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, 89 insertions, 0 deletions

diff --git a/drivers/ps3/vuart.h b/drivers/ps3/vuart.h
new file mode 100644
index 000000000..64d34efef
--- /dev/null
+++ b/drivers/ps3/vuart.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  PS3 virtual uart
+ *
+ *  Copyright (C) 2006 Sony Computer Entertainment Inc.
+ *  Copyright 2006 Sony Corp.
+ */
+
+#if !defined(_PS3_VUART_H)
+#define _PS3_VUART_H
+
+#include <asm/ps3.h>
+
+struct ps3_vuart_stats {
+	unsigned long bytes_written;
+	unsigned long bytes_read;
+	unsigned long tx_interrupts;
+	unsigned long rx_interrupts;
+	unsigned long disconnect_interrupts;
+};
+
+struct ps3_vuart_work {
+	struct work_struct work;
+	unsigned long trigger;
+	struct ps3_system_bus_device *dev; /* to convert work to device */
+};
+
+/**
+ * struct ps3_vuart_port_driver - a driver for a device on a vuart port
+ */
+
+struct ps3_vuart_port_driver {
+	struct ps3_system_bus_driver core;
+	int (*probe)(struct ps3_system_bus_device *);
+	int (*remove)(struct ps3_system_bus_device *);
+	void (*shutdown)(struct ps3_system_bus_device *);
+	void (*work)(struct ps3_system_bus_device *);
+	/* int (*tx_event)(struct ps3_system_bus_device *dev); */
+	/* int (*rx_event)(struct ps3_system_bus_device *dev); */
+	/* int (*disconnect_event)(struct ps3_system_bus_device *dev); */
+	/* int (*suspend)(struct ps3_system_bus_device *, pm_message_t); */
+	/* int (*resume)(struct ps3_system_bus_device *); */
+};
+
+int ps3_vuart_port_driver_register(struct ps3_vuart_port_driver *drv);
+void ps3_vuart_port_driver_unregister(struct ps3_vuart_port_driver *drv);
+
+static inline struct ps3_vuart_port_driver *
+	ps3_system_bus_dev_to_vuart_drv(struct ps3_system_bus_device *_dev)
+{
+	struct ps3_system_bus_driver *sbd =
+		ps3_system_bus_dev_to_system_bus_drv(_dev);
+	BUG_ON(!sbd);
+	return container_of(sbd, struct ps3_vuart_port_driver, core);
+}
+static inline struct ps3_system_bus_device *ps3_vuart_work_to_system_bus_dev(
+	struct work_struct *_work)
+{
+	struct ps3_vuart_work *vw = container_of(_work, struct ps3_vuart_work,
+		work);
+	return vw->dev;
+}
+
+int ps3_vuart_write(struct ps3_system_bus_device *dev, const void *buf,
+	unsigned int bytes);
+int ps3_vuart_read(struct ps3_system_bus_device *dev, void *buf,
+	unsigned int bytes);
+int ps3_vuart_read_async(struct ps3_system_bus_device *dev, unsigned int bytes);
+void ps3_vuart_cancel_async(struct ps3_system_bus_device *dev);
+void ps3_vuart_clear_rx_bytes(struct ps3_system_bus_device *dev,
+	unsigned int bytes);
+
+struct vuart_triggers {
+	unsigned long rx;
+	unsigned long tx;
+};
+
+int ps3_vuart_get_triggers(struct ps3_system_bus_device *dev,
+	struct vuart_triggers *trig);
+int ps3_vuart_set_triggers(struct ps3_system_bus_device *dev, unsigned int tx,
+	unsigned int rx);
+int ps3_vuart_enable_interrupt_tx(struct ps3_system_bus_device *dev);
+int ps3_vuart_disable_interrupt_tx(struct ps3_system_bus_device *dev);
+int ps3_vuart_enable_interrupt_rx(struct ps3_system_bus_device *dev);
+int ps3_vuart_disable_interrupt_rx(struct ps3_system_bus_device *dev);
+int ps3_vuart_enable_interrupt_disconnect(struct ps3_system_bus_device *dev);
+int ps3_vuart_disable_interrupt_disconnect(struct ps3_system_bus_device *dev);
+
+#endif