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, 57 insertions, 0 deletions

diff --git a/drivers/hid/hid-vivaldi.c b/drivers/hid/hid-vivaldi.c
new file mode 100644
index 000000000..cda5938fb
--- /dev/null
+++ b/drivers/hid/hid-vivaldi.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * HID support for Vivaldi Keyboard
+ *
+ * Copyright 2020 Google LLC.
+ * Author: Sean O'Brien <seobrien@chromium.org>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/input/vivaldi-fmap.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include "hid-vivaldi-common.h"
+
+static int vivaldi_probe(struct hid_device *hdev,
+			 const struct hid_device_id *id)
+{
+	struct vivaldi_data *drvdata;
+	int ret;
+
+	drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	hid_set_drvdata(hdev, drvdata);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+}
+
+static const struct hid_device_id vivaldi_table[] = {
+	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_VIVALDI, HID_ANY_ID, HID_ANY_ID) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(hid, vivaldi_table);
+
+static struct hid_driver hid_vivaldi = {
+	.name = "hid-vivaldi",
+	.id_table = vivaldi_table,
+	.probe = vivaldi_probe,
+	.feature_mapping = vivaldi_feature_mapping,
+	.driver = {
+		.dev_groups = vivaldi_attribute_groups,
+	},
+};
+
+module_hid_driver(hid_vivaldi);
+
+MODULE_AUTHOR("Sean O'Brien");
+MODULE_DESCRIPTION("HID vivaldi driver");
+MODULE_LICENSE("GPL");