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Y. Srinivasan" , Laxman Dewangan , Len Brown , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-tegra@vger.kernel.org, Russell King , Lorenzo Pieralisi , Lyude Paul , Marek Szyprowski , nouveau@lists.freedesktop.org, Palmer Dabbelt , Paul Walmsley , "Rafael J. Wysocki" , Rob Herring , Robin Murphy , Sudeep Holla , Suravee Suthikulpanit , Sven Peter , Thomas Bogendoerfer , Vineet Gupta , Vinod Koul , Wei Liu , Will Deacon Cc: Lu Baolu , Christoph Hellwig , Jerry Snitselaar , Hector Martin , Moritz Fischer , patches@lists.linux.dev, "Rafael J. Wysocki" , Rob Herring , Thierry Reding Subject: [PATCH 06/10] iommu: Replace iommu_device_lock with iommu_probe_device_lock Date: Tue, 28 Nov 2023 20:48:02 -0400 Message-ID: <6-v1-720585788a7d+811b-iommu_fwspec_p1_jgg@nvidia.com> In-Reply-To: <0-v1-720585788a7d+811b-iommu_fwspec_p1_jgg@nvidia.com> References: X-ClientProxiedBy: SA1P222CA0194.NAMP222.PROD.OUTLOOK.COM (2603:10b6:806:3c4::19) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|MW5PR12MB5649:EE_ X-MS-Office365-Filtering-Correlation-Id: 8536a7a9-4d35-47de-3bfe-08dbf074db6a X-LD-Processed: 43083d15-7273-40c1-b7db-39efd9ccc17a,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(136003)(39860400002)(396003)(366004)(376002)(346002)(230922051799003)(186009)(1800799012)(64100799003)(451199024)(5660300002)(7416002)(7366002)(7406005)(41300700001)(4326008)(8936002)(8676002)(2906002)(110136005)(316002)(66556008)(66476007)(54906003)(66946007)(2616005)(921008)(6486002)(478600001)(36756003)(6512007)(6506007)(26005)(6666004)(83380400001)(86362001)(38100700002)(4216001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 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 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8536a7a9-4d35-47de-3bfe-08dbf074db6a X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Nov 2023 00:48:09.2376 (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: vU8nM8hRTqWQk/nZDor+27mpHqRBzU3fNn/Vj2pJuFDohMSLaOPZEvzrbRjxh0aO X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW5PR12MB5649 The iommu_device_lock protects the iommu_device_list which is only read by iommu_ops_from_fwnode(). This is now always called under the iommu_probe_device_lock, so we don't need to double lock the linked list. Use the iommu_probe_device_lock on the write side too. Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommu.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 08f29a1dfcd5f8..9557c2ec08d915 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -146,7 +146,6 @@ struct iommu_group_attribute iommu_group_attr_##_name = \ container_of(_kobj, struct iommu_group, kobj) static LIST_HEAD(iommu_device_list); -static DEFINE_SPINLOCK(iommu_device_lock); static const struct bus_type * const iommu_buses[] = { &platform_bus_type, @@ -262,9 +261,9 @@ int iommu_device_register(struct iommu_device *iommu, if (hwdev) iommu->fwnode = dev_fwnode(hwdev); - spin_lock(&iommu_device_lock); + mutex_lock(&iommu_probe_device_lock); list_add_tail(&iommu->list, &iommu_device_list); - spin_unlock(&iommu_device_lock); + mutex_unlock(&iommu_probe_device_lock); for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) err = bus_iommu_probe(iommu_buses[i]); @@ -279,9 +278,9 @@ void iommu_device_unregister(struct iommu_device *iommu) for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) bus_for_each_dev(iommu_buses[i], NULL, iommu, remove_iommu_group); - spin_lock(&iommu_device_lock); + mutex_lock(&iommu_probe_device_lock); list_del(&iommu->list); - spin_unlock(&iommu_device_lock); + mutex_unlock(&iommu_probe_device_lock); /* Pairs with the alloc in generic_single_device_group() */ iommu_group_put(iommu->singleton_group); @@ -316,9 +315,9 @@ int iommu_device_register_bus(struct iommu_device *iommu, if (err) return err; - spin_lock(&iommu_device_lock); + mutex_lock(&iommu_probe_device_lock); list_add_tail(&iommu->list, &iommu_device_list); - spin_unlock(&iommu_device_lock); + mutex_unlock(&iommu_probe_device_lock); err = bus_iommu_probe(bus); if (err) { @@ -2033,9 +2032,9 @@ bool iommu_present(const struct bus_type *bus) for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) { if (iommu_buses[i] == bus) { - spin_lock(&iommu_device_lock); + mutex_lock(&iommu_probe_device_lock); ret = !list_empty(&iommu_device_list); - spin_unlock(&iommu_device_lock); + mutex_unlock(&iommu_probe_device_lock); } } return ret; @@ -2980,17 +2979,14 @@ EXPORT_SYMBOL_GPL(iommu_default_passthrough); const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode) { - const struct iommu_ops *ops = NULL; struct iommu_device *iommu; - spin_lock(&iommu_device_lock); + lockdep_assert_held(&iommu_probe_device_lock); + list_for_each_entry(iommu, &iommu_device_list, list) - if (iommu->fwnode == fwnode) { - ops = iommu->ops; - break; - } - spin_unlock(&iommu_device_lock); - return ops; + if (iommu->fwnode == fwnode) + return iommu->ops; + return NULL; } int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,