org, jannh@google.com, kaleshsingh@google.com, ngeoffray@google.com, timmurray@google.com, rppt@kernel.org References: <20240213001920.3551772-1-lokeshgidra@google.com> <20240213001920.3551772-4-lokeshgidra@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240213001920.3551772-4-lokeshgidra@google.com> User-Agent: NeoMutt/20220429 X-ClientProxiedBy: CH5P223CA0014.NAMP223.PROD.OUTLOOK.COM (2603:10b6:610:1f3::16) To DS0PR10MB7933.namprd10.prod.outlook.com (2603:10b6:8:1b8::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR10MB7933:EE_|CH3PR10MB7356:EE_ X-MS-Office365-Filtering-Correlation-Id: 0db9f876-79f0-44ee-a894-08dc2c44801a 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:DS0PR10MB7933.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(7916004)(366004)(396003)(346002)(136003)(376002)(39860400002)(230922051799003)(451199024)(186009)(1800799012)(64100799003)(2906002)(7416002)(41300700001)(6666004)(26005)(6506007)(6512007)(9686003)(6486002)(478600001)(1076003)(4326008)(86362001)(38100700002)(83380400001)(8676002)(5660300002)(8936002)(6916009)(66556008)(316002)(66476007)(33716001)(66946007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?OI7wi9622aXP3xyc0MXu7T3GiewACXMrxUkSK7dqmUb39NJQbQhjNR8pPyxr?= =?us-ascii?Q?I4dI4WGKD5mCDo7fMzsOR51NEaqJ6TW7W4Y6H5R5m2esyvN8G2v/JDklQKZn?= =?us-ascii?Q?wOeKT0MY2Z6B5zkEw/MWHcd5gmdo0r75pYlQsFqxVv8lTpH3YPsan6aFIZoH?= =?us-ascii?Q?nNoiHkSfrZ7cbiPRyeKqQIe9v0tJQ2Ob2PVZHbexsPquTWAKfPzMQqBWVy7t?= =?us-ascii?Q?EQtIurMEBAiIg9KSEPjN8HVDLrl+4yFC+CfZlViP/4fvYHp7hafuYZXC8iVl?= =?us-ascii?Q?VoKacVuAs/bCwCMu2d8H5rvVBovs2f9mvUUdsCfinBNUwlBwW8GI/fG7hfri?= =?us-ascii?Q?qSYco8Uqe9IbdfePkcJPhlGzOg+OFpF6x5tJHhFRpWYpwZtlmezzZhiyv7ma?= =?us-ascii?Q?gsG7Hc8tMR2GICVFkGbnu2TctwmjXu/2q9YgAaWRpxxswRBwKdgmvSDzU0QP?= =?us-ascii?Q?KLUXruK1dfV/kxYEINvavC8E3zt81uWBnO4UqHBULUoP6/O1+Ah8X5roW0JR?= =?us-ascii?Q?ETzrRa9ej/Hy4UH6I47FZBUQyBZFbrZ/q85KCfLPUlvrwtZhKGxVfO6amccB?= =?us-ascii?Q?JrHGG9F3TN7xrhCMYd/lpHTU1I8m9+cXjmIfRtb4XtL7PmbS8tR6DZXGEXto?= =?us-ascii?Q?5xxg2iHJ9thiVbaC9tT0rzgKM4tTApaEw3UxEqUvkU+QaqsJJT+s9Gi8RwkY?= =?us-ascii?Q?Xis9nYu6eiLfzr8eSV255sm6L2KkPStDjmXcOfZWOTzPAzV1Qug1GaR3wdAG?= =?us-ascii?Q?pfzCPyEf9YKXB4f15scyiJrXsZAGT3YnfSAPfjpRIFceGIu6odtZGJ7iu8DU?= =?us-ascii?Q?kIXsquKZ17Sgc26vHMHHU4Pzq7jUYMxv+y9Zw9w2Aqe5Hj4jeiwQDqHO1doy?= =?us-ascii?Q?mYrl/NLiDpdhWHIlFK/hnf+ER4MJeAMFEkh1sdBVq/CZ+P9vqjTXyVJYkqR4?= =?us-ascii?Q?WKD8OWYGzHh+Ez9ZSSXLnRp/kFy30AQxYYpd2U5sFylW2ieR6Pcr+6/qSWff?= =?us-ascii?Q?0GsJ9wrtP2hE8lXQ9ILIOYoD+ZFzjGL3Z5jCi/KLb2C8r9Sx4Ey1FlopFxkE?= =?us-ascii?Q?ZO2G5ZE3R5qwdcR2qOtAKvT/Spom2Dl7z56UuuagDe8QhzcnzAKEM7naULdi?= =?us-ascii?Q?DfxF0zlbP2TbLsPgnYKyd4tc4LGw0HhNjC9gZaQ2EMVDsD4DbT768nHDsTvB?= =?us-ascii?Q?2lg9UzfFicvOipptC3n7dPR78MzSbrTg9BwS0QJMdf1YGz68kbUcXy5/ooNs?= =?us-ascii?Q?TLk8DNuxAAB8Vk/05MzD7//YDJKqDP2Eg1xY2y42KeF2Y5HaX9GJuWqIpfZD?= =?us-ascii?Q?6zCGWNp3o86o8yOuYVpyJheaa4fbdtbdWKwoQ2fz1ltnzExn99W1khouUO0e?= =?us-ascii?Q?usWHxpQYdl4rswxK1k4iYZwoRjhdYV6crasgkZqPuIBgL3CpukrcaJH/4fIO?= =?us-ascii?Q?Yemun3hGesIySCIFG/l4AFrWHD6XdQ9xk0oidVoNmucLjLMwhvtLvAuwC9EH?= =?us-ascii?Q?7Z+slTqgVaSuBBbCF7w6oqrhrbJyiHT1ma+EgjgsNBVxDTHFrZYarg327bSS?= =?us-ascii?Q?Rga4wX6E/sL8Ej5INND8wioCkkV3YRBmf54NJTE9I+V2xk0y1dNuTansAb5I?= =?us-ascii?Q?LA=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: ywVDlB47Qn+XLELbsi500/cPBMDWr5QhuuiNr0FzmaHmrWuqTixhkKiN+KOeT/gqgOjVvQL8emPceih7G7PEgjscUwvc2ZFiIkJ8lv3jkMOh1OOD1ZgpRa87nhV5M2H2vGVJqnoNVmpxBS26J0Ts1KrL3gsy9anxZ1NVyvjgnkuR3NMwJsl26V096Q+hqp9oPHeYasgs8/2fQN5XSCcPV5XxztR9O4ApzUXsJP5mKttSks5QHNULa0PPs2uZ4gyWZD6TnlTrH8FBmUJKETd9IPCYX1UGCCfvE06p/37u6LJ56mBcAM5IF8wAxlfVO9LAEcxU4NppBsJX0MoaJQMzlOVZ6Ss7Upv6+LfpVSUNT4nK8A0mTOiiLgK47vwNoU4/Jfe5M9nroagHQDrbSVWK9L3wO22AFUS2eGi4sBIvf4KKdz2ZyKpSJkJhErnI6okt5MtAnfIOZjTjVEZHR3Yc1uYeDJyLFjTcYw5jHUTfct8Yh4B8zo+g4vBjwHWlVl/FxEBHn1kv88AqmrrzN3zGeBL4juFxyO+MUUXmexK/HElpjHMw/4l/6SSmBUe1ZWQ3oXevH8PrrWUPsO0fqQT614BEeJjX0Lq+OqCFELRhKLU= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0db9f876-79f0-44ee-a894-08dc2c44801a X-MS-Exchange-CrossTenant-AuthSource: DS0PR10MB7933.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Feb 2024 03:33:10.0003 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: iDZB0glLSxCo2lAJsg2LjV/TOULMikzzVgwyxWgy3Kt2uubZwAVa57tNMONki81TajIRXZRts05pzjmB88bH2Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR10MB7356 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-02-12_20,2024-02-12_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 bulkscore=0 suspectscore=0 phishscore=0 adultscore=0 spamscore=0 mlxlogscore=480 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2402130024 X-Proofpoint-GUID: -eIMHdBhzgIX5EhvBdfki-Fn1spmN2JZ X-Proofpoint-ORIG-GUID: -eIMHdBhzgIX5EhvBdfki-Fn1spmN2JZ X-Stat-Signature: 1tyn9qryei5jq1uz837mygxhxjkonezk X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 304B41C0009 X-Rspam-User: X-HE-Tag: 1707795217-537655 X-HE-Meta: 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 47jTXMZB Yui0irTENn4bYVw6eJ71zn0d3gATOXaPDebaz9SfziLWEVS5WQCxsput7hJRAtGzSGY8cIicfMmTkEKFDtfBsxo5++qO05n4mOHkKn496xs8PRATNkyrzZCNjA4/MBgYkO1JclGj7aBxQuFPDbz5bjHNWqBVv9DDWNhHdaw6D3K6YdU6HMFUZppa98IKrQ4E1GuuRjhgQwQ4lxW4w7tE1JU+yT4RF2HIBktFk4myqRXsa9d8F5FtGRT71kMzdzkJfft9GmrXegccXM7FT+qUOBbv8uBuWOw/gtXX8RNh2op81UBS6nV22b/L0l2Rnvtn50EmVgt3mUjqP3fv8r3TzJBCIw4ifAlgea/qwhZIacfji4L+AhP81lfDOtPsQjGDmIo6ItVQ8DqVCz6ffz4DDk6MLLtOhXPXCEH+Fjl1BhnZY1sM= 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: * Lokesh Gidra [240212 19:19]: > All userfaultfd operations, except write-protect, opportunistically use > per-vma locks to lock vmas. On failure, attempt again inside mmap_lock > critical section. > > Write-protect operation requires mmap_lock as it iterates over multiple > vmas. > > Signed-off-by: Lokesh Gidra > --- > fs/userfaultfd.c | 13 +- > include/linux/userfaultfd_k.h | 5 +- > mm/userfaultfd.c | 392 ++++++++++++++++++++++++++-------- > 3 files changed, 312 insertions(+), 98 deletions(-) > ... > + > +static __always_inline > +struct vm_area_struct *find_vma_and_prepare_anon(struct mm_struct *mm, > + unsigned long addr) > +{ > + struct vm_area_struct *vma; > + > + mmap_assert_locked(mm); > + vma = vma_lookup(mm, addr); > + if (!vma) > + vma = ERR_PTR(-ENOENT); > + else if (!(vma->vm_flags & VM_SHARED) && anon_vma_prepare(vma)) > + vma = ERR_PTR(-ENOMEM); Nit: I just noticed that the code below says anon_vma_prepare() is unlikely. ... > +static struct vm_area_struct *lock_mm_and_find_dst_vma(struct mm_struct *dst_mm, > + unsigned long dst_start, > + unsigned long len) > +{ > + struct vm_area_struct *dst_vma; > + int err; > + > + mmap_read_lock(dst_mm); > + dst_vma = find_vma_and_prepare_anon(dst_mm, dst_start); > + if (IS_ERR(dst_vma)) { > + err = PTR_ERR(dst_vma); It's sort of odd you decode then re-encode this error, but it's correct the way you have it written. You could just encode ENOENT instead? > + goto out_unlock; > + } > + > + if (validate_dst_vma(dst_vma, dst_start + len)) > + return dst_vma; > + > + err = -ENOENT; > +out_unlock: > + mmap_read_unlock(dst_mm); > + return ERR_PTR(err); > } > +#endif > ... > +static __always_inline > +long find_vmas_mm_locked(struct mm_struct *mm, int would probably do? > + unsigned long dst_start, > + unsigned long src_start, > + struct vm_area_struct **dst_vmap, > + struct vm_area_struct **src_vmap) > +{ > + struct vm_area_struct *vma; > + > + mmap_assert_locked(mm); > + vma = find_vma_and_prepare_anon(mm, dst_start); > + if (IS_ERR(vma)) > + return PTR_ERR(vma); > + > + *dst_vmap = vma; > + /* Skip finding src_vma if src_start is in dst_vma */ > + if (src_start >= vma->vm_start && src_start < vma->vm_end) > + goto out_success; > + > + vma = vma_lookup(mm, src_start); > + if (!vma) > + return -ENOENT; > +out_success: > + *src_vmap = vma; > + return 0; > +} > + > +#ifdef CONFIG_PER_VMA_LOCK > +static long find_and_lock_vmas(struct mm_struct *mm, This could also be an int return type, I must be missing something? ... > + *src_vmap = lock_vma_under_rcu(mm, src_start); > + if (likely(*src_vmap)) > + return 0; > + > + /* Undo any locking and retry in mmap_lock critical section */ > + vma_end_read(*dst_vmap); > + > + mmap_read_lock(mm); > + err = find_vmas_mm_locked(mm, dst_start, src_start, dst_vmap, src_vmap); > + if (!err) { > + /* > + * See comment in lock_vma() as to why not using > + * vma_start_read() here. > + */ > + down_read(&(*dst_vmap)->vm_lock->lock); > + if (*dst_vmap != *src_vmap) > + down_read(&(*src_vmap)->vm_lock->lock); > + } > + mmap_read_unlock(mm); > + return err; > +} > +#else > +static long lock_mm_and_find_vmas(struct mm_struct *mm, > + unsigned long dst_start, > + unsigned long src_start, > + struct vm_area_struct **dst_vmap, > + struct vm_area_struct **src_vmap) > +{ > + long err; > + > + mmap_read_lock(mm); > + err = find_vmas_mm_locked(mm, dst_start, src_start, dst_vmap, src_vmap); > + if (err) > + mmap_read_unlock(mm); > + return err; > } > +#endif This section is much easier to understand. Thanks. Thanks, Liam