From: Jason Gunthorpe <jgg@nvidia.com>
To: iommu@lists.linux.dev, Kevin Tian <kevin.tian@intel.com>,
linux-kselftest@vger.kernel.org
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
kvm@vger.kernel.org, Nicolin Chen <nicolinc@nvidia.com>,
Yi Liu <yi.l.liu@intel.com>
Subject: [PATCH v3 13/17] iommufd: Make destroy_rwsem use a lock class per object type
Date: Tue, 21 Mar 2023 16:14:47 -0300 [thread overview]
Message-ID: <13-v3-61d41fd9e13e+1f5-iommufd_alloc_jgg@nvidia.com> (raw)
In-Reply-To: <0-v3-61d41fd9e13e+1f5-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.
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 471a3fdff1e0b6..f80b012e1bc200 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 8597f2fb88da3a..9cba592d0482e7 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -32,6 +32,7 @@ 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;
@@ -39,7 +40,15 @@ 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:[~2023-03-21 19:15 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-21 19:14 [PATCH v3 00/17] Add iommufd physical device operations for replace and alloc hwpt Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 01/17] iommufd: Move isolated msi enforcement to iommufd_device_bind() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 02/17] iommufd: Add iommufd_group Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 03/17] iommufd: Replace the hwpt->devices list with iommufd_group Jason Gunthorpe
2023-03-23 7:21 ` Tian, Kevin
2023-03-23 14:23 ` Jason Gunthorpe
2023-03-24 1:37 ` Tian, Kevin
2023-03-24 15:02 ` Jason Gunthorpe
2023-03-28 2:32 ` Tian, Kevin
2023-03-28 11:38 ` Jason Gunthorpe
2023-03-29 3:03 ` Tian, Kevin
2023-04-11 14:31 ` Jason Gunthorpe
2023-04-12 8:27 ` Tian, Kevin
2023-04-12 11:17 ` Jason Gunthorpe
2023-04-13 2:52 ` Tian, Kevin
2023-04-14 13:31 ` Jason Gunthorpe
2023-04-20 6:15 ` Tian, Kevin
2023-04-20 15:34 ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 04/17] iommu: Export iommu_get_resv_regions() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 05/17] iommufd: Keep track of each device's reserved regions instead of groups Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 06/17] iommufd: Use the iommufd_group to avoid duplicate MSI setup Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 07/17] iommufd: Make sw_msi_start a group global Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 08/17] iommufd: Move putting a hwpt to a helper function Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 09/17] iommufd: Add enforced_cache_coherency to iommufd_hw_pagetable_alloc() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 10/17] iommufd: Reorganize iommufd_device_attach into iommufd_device_change_pt Jason Gunthorpe
2023-03-23 7:25 ` Tian, Kevin
2023-03-23 14:26 ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 11/17] iommu: Introduce a new iommu_group_replace_domain() API Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 12/17] iommufd: Add iommufd_device_replace() Jason Gunthorpe
2023-03-23 7:31 ` Tian, Kevin
2023-03-23 14:30 ` Jason Gunthorpe
2023-03-24 1:42 ` Tian, Kevin
2023-03-24 15:03 ` Jason Gunthorpe
2023-03-21 19:14 ` Jason Gunthorpe [this message]
2023-03-23 7:54 ` [PATCH v3 13/17] iommufd: Make destroy_rwsem use a lock class per object type Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 14/17] iommufd/selftest: Test iommufd_device_replace() Jason Gunthorpe
2023-03-23 7:57 ` Tian, Kevin
2023-03-23 14:32 ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 15/17] iommufd: Add IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-03-23 8:00 ` Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 16/17] iommufd/selftest: Return the real idev id from selftest mock_domain Jason Gunthorpe
2023-03-23 8:02 ` Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 17/17] iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-03-23 8:03 ` Tian, Kevin
2023-03-23 8:04 ` [PATCH v3 00/17] Add iommufd physical device operations for replace and alloc hwpt Tian, Kevin
2023-03-23 14:35 ` Jason Gunthorpe
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