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, 50 insertions, 0 deletions

diff --git a/include/acpi/acpi_numa.h b/include/acpi/acpi_numa.h
new file mode 100644
index 000000000..99b960bd4
--- /dev/null
+++ b/include/acpi/acpi_numa.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ACPI_NUMA_H
+#define __ACPI_NUMA_H
+
+#ifdef CONFIG_ACPI_NUMA
+#include <linux/numa.h>
+
+/* Proximity bitmap length */
+#if MAX_NUMNODES > 256
+#define MAX_PXM_DOMAINS MAX_NUMNODES
+#else
+#define MAX_PXM_DOMAINS (256)	/* Old pxm spec is defined 8 bit */
+#endif
+
+extern int pxm_to_node(int);
+extern int node_to_pxm(int);
+extern int acpi_map_pxm_to_node(int);
+extern unsigned char acpi_srat_revision;
+extern void disable_srat(void);
+extern int fix_pxm_node_maps(int max_nid);
+
+extern void bad_srat(void);
+extern int srat_disabled(void);
+
+#else				/* CONFIG_ACPI_NUMA */
+static inline int fix_pxm_node_maps(int max_nid)
+{
+	return 0;
+}
+static inline void disable_srat(void)
+{
+}
+static inline int pxm_to_node(int pxm)
+{
+	return 0;
+}
+static inline int node_to_pxm(int node)
+{
+	return 0;
+}
+#endif				/* CONFIG_ACPI_NUMA */
+
+#ifdef CONFIG_ACPI_HMAT
+extern void disable_hmat(void);
+#else				/* CONFIG_ACPI_HMAT */
+static inline void disable_hmat(void)
+{
+}
+#endif				/* CONFIG_ACPI_HMAT */
+#endif				/* __ACPI_NUMA_H */