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, 41 insertions, 0 deletions

diff --git a/include/drm/intel/intel-gtt.h b/include/drm/intel/intel-gtt.h
new file mode 100644
index 000000000..f53bcff01
--- /dev/null
+++ b/include/drm/intel/intel-gtt.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Common header for intel-gtt.ko and i915.ko */
+
+#ifndef _DRM_INTEL_GTT_H
+#define	_DRM_INTEL_GTT_H
+
+#include <linux/types.h>
+
+struct agp_bridge_data;
+struct pci_dev;
+struct sg_table;
+
+void intel_gmch_gtt_get(u64 *gtt_total,
+			phys_addr_t *mappable_base,
+			resource_size_t *mappable_end);
+
+int intel_gmch_probe(struct pci_dev *bridge_pdev, struct pci_dev *gpu_pdev,
+		     struct agp_bridge_data *bridge);
+void intel_gmch_remove(void);
+
+bool intel_gmch_enable_gtt(void);
+
+void intel_gmch_gtt_flush(void);
+void intel_gmch_gtt_insert_page(dma_addr_t addr,
+				unsigned int pg,
+				unsigned int flags);
+void intel_gmch_gtt_insert_sg_entries(struct sg_table *st,
+				      unsigned int pg_start,
+				      unsigned int flags);
+void intel_gmch_gtt_clear_range(unsigned int first_entry, unsigned int num_entries);
+dma_addr_t intel_gmch_gtt_read_entry(unsigned int pg,
+				     bool *is_present, bool *is_local);
+
+/* Special gtt memory types */
+#define AGP_DCACHE_MEMORY	1
+#define AGP_PHYS_MEMORY		2
+
+/* flag for GFDT type */
+#define AGP_USER_CACHED_MEMORY_GFDT (1 << 3)
+
+#endif