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, 83 insertions, 0 deletions

diff --git a/drivers/hid/hid-huawei.c b/drivers/hid/hid-huawei.c
new file mode 100644
index 000000000..ee3fc6f68
--- /dev/null
+++ b/drivers/hid/hid-huawei.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  HID driver for some huawei "special" devices
+ *
+ * Copyright (c) 2026 Miao Li <limiao@kylinos.cn>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+static const __u8 huawei_cd30_kbd_rdesc_fixed[] = {
+	0x05, 0x01,		/* Usage Page (Generic Desktop)		*/
+	0x09, 0x80,		/* Usage (System Control)		*/
+	0xa1, 0x01,		/* Collection (Application)		*/
+	0x85, 0x01,		/*   Report ID (1)			*/
+	0x19, 0x81,		/*   Usage Minimum (System Power Down)	*/
+	0x29, 0x83,		/*   Usage Maximum (System Wake Up)	*/
+	0x15, 0x00,		/*   Logical Minimum (0)		*/
+	0x25, 0x01,		/*   Logical Maximum (1)		*/
+	0x75, 0x01,		/*   Report Size (1 bit)		*/
+	0x95, 0x03,		/*   Report Count (3)			*/
+	0x81, 0x02,		/*   Input (Data,Var,Abs)		*/
+	0x95, 0x05,		/*   Report Count (5)			*/
+	0x81, 0x01,		/*   Input (Cnst,Ary,Abs)		*/
+	0xc0,			/* End Collection			*/
+	0x05, 0x0c,		/* Usage Page (Consumer)		*/
+	0x09, 0x01,		/* Usage (Consumer Control)		*/
+	0xa1, 0x01,		/* Collection (Application)		*/
+	0x85, 0x02,		/*   Report ID (2)			*/
+	0x19, 0x00,		/*   Usage Minimum (0)			*/
+	0x2a, 0x3c, 0x02,	/*   Usage Maximum (0x023C)		*/
+	0x15, 0x00,		/*   Logical Minimum (0)		*/
+	0x26, 0x3c, 0x02,	/*   Logical Maximum (0x023C)		*/
+	0x95, 0x01,		/*   Report Count (1)			*/
+	0x75, 0x10,		/*   Report Size (16 bits)		*/
+	0x81, 0x00,		/*   Input (Data,Ary,Abs)		*/
+	0xc0			/* End Collection			*/
+};
+
+static const __u8 *huawei_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				  unsigned int *rsize)
+{
+	struct usb_interface *intf = hid_is_usb(hdev) ?
+			to_usb_interface(hdev->dev.parent) : NULL;
+
+	switch (hdev->product) {
+	case USB_DEVICE_ID_HUAWEI_CD30KBD:
+		if (!intf || intf->cur_altsetting->desc.bInterfaceNumber == 1) {
+			if (*rsize != sizeof(huawei_cd30_kbd_rdesc_fixed) ||
+				memcmp(huawei_cd30_kbd_rdesc_fixed, rdesc,
+					sizeof(huawei_cd30_kbd_rdesc_fixed)) != 0) {
+				hid_info(hdev, "Replacing Huawei cd30 keyboard report descriptor.\n");
+				*rsize = sizeof(huawei_cd30_kbd_rdesc_fixed);
+				return huawei_cd30_kbd_rdesc_fixed;
+			}
+		}
+		break;
+	}
+
+	return rdesc;
+}
+
+static const struct hid_device_id huawei_devices[] = {
+	/* HUAWEI cd30 keyboard */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_HUAWEI, USB_DEVICE_ID_HUAWEI_CD30KBD)},
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, huawei_devices);
+
+static struct hid_driver huawei_driver = {
+	.name = "huawei",
+	.id_table = huawei_devices,
+	.report_fixup = huawei_report_fixup,
+};
+module_hid_driver(huawei_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miao Li <limiao@kylinos.cn>");
+MODULE_DESCRIPTION("HID driver for some huawei \"special\" devices");