Commit cecdb193 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / scan: Change the implementation of acpi_bus_trim() 



The current acpi_bus_trim() implementation is not really
straightforward and may be simplified significantly by using
acpi_walk_namespace() with acpi_bus_remove() as a post-order
callback.

Observe that acpi_bus_remove(), as called by acpi_bus_trim(), cannot
actually fail, because its first argument is guaranteed not to be
NULL thanks to the acpi_bus_get_device() check in acpi_bus_trim(),
so simply move the acpi_bus_get_device() check to acpi_bus_remove()
and use acpi_walk_namespace() to execute it for every device under
start->handle as a post-order callback.  The, run it directly for
start->handle itself.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
Acked-by: default avatarYinghai Lu <yinghai@kernel.org>
Acked-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
parent ae281795

drivers/acpi/scan.c

+15 −49
Original line number Diff line number Diff line
@@ -1374,17 +1374,20 @@ static int acpi_device_set_context(struct acpi_device *device) 
	return -ENODEV;

}



static int acpi_bus_remove(struct acpi_device *dev)

static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used,

				   void *not_used, void **ret_not_used)

{

	if (!dev)

		return -EINVAL;

	struct acpi_device *dev = NULL;



	if (acpi_bus_get_device(handle, &dev))

		return AE_OK;



	dev->removal_type = ACPI_BUS_REMOVAL_EJECT;

	device_release_driver(&dev->dev);



	acpi_device_unregister(dev);



	return 0;

	return AE_OK;

}



static int acpi_add_single_object(struct acpi_device **child,
@@ -1641,51 +1644,14 @@ EXPORT_SYMBOL(acpi_bus_add); 


int acpi_bus_trim(struct acpi_device *start)

{

	acpi_status status;

	struct acpi_device *parent, *child;

	acpi_handle phandle, chandle;

	acpi_object_type type;

	u32 level = 1;

	int err = 0;



	parent = start;

	phandle = start->handle;

	child = chandle = NULL;



	while ((level > 0) && parent && (!err)) {

		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,

					      chandle, &chandle);



	/*

		 * If this scope is exhausted then move our way back up.

	 * Execute acpi_bus_remove() as a post-order callback to remove device

	 * nodes in the given namespace scope.

	 */

		if (ACPI_FAILURE(status)) {

			level--;

			chandle = phandle;

			acpi_get_parent(phandle, &phandle);

			child = parent;

			parent = parent->parent;

			err = acpi_bus_remove(child);

			continue;

		}



		status = acpi_get_type(chandle, &type);

		if (ACPI_FAILURE(status)) {

			continue;

		}

		/*

		 * If there is a device corresponding to chandle then

		 * parse it (depth-first).

		 */

		if (acpi_bus_get_device(chandle, &child) == 0) {

			level++;

			phandle = chandle;

			chandle = NULL;

			parent = child;

		}

		continue;

	}

	return err;

	acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL,

			    acpi_bus_remove, NULL, NULL);

	acpi_bus_remove(start->handle, 0, NULL, NULL);

	return 0;

}

EXPORT_SYMBOL_GPL(acpi_bus_trim);

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