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, 138 insertions, 0 deletions

diff --git a/drivers/regulator/internal.h b/drivers/regulator/internal.h
new file mode 100644
index 000000000..b3d48dc38
--- /dev/null
+++ b/drivers/regulator/internal.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * internal.h  --  Voltage/Current Regulator framework internal code
+ *
+ * Copyright 2007, 2008 Wolfson Microelectronics PLC.
+ * Copyright 2008 SlimLogic Ltd.
+ *
+ * Author: Liam Girdwood <lrg@slimlogic.co.uk>
+ */
+
+#ifndef __REGULATOR_INTERNAL_H
+#define __REGULATOR_INTERNAL_H
+
+#include <linux/suspend.h>
+
+#define REGULATOR_STATES_NUM	(PM_SUSPEND_MAX + 1)
+
+#define rdev_crit(rdev, fmt, ...)					\
+	pr_crit("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
+#define rdev_err(rdev, fmt, ...)					\
+	pr_err("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
+#define rdev_warn(rdev, fmt, ...)					\
+	pr_warn("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
+#define rdev_info(rdev, fmt, ...)					\
+	pr_info("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
+#define rdev_dbg(rdev, fmt, ...)					\
+	pr_debug("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
+
+struct regulator_voltage {
+	int min_uV;
+	int max_uV;
+};
+
+/*
+ * struct regulator
+ *
+ * One for each consumer device.
+ * @voltage - a voltage array for each state of runtime, i.e.:
+ *            PM_SUSPEND_ON
+ *            PM_SUSPEND_TO_IDLE
+ *            PM_SUSPEND_STANDBY
+ *            PM_SUSPEND_MEM
+ *            PM_SUSPEND_MAX
+ */
+struct regulator {
+	struct device *dev;
+	struct list_head list;
+	unsigned int always_on:1;
+	unsigned int bypass:1;
+	unsigned int device_link:1;
+	int uA_load;
+	unsigned int enable_count;
+	unsigned int deferred_disables;
+	struct regulator_voltage voltage[REGULATOR_STATES_NUM];
+	const char *supply_name;
+	struct device_attribute dev_attr;
+	struct regulator_dev *rdev;
+	struct dentry *debugfs;
+};
+
+extern const struct class regulator_class;
+
+static inline struct regulator_dev *dev_to_rdev(struct device *dev)
+{
+	return container_of(dev, struct regulator_dev, dev);
+}
+
+enum regulator_get_type {
+	NORMAL_GET,
+	EXCLUSIVE_GET,
+	OPTIONAL_GET,
+	MAX_GET_TYPE
+};
+
+#ifdef CONFIG_OF
+struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+					      struct device_node *np,
+					      const char *supply);
+struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
+			         const struct regulator_desc *desc,
+				 struct regulator_config *config,
+				 struct device_node **node);
+
+struct regulator *_of_regulator_get(struct device *dev, struct device_node *node,
+				    const char *id, enum regulator_get_type get_type);
+
+struct regulator_dev *of_parse_coupled_regulator(struct regulator_dev *rdev,
+						 int index);
+
+int of_get_n_coupled(struct regulator_dev *rdev);
+
+bool of_check_coupling_data(struct regulator_dev *rdev);
+
+#else
+static inline struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+							    struct device_node *np,
+							    const char *supply)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline struct regulator_init_data *
+regulator_of_get_init_data(struct device *dev,
+			   const struct regulator_desc *desc,
+			   struct regulator_config *config,
+			   struct device_node **node)
+{
+	return NULL;
+}
+
+static inline struct regulator_dev *
+of_parse_coupled_regulator(struct regulator_dev *rdev,
+			   int index)
+{
+	return NULL;
+}
+
+static inline int of_get_n_coupled(struct regulator_dev *rdev)
+{
+	return 0;
+}
+
+static inline bool of_check_coupling_data(struct regulator_dev *rdev)
+{
+	return false;
+}
+
+#endif
+
+int _regulator_get_common_check(struct device *dev, const char *id,
+				enum regulator_get_type get_type);
+struct regulator *_regulator_get_common(struct regulator_dev *rdev, struct device *dev,
+					const char *id, enum regulator_get_type get_type);
+struct regulator *_regulator_get(struct device *dev, const char *id,
+				 enum regulator_get_type get_type);
+int _regulator_bulk_get(struct device *dev, int num_consumers,
+			struct regulator_bulk_data *consumers, enum regulator_get_type get_type);
+#endif