ACPICA: Add root node optimization to internal get namespace node function.
Detect a request for the root node (a lone backslash) up front
before invoking a full namespace lookup.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/acpica/nsutils.c b/drivers/acpi/acpica/nsutils.c
index d2dfe61..596d4cc 100644
--- a/drivers/acpi/acpica/nsutils.c
+++ b/drivers/acpi/acpica/nsutils.c
@@ -671,6 +671,8 @@
ACPI_FUNCTION_TRACE_PTR(ns_get_node, ACPI_CAST_PTR(char, pathname));
+ /* Simplest case is a null pathname */
+
if (!pathname) {
*return_node = prefix_node;
if (!prefix_node) {
@@ -679,6 +681,13 @@
return_ACPI_STATUS(AE_OK);
}
+ /* Quick check for a reference to the root */
+
+ if (ACPI_IS_ROOT_PREFIX(pathname[0]) && (!pathname[1])) {
+ *return_node = acpi_gbl_root_node;
+ return_ACPI_STATUS(AE_OK);
+ }
+
/* Convert path to internal representation */
status = acpi_ns_internalize_name(pathname, &internal_path);