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, 214 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinconf.h b/drivers/pinctrl/pinconf.h
new file mode 100644
index 000000000..fc2d6cce9
--- /dev/null
+++ b/drivers/pinctrl/pinconf.h
@@ -0,0 +1,214 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Internal interface between the core pin control system and the
+ * pin config portions
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ * Based on bits of regulator core, gpio core and clk core
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/errno.h>
+
+struct dentry;
+struct device_node;
+struct seq_file;
+
+struct pinctrl_dev;
+struct pinctrl_map;
+struct pinctrl_setting;
+
+#ifdef CONFIG_PINCONF
+
+int pinconf_check_ops(struct pinctrl_dev *pctldev);
+int pinconf_validate_map(const struct pinctrl_map *map, int i);
+int pinconf_map_to_setting(const struct pinctrl_map *map,
+			  struct pinctrl_setting *setting);
+void pinconf_free_setting(const struct pinctrl_setting *setting);
+int pinconf_apply_setting(const struct pinctrl_setting *setting);
+
+int pinconf_set_config(struct pinctrl_dev *pctldev, unsigned int pin,
+		       unsigned long *configs, size_t nconfigs);
+
+/*
+ * You will only be interested in these if you're using PINCONF
+ * so don't supply any stubs for these.
+ */
+int pin_config_get_for_pin(struct pinctrl_dev *pctldev, unsigned int pin,
+			   unsigned long *config);
+int pin_config_group_get(const char *dev_name, const char *pin_group,
+			 unsigned long *config);
+
+#else
+
+static inline int pinconf_check_ops(struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static inline int pinconf_validate_map(const struct pinctrl_map *map, int i)
+{
+	return 0;
+}
+
+static inline int pinconf_map_to_setting(const struct pinctrl_map *map,
+			  struct pinctrl_setting *setting)
+{
+	return 0;
+}
+
+static inline void pinconf_free_setting(const struct pinctrl_setting *setting)
+{
+}
+
+static inline int pinconf_apply_setting(const struct pinctrl_setting *setting)
+{
+	return 0;
+}
+
+static inline int pinconf_set_config(struct pinctrl_dev *pctldev, unsigned int pin,
+				     unsigned long *configs, size_t nconfigs)
+{
+	return -ENOTSUPP;
+}
+
+static inline int pin_config_get_for_pin(struct pinctrl_dev *pctldev, unsigned int pin,
+			   unsigned long *config)
+{
+	return -ENOTSUPP;
+}
+
+#endif
+
+#if defined(CONFIG_PINCONF) && defined(CONFIG_DEBUG_FS)
+
+void pinconf_show_map(struct seq_file *s, const struct pinctrl_map *map);
+void pinconf_show_setting(struct seq_file *s,
+			  const struct pinctrl_setting *setting);
+void pinconf_init_device_debugfs(struct dentry *devroot,
+				 struct pinctrl_dev *pctldev);
+
+#else
+
+static inline void pinconf_show_map(struct seq_file *s,
+				    const struct pinctrl_map *map)
+{
+}
+
+static inline void pinconf_show_setting(struct seq_file *s,
+					const struct pinctrl_setting *setting)
+{
+}
+
+static inline void pinconf_init_device_debugfs(struct dentry *devroot,
+					       struct pinctrl_dev *pctldev)
+{
+}
+
+#endif
+
+/*
+ * The following functions are available if the driver uses the generic
+ * pin config.
+ */
+
+#if defined(CONFIG_GENERIC_PINCONF) && defined(CONFIG_DEBUG_FS)
+
+void pinconf_generic_dump_pins(struct pinctrl_dev *pctldev,
+			       struct seq_file *s, const char *gname,
+			       unsigned int pin);
+
+void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
+				 struct seq_file *s, unsigned long config);
+#else
+
+static inline void pinconf_generic_dump_pins(struct pinctrl_dev *pctldev,
+					     struct seq_file *s,
+					     const char *gname, unsigned int pin)
+{
+	return;
+}
+
+static inline void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
+					       struct seq_file *s,
+					       unsigned long config)
+{
+	return;
+}
+#endif
+
+#if defined(CONFIG_GENERIC_PINCONF) && defined(CONFIG_OF)
+int pinconf_generic_parse_dt_config(struct device_node *np,
+				    struct pinctrl_dev *pctldev,
+				    unsigned long **configs,
+				    unsigned int *nconfigs);
+
+int pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev,
+				    unsigned int **pid, unsigned int **pmux,
+				    unsigned int *npins);
+#else
+static inline int
+pinconf_generic_parse_dt_config(struct device_node *np,
+				struct pinctrl_dev *pctldev,
+				unsigned long **configs,
+				unsigned int *nconfigs)
+{
+	return -ENOTSUPP;
+}
+
+static inline int
+pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev,
+				unsigned int **pid, unsigned int **pmux,
+				unsigned int *npins)
+{
+	return -ENOTSUPP;
+}
+#endif
+
+#if defined(CONFIG_GENERIC_PINCTRL)
+int pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
+						 struct device_node *np,
+						 struct pinctrl_map **maps,
+						 unsigned int *num_maps);
+
+int pinctrl_generic_pinmux_dt_node_to_map(struct pinctrl_dev *pctldev,
+					  struct device_node *np,
+					  struct pinctrl_map **maps,
+					  unsigned int *num_maps);
+
+int pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+			   struct device_node *np, struct pinctrl_map **maps,
+			   unsigned int *num_maps, unsigned int *num_reserved_maps,
+			   const char **group_name, unsigned int ngroups,
+			   void *data, unsigned int *pins, unsigned int npins);
+#else
+static inline int
+pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
+					     struct device_node *np,
+					     struct pinctrl_map **maps,
+					     unsigned int *num_maps)
+{
+	return -ENOTSUPP;
+}
+
+static inline int
+pinctrl_generic_pinmux_dt_node_to_map(struct pinctrl_dev *pctldev,
+				      struct device_node *np,
+				      struct pinctrl_map **maps,
+				      unsigned int *num_maps)
+{
+	return -ENOTSUPP;
+}
+
+static inline int
+pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+		       struct device_node *np, struct pinctrl_map **maps,
+		       unsigned int *num_maps, unsigned int *num_reserved_maps,
+		       const char **group_name, unsigned int ngroups,
+		       void *data, unsigned int *pins, unsigned int npins)
+{
+	return -ENOTSUPP;
+}
+#endif