ACPI: Get acpi_device's parent from the parent field

Printk modifier %pfw is used to print the full path of the device name.
This is obtained device by device until a device no longer has a parent.

On ACPI getting the parent fwnode is done by calling acpi_get_parent()
which tries to down() a semaphore. But local IRQs are now disabled in
vprintk_store() before the mutex is acquired. This is obviously a problem.

Luckily struct device, embedded in struct acpi_device, has a parent field
already. Use that field to get the parent instead of relying on
acpi_get_parent().

Fixes: 3bd32d6a2ee6 ("lib/vsprintf: Add %pfw conversion specifier for printing fwnode names")
Cc: 5.5+ <stable@vger.kernel.org> # 5.5+
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index e312eba..781e312 100644 (file)
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -1090,15 +1090,10 @@ struct fwnode_handle *acpi_node_get_parent(const struct fwnode_handle *fwnode)
                /* All data nodes have parent pointer so just return that */
                return to_acpi_data_node(fwnode)->parent;
        } else if (is_acpi_device_node(fwnode)) {
-               acpi_handle handle, parent_handle;
+               struct device *dev = to_acpi_device_node(fwnode)->dev.parent;
 
-               handle = to_acpi_device_node(fwnode)->handle;
-               if (ACPI_SUCCESS(acpi_get_parent(handle, &parent_handle))) {
-                       struct acpi_device *adev;
-
-                       if (!acpi_bus_get_device(parent_handle, &adev))
-                               return acpi_fwnode_handle(adev);
-               }
+               if (dev)
+                       return acpi_fwnode_handle(to_acpi_device(dev));
        }
 
        return NULL;