ACPI: make acpi_bus_register_driver() return success/failure, not device count

acpi_bus_register_driver() should not return the number of devices claimed.
We're not asking to find devices, we're making a driver available to devices,
including hot-pluggable devices that may appear in the future.

I audited all callers of acpi_bus_register_driver(), and except asus_acpi.c
and sonypi.c (fixed in previous patches), all either ignore the return value
or test only for failure (<0).

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/scan.c

@@ -548,10 +548,9 @@ static int acpi_start_single_object(struct acpi_device *device)
 	return_VALUE(result);
 }
 
-static int acpi_driver_attach(struct acpi_driver *drv)
+static void acpi_driver_attach(struct acpi_driver *drv)
 {
 	struct list_head *node, *next;
-	int count = 0;
 
 	ACPI_FUNCTION_TRACE("acpi_driver_attach");
 
@@ -568,7 +567,6 @@ static int acpi_driver_attach(struct acpi_driver *drv)
 			if (!acpi_bus_driver_init(dev, drv)) {
 				acpi_start_single_object(dev);
 				atomic_inc(&drv->references);
-				count++;
 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 						  "Found driver [%s] for device [%s]\n",
 						  drv->name, dev->pnp.bus_id));
@@ -577,7 +575,6 @@ static int acpi_driver_attach(struct acpi_driver *drv)
 		spin_lock(&acpi_device_lock);
 	}
 	spin_unlock(&acpi_device_lock);
-	return_VALUE(count);
 }
 
 static int acpi_driver_detach(struct acpi_driver *drv)
@@ -610,14 +607,11 @@ static int acpi_driver_detach(struct acpi_driver *drv)
  * @driver: driver being registered
  *
  * Registers a driver with the ACPI bus.  Searches the namespace for all
- * devices that match the driver's criteria and binds.  Returns the
- * number of devices that were claimed by the driver, or a negative
- * error status for failure.
+ * devices that match the driver's criteria and binds.  Returns zero for
+ * success or a negative error status for failure.
  */
 int acpi_bus_register_driver(struct acpi_driver *driver)
 {
-	int count;
-
 	ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
 
 	if (acpi_disabled)
@@ -629,9 +623,9 @@ int acpi_bus_register_driver(struct acpi_driver *driver)
 	spin_lock(&acpi_device_lock);
 	list_add_tail(&driver->node, &acpi_bus_drivers);
 	spin_unlock(&acpi_device_lock);
-	count = acpi_driver_attach(driver);
+	acpi_driver_attach(driver);
 
-	return_VALUE(count);
+	return_VALUE(0);
 }
 
 EXPORT_SYMBOL(acpi_bus_register_driver);