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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by DS3PEPF0000C37E.mail.protection.outlook.com (10.167.23.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Sun, 22 Mar 2026 19:53:59 +0000 Received: from ethanolx50f7host.amd.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Sun, 22 Mar 2026 14:53:58 -0500 From: Smita Koralahalli To: , , , , CC: Ard Biesheuvel , Alison Schofield , 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 , Smita Koralahalli , Tomasz Wolski Subject: [PATCH v8 6/9] dax: Track all dax_region allocations under a global resource tree Date: Sun, 22 Mar 2026 19:53:39 +0000 Message-ID: <20260322195343.206900-7-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260322195343.206900-1-Smita.KoralahalliChannabasappa@amd.com> References: <20260322195343.206900-1-Smita.KoralahalliChannabasappa@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: satlexmb08.amd.com (10.181.42.217) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS3PEPF0000C37E:EE_|SJ0PR12MB7007:EE_ X-MS-Office365-Filtering-Correlation-Id: 0ae48706-779c-405b-0d14-08de884cc2aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|82310400026|7416014|376014|1800799024|18002099003|56012099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700016)(82310400026)(7416014)(376014)(1800799024)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: h0UAcsauoRnItGTVl6H7S0pMnL28f9ppTOcxCzgbnXks9tJerqnHBWXu6yrBKLlAv2ygdF402JU0AxQEZ4XMVwimKzIy9iA6EqldkXdnups/wCLKNPxEvxjAANXcYIR6wCd0i7hf9L+Wb+XyRW1Svb00UeNTD0wXsmGGkx4AyVAn6hMsBurPEWv1YQQHvY02Dc870n6H4xyXYItYGrzYAhjlcAOFLsK0zuUHCkvKPrWVJvXrg1nQpvd+vYcQ5gjV/i/eVgNZ+vQtnNHjPqmxXZBINMSLFbw+gsZOWChXDwiZ20WSCcTlOPwa1+ebNu+DbG2hEbwJkc+vIfo3Y05qUylzheC53Ztx2qgErxD7xIrO5e4i8QVK8FP5isdKVrWG4QeUD4gdxpglO+sly8/5Qto/C+xVPXHDZeqvuV7LEvAprhCwJxWS3wu6dNvNkfGT X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2026 19:53:59.7269 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0ae48706-779c-405b-0d14-08de884cc2aa X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS3PEPF0000C37E.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB7007 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Introduce a global "DAX Regions" resource root and register each dax_region->res under it via request_resource(). Release the resource on dax_region teardown. By enforcing a single global namespace for dax_region allocations, this ensures only one of dax_hmem or dax_cxl can successfully register a dax_region for a given range. Suggested-by: Dan Williams Signed-off-by: Smita Koralahalli Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang --- drivers/dax/bus.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 299134c9b294..68437c05e21d 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -10,6 +10,7 @@ #include "dax-private.h" #include "bus.h" =20 +static struct resource dax_regions =3D DEFINE_RES_MEM_NAMED(0, -1, "DAX Re= gions"); static DEFINE_MUTEX(dax_bus_lock); =20 /* @@ -627,6 +628,7 @@ static void dax_region_unregister(void *region) =20 sysfs_remove_groups(&dax_region->dev->kobj, dax_region_attribute_groups); + release_resource(&dax_region->res); dax_region_put(dax_region); } =20 @@ -635,6 +637,7 @@ struct dax_region *alloc_dax_region(struct device *pare= nt, int region_id, unsigned long flags) { struct dax_region *dax_region; + int rc; =20 /* * The DAX core assumes that it can store its private data in @@ -667,14 +670,25 @@ struct dax_region *alloc_dax_region(struct device *pa= rent, int region_id, .flags =3D IORESOURCE_MEM | flags, }; =20 - if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { - dax_region_put(dax_region); - return NULL; + rc =3D request_resource(&dax_regions, &dax_region->res); + if (rc) { + dev_dbg(parent, "dax_region resource conflict for %pR\n", + &dax_region->res); + goto err_res; } =20 + if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) + goto err_sysfs; + if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region)) return NULL; return dax_region; + +err_sysfs: + release_resource(&dax_region->res); +err_res: + dax_region_put(dax_region); + return NULL; } EXPORT_SYMBOL_GPL(alloc_dax_region); =20 --=20 2.17.1