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, 43 insertions, 0 deletions

diff --git a/drivers/spi/spi-intel-platform.c b/drivers/spi/spi-intel-platform.c
new file mode 100644
index 000000000..6cbed0b2e
--- /dev/null
+++ b/drivers/spi/spi-intel-platform.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel PCH/PCU SPI flash platform driver.
+ *
+ * Copyright (C) 2016 - 2022, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "spi-intel.h"
+
+static int intel_spi_platform_probe(struct platform_device *pdev)
+{
+	struct intel_spi_boardinfo *info;
+	void __iomem *base;
+
+	info = dev_get_platdata(&pdev->dev);
+	if (!info)
+		return -EINVAL;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	return intel_spi_probe(&pdev->dev, base, info);
+}
+
+static struct platform_driver intel_spi_platform_driver = {
+	.probe = intel_spi_platform_probe,
+	.driver = {
+		.name = "intel-spi",
+		.dev_groups = intel_spi_groups,
+	},
+};
+
+module_platform_driver(intel_spi_platform_driver);
+
+MODULE_DESCRIPTION("Intel PCH/PCU SPI flash platform driver");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:intel-spi");