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/drivers/gpib/include/gpibP.h b/drivers/gpib/include/gpibP.h
new file mode 100644
index 000000000..e3938ada3
--- /dev/null
+++ b/drivers/gpib/include/gpibP.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/***************************************************************************
+ *    copyright		   : (C) 2002,2003 by Frank Mori Hess
+ ***************************************************************************/
+
+#ifndef _GPIB_P_H
+#define _GPIB_P_H
+
+#include <linux/types.h>
+
+#include "gpib_types.h"
+#include "gpib_proto.h"
+#include "gpib_cmd.h"
+#include <linux/gpib.h>
+#include <linux/gpib_ioctl.h>
+
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+int gpib_register_driver(struct gpib_interface *interface, struct module *mod);
+void gpib_unregister_driver(struct gpib_interface *interface);
+struct pci_dev *gpib_pci_get_device(const struct gpib_board_config *config, unsigned int vendor_id,
+				    unsigned int device_id, struct pci_dev *from);
+struct pci_dev *gpib_pci_get_subsys(const struct gpib_board_config *config, unsigned int vendor_id,
+				    unsigned int device_id, unsigned int ss_vendor,
+				    unsigned int ss_device, struct pci_dev *from);
+unsigned int num_gpib_events(const struct gpib_event_queue *queue);
+int push_gpib_event(struct gpib_board *board, short event_type);
+int pop_gpib_event(struct gpib_board *board, struct gpib_event_queue *queue, short *event_type);
+int gpib_request_pseudo_irq(struct gpib_board *board, irqreturn_t (*handler)(int, void *));
+void gpib_free_pseudo_irq(struct gpib_board *board);
+int gpib_match_device_path(struct device *dev, const char *device_path_in);
+
+extern struct gpib_board board_array[GPIB_MAX_NUM_BOARDS];
+
+extern struct list_head registered_drivers;
+
+#endif	// _GPIB_P_H
+