From: Jason Gunthorpe <jgg@nvidia.com>
To: iommu@lists.linux.dev, linux-kselftest@vger.kernel.org
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
Kevin Tian <kevin.tian@intel.com>,
kvm@vger.kernel.org, Lixiao Yang <lixiao.yang@intel.com>,
Matthew Rosato <mjrosato@linux.ibm.com>,
Nicolin Chen <nicolinc@nvidia.com>, Yi Liu <yi.l.liu@intel.com>
Subject: [PATCH v6 15/19] iommufd: Make destroy_rwsem use a lock class per object type
Date: Thu, 20 Apr 2023 15:51:30 -0300 [thread overview]
Message-ID: <15-v6-fdb604df649a+369-iommufd_alloc_jgg@nvidia.com> (raw)
In-Reply-To: <0-v6-fdb604df649a+369-iommufd_alloc_jgg@nvidia.com>
The selftest invokes things like replace under the object lock of its
idev which protects the idev in a similar way to a real user.
Unfortunately this triggers lockdep. A lock class per type will solve the
problem.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/iommufd/iommufd_private.h | 1 +
drivers/iommu/iommufd/main.c | 11 ++++++++++-
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index a5d5a47641346f..d97bac38b7a41d 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -119,6 +119,7 @@ enum iommufd_object_type {
#ifdef CONFIG_IOMMUFD_TEST
IOMMUFD_OBJ_SELFTEST,
#endif
+ IOMMUFD_OBJ_MAX,
};
/* Base struct for all objects with a userspace ID handle. */
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 5b7f70543adb24..f219e47d882525 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -33,6 +33,7 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
size_t size,
enum iommufd_object_type type)
{
+ static struct lock_class_key obj_keys[IOMMUFD_OBJ_MAX];
struct iommufd_object *obj;
int rc;
@@ -40,7 +41,15 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
if (!obj)
return ERR_PTR(-ENOMEM);
obj->type = type;
- init_rwsem(&obj->destroy_rwsem);
+ /*
+ * In most cases the destroy_rwsem is obtained with try so it doesn't
+ * interact with lockdep, however on destroy we have to sleep. This
+ * means if we have to destroy an object while holding a get on another
+ * object it triggers lockdep. Using one locking class per object type
+ * is a simple and reasonable way to avoid this.
+ */
+ __init_rwsem(&obj->destroy_rwsem, "iommufd_object::destroy_rwsem",
+ &obj_keys[type]);
refcount_set(&obj->users, 1);
/*
--
2.40.0
next prev parent reply other threads:[~2023-04-20 18:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-20 18:51 [PATCH v6 00/19] Add iommufd physical device operations for replace and alloc hwpt Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 01/19] iommufd: Move isolated msi enforcement to iommufd_device_bind() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 02/19] iommufd: Add iommufd_group Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 03/19] iommufd: Replace the hwpt->devices list with iommufd_group Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 04/19] iommu: Export iommu_get_resv_regions() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 05/19] iommufd: Keep track of each device's reserved regions instead of groups Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 06/19] iommufd: Use the iommufd_group to avoid duplicate MSI setup Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 07/19] iommufd: Make sw_msi_start a group global Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 08/19] iommufd: Move putting a hwpt to a helper function Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 09/19] iommufd: Add enforced_cache_coherency to iommufd_hw_pagetable_alloc() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 10/19] iommufd: Allow a hwpt to be aborted after allocation Jason Gunthorpe
2023-04-21 7:29 ` Tian, Kevin
2023-04-20 18:51 ` [PATCH v6 11/19] iommufd: Fix locking around hwpt allocation Jason Gunthorpe
2023-04-21 7:30 ` Tian, Kevin
2023-04-20 18:51 ` [PATCH v6 12/19] iommufd: Reorganize iommufd_device_attach into iommufd_device_change_pt Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 13/19] iommu: Introduce a new iommu_group_replace_domain() API Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 14/19] iommufd: Add iommufd_device_replace() Jason Gunthorpe
2023-04-20 18:51 ` Jason Gunthorpe [this message]
2023-04-20 18:51 ` [PATCH v6 16/19] iommufd/selftest: Test iommufd_device_replace() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 17/19] iommufd: Add IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 18/19] iommufd/selftest: Return the real idev id from selftest mock_domain Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 19/19] iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-04-21 1:35 ` [PATCH v6 00/19] Add iommufd physical device operations for replace and alloc hwpt Nicolin Chen
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