From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CO1PR03CU002.outbound.protection.outlook.com (mail-westus2azon11010064.outbound.protection.outlook.com [52.101.46.64]) (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 C3574407593; Tue, 24 Mar 2026 18:49:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.46.64 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774378194; cv=fail; b=P8LbvOH1CB/DtOkLgED8DoVRC9drpbC6aHL6/YdNZ3AHy9SYz4n+VgtFMGR6ZGYZ2kIJc8GCC17pROdyOw0bQfv8qQ0sky32iUUnG7yXhPTL5gA87ZvXktCF/aDb1l6MDtChfUkTZH9+/OSkKYGdA9/ZEI2SIGPYeeZm1Zuzq5o= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774378194; c=relaxed/simple; bh=v+ocEoyVHuGLPqu+qAxkQDW892fcIZyVTWZTQtvq8Z0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=oRYPeEDPM2m1H/4l7drT8uWrDudEnCriaYldK+rVpmKk/A/YLR0wwUDZM287v6fPAxqMamV6p7kW6aN6+VES5sSPu2Mcq1tHfWRLdSuUQDNgL9cwsTG/7/xwPBoxxtSdBwqSUusKmwBt+FnQ/MQRp9h40Mus+kBVp7zNIAZqMrw= 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=tXADJqMj; arc=fail smtp.client-ip=52.101.46.64 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="tXADJqMj" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=K0Prr5KAE5rncM50+aejTUhbvgTIWsOd6xAq8RH8hHDr2+qa+Qkkpp/D7HUVcUJPO4rdN3p1WSxq3MDjbuKmFjCXAzpv5bt4ry11CCr1ThPt+n0MNGz4PGLHi3vKddx1DEWkgZkN4qvDt4flHz/2NwpM+rA7Xn9F2+KN9FBcNr+hwab9zwV9sqy2URdkpFfWMyrpymYlnInyC63xBR5xbfnu45ZJWoRh5C1d/So+piX5sj0vWEWX850avVCyElkSI6fe0UdE2Svn7eN8nsAbfVlxwVtLw+1lu3b9HFTGQ672nOosXiCBgLvsbaBdm6gESjDs9XRUh5Ujba6Rt2qOew== 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=1bziRk3oAwbtzaxlygyg/dc4uD+31PiC3dcYC46IltA=; b=EImrWnkKsO62/N3LfqJLs8OKnOLY9eCiHe9wwh4kb0J2JYX52NVODiWHl1p5CVuuNGeKiqqFPBOrEVCEPNtC8/i4uCuwme5AL7EeUZSS1WacVH+0Ch3WsOdn7G4d0sUv+bHn33Cmc+mGAUE+qaFu7ReuiEs2pGU6RxmQbN/Aezc/WRnn0CUERXTVuV4YkeopE6aFrW3uw0nsLhAPKWsZ4j1IOiHsNU5HXrtIfZrw153c3yzNwNmF9qTfxRYoIDzzSxCM2cjyiqg6KbUQdRgP8f/J/7024eNTrvpNfO2ShAPhD5UC9MfQFW9Oqszxs+e1hft9Rk/7QxAlmlUwKWGrnQ== 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=1bziRk3oAwbtzaxlygyg/dc4uD+31PiC3dcYC46IltA=; b=tXADJqMj3S58oaSaTotmqMv/JuDtkEq76wF/XSk8w1bRmkS+L94AvykfJ2rnyoJorVYMxd3Q5I4YTQ7OT/M7RRXcB4Y1yobj9IXjUwGZu/Y3u0UqU8Op3/LnBWBel4ZLV+8etnHS1xOtIj1X2fhwrm/QCPM4+TbstL9dh8/PEkk1nlMdPhHWGw8zwPOHJzcByg5eJ3CQs5BQwycxnQS8xCsDajKeESUbVpg7cCytbADwWV7/SjwddDoObZ05f6GHH9dpUTuV9mREqLKK7UgDUH3xyiWKs4cGPLCqjspIjalGfPkFRwnM7bOjf1b56ktLj6PeZxKVjNN90B8kftVZXQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB8202.namprd12.prod.outlook.com (2603:10b6:8:e1::13) by DS7PR12MB9526.namprd12.prod.outlook.com (2603:10b6:8:251::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.16; Tue, 24 Mar 2026 18:49:47 +0000 Received: from DS7PR12MB8202.namprd12.prod.outlook.com ([fe80::38fd:4146:aea:639e]) by DS7PR12MB8202.namprd12.prod.outlook.com ([fe80::38fd:4146:aea:639e%6]) with mapi id 15.20.9745.019; Tue, 24 Mar 2026 18:49:46 +0000 From: Andy Roulin To: netdev@vger.kernel.org Cc: bridge@lists.linux.dev, Nikolay Aleksandrov , Ido Schimmel , Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Petr Machata , linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Roulin Subject: [PATCH net-next 2/3] docs: net: bridge: document stp_mode attribute Date: Tue, 24 Mar 2026 11:49:41 -0700 Message-ID: <20260324184942.2828691-3-aroulin@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260324184942.2828691-1-aroulin@nvidia.com> References: <20260324184942.2828691-1-aroulin@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: SJ0PR03CA0386.namprd03.prod.outlook.com (2603:10b6:a03:3a1::31) To DS7PR12MB8202.namprd12.prod.outlook.com (2603:10b6:8:e1::13) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB8202:EE_|DS7PR12MB9526:EE_ X-MS-Office365-Filtering-Correlation-Id: 1686104c-e468-4e37-484e-08de89d61ec3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|1800799024|376014|366016|18002099003|56012099003|22082099003; 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:DS7PR12MB8202.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(1800799024)(376014)(366016)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?7pUAE4XZvsXvwaUZRG3FDq1dEW5xsfJeEa/4Dm/XsMY6a8HF+nIUWmDN/7A9?= =?us-ascii?Q?tEq9tipAFvQACWYAgNEPc2Y026ysmndOYRtPlLGEA8WXixjvKcKz69BY6itr?= =?us-ascii?Q?HTuW2KDqtKzKLuk71R6LJ078NYSa54kxn7Ps5/T9ZAhbbWfGAW1oUhH5mUHC?= =?us-ascii?Q?RLL6tjgjTchUvWgT+P9wkWbDwqPl9xg0Su4tTQzgX7y11THRcgQ0GxPXj1KA?= =?us-ascii?Q?1RtyQrHrHatowta4XSuJcn9x+0I9lnclxr15Z52/AiXyWaVxOF0/jBfTEL8u?= =?us-ascii?Q?lIUul1uM7nTjMR5KKgbeIz67yJ4JSua/jqftnkTEu662DaZrX2VXQBFJK4p8?= =?us-ascii?Q?fIgjoZM62OwDzyk5pGL6pFo0v3AdYsjNnXdVi9PFkoARCCcGpZ9skDJSyj2Q?= =?us-ascii?Q?LfacK9KTXFXeOTm/JpU6swBrqDKNpFZX5SbMWhhMlZoH9sBtC/ELFjyH2mFu?= =?us-ascii?Q?g8fZwbfnT/O8ty1ws42Me6HEgbG8pDCPlDb5YeXTsuDZ9zoNU70ebjj3reP/?= =?us-ascii?Q?dXhJ3+FZwFdr6bjU3ZhFK6rk6cWa5FJ+WZcYK4HWWLf6Ym21TNwNcBh3v8yd?= =?us-ascii?Q?cm+qAT+Hmv2O5yT53lSoWoDO6hpRM7KeA1VJkwokaiLyFhYWE5Fuy7MLL5Dk?= =?us-ascii?Q?GWlMrKNmI7vxyo9brYMqiKFHyicArvvJJBObbM7gvuOmuYwy5mmCu7Fwb5xi?= =?us-ascii?Q?w0BydvrKqv3U5wMxk/8hWNAg3wxkeQEIHDgG+EEu6jLThEBgMAhsm5meeJUj?= =?us-ascii?Q?26Ab4yaqLiWMrKd5Vh/PNZzrrQkC1MMkVRqeA1GyrSILLtZ7rOA64Dkyk3/C?= =?us-ascii?Q?UCeziODYcsarMZkQGdEL+R8P7jMUgbDWkO5B8mf3p6rHuw1wWmwGbD41RNaL?= =?us-ascii?Q?hrU2ffA6jaUmUngwdycs93N+z4xG69KCQlr44BTwqR6smWyDxkvnF9NmjbII?= =?us-ascii?Q?jlm/O+3Tq69f0KN6P3mmwgJ5hMRpW0/ExonCjM5sdoG47Y9fwAWMO8D0plWV?= =?us-ascii?Q?kBHXVf+TDzTjOikE6SmzBT5+YGH07c5tAceIFLJymZMYwRjSdsiM/pHjCLDO?= =?us-ascii?Q?csTc5vd314D/sJBPLFla869MIXZXsbYXDNsA38G0bEk97MRBI22G1A74rDlp?= =?us-ascii?Q?jjebGgypZ98zqe2nuGTc7CoX0w42kQN7DDVkfOVoTr/3jiiyt6Fbh9hYDcY+?= =?us-ascii?Q?27I+w1NGUOKOA1H9uZZZoWrKbiJ7pD/zzfw6nudQoaaAmSuQ+mVxcNszSfwS?= =?us-ascii?Q?uQ7piabutCRwyWO5ZtQLIS3zm8tLQuDeCFW+EnboREtz2G3CLyK6amNCkz+Y?= =?us-ascii?Q?Z5ZGtiVDgdToxSw06609F/3MA1im9idyvKJQld/o4pGpOjVot3PUd/v2gOvO?= =?us-ascii?Q?8wrpQwZMh+er9frxdq26Zy23dI+qqRmABbjz6yc4eSpf0y5TR/YV7GSfXaX3?= =?us-ascii?Q?U1GCDFsaDZaH1R8CeQhvd5M/zPdumwX19NrXEuZdaRYFaN+ObUFfiEQgurJy?= =?us-ascii?Q?/oIfe5XeqiPxCH9rpP/dIcB+mg47nB4YLNAjzpws7lrLypKnJfF9lHfqEWs/?= =?us-ascii?Q?EYaRJM17JAu3LJkRCRDXy45oCHGKkyJtcWlWbzK3aXoA7Vz4eckJXL3b5lW1?= =?us-ascii?Q?Lf7X4WNu2G56AExUSgCUzQ6HibJaWQeaew3g/uFaboViWbVD6CizK91jLO6b?= =?us-ascii?Q?h/Ur5/WEZBNfItpv8CmvhShosm142rtquTE77EZE8QTV/A0arkWE9TYbfYDJ?= =?us-ascii?Q?WDd17xpxxA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1686104c-e468-4e37-484e-08de89d61ec3 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB8202.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Mar 2026 18:49:46.7169 (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: IhU8lJjyIKzAETuRlPFdvdFMBcWrOFKcfOw7dVr/JgtcAq7KBQd1Tj0fRuB4/6U93h53bPgG2FC/8VqqiNWNIQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB9526 Add documentation for the IFLA_BR_STP_MODE bridge attribute in the "User space STP helper" section of the bridge documentation. Reference the BR_STP_MODE_* values via kernel-doc and describe the use case for network namespace environments. Reviewed-by: Ido Schimmel Signed-off-by: Andy Roulin --- Documentation/networking/bridge.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst index ef8b73e157b26..c1e6ea52c9e59 100644 --- a/Documentation/networking/bridge.rst +++ b/Documentation/networking/bridge.rst @@ -148,6 +148,28 @@ called by the kernel when STP is enabled/disabled on a bridge stp_state <0|1>``). The kernel enables user_stp mode if that command returns 0, or enables kernel_stp mode if that command returns any other value. +STP mode selection +------------------ + +The ``IFLA_BR_STP_MODE`` bridge attribute allows explicit control over how +STP operates when enabled, bypassing the ``/sbin/bridge-stp`` helper +entirely for the ``user`` and ``kernel`` modes. + +.. kernel-doc:: include/uapi/linux/if_link.h + :doc: Bridge STP mode values + +The default mode is ``BR_STP_MODE_AUTO``, which preserves the traditional +behavior of invoking the ``/sbin/bridge-stp`` helper. The ``user`` and +``kernel`` modes are particularly useful in network namespace environments +where the helper mechanism is not available, as ``call_usermodehelper()`` +is restricted to the initial network namespace. + +Example:: + + ip link set dev br0 type bridge stp_mode user stp_state 1 + +The mode can only be changed while STP is disabled. + VLAN ==== -- 2.43.0