x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 171 insertions, 0 deletions

diff --git a/Documentation/gpu/imagination/uapi.rst b/Documentation/gpu/imagination/uapi.rst
new file mode 100644
index 000000000..7502413d0
--- /dev/null
+++ b/Documentation/gpu/imagination/uapi.rst
@@ -0,0 +1,171 @@
+====
+UAPI
+====
+The sources associated with this section can be found in ``pvr_drm.h``.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR UAPI
+
+OBJECT ARRAYS
+=============
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_obj_array
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: DRM_PVR_OBJ_ARRAY
+
+IOCTLS
+======
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL interface
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: PVR_IOCTL
+
+DEV_QUERY
+---------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL DEV_QUERY interface
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_dev_query
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_dev_query_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_dev_query_gpu_info
+                 drm_pvr_dev_query_runtime_info
+                 drm_pvr_dev_query_hwrt_info
+                 drm_pvr_dev_query_quirks
+                 drm_pvr_dev_query_enhancements
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_heap_id
+                 drm_pvr_heap
+                 drm_pvr_dev_query_heap_info
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_static_data_area_usage
+                 drm_pvr_static_data_area
+                 drm_pvr_dev_query_static_data_areas
+
+CREATE_BO
+---------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL CREATE_BO interface
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_create_bo_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for CREATE_BO
+
+GET_BO_MMAP_OFFSET
+------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL GET_BO_MMAP_OFFSET interface
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_get_bo_mmap_offset_args
+
+CREATE_VM_CONTEXT and DESTROY_VM_CONTEXT
+----------------------------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL CREATE_VM_CONTEXT and DESTROY_VM_CONTEXT interfaces
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_create_vm_context_args
+                 drm_pvr_ioctl_destroy_vm_context_args
+
+VM_MAP and VM_UNMAP
+-------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL VM_MAP and VM_UNMAP interfaces
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_vm_map_args
+                 drm_pvr_ioctl_vm_unmap_args
+
+CREATE_CONTEXT and DESTROY_CONTEXT
+----------------------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL CREATE_CONTEXT and DESTROY_CONTEXT interfaces
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_create_context_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ctx_priority
+                 drm_pvr_ctx_type
+                 drm_pvr_static_render_context_state
+                 drm_pvr_static_render_context_state_format
+                 drm_pvr_reset_framework
+                 drm_pvr_reset_framework_format
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_destroy_context_args
+
+CREATE_FREE_LIST and DESTROY_FREE_LIST
+--------------------------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL CREATE_FREE_LIST and DESTROY_FREE_LIST interfaces
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_create_free_list_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_destroy_free_list_args
+
+CREATE_HWRT_DATASET and DESTROY_HWRT_DATASET
+--------------------------------------------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL CREATE_HWRT_DATASET and DESTROY_HWRT_DATASET interfaces
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_create_hwrt_dataset_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_create_hwrt_geom_data_args
+                 drm_pvr_create_hwrt_rt_data_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_destroy_hwrt_dataset_args
+
+SUBMIT_JOBS
+-----------
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: PowerVR IOCTL SUBMIT_JOBS interface
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for the drm_pvr_sync_op object.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_ioctl_submit_jobs_args
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for SUBMIT_JOB ioctl geometry command.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for SUBMIT_JOB ioctl fragment command.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for SUBMIT_JOB ioctl compute command.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :doc: Flags for SUBMIT_JOB ioctl transfer command.
+
+.. kernel-doc:: include/uapi/drm/pvr_drm.h
+   :identifiers: drm_pvr_sync_op
+                 drm_pvr_job_type
+                 drm_pvr_hwrt_data_ref
+                 drm_pvr_job
+
+Internal notes
+==============
+.. kernel-doc:: drivers/gpu/drm/imagination/pvr_device.h
+   :doc: IOCTL validation helpers
+
+.. kernel-doc:: drivers/gpu/drm/imagination/pvr_device.h
+   :identifiers: PVR_STATIC_ASSERT_64BIT_ALIGNED PVR_IOCTL_UNION_PADDING_CHECK
+                 pvr_ioctl_union_padding_check