From 2c22e6520ac87d8b12d4d9941e81d4119f2d903c Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 25 Nov 2013 00:52:21 +0100 Subject: [PATCH] ACPI / scan: Use direct recurrence for device hierarchy walks 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 --- drivers/acpi/scan.c | 120 +++++++++++++++++--------------------------- 1 file changed, 45 insertions(+), 75 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index cf773c918102..311904c720b1 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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; - - ok: + if (!ret) { + ret = device_attach(&device->dev); + if (ret < 0) + return; + } device->flags.visited = true; - return AE_OK; - err: - device->flags.visited = false; - return AE_CTRL_DEPTH; + ok: + 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; -} -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; + if (device) { + acpi_bus_attach(device); + return 0; } - return AE_OK; + return -ENODEV; } +EXPORT_SYMBOL(acpi_bus_scan); /** - * 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); -- 2.45.2