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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 SJ5PEPF000001D1.mail.protection.outlook.com (10.167.242.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Thu, 19 Mar 2026 01:15:19 +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; Wed, 18 Mar 2026 20:15:18 -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 v7 4/7] dax: Track all dax_region allocations under a global resource tree Date: Thu, 19 Mar 2026 01:14:57 +0000 Message-ID: <20260319011500.241426-5-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260319011500.241426-1-Smita.KoralahalliChannabasappa@amd.com> References: <20260319011500.241426-1-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: SJ5PEPF000001D1:EE_|MW6PR12MB8759:EE_ X-MS-Office365-Filtering-Correlation-Id: a4ddbffc-5981-4e37-a379-08de8554fcb5 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|82310400026|376014|1800799024|36860700016|56012099003|22082099003|18002099003; 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)(7416014)(82310400026)(376014)(1800799024)(36860700016)(56012099003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: JeCOHLyZ6pdGw6U5oph9VSJ9QS/U9NG4GfWW7ZL7x11HYEaq7AciKuZNibdZcQeXX41nMX5ZKQriKoom5tPFkTKhPdqOnzMQ0SSIKFKM3xJiWWRXRqR6REyHj9gnrK/SVnLWBdwh8jXIQ23mKlKxfbsg8YWB3iD88MwmSIujs+mIDi5Av3ldDr4mzw2R3dadwoPQ+tODXnVjdeCT467zINpalXqAxxmT6P5UEVVy2WABiQ52uQJ9bEvLZw0wOF4IWZ8cEUQJsRADcE6uWbAJd9ZgSdPBJnKPsmgKobk50L+L+7GJnT8qQhmt0Dhxj99BWgzeSRT4MHM8yHVBCzW5VId0yQEEJ2xRgi4lDyrgIS/r2lMGnU6GErpND/3XDcAKY/D2u448Xw1xm3CPVmOfU9VOhow0GtryHxsvdkh4hBSCAy6QpAunw8WGqNBx7RWq X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 01:15:19.5582 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a4ddbffc-5981-4e37-a379-08de8554fcb5 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: SJ5PEPF000001D1.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW6PR12MB8759 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 --- 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 c94c09622516..448e2bc285c3 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 /* @@ -625,6 +626,7 @@ static void dax_region_unregister(void *region) { struct dax_region *dax_region =3D region; =20 + release_resource(&dax_region->res); sysfs_remove_groups(&dax_region->dev->kobj, dax_region_attribute_groups); dax_region_put(dax_region); @@ -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)) { - kfree(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: + kfree(dax_region); + return NULL; } EXPORT_SYMBOL_GPL(alloc_dax_region); =20 --=20 2.17.1