ACPI: glue: Introduce acpi_find_child_by_adr()

Rearrange the ACPI device lookup code used internally by
acpi_find_child_device() so it can avoid extra checks after finding
one object with a matching _ADR and use it for defining
acpi_find_child_by_adr() that will allow the callers to find a given
ACPI device's child matching a given bus address without doing any
other checks in check_one_child().

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>

drivers/acpi/glue.c

···
 	struct acpi_device *adev;
 	u64 address;
 	int score;
+	bool check_sta;
 	bool check_children;
 };
 
···
 		return 0;
 
 	if (!wd->adev) {
-		/* This is the first matching object.  Save it and continue. */
+		/*
+		 * This is the first matching object, so save it.  If it is not
+		 * necessary to look for any other matching objects, stop the
+		 * search.
+		 */
 		wd->adev = adev;
-		return 0;
+		return !(wd->check_sta || wd->check_children);
 	}
 
 	/*
···
 	return 0;
 }
 
-struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
-					   u64 address, bool check_children)
+static struct acpi_device *acpi_find_child(struct acpi_device *parent,
+					   u64 address, bool check_children,
+					   bool check_sta)
 {
 	struct find_child_walk_data wd = {
 		.address = address,
 		.check_children = check_children,
+		.check_sta = check_sta,
 		.adev = NULL,
 		.score = 0,
 	};
···
 
 	return wd.adev;
 }
+
+struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
+					   u64 address, bool check_children)
+{
+	return acpi_find_child(parent, address, check_children, true);
+}
 EXPORT_SYMBOL_GPL(acpi_find_child_device);
+
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr)
+{
+	return acpi_find_child(adev, adr, false, false);
+}
+EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);
 
 static void acpi_physnode_link_name(char *buf, unsigned int node_id)
 {

include/acpi/acpi_bus.h

···
 }
 struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
 					   u64 address, bool check_children);
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr);
 int acpi_is_root_bridge(acpi_handle);
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle);