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, 98 insertions, 0 deletions

diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
new file mode 100644
index 000000000..bff2ca035
--- /dev/null
+++ b/include/acpi/acpi_drivers.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  acpi_drivers.h  ($Revision: 31 $)
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ */
+
+#ifndef __ACPI_DRIVERS_H__
+#define __ACPI_DRIVERS_H__
+
+#define ACPI_MAX_STRING			80
+
+/*
+ * _HID definitions
+ * HIDs must conform to ACPI spec(6.1.4)
+ * Linux specific HIDs do not apply to this and begin with LNX:
+ */
+
+#define ACPI_POWER_HID			"LNXPOWER"
+#define ACPI_PROCESSOR_OBJECT_HID	"LNXCPU"
+#define ACPI_SYSTEM_HID			"LNXSYSTM"
+#define ACPI_THERMAL_HID		"LNXTHERM"
+#define ACPI_BUTTON_HID_POWERF		"LNXPWRBN"
+#define ACPI_BUTTON_HID_SLEEPF		"LNXSLPBN"
+#define ACPI_VIDEO_HID			"LNXVIDEO"
+#define ACPI_BAY_HID			"LNXIOBAY"
+#define ACPI_DOCK_HID			"LNXDOCK"
+#define ACPI_ECDT_HID			"LNXEC"
+/* SMBUS HID definition as supported by Microsoft Windows */
+#define ACPI_SMBUS_MS_HID		"SMB0001"
+/* Quirk for broken IBM BIOSes */
+#define ACPI_SMBUS_IBM_HID		"SMBUSIBM"
+
+/*
+ * For fixed hardware buttons, we fabricate acpi_devices with HID
+ * ACPI_BUTTON_HID_POWERF or ACPI_BUTTON_HID_SLEEPF.  Fixed hardware
+ * signals only an event; it doesn't supply a notification value.
+ * To allow drivers to treat notifications from fixed hardware the
+ * same as those from real devices, we turn the events into this
+ * notification value.
+ */
+#define ACPI_FIXED_HARDWARE_EVENT	0x100
+
+/* --------------------------------------------------------------------------
+                                       PCI
+   -------------------------------------------------------------------------- */
+
+
+/* ACPI PCI Interrupt Link */
+
+int acpi_irq_penalty_init(void);
+int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
+			       int *polarity, char **name, u32 *gsi);
+int acpi_pci_link_free_irq(acpi_handle handle);
+
+/* ACPI PCI Device Binding */
+
+struct pci_bus;
+
+#ifdef CONFIG_PCI
+struct pci_dev *acpi_dev_get_pci_dev(struct acpi_device *adev);
+#else
+static inline struct pci_dev *acpi_dev_get_pci_dev(struct acpi_device *adev)
+{
+	return NULL;
+}
+#endif
+
+static inline struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
+{
+	return acpi_dev_get_pci_dev(acpi_fetch_acpi_dev(handle));
+}
+
+/* Arch-defined function to add a bus to the system */
+
+struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root);
+
+#ifdef CONFIG_X86
+void pci_acpi_crs_quirks(void);
+#else
+static inline void pci_acpi_crs_quirks(void) { }
+#endif
+
+/*--------------------------------------------------------------------------
+                                  Dock Station
+  -------------------------------------------------------------------------- */
+
+#ifdef CONFIG_ACPI_DOCK
+extern int is_dock_device(struct acpi_device *adev);
+#else
+static inline int is_dock_device(struct acpi_device *adev)
+{
+	return 0;
+}
+#endif /* CONFIG_ACPI_DOCK */
+
+#endif /*__ACPI_DRIVERS_H__*/