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, 87 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/firebee.c b/arch/m68k/coldfire/firebee.c
new file mode 100644
index 000000000..3b9d4fc6f
--- /dev/null
+++ b/arch/m68k/coldfire/firebee.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/***************************************************************************/
+
+/*
+ *	firebee.c -- extra startup code support for the FireBee boards
+ *
+ *	Copyright (C) 2011, Greg Ungerer (gerg@snapgear.com)
+ */
+
+/***************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/physmap.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+
+/***************************************************************************/
+
+/*
+ *	8MB of NOR flash fitted to the FireBee board.
+ */
+#define	FLASH_PHYS_ADDR		0xe0000000	/* Physical address of flash */
+#define	FLASH_PHYS_SIZE		0x00800000	/* Size of flash */
+
+#define	PART_BOOT_START		0x00000000	/* Start at bottom of flash */
+#define	PART_BOOT_SIZE		0x00040000	/* 256k in size */
+#define	PART_IMAGE_START	0x00040000	/* Start after boot loader */
+#define	PART_IMAGE_SIZE		0x006c0000	/* Most of flash */
+#define	PART_FPGA_START		0x00700000	/* Start at offset 7MB */
+#define	PART_FPGA_SIZE		0x00100000	/* 1MB in size */
+
+static struct mtd_partition firebee_flash_parts[] = {
+	{
+		.name	= "dBUG",
+		.offset	= PART_BOOT_START,
+		.size	= PART_BOOT_SIZE,
+	},
+	{
+		.name	= "FPGA",
+		.offset	= PART_FPGA_START,
+		.size	= PART_FPGA_SIZE,
+	},
+	{
+		.name	= "image",
+		.offset	= PART_IMAGE_START,
+		.size	= PART_IMAGE_SIZE,
+	},
+};
+
+static struct physmap_flash_data firebee_flash_data = {
+	.width		= 2,
+	.nr_parts	= ARRAY_SIZE(firebee_flash_parts),
+	.parts		= firebee_flash_parts,
+};
+
+static struct resource firebee_flash_resource = {
+	.start		= FLASH_PHYS_ADDR,
+	.end		= FLASH_PHYS_ADDR + FLASH_PHYS_SIZE,
+	.flags		= IORESOURCE_MEM,
+};
+
+static struct platform_device firebee_flash = {
+	.name		= "physmap-flash",
+	.id		= 0,
+	.dev		= {
+		.platform_data = &firebee_flash_data,
+	},
+	.num_resources	= 1,
+	.resource	= &firebee_flash_resource,
+};
+
+/***************************************************************************/
+
+static int __init init_firebee(void)
+{
+	platform_device_register(&firebee_flash);
+	return 0;
+}
+
+arch_initcall(init_firebee);
+
+/***************************************************************************/