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, 98 insertions, 0 deletions

diff --git a/drivers/hid/hid-retrode.c b/drivers/hid/hid-retrode.c
new file mode 100644
index 000000000..7997627fd
--- /dev/null
+++ b/drivers/hid/hid-retrode.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for Retrode 2 controller adapter and plug-in extensions
+ *
+ *  Copyright (c) 2017 Bastien Nocera <hadess@hadess.net>
+ */
+
+/*
+ */
+
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+#define CONTROLLER_NAME_BASE "Retrode"
+
+static int retrode_input_configured(struct hid_device *hdev,
+					struct hid_input *hi)
+{
+	struct hid_field *field = hi->report->field[0];
+	const char *suffix;
+	int number = 0;
+	char *name;
+
+	switch (field->report->id) {
+	case 0:
+		suffix = "SNES Mouse";
+		break;
+	case 1:
+	case 2:
+		suffix = "SNES / N64";
+		number = field->report->id;
+		break;
+	case 3:
+	case 4:
+		suffix = "Mega Drive";
+		number = field->report->id - 2;
+		break;
+	default:
+		hid_err(hdev, "Got unhandled report id %d\n", field->report->id);
+		suffix = "Unknown";
+	}
+
+	if (number)
+		name = devm_kasprintf(&hdev->dev, GFP_KERNEL,
+				"%s %s #%d", CONTROLLER_NAME_BASE,
+				suffix, number);
+	else
+		name = devm_kasprintf(&hdev->dev, GFP_KERNEL,
+				"%s %s", CONTROLLER_NAME_BASE, suffix);
+
+	if (!name)
+		return -ENOMEM;
+
+	hi->input->name = name;
+
+	return 0;
+}
+
+static int retrode_probe(struct hid_device *hdev,
+			const struct hid_device_id *id)
+{
+
+	int ret;
+
+	/* Has no effect on the mouse device */
+	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct hid_device_id retrode_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_FUTURE_TECHNOLOGY, USB_DEVICE_ID_RETRODE2) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, retrode_devices);
+
+static struct hid_driver retrode_driver = {
+	.name             = "hid-retrode",
+	.id_table         = retrode_devices,
+	.input_configured = retrode_input_configured,
+	.probe            = retrode_probe,
+};
+
+module_hid_driver(retrode_driver);
+
+MODULE_DESCRIPTION("HID driver for Retrode 2 controller adapter and plug-in extensions");
+MODULE_LICENSE("GPL");