From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 0F508625; Tue, 27 Jan 2026 20:03:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769544220; cv=fail; b=VaoFvCZ4Mg7J7DC29oDKhYKYy4Wts3deVFxMwU76+IQNIPxwml3rv5UN+FGjhgZgR+Ate+NjuHC8YtDfCKz6XRqQYR1+HVzStUiMqpiflosMz474yqgEytMSYflZXNwPMNtCpLpT1Q+7aEjHf9GuZyq+rhDHE4PKRaZuRKx9X+c= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769544220; c=relaxed/simple; bh=DTeZopToOez4URvHaO48uEgYcY6cknrsnnOAhu2q6yg=; h=Date:From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=oMJ80riyG7yKtwDXYf5h8KPhzgcc1nqcuYn9h35nIsX6SoNbixjMy7rg18X50fZqykVvU7XnUJZ25RxNo8lsvgSMTIEHxgIl/EkEaJMGo09xNPBiF6ECLhcghYQrdO1lJVQWPvpQy6PVe/efkZ0Stf3/NIoQbFshPu0MWH+MuzU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=O52S8ndk; arc=fail smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="O52S8ndk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1769544217; x=1801080217; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=DTeZopToOez4URvHaO48uEgYcY6cknrsnnOAhu2q6yg=; b=O52S8ndkurWTiB4ghJqx4VnbhIWrKTMFiSMHYiVxeCQzEmJBI9Grzk8u ujBJJUAVDu7mSTcI1oItoUqo2aWZYwJ+r64tQqfjpvzHVm20LobXlQvud Lr0DIGEdLzEFUmyGYIckMzLOKAbUthPuPLsgqXXLHQdqfLxy9TwU0FwwE YBCTF8JDJArbPFG+BgQkrofFsT7uuovdvHqopQyXLMF97nywIudLTZApj 80s6q7rl13MGrymawwzXRKj3XHYQiqJDuxa1WkIcyeZKqMPWMfv4gYvns haGqeedhJYyujsAWZODCQdKbspX8D6s/ke1YDuZdxYVqxEnp/YCNk3HTZ g==; X-CSE-ConnectionGUID: sRbNQjIUQnOupu1p3tlwnQ== X-CSE-MsgGUID: cZAyvC9qSsaL6y9LjSHIKg== X-IronPort-AV: E=McAfee;i="6800,10657,11684"; a="74375167" X-IronPort-AV: E=Sophos;i="6.21,257,1763452800"; d="scan'208";a="74375167" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2026 12:03:36 -0800 X-CSE-ConnectionGUID: lbxyO6JkSM+pCxTRbT1fTQ== X-CSE-MsgGUID: 4vfxTpemRTO6xKXV4ZXxBA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,257,1763452800"; d="scan'208";a="208512672" Received: from orsmsx903.amr.corp.intel.com ([10.22.229.25]) by fmviesa009.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2026 12:03:35 -0800 Received: from ORSMSX902.amr.corp.intel.com (10.22.229.24) by ORSMSX903.amr.corp.intel.com (10.22.229.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35; Tue, 27 Jan 2026 12:03:34 -0800 Received: from ORSEDG901.ED.cps.intel.com (10.7.248.11) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35 via Frontend Transport; Tue, 27 Jan 2026 12:03:34 -0800 Received: from DM5PR21CU001.outbound.protection.outlook.com (52.101.62.6) by edgegateway.intel.com (134.134.137.111) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35; Tue, 27 Jan 2026 12:03:34 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=r+WQmMXTk/nh0k9pnigEAZ/37WMedU66GwfynuE3UDAKZqzwYNDr50FkIEaWDLx44SDhlJz/n8rntRCu8dJxEtNw72cQJaO1CYvOBw8OKg46HbQaw70J8/pOeOPgJCaYjAz955nAgdcY9V691TxqfFVVL2nv76c/JnOUdCYnhFcXSgkTUPCX+i6ay4YlfprOGwDwDuGOzAg3DMevxz3IsPW6AuGUogPX1ff9BdiVp7Sxq8cZtJ7fLRDrMN8ee478+fwvXQKFhpL+sg3L03eCNrxRpxe5wkbng6ixeMTJ++ipUrPr6J5yFBRenijROe3o7NAzpwC5gXNLBigj5ShAnQ== 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=ySbqJgsl72ub4wHZ00hHO94brE3nh2IlwTF+d0ZUBR4=; b=b1TniEWG9or0NoSNIQN+8GR3JMsdZoqatTAewnduZv/blDw+rG/pBj8iMzYn5rw8Chvs+nVmZkrQadXzQCWVwpc44eulJlnbAKp6datVgqvLQrYVu4pFAjJTKl6hgcvsCDVPSG+WOVPrJmVsefgGszAbx/WO+9BGetP2ef+mtnpwreEVHzTRkQv1DKNrH2BIvgxQonDgTPw8cYVN4spVKrQf92nfUMMyQf+J9WVb5gqleprPEc8Llx2UCacRbnpkVymjaBndtLr8pO2c6an6LxdOz6yV/Qudy4KBdnmsMXXXfOzyAmE6PmVuaaCLRgIYFkQQ/MsOiCDchCxfnJz98g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from DS4PPF0BAC23327.namprd11.prod.outlook.com (2603:10b6:f:fc02::9) by DM3PPF1CEB6B7EF.namprd11.prod.outlook.com (2603:10b6:f:fc00::f10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.16; Tue, 27 Jan 2026 20:03:31 +0000 Received: from DS4PPF0BAC23327.namprd11.prod.outlook.com ([fe80::46c9:7f71:993d:8aee]) by DS4PPF0BAC23327.namprd11.prod.outlook.com ([fe80::46c9:7f71:993d:8aee%8]) with mapi id 15.20.9564.006; Tue, 27 Jan 2026 20:03:31 +0000 Date: Tue, 27 Jan 2026 12:03:25 -0800 From: Alison Schofield To: Smita Koralahalli CC: , , , , , Ard Biesheuvel , Vishal Verma , Ira Weiny , Dan Williams , Jonathan Cameron , Yazen Ghannam , Dave Jiang , Davidlohr Bueso , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , "Ying Huang" , Yao Xingtao , Peter Zijlstra , Greg Kroah-Hartman , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , Zhijian Li , Borislav Petkov , Tomasz Wolski Subject: Re: [PATCH v5 5/7] dax: Introduce dax_cxl_mode for CXL coordination Message-ID: References: <20260122045543.218194-1-Smita.KoralahalliChannabasappa@amd.com> <20260122045543.218194-6-Smita.KoralahalliChannabasappa@amd.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260122045543.218194-6-Smita.KoralahalliChannabasappa@amd.com> X-ClientProxiedBy: BY5PR17CA0015.namprd17.prod.outlook.com (2603:10b6:a03:1b8::28) To DS4PPF0BAC23327.namprd11.prod.outlook.com (2603:10b6:f:fc02::9) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS4PPF0BAC23327:EE_|DM3PPF1CEB6B7EF:EE_ X-MS-Office365-Filtering-Correlation-Id: e76621fa-8199-4aa4-866e-08de5ddf24b4 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: =?us-ascii?Q?I6Y5wKs8+aE+evqgNGjFq7TjzwlW6cd1m1iu4UkaDnchbaMlTWWCJDmSD8uV?= =?us-ascii?Q?Jx40SImZk8tM0IwqRQPYKJ+egbIuqm1IbBkzt5HuUKV7plXiEa4c6M63Enfu?= =?us-ascii?Q?njh3wMc0ZtCSRKq0HBGx7IynajihJo9IM+oYcBrQv6ri5u+dp/oXspK7Jm+L?= =?us-ascii?Q?+MvGcGbLnFyaJo0Nre84U8WeTXWIq0/ZPjazF0b2fWLfuiGkWUfiX1jrR6lo?= =?us-ascii?Q?JL8dOEzPITr8l4xDRfnGLZJnupTBZPTOt+HeHWxUvSDwmG/t69xcntyl2tX2?= =?us-ascii?Q?DSTOI3sJb6jMcrp31bL1SxyzlHyGESAOc8u3hgXFi7kdiltYHP5jExqOoIgK?= =?us-ascii?Q?Aju8+Imp9Iz1zauR7rpAQiSxwhWHyqAaGIhA0dbiO0bBMUWutMZBf/lqwWlz?= =?us-ascii?Q?TgOY8Yne8loMbGTuGJEvXPyp2DM2qLscNmKYXYHS1rkpVYqSFu2AXsRdEdwJ?= =?us-ascii?Q?6QpAUd+uJD4UoXwQYJuu7CWdpAx5q0IhrO2xhaa4IPRSjp1OA+m/Bq26QXgO?= =?us-ascii?Q?Ysu2/7HxEpMUioHM+N2oOwIrWtlcP0wyZgl7yknjJfge8K6AlEH6hesU3A47?= =?us-ascii?Q?FhmiCyyY+YncCG+o+SV+pqZ+9u7zMXeOiO/xhOHYKQQO8FRwM7AvUvT5ZQu+?= =?us-ascii?Q?ZOkeB5SzxfMimhnhzsMUrsT5BM+ry9QTi8rREhWolUvadCcBSxPKpudRUabP?= =?us-ascii?Q?UpA50RXq2efXNryf6O+wdtnQUEmNj2rskE1CAjAqe2IrQJslaX6FVzjBGHWa?= =?us-ascii?Q?679q0BsFgFn/L9IG4C/pj6pHKJCGNV70+aq8xEWq6nrUNkUnHUm0nlS+QzM/?= =?us-ascii?Q?rBRfTkWABF0Asz4TphqPg34AWCTX6axCTvaKgfGL7ZtJjcF+Ax9NyCGkUo1S?= =?us-ascii?Q?zvKKhzQ2MxQLJLMa2KWOU+XHGJdrUHquJJ5f5gHJWl+6H/9K2fBR2lg3EkUq?= =?us-ascii?Q?ClLlfu+iRnQxpWTwMZmvTDewl/8YWSBR30HVstcGInqv5oMAAvyzVq/PfI2y?= =?us-ascii?Q?Y8Pgc30qXOLUzj7NqPQtMvcVULGjURZag7qjy3Fqw2caPsJ5dLpWtk+T3Mc5?= =?us-ascii?Q?k2luruV7JltOvksaFb924M8AkeqykrR0lOlOrwoV1uW8c0PwX0bDsPO6pV5s?= =?us-ascii?Q?T7Gu++zTzVPChUpGoodEO0E1jjvkOn2zBegeAWuKXAONlNCamrF2VRPi1YCX?= =?us-ascii?Q?mqrq7RFWCOrVWylbay30YG480JCKpN7A2f5rv+kFz644JJ9cMWUYir66PlPB?= =?us-ascii?Q?AvsacuLFw32nPKb6x/qS/8Kmz268V+xPiycUXcgZq6b4T9CO5Ztk4rqE7a9b?= =?us-ascii?Q?d+sPJBD86OEH04g9I39h+KbQKxYE5NiQ9kDV8DPS7vWc6I/1gTidGqchLRtl?= =?us-ascii?Q?jx2w94IwmoNQTXp4/DPHHi027OY9bfx2fh6MLLWVmdps2fkNhR2C+8l1p37Y?= =?us-ascii?Q?fSUwtNmHo8uGSeQj1q8GcOVOwGB0hGzIyL9xo4Pk3Yary10iOv3NOBeRjIhc?= =?us-ascii?Q?qLENDH2nTjhkWsVfuNf0jTyVul9MYlCqiDGr2g/xCRtNhYegG7Zo8pEA9++g?= =?us-ascii?Q?qWFC2bB1A+3BgG+phxA=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS4PPF0BAC23327.namprd11.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: =?us-ascii?Q?dxz/+Ogo8ejZPlAigGKVBgVQR9bZgpTdELNWWrTURoTwq8qkVBZe6D6kr9wl?= =?us-ascii?Q?YCzzvGlmw3/LniQX3486bcNwBdBdMRicYO0JbKlIcTQNA8X5zuY6K18Ihni7?= =?us-ascii?Q?B5/Quqd7AAMvSxdp95SFXXjZ30pyiw5lkqVQmJ/gpFh56eCLtPhHmljDGnqK?= =?us-ascii?Q?2HSXr5DxYu7Qa5XKYwfDpUC7jfe9QP5XKg19Blx1BWAPxrAqh8GqR5pCAvg1?= =?us-ascii?Q?QTKO7fzxAVuEEUG/RpBlAJSpnHyrsNGgN9WqeswLGXif06iIFbOKUEyvOraI?= =?us-ascii?Q?23Tq9ykcPizpIm5Ug3FbEppu8NBLkCYs8zR8unwsoqhE50i/fSJkAoFhuAtU?= =?us-ascii?Q?1nut23wE/eYJK7CImix+MUVPT14CnLb7D3pC0gRqioM1gZZisfxTxuCoghOd?= =?us-ascii?Q?lfKRlSuWUKkThgFkPvT2vRjwoh0TwNHBI/ho3WPt7Ul0AYoGL3IGPDJtg13T?= =?us-ascii?Q?fRuGyBeBLwEdqXD6r3ZGrdoutZxU1CWnG6ocFKYO81wMQC2jySDr4L7PnD0z?= =?us-ascii?Q?/uiR91/NtNn/OUlscw/0YiBZhGTFxK43YU5dESw6+dsvsxLPKinXo4WGB6So?= =?us-ascii?Q?B3oV9jMD00oAXWH0ZEHuHITAWZfn7cDdhZUtMAl1FZzm9UVMCEEjrbVCpgjI?= =?us-ascii?Q?L1K5q+dFuu+B4KytJIm0GHi3NcRDXy95vfcn7w7LOm1E7xQoutFfRa8Q7iPM?= =?us-ascii?Q?uQasfGWXUWlIV3aYWjzFMt9Y6JWbKwcnB9hRWZ/IqkHw6kHMz6/kokc1fjaW?= =?us-ascii?Q?THIh+S2P9Md/Q8mX6mWE8OcSU9ONX2swlzKpgia/3JVOU9EDtUPLddYJ2f9o?= =?us-ascii?Q?ZyzcMeP+b/QNS40VxcLyOSLYFIux1RLFVCCT6KKnta2KTvBbAzvojY9yd729?= =?us-ascii?Q?FN2Ikh7pErcxQvB+OXx3sqc5Bqpp1WSpKuSA8eTUbdidASCY/uzDStJYwG4u?= =?us-ascii?Q?urWh9QmDJPD92RqEh6CRRxabmvH3OR8UkZqU6piFS6xNhATAMv5w7ZbNzIt6?= =?us-ascii?Q?0LAnbczm5NvJQWWNY+PaAw06J5swhllvNEmP+aTJvgX05gumhT8OqamIm+Rp?= =?us-ascii?Q?hmGzH8qivucneJhOTNtBm5FQpJ/r1iwRUJq3ZZIboxXCZDe1a7VzrjKsBUCF?= =?us-ascii?Q?gYfqkGIMDmoslyJOh6W+yY0IZNSWIeBSuc8aII7YrGohvYEWiswGz2coXW64?= =?us-ascii?Q?Xko1a6kxmZ01tlrJMHwWtd7GichkbDiCfgMeaNoQ7WX0su68QICGmnPHjVbr?= =?us-ascii?Q?UdM3cy5PWtzoMAVgE8hdtwo7Ai+ADKUOD2mQt6CG/ZEICJh/ZchNZvmp/AYg?= =?us-ascii?Q?qPfolJRIjx9HnrsLR7ehxFLbeCJ/tqhFtOHKMkYQAUizAB1CExjsPWIGAcXc?= =?us-ascii?Q?am6W29E4wuhG5wDHIX/eqgFDsH/x4z32foQy6XbxSNOeZJIR66yNK28exeqb?= =?us-ascii?Q?QVaqRUNWcuCqry44oFg0F+sz7/L5AEcor/k+38JM/HyL6u9NcUp1k213N/hz?= =?us-ascii?Q?CuFUB52pP9jFhyTnSc3XOpQAd/pU48z59oA2g12u7CRtPStti98Kxm3IS1ny?= =?us-ascii?Q?A+B/IH+jMKVLtAfUPn3VTo4eQpqjIHVIPoMRWNWB7r19G+vUmWM4Xnnh4u51?= =?us-ascii?Q?/Hn/oBrpafPTxsK2mbMH4a7DMGfGnJkwYwn2g4o/FzLKgIVsswNMP3Jhoedh?= =?us-ascii?Q?iBzpXletoiuJvtsnJ3D6V5xGEAo4G8+KvZSGaPfeAyTWNDaK698/CtM9mVl5?= =?us-ascii?Q?XyKDCNX2tic9QDgvBCTG5O8ukPqsSEA=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: e76621fa-8199-4aa4-866e-08de5ddf24b4 X-MS-Exchange-CrossTenant-AuthSource: DS4PPF0BAC23327.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Jan 2026 20:03:31.0577 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: CI0Pv1qJ+HbC/3HfSjQUv/wsNDz3v6s9daTbp2X+e3GyhWlk29VHT+D+L/ftjiXfEBRqsqjEscQCwpbSqZ3l7snEBmqLZsqJEBZgIrECWDM= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM3PPF1CEB6B7EF X-OriginatorOrg: intel.com On Thu, Jan 22, 2026 at 04:55:41AM +0000, Smita Koralahalli wrote: > Introduce dax_cxl_mode to coordinate between dax_cxl and dax_hmem when > handling CXL tagged memory ranges. > > This patch defines the dax_cxl_mode enum and establishes a default policy. > Subsequent patches will wire this into dax_cxl and dax_hmem to decide > whether CXL tagged memory ranges should be deferred, registered or > dropped. same as DaveJ comment. Fold into next patch that uses it and grow the explanation of the state machine in that commit log. Also add in code comments to this enum. > > No functional changes. > > Signed-off-by: Smita Koralahalli > --- > drivers/dax/bus.c | 3 +++ > drivers/dax/bus.h | 8 ++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index fde29e0ad68b..72bc5b76f061 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -24,6 +24,9 @@ DECLARE_RWSEM(dax_region_rwsem); > */ > DECLARE_RWSEM(dax_dev_rwsem); > > +enum dax_cxl_mode dax_cxl_mode = DAX_CXL_MODE_DEFER; > +EXPORT_SYMBOL_GPL(dax_cxl_mode); > + > #define DAX_NAME_LEN 30 > struct dax_id { > struct list_head list; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..a40cbbf1e26b 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -41,6 +41,14 @@ struct dax_device_driver { > void (*remove)(struct dev_dax *dev); > }; > > +enum dax_cxl_mode { > + DAX_CXL_MODE_DEFER, > + DAX_CXL_MODE_REGISTER, > + DAX_CXL_MODE_DROP, > +}; > + > +extern enum dax_cxl_mode dax_cxl_mode; > + > int __dax_driver_register(struct dax_device_driver *dax_drv, > struct module *module, const char *mod_name); > #define dax_driver_register(driver) \ > -- > 2.17.1 >