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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 CH1PEPF0000AD80.mail.protection.outlook.com (10.167.244.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.382.8 via Frontend Transport; Wed, 2 Sep 2026 20:57:34 +0000 Received: from [10.236.189.59] (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 15.2.2562.46; Wed, 2 Sep 2026 15:57:32 -0500 Message-ID: <0e931d5e-4290-4bcf-8ccf-eac643e4db99@amd.com> Date: Wed, 2 Sep 2026 15:57:31 -0500 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: "Cheatham, Benjamin" Subject: Re: [PATCH v20 6/9] PCI: Cache PCI DSN into pci_dev->dsn during probe To: Terry Bowman , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Davidlohr Bueso , Bjorn Helgaas , "Dan Williams" , "Rafael J . Wysocki" , Jonathan Corbet , CC: Tony Luck , Borislav Petkov , "Hanjun Guo" , Mauro Carvalho Chehab , "Shuai Xue" , Len Brown , Ira Weiny , Li Ming , Shuah Khan , Richard Cheng , "Robert Richter" , Lukas Wunner , , , , References: <20260902133933.2992457-1-terry.bowman@amd.com> <20260902133933.2992457-7-terry.bowman@amd.com> Content-Language: en-US In-Reply-To: <20260902133933.2992457-7-terry.bowman@amd.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH1PEPF0000AD80:EE_|SJ2PR12MB7846:EE_ X-MS-Office365-Filtering-Correlation-Id: 9efc16d7-2554-4552-953c-08df0934cfe9 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|82310400026|1800799024|23010399003|7416014|376014|10067099003|6133799003|56012099006|11063799006|22082099003|4143699003|18002099003|921020; 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)(1800799024)(23010399003)(7416014)(376014)(10067099003)(6133799003)(56012099006)(11063799006)(22082099003)(4143699003)(18002099003)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: E7DgWf6DTPOfSynjKxI1lCxrhI5vFUMIPzZpZSxfwbf4aFD3PqTpkxXUv4Q5peMt2AA5n/wtXWeqHXjMAqZUKOAhYYiMzruc1JQc0itTMIvDctiWnfXazeJDbwDvYAZtzpn3vI5sGtVXAZSCWjE/ypPfUzOqph2DxJyIhgOE2KBv6Ib/hPlhzv0BUmuykNrWzL1tJixaWzzdUZJX0IEMKdUbcJvfegBS/O0brHPhONFsy7Tie9lnY2Q6aNvUxdeKWmZZ84DiXnIgp124MmNuWC+ITNBA4ZXmSVoNT1irvyJcoTrdjZaJezq3Hq6brb/ZDnyevnDDrsY2dZcFJaJcoA6B203bBliAVbpiK2dZ9AF5lrDFU43LROVWK3SPh7Bml4WXf3EJgANRAqviHhqjqI1pZ2OeMWT6+3QJRH1rFN+RLcP72GfVat1E4dMqsn5t X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2026 20:57:34.0509 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 9efc16d7-2554-4552-953c-08df0934cfe9 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: CH1PEPF0000AD80.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB7846 On 9/2/2026 8:39 AM, Terry Bowman wrote: > Subsequent CXL error-reporting code paths need to log the PCI Device > Serial Number (DSN) as part of trace events emitted from interrupt or > panic context. Computing the DSN there via pci_get_dsn() requires PCI > configuration space reads, which are slow, can fail when the link is > down or frozen, and may not be safe in some contexts. > > Add a u64 dsn field to struct pci_dev and populate it from pci_get_dsn() > during pci_init_capabilities() at probe time via pci_dsn_init(). Only > write dev->dsn when the read succeeds. The zero initial value from > pci_dev allocation already represents 'no DSN available.' > > Remove the now-redundant dsn member from the pciehp struct controller > along with its kernel-doc. Drop the pci_get_slot()/pci_dev_put() pairs > in pciehp_configure_device() and pcie_init() that existed solely to > read the DSN into ctrl->dsn. Use pdev->dsn in pciehp_device_replaced() > for the device-replacement comparison. > > pci_get_dsn() is not modified because it remains a pure config-space read > with no side effects on pci_dev. The cache is written exclusively by > pci_dsn_init() at probe time. > > Signed-off-by: Terry Bowman > Reviewed-by: Dave Jiang > Reviewed-by: Jonathan Cameron > Reviewed-by: Alison Schofield > > --- Reviewed-by: Ben Cheatham