{"id":2224152,"url":"http://patchwork.ozlabs.org/api/patches/2224152/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/3f5d229267d1f4d918641bc5b896f54b5c4b7782.1776381841.git.nicolinc@nvidia.com/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<3f5d229267d1f4d918641bc5b896f54b5c4b7782.1776381841.git.nicolinc@nvidia.com>","list_archive_url":null,"date":"2026-04-16T23:28:35","name":"[v3,06/11] iommu: Defer __iommu_group_free_device() to be outside group->mutex","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"3c0e0e7b3024a9aaced2278e7c9b84c53e01bb87","submitter":{"id":82183,"url":"http://patchwork.ozlabs.org/api/people/82183/?format=json","name":"Nicolin Chen","email":"nicolinc@nvidia.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/3f5d229267d1f4d918641bc5b896f54b5c4b7782.1776381841.git.nicolinc@nvidia.com/mbox/","series":[{"id":500217,"url":"http://patchwork.ozlabs.org/api/series/500217/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=500217","date":"2026-04-16T23:28:31","name":"iommu/arm-smmu-v3: Quarantine device upon ATC invalidation timeout","version":3,"mbox":"http://patchwork.ozlabs.org/series/500217/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224152/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224152/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256\n header.s=selector2 header.b=tZgIEqis;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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Wysocki\" , Len Brown ,\n\tPranjal Shrivastava , Mostafa Saleh ,\n\tLu Baolu , Kevin Tian ,\n\t, ,\n\t, ,\n\t, , Shuai Xue\n\t","Subject":"[PATCH v3 06/11] iommu: Defer __iommu_group_free_device() to be\n outside group->mutex","Date":"Thu, 16 Apr 2026 16:28:35 -0700","Message-ID":"\n <3f5d229267d1f4d918641bc5b896f54b5c4b7782.1776381841.git.nicolinc@nvidia.com>","X-Mailer":"git-send-email 2.43.0","In-Reply-To":"","References":"","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Content-Type":"text/plain","X-NV-OnPremToCloud":"ExternallySecured","X-EOPAttributedMessage":"0","X-MS-PublicTrafficType":"Email","X-MS-TrafficTypeDiagnostic":"CO1PEPF00012E83:EE_|CY5PR12MB6406:EE_","X-MS-Office365-Filtering-Correlation-Id":"91f09374-ca9b-463a-aebf-08de9c1002f0","X-MS-Exchange-SenderADCheck":"1","X-MS-Exchange-AntiSpam-Relay":"0","X-Microsoft-Antispam":"\n\tBCL:0;ARA:13230040|1800799024|82310400026|36860700016|376014|7416014|22082099003|56012099003|18002099003;","X-Microsoft-Antispam-Message-Info":"\n\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","X-Forefront-Antispam-Report":"\n\tCIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(1800799024)(82310400026)(36860700016)(376014)(7416014)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101;","X-MS-Exchange-AntiSpam-MessageData-ChunkCount":"1","X-MS-Exchange-AntiSpam-MessageData-0":"\n\tos7agqf34mPecweExe+OIEBp8GwocEy/KZez7ZlGh3WTUuX4t1/X+ihltYyaBfcMwnrDv6DsA3jr0fyZo2iGWymV79AqFQRbXzf29ig+IgS5+O3ydSUEnJWf3SplM3+ll6oKsoJVolTQnyAjtmvqZs1YOksE2qvVkiWaYg32CQTS7792E9LYcNVP71elmsPUWp6nB8cdaDxtAAcnL7BEacXRWXXQABU9+8DkdF1ZeUACpFXfTpSeM2yQFmk+MLkCh/VHkeCypAqMU81wfwwKo1INvn6tD0FfPQFMl5MVtfsPBDFOIAosHXTJsw89SAxZfiZ9+LvUXEWm8Wgo6YDDNZv1uLoLX70DAcNOnu7mrU/h4a0bMHbRwTYlZmFsXogHq7RdJ+r7BzNDS3TfKphb9FA76PBZdbM7OUacIdJ7pguDcfA1+haPfBMAGgaKESY4","X-OriginatorOrg":"Nvidia.com","X-MS-Exchange-CrossTenant-OriginalArrivalTime":"16 Apr 2026 23:29:31.5004\n (UTC)","X-MS-Exchange-CrossTenant-Network-Message-Id":"\n 91f09374-ca9b-463a-aebf-08de9c1002f0","X-MS-Exchange-CrossTenant-Id":"43083d15-7273-40c1-b7db-39efd9ccc17a","X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp":"\n TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com]","X-MS-Exchange-CrossTenant-AuthSource":"\n\tCO1PEPF00012E83.namprd03.prod.outlook.com","X-MS-Exchange-CrossTenant-AuthAs":"Anonymous","X-MS-Exchange-CrossTenant-FromEntityHeader":"HybridOnPrem","X-MS-Exchange-Transport-CrossTenantHeadersStamped":"CY5PR12MB6406"},"content":"__iommu_group_remove_device() holds group->mutex across the entire call to\n__iommu_group_free_device() that performs sysfs removals, tracing, and the\nfinal kfree_rcu(). But in fact, most of these operations don't really need\nthe group->mutex.\n\nThe group_device structure will support a work_struct to quarantine broken\ndevices asynchronously. The work function must hold group->mutex to safely\nupdate group state. cancel_work_sync() must be called, to cancel that work\nbefore freeing the device. But doing so under group->mutex would deadlock\nif the worker is already running and waiting to acquire the same lock.\n\nSeparate the assertion from __iommu_group_free_device() to another helper\n__iommu_group_empty_assert_owner_cnt().\n\nDefer the __iommu_group_free_device() until the mutex is released.\n\nThis is a preparatory refactor with no functional change.\n\nSigned-off-by: Nicolin Chen \n---\n drivers/iommu/iommu.c | 35 +++++++++++++++++++++++------------\n 1 file changed, 23 insertions(+), 12 deletions(-)","diff":"diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c\nindex d1be62a07904a..810e7b94a1ae2 100644\n--- a/drivers/iommu/iommu.c\n+++ b/drivers/iommu/iommu.c\n@@ -627,6 +627,19 @@ static struct iommu_domain *pasid_array_entry_to_domain(void *entry)\n \n DEFINE_MUTEX(iommu_probe_device_lock);\n \n+static void __iommu_group_empty_assert_owner_cnt(struct iommu_group *group)\n+{\n+\tlockdep_assert_held(&group->mutex);\n+\t/*\n+\t * If the group has become empty then ownership must have been\n+\t * released, and the current domain must be set back to NULL or\n+\t * the default domain.\n+\t */\n+\tif (list_empty(&group->devices))\n+\t\tWARN_ON(group->owner_cnt ||\n+\t\t\tgroup->domain != group->default_domain);\n+}\n+\n static int __iommu_probe_device(struct device *dev, struct list_head *group_list)\n {\n \tstruct iommu_group *group;\n@@ -700,10 +713,12 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list\n \n err_remove_gdev:\n \tlist_del_rcu(&gdev->list);\n-\t__iommu_group_free_device(group, gdev);\n+\t__iommu_group_empty_assert_owner_cnt(group);\n err_put_group:\n \tiommu_deinit_device(dev);\n \tmutex_unlock(&group->mutex);\n+\tif (!IS_ERR(gdev))\n+\t\t__iommu_group_free_device(group, gdev);\n \tiommu_group_put(group);\n \n \treturn ret;\n@@ -732,20 +747,13 @@ static void __iommu_group_free_device(struct iommu_group *group,\n {\n \tstruct device *dev = grp_dev->dev;\n \n+\tlockdep_assert_not_held(&group->mutex);\n+\n \tsysfs_remove_link(group->devices_kobj, grp_dev->name);\n \tsysfs_remove_link(&dev->kobj, \"iommu_group\");\n \n \ttrace_remove_device_from_group(group->id, dev);\n \n-\t/*\n-\t * If the group has become empty then ownership must have been\n-\t * released, and the current domain must be set back to NULL or\n-\t * the default domain.\n-\t */\n-\tif (list_empty(&group->devices))\n-\t\tWARN_ON(group->owner_cnt ||\n-\t\t\tgroup->domain != group->default_domain);\n-\n \tkfree(grp_dev->name);\n \tkfree_rcu(grp_dev, rcu);\n }\n@@ -754,7 +762,7 @@ static void __iommu_group_free_device(struct iommu_group *group,\n static void __iommu_group_remove_device(struct device *dev)\n {\n \tstruct iommu_group *group = dev->iommu_group;\n-\tstruct group_device *device;\n+\tstruct group_device *device, *to_free = NULL;\n \n \tmutex_lock(&group->mutex);\n \tfor_each_group_device(group, device) {\n@@ -762,15 +770,18 @@ static void __iommu_group_remove_device(struct device *dev)\n \t\t\tcontinue;\n \n \t\tlist_del_rcu(&device->list);\n-\t\t__iommu_group_free_device(group, device);\n+\t\t__iommu_group_empty_assert_owner_cnt(group);\n \t\tif (dev_has_iommu(dev))\n \t\t\tiommu_deinit_device(dev);\n \t\telse\n \t\t\tdev->iommu_group = NULL;\n+\t\tto_free = device;\n \t\tbreak;\n \t}\n \tmutex_unlock(&group->mutex);\n \n+\tif (to_free)\n+\t\t__iommu_group_free_device(group, to_free);\n \t/*\n \t * Pairs with the get in iommu_init_device() or\n \t * iommu_group_add_device()\n","prefixes":["v3","06/11"]}