From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.56.23 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1792516600; b=tqvUe2MbKPpkI0mLsd8nhaTUgAfUH5CaI/6yzben/QKoqJhNgYALL7e2dASJz11qPjYP kuheUYCX9g42Ovj9Rc8O0M1GNPsa39azUCaWQ7BBLWgm0UkdO6GNSZrkfsbmlvb6g+D0I 4HO9py4WO/8Kk/PvRZVF2zg8Am8iesP1g0KBhEJjl13HE2P8rsxuXR9Mv/Zyx6nEXsHgg Of9fc2fLUeY6BVwcwfqAnu8AbOv6lbupxqBhHDSVbPHx1QnLcXxzmfoizM72HCYUhjNWj mbOoyobl81i1lMOaWI0T7X8mAxmfjSqcmSBMY3paOJbr4p5+Hq3XN2vkMcFC0AvvceQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792516600; h=DMARC-Filter:DKIM-Signature:Received:Received:Date:From:To:Cc: Subject:Message-ID:References:Content-Type:Content-Disposition: In-Reply-To:X-ClientProxiedBy:MIME-Version:X-MS-PublicTrafficType: X-MS-TrafficTypeDiagnostic:X-MS-Office365-Filtering-Correlation-Id: X-MS-Exchange-SenderADCheck:X-MS-Exchange-AntiSpam-Relay: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-OriginatorOrg: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped; bh=XCHFZnKMWUqLXxhplJfD8uiXCuW0fj33u4JuSgVDdtM=; b=rFLyrsrLgSMTPey5409kRI453iwmcL/SQknrPKvXVsATIelinJba8yhcv3uar98s68/F Y58E9f319S4CEnyGiqU9n0FSEeIlXNtV4Xn5+9gKN+JuNcWZ3xaUdfW/1avtKrUjMl4L5 i72SFDSRvy8YFdfIsSx7zQIZKbJ1h7DJoQZjlqX3esCXxDsT0/6BsH8uzoWWIHoZn6M09 YfIe3Cuzm4RP7i+b24wR9DiO5pPz/KPo7ciNFayf7tAHSEpCCxaAwlpCuDvVWaMylvxZ5 J/s4uyVc8xEzSBICf40u/LHPUEFgh35lMrZ8tKPPiF9Q10wQ1xbGLAm3KDBQQ5eWE1w== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b="hGHA2sN/"; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.56.23 Received: from BN1PR04CU002.outbound.protection.outlook.com (mail-eastus2azon11010023.outbound.protection.outlook.com [52.101.56.23]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (secp384r1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D3E6A606B518; Tue, 20 Oct 2026 17:16:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D3E6A606B518 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, unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b=hGHA2sN/ ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=drnCUHC4cg/iEMs0v1qrAzAQqkI26g8JBonoy+GU91+DMf5z6qoi2buwwKYMFSJp/8i+wKwWJop8MDINZmV9QKPdN1vPuOTjPH0mRd5tJIr8rU3bPZP5gZxn4LF8X23m/4MLsxjNPDGH/l0VntpETr/zfUC0DlO7lR86di1v9PXp6okOidAqlLy2aHUmb5hXndXeDNc4PpVs0vAdwAGg9aidxUAVhw0eAOpy2+1dpymTkiqOuUrygdWUMOcDic6V93DBFm29lvI4F/sUhUh7TJdhPZql/ixRHD2MNjn4XpZBeCgnjXK5p+gMDpvAYEYEW3VpJBOQsDaTSRDn2DfJjQ== 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=XCHFZnKMWUqLXxhplJfD8uiXCuW0fj33u4JuSgVDdtM=; b=UAooco2sJpoIBHskCsSmEjIzGpkl9FyNO4+Ll5a0Pi0R7efO1Fiy2UWQmzuiPAWZR+htouYqlBrlso0PhAEZRalbfJ4HUHe+IT61LrXpBE7jj+uKt90cXbWk2TGeHCdt4EP6Jae7PbUp3JR3tZ/cyPIOxNSpqiCj1l58B6bFRayPlVAxtC4jvTb2yabc/yym3xOj32VpdKMm02+hcRDYqNpbZKd6t7OjbzaKw/q7ldLirlN2+uhBG6jjqAWyfkb4Iyy/+dUpitE9xsOrtJOVHlq3CwONjHjS0rZ+7b4ZaDqtMd3kLmfe48V1yarig1R0bkvX5m5HLm6ZHbBy2Y57uQ== 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=XCHFZnKMWUqLXxhplJfD8uiXCuW0fj33u4JuSgVDdtM=; b=hGHA2sN/8yuZE0S139a8PPcOEk/gldR5p9PKjRwWf0RbxlXI2g7LeboEqFOF9blB/XMWwXQl4di5lrsyIi9PjlxGevpWNMzU/9Hbgz8O/DjpRBc1k7kXdfpRuqSI14k5nk3+6/3ZWWfB2Ld/jPMkGUb44vktq3LeBUdj9a0wqWlMLyUPlhFUYsajpYLuWThYFy8WGAthlrJzeFvEGDyyBbSkdKbPm8Ca9/05dyZLa2YvM23Ha5R0/vTfi46DfK0NAMayCWxzPPh5U7+izf6Ke7/XI+Pg7N3Ir7hjjUfKYmX9ENeZ7dyi1F7kOqkzkepRcn9jzZxkW5Qmee2ubco93Q== Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) by IA1PR12MB8555.namprd12.prod.outlook.com (2603:10b6:208:44f::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.522.19; Tue, 20 Oct 2026 17:16:31 +0000 Received: from PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499]) by PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499%3]) with mapi id 15.21.0546.012; Tue, 20 Oct 2026 17:16:31 +0000 Date: Tue, 20 Oct 2026 20:16:23 +0300 From: Ido Schimmel To: Haishuang Yan Cc: netdev@vger.kernel.org, "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern , William Tu , linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 2/2] erspan: skip the platform specific sub-header of ERSPAN type III Message-ID: <20261020171623.GB3236673@shredder> References: <20261018090236.2487997-1-yanhaishuang@cmss.chinamobile.com> <20261018090236.2487997-3-yanhaishuang@cmss.chinamobile.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261018090236.2487997-3-yanhaishuang@cmss.chinamobile.com> X-ClientProxiedBy: TL2P290CA0010.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:2::8) To PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB7957:EE_|IA1PR12MB8555:EE_ X-MS-Office365-Filtering-Correlation-Id: b296c98b-b6c1-4ac5-a3bf-08df2ecde296 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|23010399003|7416014|1800799024|261009223027099003|10067099003|56012099006|18002099003|22082099003|4143699003|11063799006; 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:PH0PR12MB7957.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(23010399003)(7416014)(1800799024)(261009223027099003)(10067099003)(56012099006)(18002099003)(22082099003)(4143699003)(11063799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Ot3PqJnt64Vfi1ay8fe73VALCOVcjnKH9z2h+MEud6WzE0N4Rsj014znhLqP?= =?us-ascii?Q?YaDAkixt2uN0jH4M8eDR7+SZSG2JGXA5JvKBLjURb4FUanKjge/pyfDmT+ra?= =?us-ascii?Q?6L7bwf9K9ljwe3sUmDfp9HS3AcQtT2ApxmaV345+3U+UydXmkVDf06gEJCYN?= =?us-ascii?Q?0jotswzQJl5O0O8wiypA2y4+GTvi0WDruKP6FQLiPTfT3N52Qb8ko0QMq7RQ?= =?us-ascii?Q?vhSddCy0dKbFrMPzmBZ4F6tySzxSDBmShWc8EMyQlRSPq/BszrtslLPSCEW5?= =?us-ascii?Q?HGkGoPFYNGoLiaIskicHpBjd4pPcgIwfwbXK3fpMoM8t+d+CGaIQo6apIBuT?= =?us-ascii?Q?E3mtAiChQwFjkVZ7QuFag+mGFNDi5bJRWmS9R+A0dzhF/WH6vMvR7RhQmxoS?= =?us-ascii?Q?+/Xm40sPSqdHuZHiPGadwFWat0NhUoxEKNMWOTaDGaCVaWo7POOCU8laPvjy?= =?us-ascii?Q?OWWtqDK8TQgWt4/e03GDMZxWPw3AxvuxnBguu0Fg1iu+PRkKWnBCJ1bno/Ve?= =?us-ascii?Q?Wj6cNAIp43kd+w/eNTBjg1ilJu+FObj6eYOCG9w3RwcuZR5CQnwiZ5jzKVUP?= =?us-ascii?Q?egjYBFgZO5p0abqTKv7TUl2bnHCQsDOZ4Fqe+zVdMLpVVCEQOPmhRbusym1V?= =?us-ascii?Q?ufxXZkptf/XAqTgvvNa11cWStZNRUKvDIQrO8x6e7Kmk1A5GBgG5ZmYzA4Hy?= =?us-ascii?Q?0vnOul5eAUUrMv3o9/I5cTOQVK8vnKrO/JdqwU0UiZavfKqVdjwnZ6zRz26u?= =?us-ascii?Q?TXCQjWOj4I4iyiDsg/86+zNlctYOzSL1ONPguoNItdSkz6HOzibPz9PSaif7?= =?us-ascii?Q?cPkIpakMh1CkeE5UqeiUgnlnWKukihtSowbACxbXwQeQxoxOCQCTlkF8E5bw?= =?us-ascii?Q?PFBqbdu05nozCcsl8wDKZt1F/qsgNkZ+lOUhebbgkfZ6ZnqRgu8QLOGtnH2q?= =?us-ascii?Q?JyxrSd4CCWfKlMyT/WATr9KBy51RfnMGZXWfe3q5sNpqBrkIsl1NOE83XoJE?= =?us-ascii?Q?UjWhoG37pMH2mNT22a8lxnZHi0HqSEAEjaqydOSmRZQ5DsMwPyFuQl//ikCA?= =?us-ascii?Q?KOYetoxkX/cjoJKjJ943hwYV7gcHpLMdK2/DRqchs8CbtKZZpIZti+TEk4oo?= =?us-ascii?Q?ScodBuGCsbMEgptnybvRmmiGeE0i/MyisgA/GYy3tLxhlYWg0gqJ7giG8Oea?= =?us-ascii?Q?xvbItUrLNMTvBuyu9D62+nihIPI9Ry9QgE80DwtU42qm0yXY67pOmrR2qtTr?= =?us-ascii?Q?EjN2wxrr85s5KRSd0edLZFOqwwzyPlrHo7V8dpSeFiUfLwhXgJ96JYQSBfW8?= =?us-ascii?Q?WsTA+vJKJeaA/RpSp78kY+JOtkpeROK9pJeIxcdetyYw6MrnnumjagUwetF+?= =?us-ascii?Q?vKYAT4mJBN03+wrkjVX+GI2umy1O3SudC1LF7zGimn/piAeBWAbDR5YVrgfz?= =?us-ascii?Q?eVcqPpDSAX/YEsF/W3dmM5Pd3cf/O1u7OH5Ljq1HMaljtCgkOFd5pnsLm3kG?= =?us-ascii?Q?rxH1thOWHn2QdkcMEC8Wa4tFsoeeQKKDqNJs71IVs+OEE+S0cJdNpaPVOlKf?= =?us-ascii?Q?ax/NocB4WJ8N17DKWV7jIlx6pLId69hBvY6dq4Ybz9fSbW4ZXCfdCSW91plN?= =?us-ascii?Q?vpw7IHof3KYo9aRrFaqIGsRD4bmA5jVrLmxIIfED9Eau1/uW9P1yLXpQYaka?= =?us-ascii?Q?p0T+jOeR+4tMOaocHTJpnXr1PhHsfoPK8XjIyFRNksUp7dLn?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b296c98b-b6c1-4ac5-a3bf-08df2ecde296 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB7957.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Oct 2026 17:16:31.5731 (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: KdF4/wo9N69PkWjdKpc/yL1Ajz0/K/+jdi5FFnuGa+CEb5vfYhk5PcVtMv06r69zbwPXfmFaldcFE9AhlNCYNw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8555 On Sun, Oct 18, 2026 at 05:02:36PM +0800, Haishuang Yan wrote: > The ERSPAN type III header has an O flag, which tells whether an > optional platform specific sub-header of 8 octets follows it. The > ERSPAN payload starts after that sub-header when the flag is set [1]. > > Linux never sets the flag on transmit, but it ignores it on receive > too. When a peer sends the sub-header, its 8 bytes are passed up as the > start of the mirrored Ethernet frame, so the frame is corrupted. > > Pull the sub-header as well when the O flag is set. The collect_md > metadata still only carries the fixed part of the type III header. > > [1] https://datatracker.ietf.org/doc/html/draft-foschiano-erspan-03 > > Signed-off-by: Haishuang Yan The cover letter says this was tested with hand-built packets. Do you have a device that actually sends the sub-header? If not, then I don't see a reason to add more dead code to this driver which nobody seems to care about given the lack of reviews.