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, 142 insertions, 0 deletions

diff --git a/drivers/hid/hid-vivaldi-common.c b/drivers/hid/hid-vivaldi-common.c
new file mode 100644
index 000000000..b12bb5cc0
--- /dev/null
+++ b/drivers/hid/hid-vivaldi-common.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for ChromeOS HID Vivaldi keyboards
+ *
+ * Copyright (C) 2022 Google, Inc
+ */
+
+#include <linux/export.h>
+#include <linux/hid.h>
+#include <linux/input/vivaldi-fmap.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include "hid-vivaldi-common.h"
+
+#define MIN_FN_ROW_KEY 1
+#define MAX_FN_ROW_KEY VIVALDI_MAX_FUNCTION_ROW_KEYS
+#define HID_VD_FN_ROW_PHYSMAP 0x00000001
+#define HID_USAGE_FN_ROW_PHYSMAP (HID_UP_GOOGLEVENDOR | HID_VD_FN_ROW_PHYSMAP)
+
+/**
+ * vivaldi_feature_mapping - Fill out vivaldi keymap data exposed via HID
+ * @hdev: HID device to parse
+ * @field: HID field to parse
+ * @usage: HID usage to parse
+ *
+ * Note: this function assumes that driver data attached to @hdev contains an
+ * instance of &struct vivaldi_data at the very beginning.
+ */
+void vivaldi_feature_mapping(struct hid_device *hdev,
+			     struct hid_field *field, struct hid_usage *usage)
+{
+	struct vivaldi_data *data = hid_get_drvdata(hdev);
+	struct hid_report *report = field->report;
+	u8 *report_data, *buf;
+	u32 report_len;
+	unsigned int fn_key;
+	int ret;
+
+	if (field->logical != HID_USAGE_FN_ROW_PHYSMAP ||
+	    (usage->hid & HID_USAGE_PAGE) != HID_UP_ORDINAL)
+		return;
+
+	fn_key = usage->hid & HID_USAGE;
+	if (fn_key < MIN_FN_ROW_KEY || fn_key > MAX_FN_ROW_KEY)
+		return;
+
+	if (fn_key > data->num_function_row_keys)
+		data->num_function_row_keys = fn_key;
+
+	report_data = buf = hid_alloc_report_buf(report, GFP_KERNEL);
+	if (!report_data)
+		return;
+
+	report_len = hid_report_len(report);
+	if (!report->id) {
+		/*
+		 * hid_hw_raw_request() will stuff report ID (which will be 0)
+		 * into the first byte of the buffer even for unnumbered
+		 * reports, so we need to account for this to avoid getting
+		 * -EOVERFLOW in return.
+		 * Note that hid_alloc_report_buf() adds 7 bytes to the size
+		 * so we can safely say that we have space for an extra byte.
+		 */
+		report_len++;
+	}
+
+	ret = hid_hw_raw_request(hdev, report->id, report_data,
+				 report_len, HID_FEATURE_REPORT,
+				 HID_REQ_GET_REPORT);
+	if (ret < 0) {
+		dev_warn(&hdev->dev, "failed to fetch feature %d\n",
+			 field->report->id);
+		goto out;
+	}
+
+	if (!report->id) {
+		/*
+		 * Undo the damage from hid_hw_raw_request() for unnumbered
+		 * reports.
+		 */
+		report_data++;
+		report_len--;
+	}
+
+	ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, report_data,
+				   report_len, report_len, 0);
+	if (ret) {
+		dev_warn(&hdev->dev, "failed to report feature %d\n",
+			 field->report->id);
+		goto out;
+	}
+
+	data->function_row_physmap[fn_key - MIN_FN_ROW_KEY] =
+		field->value[usage->usage_index];
+
+out:
+	kfree(buf);
+}
+EXPORT_SYMBOL_GPL(vivaldi_feature_mapping);
+
+static ssize_t function_row_physmap_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct vivaldi_data *data = hid_get_drvdata(hdev);
+
+	return vivaldi_function_row_physmap_show(data, buf);
+}
+
+static DEVICE_ATTR_RO(function_row_physmap);
+static struct attribute *vivaldi_sysfs_attrs[] = {
+	&dev_attr_function_row_physmap.attr,
+	NULL
+};
+
+static umode_t vivaldi_is_visible(struct kobject *kobj, struct attribute *attr,
+				  int n)
+{
+	struct hid_device *hdev = to_hid_device(kobj_to_dev(kobj));
+	struct vivaldi_data *data = hid_get_drvdata(hdev);
+
+	if (!data->num_function_row_keys)
+		return 0;
+	return attr->mode;
+}
+
+static const struct attribute_group vivaldi_attribute_group = {
+	.attrs = vivaldi_sysfs_attrs,
+	.is_visible = vivaldi_is_visible,
+};
+
+const struct attribute_group *vivaldi_attribute_groups[] = {
+	&vivaldi_attribute_group,
+	NULL,
+};
+EXPORT_SYMBOL_GPL(vivaldi_attribute_groups);
+
+MODULE_DESCRIPTION("Helpers for ChromeOS HID Vivaldi keyboards");
+MODULE_LICENSE("GPL");