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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 381CCC5AE59 for ; Tue, 3 Jun 2025 10:42:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 07EE010E19B; Tue, 3 Jun 2025 10:42:46 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=amd.com header.i=@amd.com header.b="cQQpPzrf"; dkim-atps=neutral Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2066.outbound.protection.outlook.com [40.107.243.66]) by gabe.freedesktop.org (Postfix) with ESMTPS id 78C5210E19B for ; Tue, 3 Jun 2025 10:42:39 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=QOYuCfo2fSx45oBHmg8SPwCLQ9/S0pMGq/y71kBnFL/1a1anLTjWnHM8jP6P9gdjk2wROilvQ8B/rRL8crEJPQwXCBmCOK6XupyL4sG+3FnqH1R6+FSi4+Tjrk6aw+9z/sZsiQ13IL8Pd/lwqb6kpL2Vt+f4qFSvXd2bWsTcwpiIPwBZ+LNF7GWW2CVx6XwDQiEH/UipofT8IUro3v3kRBPb6ofjoSW9aQ4o8TDoWJuYgUmcDGf2m5PolzMUVFCLo7J3qe/m6Wo8S4/OExD+VDnQlA2myS4d1vSvGk+MWmt+hbSPcyub4Z0WKiy6aN80L4E3P2vuWwkW00OHJ8SbrA== 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=m8tyd3y/5UeOKysL/tMZuJCliFYoGRCphFtDLv37FzE=; b=yifeOnMgVC/wj9Kn9AUyC+d05br07kqlrKq3woKUbhmJFA0cNVRIjk08LxQrLkiOHfptxcfIhy0OqLGShgoqP/3QCEaJ4rwjjmGfb7geHM9p+BY8jNtLMC6squ+uaGuuKlt2S+H9JxY3WgApW2m0jPsWV5+phko92fBz2h7WdsxAbb2+oLL8V76BVJKwyBgmMGV6jLzxrqh98VkSVGAZ+J9u31ujeD80hZY8VXjPXCtm49bhv64hWw+bmSr+qKvjwE0tJlGKr170kcPXNw0+ncEsKxsEJPza88Z59LOi5+gXIxDPF9rECAbYZqKHpGMLAVBBomwp8DSEfXPgsO+suA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=m8tyd3y/5UeOKysL/tMZuJCliFYoGRCphFtDLv37FzE=; b=cQQpPzrfMSuH/TfZ1M+uPOH0KhBWlAiyBp6qKjfA5+2N/TGa58iBLfBfKKHZVrBhSn71FQFADV+/WbiJVcOQJyZfTZ1xBQ1osYk5r8AZiYwPcaqaPBl4XsYenRzRMDxXBbD+oY81rKrF7Au2Y+nGW7k9CxsPauKJoXQfCYpFzC8= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) by PH0PR12MB7863.namprd12.prod.outlook.com (2603:10b6:510:28b::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8769.29; Tue, 3 Jun 2025 10:42:35 +0000 Received: from PH7PR12MB5685.namprd12.prod.outlook.com ([fe80::46fb:96f2:7667:7ca5]) by PH7PR12MB5685.namprd12.prod.outlook.com ([fe80::46fb:96f2:7667:7ca5%7]) with mapi id 15.20.8722.031; Tue, 3 Jun 2025 10:42:35 +0000 Message-ID: Date: Tue, 3 Jun 2025 12:42:26 +0200 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/4] dmabuf: Implement copy_file_range callback for dmabuf direct I/O prep To: wangtao , sumit.semwal@linaro.org, kraxel@redhat.com, vivek.kasireddy@intel.com, viro@zeniv.linux.org.uk, brauner@kernel.org, hughd@google.com, akpm@linux-foundation.org, amir73il@gmail.com Cc: benjamin.gaignard@collabora.com, Brian.Starkey@arm.com, jstultz@google.com, tjmercier@google.com, jack@suse.cz, baolin.wang@linux.alibaba.com, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, bintian.wang@honor.com, yipengxiang@honor.com, liulu.liu@honor.com, feng.han@honor.com References: <20250603095245.17478-1-tao.wangtao@honor.com> <20250603095245.17478-3-tao.wangtao@honor.com> Content-Language: en-US From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: <20250603095245.17478-3-tao.wangtao@honor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: FR2P281CA0032.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:14::19) To PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5685:EE_|PH0PR12MB7863:EE_ X-MS-Office365-Filtering-Correlation-Id: eee55a24-341f-458c-6d70-08dda28b59eb X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; ARA:13230040|366016|7416014|376014|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?NGxXUjRrTk9TM0pISnFiRlkySnhHZXNpRjJkc3NISWExaW14ekpsVU12Y0Fu?= =?utf-8?B?T1BlY3VKNEZwTjUyY1JHQjlCdS8vUllCVkpCZmp3OWJ3akZmSXVQVW8yM0FQ?= =?utf-8?B?c0o5cDUwcUFFYWxVNUFiNXBvY0E1OHZaejlJWWZBNllsYVJTRUltTnU5cFhG?= =?utf-8?B?VllUM1R1M25rWi8xeE5oUmd2NVhYWjFiOFBLQ3MrUm5PcDdmZldTek1ZMnN4?= =?utf-8?B?MmF2L0hVRkRuMEJ6MWpWY3ptN0xuYTlTVDJqUjI2NTZub2ZiNFFtYkozajlS?= =?utf-8?B?NEpIaCtiZWJ0elRSeUMwNzYwQUJKWExCNFVURG1xRjM0NENwOWZsQTZQalg2?= =?utf-8?B?eTFUNE9qU29yUUcxN0RYSXpFNk51MG9yOENSN0ROUi9PWWQ5Z2VsVUNXYWt4?= =?utf-8?B?Wjd4c200T2czMDhNL1hSVVlia0F6NVJMYjNiRWZxbWFObTF2emVrSk1EYXlS?= =?utf-8?B?c3dZQ1ZTTlJGTUtTZnR1cHptSjV4dUhCc0pwSHVNcjVOb21id2Vacm5abVoz?= =?utf-8?B?Z3loekh3K1lpcjFuTThSQmE2clBRWEt2Vy9YWlQ2L3ArWkU5d252NkJjZjla?= =?utf-8?B?aGtrMWRjS3pHVVNkMmpqR2R5QW1vcndVK01MZHA3TGNzQUduM3E3K3BMRXNM?= =?utf-8?B?anJHbHplK1g1dWhDdHd2eTVvSEhiVUVKNFdFem05NU5PUzRLNGF2ZWdrcHdP?= =?utf-8?B?SzY1QWljRDJVUEtrdEM5VUh6UDZlSGo0OUR6ZzMyK3JvRjB1NnVpL2wwdzR1?= =?utf-8?B?SVBaRWRyR2hndWU2eTRKdkdwK3hEdm5RQllLbmc4eDJsSGFqdzl5azlSRzJ4?= =?utf-8?B?bzNkbnNhR2tZSUQ3NGNrQXdVcy9TVmRzTjRaby8zR1lCUks5TTV6ZjNpQWRL?= =?utf-8?B?bUZTQVNVVHcraC9QSUU0TCtZVkF6M3p5L1NxQkhBR2pDSm84ZFJHbTJ1UjBP?= =?utf-8?B?WG1QWjRsbGhKSHBhdDllQ3N3N0lpL3BwVVZmSDlFbFdPZjdOQ0Q0dHZ6dG1z?= =?utf-8?B?dGc1U3hvZi81amdDZXFxS29qYTRRdFJhamd4NUNHY0FROXV0TGpiOU1CZzZw?= =?utf-8?B?a2h2VWhqdkNsRGV3WndSYWFSUHE5NzhHdWlvZFJrUjdRS1FKNjdxOVNaZVVZ?= =?utf-8?B?dmJpU2dqZnZUelliMlVjRjk1bVloVVYrUThwQmJ4VWtmdlR1QnYyK200bkFN?= =?utf-8?B?VnlLc3VmcGxNYmVBaEZrQmVCRERUVDZvbytNV0s2RFVtM0crRzBCdGtCczJ2?= =?utf-8?B?QjN0RkR2Znhlcnl1MTQyb0lmNFlLVU5PMEVTeWtHcmxKWVlhOVNIOWkwdXBn?= =?utf-8?B?TVVJTmVwVFlFenpDL04zYTRCL0FWQ1FYbGU2eFk1SkF1dUFrM1VNSWExZHBm?= =?utf-8?B?OWxpSVhLUSs1QjNIbHhCdDByWGg5TUV0NTlxSEZiUjFSOXFIS2gzVHNFVFZI?= =?utf-8?B?bThGZnl2ZkZjUzJQQTB3MVFFeDJIcmExVlViUnFob0RSYnVPTzJpMFFESzFJ?= =?utf-8?B?NG5GUFdDNkRJOWpaWlpCY1ZndmtWZ0E1UkRqNTFJQzJESFZIQzN5UzdQUVZT?= =?utf-8?B?MXFaaVlvOXFGZnNpZU5xNDhlbXg3Z0djK0RiQ1VuY0gvQWpIeVUyaXcvcGgw?= =?utf-8?B?cU9nTjVnWEtHRUtRR01HbTFtUzgxT01hdGdhR2ZxbVZ4UzVHQ0V6bzNZQXJp?= =?utf-8?B?ZEpkQytHUXJCeVJZQUpwK0NiQ2hvWWZ0Y04xaXd3QW9PNGlMSXNFZ3l2UUZw?= =?utf-8?B?cythUlUyaGpnNnRtaVhVQ2FuZWtRNmF4SE1hR3B1STUxellvK1dtZElxdWg5?= =?utf-8?B?Y2o3NzU2OHJid0RQOXRYY2wyTWROZ1dwaGdhSzFudURXTExDZGhURjdVYlNF?= =?utf-8?B?bmNzTUQvc3RLT2owOFpPMGtyRDFaTkJQeFpIMER5Y3Y0Z2VkOHVHY2Vacll4?= =?utf-8?Q?zVtyxkbP/E8=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:PH7PR12MB5685.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230040)(366016)(7416014)(376014)(1800799024)(7053199007); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?dlBjVG5nUlY1QWEybm9JdTY1QnlFTm43MlhXV0JHaUtJcWFoV2F5WWZHUEZS?= =?utf-8?B?VlNpYTRxeUhsODVpdS9lWklKQkpzN1YzcUY0VDZhTnRkMnJtRnMyaUtSR3pX?= =?utf-8?B?SzFERDNvRVFvb1A0U2hLZlZGdkc2NHkzZGFwelRxSEtQd1pGWnhQNFE1cnRa?= =?utf-8?B?ZmdNa2x5dkwzUmpyaFlZaFFZK1NwdWJ0USsrdGFVZ3I4RjcwZDRxNXk0K0tj?= =?utf-8?B?aWgydEVkbzd2elFaUFNyZVlkdnp6QUxueWNieHBLQ3o1N3V1WjR0WTJPL3dZ?= =?utf-8?B?Z09kVlRxVitFSmIrMkx6WDlHalZlbXFqclpCMko0ZTA1aU1aWlBMWlprQmR4?= =?utf-8?B?TmV6TVZLRmoxWS8vYmhVMkk0Zi9NZlBHREJjYW1ob3RRaTAzcEhzOXBGL21z?= =?utf-8?B?bHZBTkk4RXF3UTRoRE5VZ1pvNEs2VHlQUGhMbHFYbTUvNjlGWTBGVTJPa3Qv?= =?utf-8?B?RU9iMlFrYnJLWklyMFY1em5SV2szN2kzSVY1TlZsZDl5RmJnbkx3VER4ZjJY?= =?utf-8?B?b05ITmVrRHR0L3dhZTlsUVJ1ZHcwK1FaT0FJSjJuTkpmTW5ZRUNTNzZGMWJH?= =?utf-8?B?bmVibEJGTDM5MjZpdm1MUWlhQXNseFdodUtXV3FYd2szcHlXdk54ZVpkeitj?= =?utf-8?B?UkFRRjNVdHd3U29WUXRFNitIMVZoN3ZGczBUQW5BamJ0VlNWbUdaOUgyY28w?= =?utf-8?B?QTlHQTQ1ZThJYUIxNEJnMFpYa2c0NDhvUWcvWFRLZzVoSzhzMXBFenQ5VUoz?= =?utf-8?B?ZTNPbE1PeUJJak1scVpYVndsTVZZaFA5bHRsRGhGSmplM0lhcVF5Z2U2Tmw1?= =?utf-8?B?VFB2RTlKSzhkeE9LS290Z21HV3U4VUdITkIzMFlHMXZqaWdodUZsRmlGUWR6?= =?utf-8?B?QzBlWDR2VEhRSjVmQWxWb3BCYkZkOVZ3QU5MbTArM3RoblZWRGpQeDBnUHVZ?= =?utf-8?B?SVQvZDNmRCs0dFY2VEtydThaL1Q2dW5PZnB5WWRnK3dKczQvRitOeVVEWUtw?= =?utf-8?B?YlpHRUxNMXZqNXZROG5vbmkrYVpuT0pvTDVlYk1MS0FxR1RIVlZ0d0lpdlJx?= =?utf-8?B?Y0pXUzlFQ2lsYXY3Ulh0MEo3ZG84aXJabGY2eEdHaUZjc2llclJrUUNPeFgz?= =?utf-8?B?eTNSaHBmc3Z4YnpxQ0ZpaE9qY0piWFNqZExzUUovMVFYYmFDcFNQTnBYY1dD?= =?utf-8?B?TVBHeVd2Q3ZlWGwvZCtNR3ZTVlY5ekdKQ0lkekQ1QlRDZ3cyMDlPQ2pHRG9P?= =?utf-8?B?ZHNwOEhjTjd2NDRiTURNMVlkVlE5ZXdyS2docmJYNnlrbkZ0SExTNEtJaGRK?= =?utf-8?B?UDI4aTQzUXZseEtqeWRoVG91M3VOM2ZVZUVIZVQ0THJRN1FQU3AyM09rTGRw?= =?utf-8?B?b3VRSkJyUnJaWktnc252YStFa0laTXhKTGNJMWNWOC9OR0xGMjAvNmdERHVT?= =?utf-8?B?dDNZMzgyaVpzRXJDTWR6VjllRWVZNEluS2V1aW5yTkFESmFjMzhXbzR1eG1S?= =?utf-8?B?ZDBmbjhvZ2Y2ZGlJTWxoeW53ODVXTzJRbCtaNEJQdll3RDFIdUFJR1BQWnVi?= =?utf-8?B?dVpJUEtBVVVCaVpvelE2ei9pY0RnYys4MS9DeUR2cTM2eEdEMk05azZoeGZt?= =?utf-8?B?NHJSSUc2cWRUaFFOVjFtM1RnMkdoSTlGcUFxUGJGUGIyL1RObnlJTllRWncv?= =?utf-8?B?NlVQTGRaZVU1KytaRXhoZGY5VDM0dTAzU0M1MlNFZ1p4NS9PaTRyUlhUcXV1?= =?utf-8?B?ZitiU2ZWamZoNXU0MmFBNC8yVUhvd0RXOWwwRDlCMnJaZWlhLzBZdGhFbC9w?= =?utf-8?B?WU1zOEhJZG96Und0QXo3VjFYNmRNdnVJR2oveHM1em1KaXFYNEF0Q0hTZ3Bk?= =?utf-8?B?clBIREhKN252ZTFDQUtzNHJwSnRRZjNEZlFtYi9OcVJEWEdMWGhDUkhSUWpP?= =?utf-8?B?WDNpZWdZSU95aS9EMVhhWGhPZ0xiUDhUMEkyRWdaVlNwd1ErTFhTZzFEejFl?= =?utf-8?B?ZXdTTEcwUjFuMExmOGM2RUcyeXRDVTlkSEgrbUZCK2g3azNjdW16UVU1by9l?= =?utf-8?B?ZUlIN3FyRnpkS2YxQ1ltR25adkJydnRnZ3BBcWQrZE81WDFNTGRCb3J5bU44?= =?utf-8?Q?c1BOZkvIEs880Nn6eKDrR6dPn?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: eee55a24-341f-458c-6d70-08dda28b59eb X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5685.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Jun 2025 10:42:35.1066 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: +24txkdycrIt8FJrCmtdPOj9jjG5rNw8iIm6u+Z1YMmMhyn5ep3tP8c2YCMGs1UP X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB7863 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 6/3/25 11:52, wangtao wrote: > First determine if dmabuf reads from or writes to the file. > Then call exporter's rw_file callback function. > > Signed-off-by: wangtao > --- > drivers/dma-buf/dma-buf.c | 32 ++++++++++++++++++++++++++++++++ > include/linux/dma-buf.h | 16 ++++++++++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 5baa83b85515..fc9bf54c921a 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -523,7 +523,38 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) > spin_unlock(&dmabuf->name_lock); > } > > +static ssize_t dma_buf_rw_file(struct dma_buf *dmabuf, loff_t my_pos, > + struct file *file, loff_t pos, size_t count, bool is_write) > +{ > + if (!dmabuf->ops->rw_file) > + return -EINVAL; > + > + if (my_pos >= dmabuf->size) > + count = 0; > + else > + count = min_t(size_t, count, dmabuf->size - my_pos); > + if (!count) > + return 0; > + > + return dmabuf->ops->rw_file(dmabuf, my_pos, file, pos, count, is_write); > +} > + > +static ssize_t dma_buf_copy_file_range(struct file *file_in, loff_t pos_in, > + struct file *file_out, loff_t pos_out, > + size_t count, unsigned int flags) > +{ > + if (is_dma_buf_file(file_in) && file_out->f_op->write_iter) > + return dma_buf_rw_file(file_in->private_data, pos_in, > + file_out, pos_out, count, true); > + else if (is_dma_buf_file(file_out) && file_in->f_op->read_iter) > + return dma_buf_rw_file(file_out->private_data, pos_out, > + file_in, pos_in, count, false); > + else > + return -EINVAL; > +} > + > static const struct file_operations dma_buf_fops = { > + .fop_flags = FOP_MEMORY_FILE, > .release = dma_buf_file_release, > .mmap = dma_buf_mmap_internal, > .llseek = dma_buf_llseek, > @@ -531,6 +562,7 @@ static const struct file_operations dma_buf_fops = { > .unlocked_ioctl = dma_buf_ioctl, > .compat_ioctl = compat_ptr_ioctl, > .show_fdinfo = dma_buf_show_fdinfo, > + .copy_file_range = dma_buf_copy_file_range, > }; > > /* > diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h > index 36216d28d8bd..d3636e985399 100644 > --- a/include/linux/dma-buf.h > +++ b/include/linux/dma-buf.h > @@ -22,6 +22,7 @@ > #include > #include > #include > +#include > > struct device; > struct dma_buf; > @@ -285,6 +286,21 @@ struct dma_buf_ops { > > int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map); > void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map); > + > + /** > + * @rw_file: > + * > + * If an Exporter needs to support Direct I/O file operations, it can > + * implement this optional callback. The exporter must verify that no > + * other objects hold the sg_table, ensure exclusive access to the > + * dmabuf's sg_table, and only then proceed with the I/O operation. Explain why and not what. E.g. something like "Allows direct I/O between this DMA-buf and the file". Completely drop mentioning the sg_table, that is irrelevant. Exclusive access depends on how the exporter implements the whole thing. Regards, Christian. > + * > + * Returns: > + * > + * 0 on success or a negative error code on failure. > + */ > + ssize_t (*rw_file)(struct dma_buf *dmabuf, loff_t my_pos, > + struct file *file, loff_t pos, size_t count, bool is_write); > }; > > /**