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, 130 insertions, 0 deletions

diff --git a/drivers/leds/leds-wrap.c b/drivers/leds/leds-wrap.c
new file mode 100644
index 000000000..794697e16
--- /dev/null
+++ b/drivers/leds/leds-wrap.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LEDs driver for PCEngines WRAP
+ *
+ * Copyright (C) 2006 Kristian Kielhofner <kris@krisk.org>
+ *
+ * Based on leds-net48xx.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/scx200_gpio.h>
+#include <linux/module.h>
+
+#define DRVNAME "wrap-led"
+#define WRAP_POWER_LED_GPIO	2
+#define WRAP_ERROR_LED_GPIO	3
+#define WRAP_EXTRA_LED_GPIO	18
+
+static struct platform_device *pdev;
+
+static void wrap_power_led_set(struct led_classdev *led_cdev,
+		enum led_brightness value)
+{
+	if (value)
+		scx200_gpio_set_low(WRAP_POWER_LED_GPIO);
+	else
+		scx200_gpio_set_high(WRAP_POWER_LED_GPIO);
+}
+
+static void wrap_error_led_set(struct led_classdev *led_cdev,
+		enum led_brightness value)
+{
+	if (value)
+		scx200_gpio_set_low(WRAP_ERROR_LED_GPIO);
+	else
+		scx200_gpio_set_high(WRAP_ERROR_LED_GPIO);
+}
+
+static void wrap_extra_led_set(struct led_classdev *led_cdev,
+		enum led_brightness value)
+{
+	if (value)
+		scx200_gpio_set_low(WRAP_EXTRA_LED_GPIO);
+	else
+		scx200_gpio_set_high(WRAP_EXTRA_LED_GPIO);
+}
+
+static struct led_classdev wrap_power_led = {
+	.name			= "wrap::power",
+	.brightness_set		= wrap_power_led_set,
+	.default_trigger	= "default-on",
+	.flags			= LED_CORE_SUSPENDRESUME,
+};
+
+static struct led_classdev wrap_error_led = {
+	.name		= "wrap::error",
+	.brightness_set	= wrap_error_led_set,
+	.flags			= LED_CORE_SUSPENDRESUME,
+};
+
+static struct led_classdev wrap_extra_led = {
+	.name           = "wrap::extra",
+	.brightness_set = wrap_extra_led_set,
+	.flags			= LED_CORE_SUSPENDRESUME,
+};
+
+static int wrap_led_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = devm_led_classdev_register(&pdev->dev, &wrap_power_led);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_led_classdev_register(&pdev->dev, &wrap_error_led);
+	if (ret < 0)
+		return ret;
+
+	return  devm_led_classdev_register(&pdev->dev, &wrap_extra_led);
+}
+
+static struct platform_driver wrap_led_driver = {
+	.probe		= wrap_led_probe,
+	.driver		= {
+		.name		= DRVNAME,
+	},
+};
+
+static int __init wrap_led_init(void)
+{
+	int ret;
+
+	if (!scx200_gpio_present()) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = platform_driver_register(&wrap_led_driver);
+	if (ret < 0)
+		goto out;
+
+	pdev = platform_device_register_simple(DRVNAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		ret = PTR_ERR(pdev);
+		platform_driver_unregister(&wrap_led_driver);
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+static void __exit wrap_led_exit(void)
+{
+	platform_device_unregister(pdev);
+	platform_driver_unregister(&wrap_led_driver);
+}
+
+module_init(wrap_led_init);
+module_exit(wrap_led_exit);
+
+MODULE_AUTHOR("Kristian Kielhofner <kris@krisk.org>");
+MODULE_DESCRIPTION("PCEngines WRAP LED driver");
+MODULE_LICENSE("GPL");
+