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, 73 insertions, 0 deletions

diff --git a/include/asm-generic/topology.h b/include/asm-generic/topology.h
new file mode 100644
index 000000000..9865ba48c
--- /dev/null
+++ b/include/asm-generic/topology.h
@@ -0,0 +1,73 @@
+/*
+ * linux/include/asm-generic/topology.h
+ *
+ * Written by: Matthew Dobson, IBM Corporation
+ *
+ * Copyright (C) 2002, IBM Corp.
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to <colpatch@us.ibm.com>
+ */
+#ifndef _ASM_GENERIC_TOPOLOGY_H
+#define _ASM_GENERIC_TOPOLOGY_H
+
+#ifndef	CONFIG_NUMA
+
+/* Other architectures wishing to use this simple topology API should fill
+   in the below functions as appropriate in their own <asm/topology.h> file. */
+#ifndef cpu_to_node
+#define cpu_to_node(cpu)	((void)(cpu),0)
+#endif
+#ifndef set_numa_node
+#define set_numa_node(node)
+#endif
+#ifndef set_cpu_numa_node
+#define set_cpu_numa_node(cpu, node)
+#endif
+#ifndef cpu_to_mem
+#define cpu_to_mem(cpu)		((void)(cpu),0)
+#endif
+
+#ifndef cpumask_of_node
+#define cpumask_of_node(node)	((void)(node), cpu_online_mask)
+#endif
+#ifndef pcibus_to_node
+#define pcibus_to_node(bus)	((void)(bus), -1)
+#endif
+
+#ifndef cpumask_of_pcibus
+#define cpumask_of_pcibus(bus)	(pcibus_to_node(bus) == -1 ?		\
+				 cpu_all_mask :				\
+				 cpumask_of_node(pcibus_to_node(bus)))
+#endif
+
+#endif	/* !CONFIG_NUMA */
+
+#if !defined(CONFIG_NUMA) || !defined(CONFIG_HAVE_MEMORYLESS_NODES)
+
+#ifndef set_numa_mem
+#define set_numa_mem(node)
+#endif
+#ifndef set_cpu_numa_mem
+#define set_cpu_numa_mem(cpu, node)
+#endif
+
+#endif	/* !CONFIG_NUMA || !CONFIG_HAVE_MEMORYLESS_NODES */
+
+#endif /* _ASM_GENERIC_TOPOLOGY_H */