ACPI: Reduce the usage of struct acpi_bus_ops

Objects of type struct acpi_bus_ops are currently used to pass
information between different parts of the ACPI namespace scanning
code, sometimes in quite convoluted ways.  It turns out that that
is not necessary in some cases, so simplify the code by reducing
the utilization of struct acpi_bus_ops objects where clearly
possible.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>

drivers/acpi/scan.c

@@ -1527,7 +1527,6 @@ end:
 static void acpi_bus_add_power_resource(acpi_handle handle)
 {
 	struct acpi_bus_ops ops = {
-		.acpi_op_add = 1,
 		.acpi_op_start = 1,
 		.acpi_op_match = 1,
 	};
@@ -1581,7 +1580,6 @@ static int acpi_bus_type_and_status(acpi_handle handle, int *type,
 static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
 				      void *context, void **return_value)
 {
-	struct acpi_bus_ops *ops = context;
 	struct acpi_device *device = NULL;
 	int type;
 	unsigned long long sta;
@@ -1605,11 +1603,13 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
 	}
 
 	acpi_bus_get_device(handle, &device);
-	if (ops->acpi_op_add && !device) {
-		struct acpi_bus_ops add_ops = *ops;
+	if (!device) {
+		struct acpi_bus_ops ops = {
+			.acpi_op_start = !!context,
+			.acpi_op_match = 0,
+		};
 
-		add_ops.acpi_op_match = 0;
-		acpi_add_single_object(&device, handle, type, sta, &add_ops);
+		acpi_add_single_object(&device, handle, type, sta, &ops);
 		if (!device)
 			return AE_CTRL_DEPTH;
 
@@ -1650,17 +1650,18 @@ static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used,
 	return status;
 }
 
-static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops,
+static int acpi_bus_scan(acpi_handle handle, bool start,
 			 struct acpi_device **child)
 {
 	void *device = NULL;
 	acpi_status status;
 	int ret = -ENODEV;
 
-	status = acpi_bus_check_add(handle, 0, ops, &device);
+	status = acpi_bus_check_add(handle, 0, (void *)start, &device);
 	if (ACPI_SUCCESS(status))
 		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-				    acpi_bus_check_add, NULL, ops, &device);
+				    acpi_bus_check_add, NULL, (void *)start,
+				    &device);
 
 	if (!device)
 		goto out;
@@ -1694,9 +1695,7 @@ int
 acpi_bus_add(struct acpi_device **child,
 	     struct acpi_device *parent, acpi_handle handle, int type)
 {
-	struct acpi_bus_ops ops = { .acpi_op_add = 1, };
-
-	return acpi_bus_scan(handle, &ops, child);
+	return acpi_bus_scan(handle, false, child);
 }
 EXPORT_SYMBOL(acpi_bus_add);
 
@@ -1794,12 +1793,10 @@ static int acpi_bus_scan_fixed(void)
 {
 	int result = 0;
 	struct acpi_device *device = NULL;
-	struct acpi_bus_ops ops;
-
-	memset(&ops, 0, sizeof(ops));
-	ops.acpi_op_add = 1;
-	ops.acpi_op_start = 1;
-	ops.acpi_op_match = 1;
+	struct acpi_bus_ops ops = {
+		.acpi_op_start = 1,
+		.acpi_op_match = 1,
+	};
 
 	/*
 	 * Enumerate all fixed-feature devices.
@@ -1825,11 +1822,6 @@ static int acpi_bus_scan_fixed(void)
 int __init acpi_scan_init(void)
 {
 	int result;
-	struct acpi_bus_ops ops;
-
-	memset(&ops, 0, sizeof(ops));
-	ops.acpi_op_add = 1;
-	ops.acpi_op_start = 1;
 
 	result = bus_register(&acpi_bus_type);
 	if (result) {
@@ -1843,7 +1835,7 @@ int __init acpi_scan_init(void)
 	/*
 	 * Enumerate devices in the ACPI namespace.
 	 */
-	result = acpi_bus_scan(ACPI_ROOT_OBJECT, &ops, &acpi_root);
+	result = acpi_bus_scan(ACPI_ROOT_OBJECT, true, &acpi_root);
 
 	if (!result)
 		result = acpi_bus_scan_fixed();