From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BL2PR02CU003.outbound.protection.outlook.com (mail-eastusazon11011068.outbound.protection.outlook.com [52.101.52.68]) (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 9CE5B2D2391; Mon, 20 Oct 2025 13:14:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.52.68 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760966064; cv=fail; b=a0sQb7sq17uX90mfBXBPAuCAQ+n3FYU9CklH5qbNuT65URapt8U/nmTbQZfYWgBai/4xn8EbPq0VmqLMr25GLZrixf2gymdOM1VC2OOmDg1VqfLQwBSeBDmthgaH5EFm5PecYMZu6FCq8LGZEV4HrfazB4NFmR6LYlSyhS0NuTs= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760966064; c=relaxed/simple; bh=kOSuUbY76fkHiubFdTQZ+ya9FcSTnc1Hsx00J1FXeAQ=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=okAdylIhbhFUJT2Q3p7Y4rSPO3pUkd5FMp7q1/vbrvzqi1uFt/oEx2Gg/PglDkKWlKRNupRVe77pkakrJuWxI3tFyskI+5tskfy7feDnx+ZaqAg1RgPAjHn3/b6pnhbRrDvJPH/ztIINg0kQyXlgxGNVZEO+KLqwjrS6mqwMPVA= 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=I9TDiMKW; arc=fail smtp.client-ip=52.101.52.68 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="I9TDiMKW" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MrzpPA5i94EvEyx60neIius7leKRgL5pF8QF3bOo5TB/FU1zJZGUxP4zNHD+Y/7u3wqbZkk79VjyDf1uSVEkf2nT9CzZCE8hspF+BgWcFb7KsKTNDKFCDAK962uh9IBWlozCISS9BF6OVefN58MtXUHz/Hgjk9HJsMoZhghBrQzeORzDXZiKdIhpNeYXrtPWwhE5R4BWvVOTivm0X+lb00U1fOwZDePgNNjESudoyQLr/HnJbhBadUr+F9LodiJcQsEip664tt+UzPrr8v8vgPxPEAol+HSDiSAHWrMolTvhW36E95u9IjX0a2j6W9taDUSYOpRro1IA2yWJWBWS3Q== 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=g/xAhEPdrCK7JzGGZ23ruMt4w7fGstjGlW1v3WB/k4s=; b=Ap5O4/YAq/QqFmvo11OWHzVr7CtneIkGolo40xMEQFx+zPYp8SMoO6ff84Y+CpmqVIPBY8O0j81Ov7wVnIOF16C30ZNwnHo62C4NCR7SoEw0FH2stLNXOA0JqABQLzQ7/dyMRnMhlJaLHSmuZU01FIZvrEr21PKerOnBcmlY0ixRY2XUL+jsBwLrYY+YSCA4qLlndynlzT4fPXBNE/iOe6OQIxaBcH+yaAOT3hIO6OJnSoQCQYqbk+vovFlU+rCAUwWwg0mT618v3CYfzwTU0jO+Q4a+dnh7YNP5pMwO08ukSwUf7jsf0iUwZUksJDYJCr5P877fJBR6/Vi537FxRQ== 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=g/xAhEPdrCK7JzGGZ23ruMt4w7fGstjGlW1v3WB/k4s=; b=I9TDiMKW7HA+TWyHbqwbSfxrSgrHWKtbtznvfCm4jIpPSAyF5tuLlU5+Q7flcPZ695SHyewl/1DFXvWsKAbXScrHXJsSJYCDhWk/E9bf1HblK2Se9MsYxl52CjzZdzBUF/qfWsOoPqcbNBAcfybu3TUys49BsWn8mEnxR1v7Gfy0Bkmrdlmr3+vN6AFvSlSxQd5XEGDVDDsVlNKYvHMKr8Kbf8sjPNOenelxd+cX8CvRaFx91TyyBdJFof2jYy7T1p9orfRE57Gf2fRaHJqPjTYmsFTt9QnMX6btPzlBHbx1o4VTpa2kAPSXYtlbi0sJDMsn4HDiVQ6k3UHFPztTqQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) by MN2PR12MB4334.namprd12.prod.outlook.com (2603:10b6:208:1d1::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9228.17; Mon, 20 Oct 2025 13:14:19 +0000 Received: from MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b]) by MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b%4]) with mapi id 15.20.9228.015; Mon, 20 Oct 2025 13:14:19 +0000 Date: Mon, 20 Oct 2025 10:14:17 -0300 From: Jason Gunthorpe To: Christoph Hellwig Cc: Leon Romanovsky , Alex Williamson , Leon Romanovsky , Andrew Morton , Bjorn Helgaas , Christian =?utf-8?B?S8O2bmln?= , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: Re: [PATCH v5 4/9] PCI/P2PDMA: Export pci_p2pdma_map_type() function Message-ID: <20251020131417.GN316284@nvidia.com> References: <0fa715706e1adf5e26199dc3eaa3b1ff3b14db67.1760368250.git.leon@kernel.org> <20251017121447.GH3901471@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SA9PR13CA0093.namprd13.prod.outlook.com (2603:10b6:806:24::8) To MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR12MB3613:EE_|MN2PR12MB4334:EE_ X-MS-Office365-Filtering-Correlation-Id: 70f5d0ca-0780-4bc8-e865-08de0fda93b8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?b8joZkN0/h9N0cTScTXpGlY+QCxIzckVOo2+SUUfCzclXooinPWxlpPD5y+Q?= =?us-ascii?Q?E/7ayuHiKwr+ke38/IJFK8Iuwc9HASoLkYnSGw0/RR2b6IYpq8sGWq1uucCS?= =?us-ascii?Q?7IFSpGqjGNzpKegd2gm9Z1NLMsjJdn1EVoT/qYf+3GJywLIZI7Hb0KtG8CtK?= =?us-ascii?Q?EulAgrq9kEEpOeAI3uCSmodlBPgVJZ8jgcASaBbVF7+FeDtqU4NQBAsZoSx6?= =?us-ascii?Q?Sv+xER1A0++imaYoSic5PKEy7r9MpxJCL6X4BcrdM+QjRO5xZGhhr+SmepkL?= =?us-ascii?Q?oLejVPK39wzuOTpBtfhtC4GWdg0VjrKZVe2i3XmXuhFMM89kUGbTdBZuLmgg?= =?us-ascii?Q?kaMGahdxrRs1Z1MYZgtpcmpFuD89CcxDA5tZYVO/7cH9w5Pqj3zCtHtBmFuJ?= =?us-ascii?Q?Tk3xNCpUepuHEy/foPy5HiG9qiZGe3DOIfGxkOgcJmUre7ttOqDRLL/U05jC?= =?us-ascii?Q?Qy8uWjjhYTttRlbnGlhHiq1Orp1Kn/9zMj8HnUsNSW4dvxuegdsgL7TN7Hut?= =?us-ascii?Q?SrGdF9QjjoRRZpBZcUqnHTndChbgKKsjhDRGQ+GOVIbv2LW95FjbEOdlT5TE?= =?us-ascii?Q?Zp4pBAQBuPSkzWAugGEphtgHvIQ3I04gzpNB6iz7YfVaypj+kby8e4fS+TY4?= =?us-ascii?Q?dRjWnKB0gusi84OGSWHzxjwLZM6TscsOhnq7F7LGAx4YJU4a5ZX6EhUuCRwK?= =?us-ascii?Q?KEoG8V/YtP/2r655u2eaS2YcfGngmOLnd6AjFhVtzYGy6+vdpqiSBy1x2AaT?= =?us-ascii?Q?lMb5nhLBa01J2QB9K2W+Y//M/t8Tv+qBuiTORmN+NcOyvJAlCKbF3MEdVCPe?= =?us-ascii?Q?VK6CkzUxkIBA20UzLtU/bpYHVIe/4rD9w5cLiFWoCxsoLkaB8dyPJXm+TXgZ?= =?us-ascii?Q?1A1BI/zT65q2xMocseJbdnp7iYI5tpYVR2Vw8vsHCXEULH4GoRwHqAZDwkwd?= =?us-ascii?Q?uiUTyieVDHZv2PyC2wzBQEiCYm+u0+/LGuYdK4a3lCD9S58veoljfM21ZVju?= =?us-ascii?Q?GW0AgnuFLcIgFFE0ThDFXM5tNV7rzGWTxk30cpXmnbvkZpT1xX/gSXGu99yl?= =?us-ascii?Q?3ffOf7PcxTNSb6qWsLU4LDrw04ncDxuCTMAdQ9hz/GpAXBFXt3ounjVBg+e5?= =?us-ascii?Q?hFVEwj6YutYz9U3ylHRCw0z1/WwUF3uIc6P+dRSH0JMslqusS4KuIulHQJr2?= =?us-ascii?Q?3VJbWp2SyjSGiVcaYrOUcOmBd/J0Jt3+GgEDViEFZb94Zdb2nXaXp0Z95qKR?= =?us-ascii?Q?ZRskr0i+jwOTI9XWH+Ly2rbYjlVsc3GROwRvLLTz7gz3WvBylQk86GC0jcHd?= =?us-ascii?Q?FELno61k61GZDTih8xKq3dnb1nQxoDfqk5cuBQtxjhT7BHlbF5BjR97HQTbu?= =?us-ascii?Q?S21LgNt7QROouxx3cpy10uBx912TUXABICySUgwAITtRDZrvA3ZTps/ap5Fp?= =?us-ascii?Q?/4Xp5D2bNdeNg3ohDUZVuVrAVRTeaq6Va0c+QgQuKqWBKicrd0rYIw=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR12MB3613.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?5/FCbxZF3EcF6IVjezMmolqCLTK8l+FzsfT1KSHSMtBbKcAVMXkIj0eewVqD?= =?us-ascii?Q?TuKqv4QVURMbUgnRhjswyaTL1EDdzBq5XYIcQbXyuBYSOBQG76n2Jhe+7zVs?= =?us-ascii?Q?qTJmy6B5hynEUr3WIcLE1oDJuFGIeBg2QCweYLzGAv0+ONg2OBoBdFtAiOoD?= =?us-ascii?Q?SxKy3lZIdxCLUaXhm32fI7rKwWUv1DRycG82SQNAFRDGXgies+fyDl/FPbP2?= =?us-ascii?Q?riyWjuGmdPgGMrUhZ67/5A0zG8sjsia3vIhonnMpIxNuSIy97MYQ294uSNnY?= =?us-ascii?Q?viAgjJc0RMYw8stUHDtf+rp5yashs5GhW3sSql5z7Pe3hvYvODlzNv/nuGvB?= =?us-ascii?Q?koM7doslwd4LjLayTyGiyPF5+ZFWdcN5LjuWp7Tfv490Nbs/alMjv95YWjQj?= =?us-ascii?Q?ISE0/2JstBDXlrZsCixD2RLfEmWzwlsik055Kbt+wEP5SwkWLP+QpSTjEpty?= =?us-ascii?Q?Ssu24jFJkwgFLfKXId8fR1Ms4O/0I/VP/aLcewOXb251LhHfyYq4lkdsw9K3?= =?us-ascii?Q?C2htt4JkbPSjqasKuluNWZ54m7rVeuOtosL+NcrnKYPVYTaKJpV8iEx+Z6Qp?= =?us-ascii?Q?s0+QHYoEyvL184nJVPWyp5yRS6fBBMWtiXW5KT47aIpSIZWL0/ElgZh8kB5q?= =?us-ascii?Q?x9q8iEq25fVtbpOzS4hM2NWNCdTqhqzNLz6QMjAqnCeXZazgoCjkFaKs3J0P?= =?us-ascii?Q?GxlT61CDVi7VE3+rnR0Q/lLjjbt/iv4dP2+uH9nGwFBWXio94ZCY3cryFobZ?= =?us-ascii?Q?ZSGz7oy2oE+B95PUtmfFq9T2/EL+TUSlwkwgkc2Xfg51iMkxxd7UvPbgS/Z5?= =?us-ascii?Q?x1oGKJS7s1fNiJJUEVGj10cxWCWFsUPTJAkjm4xAIIYVq2FuG9eMSq/VjQGd?= =?us-ascii?Q?slaNqbIEg/H4/p5wXqNnhGCmfFxpwyy+BxZBEoEnAEQXJNQPbxbBkHH4oS72?= =?us-ascii?Q?ctEes0Rui37zVQV3d6Sq44Laj/m35uplqDEetwNZvLeEvUU+12TZggjyctJH?= =?us-ascii?Q?oDywnv+Y4+KDsa3KBD0AYluNgZySfwIUz0Ee277UnaIjBp7KrxEQNpQV7+j5?= =?us-ascii?Q?Xaif1cmsqUb4dda15OL996Rq76Pghgu0/VvLK80VuU/Ow9tncnI6uqEge4LG?= =?us-ascii?Q?Ae4pl31CTYkmX+Kzxqo6oMrPGy6mYMMeuyk9wPfGLaDB0+74ahgcKrmgwclI?= =?us-ascii?Q?QDVvt026JIW7Air+tkLA3nMwC3xr2oDbktuOZt1BD7zl3CbaQ1pkhhxcrnVe?= =?us-ascii?Q?YG3AuuLIITdALZfXQwak8hhnHiufAc0q9dqjx8gXSf6sk+R/y7S6NarpFEFv?= =?us-ascii?Q?q6OzmlVVnTJ2ND0Lmrba5ZpWTjMUdaSRbEarHpd5YresbVp0HyZflajkx5Vt?= =?us-ascii?Q?hUyclZetKzcCGiBzOxDd0PPmyhMw+fxC9HsnyuVCtzXedq5TKder6miJeKaX?= =?us-ascii?Q?lctUHx1hDM+NYDNwSvI6fwVKcrtT8cPbk1+WynSwGNNh12NwHkAlcn0W/j3x?= =?us-ascii?Q?UYEVAIpH7PLzIxuVfyupOQjOJTqawc9IaUWiZCiYXpSMfk98sZGg+dNoUOja?= =?us-ascii?Q?DLN39+Kkytck41uWAINLYPpYHF2n6ADRaSXTkxEJ?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 70f5d0ca-0780-4bc8-e865-08de0fda93b8 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3613.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Oct 2025 13:14:19.2031 (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: V9sVEPkJmgkdE09DNOGndubxcCIH7wcoFoZoRf01i6x4VsEMvvKi6RXUISyr/NGs X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4334 On Mon, Oct 20, 2025 at 05:29:06AM -0700, Christoph Hellwig wrote: > On Fri, Oct 17, 2025 at 09:14:47AM -0300, Jason Gunthorpe wrote: > > On Thu, Oct 16, 2025 at 11:31:53PM -0700, Christoph Hellwig wrote: > > > > > > Nacked-by: Christoph Hellwig > > > > > > As explained to you multiple times, pci_p2pdma_map_type is a low-level > > > helper that absolutely MUST be wrapper in proper accessors. > > > > You never responded to the discussion: > > > > https://lore.kernel.org/all/20250727190252.GF7551@nvidia.com/ > > > > What is the plan here? Is the new DMA API unusable by modules? That > > seems a little challenging. > > Yes. These are only intended to be wrapped by subsystems. Sure, but many subsystems are fully modular too.. RDMA for example. Well, lets see what comes in the future.. > Yes, that sounds much better. And dmabuf in general could use some > deduplicating of their dma mapping patterns (and eventual fixing). Yes, it certainly could, but I wanted to tackle this later.. I think adding some 'dmabuf create a map for this list of phys on this provider' is a good simplifed primitive. Simple drivers like VFIO that only want to expose MMIO can just call it directly. Once this is settled I want to have RDMA wrap some of its MMIO VMAs in DMABUF as well, so I can see at least two users of the helper. Jason