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ACPI / scan: Use direct recurrence for device hierarchy walks

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Rework acpi_bus_trim() and acpi_bus_device_attach(), which is
renamed as acpi_bus_attach(), to walk the list of each device
object's children directly and call themselves recursively for
each child instead of using acpi_walk_namespace().  This
simplifies the code quite a bit and avoids the overhead of
callbacks and the ACPICA's internal processing which are not
really necessary for these two routines.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2013-11-25 00:52:21 +01:00
parent 25db115b0b
commit 2c22e6520a
1 changed files with 45 additions and 75 deletions
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120
drivers/acpi/scan.c
View file

@ -1909,54 +1909,40 @@ static int acpi_scan_attach_handler(struct acpi_device *device)
return ret;
}
static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used,
void *not_used, void **ret_not_used)
static void acpi_bus_attach(struct acpi_device *device)
{
struct acpi_device *device;
unsigned long long sta;
struct acpi_device *child;
int ret;
/*
* Ignore errors ignored by acpi_bus_check_add() to avoid terminating
* namespace walks prematurely.
*/
if (acpi_bus_type_and_status(handle, &ret, &sta))
return AE_OK;
if (acpi_bus_get_device(handle, &device))
return AE_CTRL_DEPTH;
acpi_set_device_status(device, sta);
acpi_bus_get_status(device);
/* Skip devices that are not present. */
if (!acpi_device_is_present(device))
goto err;
if (!acpi_device_is_present(device)) {
device->flags.visited = false;
return;
}
if (device->handler)
return AE_OK;
goto ok;
if (!device->flags.initialized) {
acpi_bus_update_power(device, NULL);
device->flags.initialized = true;
}
device->flags.visited = false;
ret = acpi_scan_attach_handler(device);
if (ret < 0)
goto err;
return;
device->flags.match_driver = true;
if (ret > 0)
goto ok;
ret = device_attach(&device->dev);
if (ret < 0)
goto err;
if (!ret) {
ret = device_attach(&device->dev);
if (ret < 0)
return;
}
device->flags.visited = true;
ok:
device->flags.visited = true;
return AE_OK;
err:
device->flags.visited = false;
return AE_CTRL_DEPTH;
list_for_each_entry(child, &device->children, node)
acpi_bus_attach(child);
}
/**
@ -1976,64 +1962,48 @@ static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used,
int acpi_bus_scan(acpi_handle handle)
{
void *device = NULL;
int error = 0;
if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device)))
acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
acpi_bus_check_add, NULL, NULL, &device);
if (!device)
error = -ENODEV;
else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))
acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
acpi_bus_device_attach, NULL, NULL, NULL);
return error;
if (device) {
acpi_bus_attach(device);
return 0;
}
return -ENODEV;
}
EXPORT_SYMBOL(acpi_bus_scan);
static acpi_status acpi_bus_device_detach(acpi_handle handle, u32 lvl_not_used,
void *not_used, void **ret_not_used)
{
struct acpi_device *device = NULL;
if (!acpi_bus_get_device(handle, &device)) {
struct acpi_scan_handler *dev_handler = device->handler;
if (dev_handler) {
if (dev_handler->detach)
dev_handler->detach(device);
device->handler = NULL;
} else {
device_release_driver(&device->dev);
}
/*
* Most likely, the device is going away, so put it into D3cold
* before that.
*/
acpi_device_set_power(device, ACPI_STATE_D3_COLD);
device->flags.initialized = false;
device->flags.visited = false;
}
return AE_OK;
}
/**
* acpi_bus_trim - Remove ACPI device node and all of its descendants
* @start: Root of the ACPI device nodes subtree to remove.
* acpi_bus_trim - Detach scan handlers and drivers from ACPI device objects.
* @adev: Root of the ACPI namespace scope to walk.
*
* Must be called under acpi_scan_lock.
*/
void acpi_bus_trim(struct acpi_device *start)
void acpi_bus_trim(struct acpi_device *adev)
{
struct acpi_scan_handler *handler = adev->handler;
struct acpi_device *child;
list_for_each_entry_reverse(child, &adev->children, node)
acpi_bus_trim(child);
if (handler) {
if (handler->detach)
handler->detach(adev);
adev->handler = NULL;
} else {
device_release_driver(&adev->dev);
}
/*
* Execute acpi_bus_device_detach() as a post-order callback to detach
* all ACPI drivers from the device nodes being removed.
* Most likely, the device is going away, so put it into D3cold before
* that.
*/
acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL,
acpi_bus_device_detach, NULL, NULL);
acpi_bus_device_detach(start->handle, 0, NULL, NULL);
acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
adev->flags.initialized = false;
adev->flags.visited = false;
}
EXPORT_SYMBOL_GPL(acpi_bus_trim);