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, 50 insertions, 0 deletions

diff --git a/drivers/hid/hid-penmount.c b/drivers/hid/hid-penmount.c
new file mode 100644
index 000000000..b9edc8e75
--- /dev/null
+++ b/drivers/hid/hid-penmount.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for PenMount touchscreens
+ *
+ *  Copyright (c) 2014 Christian Gmeiner <christian.gmeiner <at> gmail.com>
+ *
+ *  based on hid-penmount copyrighted by
+ *    PenMount Touch Solutions <penmount <at> seed.net.tw>
+ */
+
+/*
+ */
+
+#include <linux/module.h>
+#include <linux/hid.h>
+#include "hid-ids.h"
+
+static int penmount_input_mapping(struct hid_device *hdev,
+		struct hid_input *hi, struct hid_field *field,
+		struct hid_usage *usage, unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON) {
+		if (((usage->hid - 1) & HID_USAGE) == 0) {
+			hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+			return 1;
+		} else {
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id penmount_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_PENMOUNT, USB_DEVICE_ID_PENMOUNT_6000) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, penmount_devices);
+
+static struct hid_driver penmount_driver = {
+	.name = "hid-penmount",
+	.id_table = penmount_devices,
+	.input_mapping = penmount_input_mapping,
+};
+
+module_hid_driver(penmount_driver);
+
+MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
+MODULE_DESCRIPTION("PenMount HID TouchScreen driver");
+MODULE_LICENSE("GPL");