From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (mail-mw2nam12on2040.outbound.protection.outlook.com [40.107.244.40]) (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 BC9B078C9C; Mon, 8 Sep 2025 13:32:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.244.40 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757338350; cv=fail; b=b/+tKENXMoIo7ooKDUoeJyfUmvk0B+J4gk3WcfrWgbf2XcZcZnCe2yZPd7pY2Jt7y/Kb7maigf6b3wA3U4CjLziK4JhrcHZvilL8YqoHbgPvrT4biy7TnIM+ln4FABNPOPkkTfOaMms/ckpv7EMHumxPnY+JJo6+Pj4srKnKvqg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757338350; c=relaxed/simple; bh=S5ekSVJFUXHAEccaPuC231TU9lZc1QMmssp+SMH5ixQ=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=Cm5AnTSFA9XyT2NDSrtIch/seYWCcv8nZEXm5fiYz3aOsuaQOj+yYBkmmBswPKlHVGYDCYhdvHzmbyZMHeMeBZOMvUMksrKHJ1A/5TXOvESlo85YYMd+N093AKTp9uf6n8YniH3sq7MXsn7BQ1gUt7UspP1dbcWnGwgkaMon710= 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=umqPj4zc; arc=fail smtp.client-ip=40.107.244.40 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="umqPj4zc" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MSXEQZKwYEaZ3VNJhatwgR9CFxZONQKMTzr4Gfrxi5W4nAjP68t2LsTlLjODpP9yj28sXZgQml9BxIZHJjcx2JkkUU5N7lpF897Hu2zeDVaWMRvE9NY8p0x6fcd6eYZUeFFD5uYkNBYWH+e2207yff4spZiw1rOgrFZEHIs/XAGfQ/M0vDtFmqcbPlhnUiDyKr3UXMBjeMy9B09Vzr6U4YMUlmbmqE0TqDxZr/EITCcRwKdrr5wsfO+YKxeofhPMDdJS/EE9VjJGeN5tZvlzoJkpMUgQJjivksuKpLJZbbocY4oySpFe4uyusq5qsJOrYPiEd+R0MSzYiR7KB7GAmA== 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=uBi1FVpshr0fT1WbsHlc8+T7+Ir3NcjHPqPXVABKwoY=; b=M3EjhyWj/LxvVISsAf6on0H8ARUb2Le+3CX7C9h0rp3oVNcEzEtmyjckM9fTEnWdA2qrL3Ryg2O13F+YZIvfAcvWTzM7MUz1IMNQk1OEBEXSrphymQc6L9fBtSJe15hIsnUOc9CGUYhVJ5PxVbY4jbxhvJMznULILRn+xFqlYmcGh4EA+XfB0XZucadb1BjdlozKX5tfOePkuJi/ZIZKm8wCKscS3apJDzdz2blXbUz1V7GLiE5gp2drCBdCNg6KtDMqTkiuFw+cPBcgw7jDa1zyzxzxz5tGhC66TpFiLi+lW10yqbM6XJRgZWAnVuCi82nvR/qhb4za6YSA/HR7qQ== 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=uBi1FVpshr0fT1WbsHlc8+T7+Ir3NcjHPqPXVABKwoY=; b=umqPj4zcwH8q9hq4oSJovDWDjGeaUBPJJ65UEzkyUgh0W8p5w6MrnaYa1Ms8Ie9gT5lAVkvf+QkEjsMH39NeNbhEScfU0MvdKn3+e3NPkg3IeYJ8c33jawkuckcGxUp1f/qmjOzvMfj1LQv6x+6wPfCuvHbFJf6IIvA5n4UoIZS5jAXmj68iGbqSEMpLIfXBM6cU83XyMClkDSvkBtpjpR7s5KvBzRJ2yXuhhKdqeHidxcFevMmgZ5Ldm8u9Z/Y3wMh2eQgDkuVXe7+TjPzlhpWt1AIGk5qvc00yg1QgBPm7n4oWosH4CcTfu/lwjk/HV2jZt5yIhSEU/j8NQt30iA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) by CH1PPFC8B3B7859.namprd12.prod.outlook.com (2603:10b6:61f:fc00::622) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9052.30; Mon, 8 Sep 2025 13:32:26 +0000 Received: from PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632]) by PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632%2]) with mapi id 15.20.9094.017; Mon, 8 Sep 2025 13:32:26 +0000 Date: Mon, 8 Sep 2025 10:32:24 -0300 From: Jason Gunthorpe To: Lorenzo Stoakes Cc: Andrew Morton , Jonathan Corbet , Matthew Wilcox , Guo Ren , Thomas Bogendoerfer , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "David S . Miller" , Andreas Larsson , Arnd Bergmann , Greg Kroah-Hartman , Dan Williams , Vishal Verma , Dave Jiang , Nicolas Pitre , Muchun Song , Oscar Salvador , David Hildenbrand , Konstantin Komarov , Baoquan He , Vivek Goyal , Dave Young , Tony Luck , Reinette Chatre , Dave Martin , James Morse , Alexander Viro , Christian Brauner , Jan Kara , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Hugh Dickins , Baolin Wang , Uladzislau Rezki , Dmitry Vyukov , Andrey Konovalov , Jann Horn , Pedro Falcato , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-csky@vger.kernel.org, linux-mips@vger.kernel.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-mm@kvack.org, ntfs3@lists.linux.dev, kexec@lists.infradead.org, kasan-dev@googlegroups.com Subject: Re: [PATCH 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers Message-ID: <20250908133224.GE616306@nvidia.com> References: <20250908125101.GX616306@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN0PR03CA0020.namprd03.prod.outlook.com (2603:10b6:208:52f::27) To PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5757:EE_|CH1PPFC8B3B7859:EE_ X-MS-Office365-Filtering-Correlation-Id: 1296e94b-a083-4b54-6cf9-08ddeedc263b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?pbGdCwQtUkBy1XWPzFEuCSxAdxGU6ymWkpWa7puKYk2lOQtfEGnVj4mOqyw7?= =?us-ascii?Q?DEqvv2249Hq4je6j1kic8/cnMwIAKU2b5AivI4NrculouXZX1S86JLng5w02?= =?us-ascii?Q?kHdwq6wM/064mWbKGrrXoyk9oXIj8xKBbacL0DNha0AfzfZa7hsesPwQeGTS?= =?us-ascii?Q?6WcCq4GQnXFDhYxVEpW5+cGzmbubab5QvWyQgFS24glDaS/uDV0yQ1Skwluk?= =?us-ascii?Q?DqPnKt29dedTeFwNNjg2Uu+yT6GbAhcJ6HIr5R0myY6bQa6BordVNcrtA5OL?= =?us-ascii?Q?67CELdskAAgtr7NJDew/NZfyk7ZNq9x6DokZzUx5KrlN8Hc4bM33Oqm0lwgY?= =?us-ascii?Q?JKiZYsPn6CjV7A/d3qnW18+JuJdk3fk3i3BSuapnJLkeuW86CzNSEtVMUq6T?= =?us-ascii?Q?nBvQtf+pJce7jriOfxgnFxj0JrCrLHCfjhDeTm2znZI3eSFKAz1gdlECdgav?= =?us-ascii?Q?DYJ51dZmSxe1xVaoTDTj+fWV+GqZkoYBAhAmQ6mdluQinPmm10paDnXCxYbT?= =?us-ascii?Q?k/RohGAQ6fwv43R14TUAO3nI4IeELSjssnPI98Noswq19gB8o6//y6n8oIBv?= =?us-ascii?Q?sowz3Hlz7DT4UNNNMU1TTWv28y8utuTrFPsNAngfngZxZAHG+IOrm8kFpiPP?= =?us-ascii?Q?MQXG5kHJo3o3BF4S2kxbJ3wYZW1FMJGuuyURQ6NBZOvG41GAC1plt7FdH+eQ?= =?us-ascii?Q?pdUQZRrABthEG3NvMQ57P0siy+3JfYY1za3GmnMkcwt5jVTyHyNkX3vowlsX?= =?us-ascii?Q?eJKyMoIDZHPGpIt+PdQ8l02VdzK8XYMaksDsLqLdDIE7OD92OyDqBA1tRzDA?= =?us-ascii?Q?FjUEf3tVIGHXbMqf8nJNpdOkNcKF2m2OhgfJgfo3yHW9n4j3blo+E0ayXL/S?= =?us-ascii?Q?QjYwjKegDLrnoiU0ue7XoZCmQYsxkZ9YfjkFWkjJMq4DfnrgErYVEd2BC8cX?= =?us-ascii?Q?Xt+h1HLDeGDhLsUVsyq5YzfhVy4wuNFjsZtcGJelqcaP/AsJqNPpLFMHc1Z2?= =?us-ascii?Q?S4q6VvwDDrTehOa9ujxtAu2XB4qnQHa+2x85fclPZGA3p6ZarfGqre1lQem7?= =?us-ascii?Q?7KAOP9QVhbLnmjf8Z3LEW0HVh1QWgWHPAQTZ6lhHJyKhq1Xri2Opp8gszD0w?= =?us-ascii?Q?rUQw5yIbabLeJ9wyabgtv6Q6hVZYq8MToiEcn4IIr1N5LdxV2z1OwKZLZbBD?= =?us-ascii?Q?O9TfFXuA7H7uPFlHEAS4aqHUh8p6K9E8W7CDcbMFf4KBsqw5c7MTdZQkj2xn?= =?us-ascii?Q?ZLzBiQNihUg/ITMDoxldx7p0GaE5tNzAFhyYBfmr/f2ee7R9C1MT79Nl4t2D?= =?us-ascii?Q?6AivkHWeMQSO47JExnn0e04RBG9PWA85cznHo6hnnxb4Pz08cbmWRVksrC7a?= =?us-ascii?Q?JIzs7eEjJ1RM0+7gjCgdexmWWSx20z8+tNsQk7fvUvKy8BDZ7w=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR12MB5757.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?cWluRfwjDRHkIbbSj/V4gzAvYEhm+rAPYVuK3KKOz+XhVc4jmgXAf0f2JhVW?= =?us-ascii?Q?3RtZG70f1N2c7PeMoSdlLtd8ggMtwbUA1MSDbTH+l4TrbUJ9Psk/T0nYP0rW?= =?us-ascii?Q?q+6NXhgSF4X5lYsfYNxrx4eDgZzHno14eN2tYg2GtcgMGbHS/lHL+sndpmy4?= =?us-ascii?Q?lW5vJZKnR8ULPwehbnfbUYHv1bUAUQicLbwQBxom6pbsDDRueMWV5EvZGcWC?= =?us-ascii?Q?Ca+xhyTK9U/stsJ5YUxZKHLAUekqwqp+WgG6mIjgnes+HXhkhv77aGtwMLiH?= =?us-ascii?Q?57Z2BkSvgQfbgtBjfZfFhE03HrwEPOVWrm2mzfO6wwRAumTujtQDxVaSvJF4?= =?us-ascii?Q?vGJA1S4gOuQK8WirrV3agNkSAuPta1C0QJOrtykiiB98m3hcTPXURnSW/3XF?= =?us-ascii?Q?Si0mrXTcAzQPoWj5iW30Ps62qOwZaie9fYyr9eEhVPHJfdcp80SEZBVlWyFr?= =?us-ascii?Q?4KSaeN9ltcNCrXl7XlgY2gMcmZZczYz7cCMFsFcYTzxpG2C8YONAw97vvVMi?= =?us-ascii?Q?WIEsrnVaCuYyvYTYOmQJqTZTdz3EDCYheiRkePmBpxE26h+b6Kq9xDnom3lT?= =?us-ascii?Q?hAU83w+Z4tiKJeymfhYnG+8BKpsmrYP4ogJMaZXWnhov4BJ0heS3V1XEEZJR?= =?us-ascii?Q?KFaWZXXx8r9QfruNFjArWZoBjuQEzfBtkWI872ymCnZoUPNZiI4rDjsm9NDz?= =?us-ascii?Q?mwIFqgm7z1mA+mZshBeVSd1vqvoOSyE86lk3VoBuINCOFuxtXLQWP8EqC0Rp?= =?us-ascii?Q?H+zL8GExBgc44sliX47Wjg8DDONQA0yB/l7HtT4O0DfBQKBmTXBFkxlKve95?= =?us-ascii?Q?dtp+0YVmBitZCDeuLsTdzR+67dEBZKRSGxRtW/7ZeBSk4LixF/3QEG9lB9Jm?= =?us-ascii?Q?Fb0sDzdduJIaSMEovZyq650G83cw8vba5BIiMXmCXCtYrDH4kDCQmJ7gAM79?= =?us-ascii?Q?yza0MF1DtNYK11cFgBDkStPmqjM7UlB89nc8xYtVecZEAak9EUitury93mRY?= =?us-ascii?Q?6xFXnHpnoXYqSd5wfZsYeRQNEJdQVPmIVzigF/uy2E4m2vlF5gT02ogsvZ5a?= =?us-ascii?Q?OjCUJc1Fb1oe3dzHuKA6bq2kkPAG8Tx2SlZ9C0pAuOrMGBshLZsb1sPmNiQX?= =?us-ascii?Q?qYTd0jwSWKHWOLijtLKxWpDACtXLPZYyUTzsIxukBwvEWIGbJt7ycFWKfu4O?= =?us-ascii?Q?8haVm00CFRdSXl5p5qlm6RkmDsSsv0r3T4yuuBxW5RMqtJ8nPULXpeimqUUq?= =?us-ascii?Q?AXVpjLEzkym0v5s0iHmfntLflk9tlNhJpQ/71W5TwtCHnGKdBV95CaVZLOHV?= =?us-ascii?Q?Bu9H0w0Y2VhjXk0QbDsfRwPQ1BVdZ1p3RyYworn/zuJvopPG8JXwOuNwG6nD?= =?us-ascii?Q?WZS6sniA83otjD8a4iyKq4f/0Uv6CLVqhEAEm0+kWri8PIExjxyB8R6Wa9qb?= =?us-ascii?Q?ZOP1NngUt1coAKwmQOcjri18j82Jq0uiU/FF15gmgg/6RCwH2ET1IKklkU/9?= =?us-ascii?Q?HRgMt20T0Ernl/NmX+olEjTyWxIKzreWbYum7KyYb5kI3C9dN+gi6D7jI8fy?= =?us-ascii?Q?DcZJvHJA20Z5dMwV/fY=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1296e94b-a083-4b54-6cf9-08ddeedc263b X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Sep 2025 13:32:26.0123 (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: +YdG2Z9wJsLcOm97NeNGzP0EsYJQ7Sg+4VCbYQF4vWiX9t8lrZw4zZKBGT3790aW X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH1PPFC8B3B7859 On Mon, Sep 08, 2025 at 02:12:00PM +0100, Lorenzo Stoakes wrote: > On Mon, Sep 08, 2025 at 09:51:01AM -0300, Jason Gunthorpe wrote: > > On Mon, Sep 08, 2025 at 12:10:34PM +0100, Lorenzo Stoakes wrote: > > > static int secretmem_mmap_prepare(struct vm_area_desc *desc) > > > { > > > - const unsigned long len = desc->end - desc->start; > > > + const unsigned long len = vma_desc_size(desc); > > > > > > if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0) > > > return -EINVAL; > > > > I wonder if we should have some helper for this shared check too, it > > is a bit tricky with the two flags. Forced-shared checks are pretty > > common. > > Sure can add. > > > > > vma_desc_must_be_shared(desc) ? > > Maybe _could_be_shared()? It is not could, it is must. Perhaps !vma_desc_cowable() Is what many drivers are really trying to assert. Jason