On Mon, 2013-01-14 at 22:39 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> Make acpi_bus_trim() work in analogy with acpi_bus_scan() and carry
> out two passes such that ACPI drivers will be detached from device
> nodes being removed in the first pass and the device nodes themselves
> will be removed in the second pass.
>
> For this purpose split the driver unregistration out of
> acpi_bus_remove() into a new routine, acpi_bus_device_detach(), that
> will be executed by acpi_bus_trim() in the additional first pass as
> a post-order callback.
>
> This is necessary, because some ACPI drivers' .remove() routines
> unregister struct device objects associated with the ACPI device
> nodes being removed and that needs to happen while the ACPI
> device nodes are still around (for example, in case they need to be
> used for power management or similar things at that time).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
I'd suggest to add some comment stating that acpi_bus_device_detach()
acpi_bus_remove() are post-order callbacks. I do not think many people
recognize it by just looking the calls to acpi_walk_namespace().
Otherwise, the patchset looks good. For the patch series:
Acked-by: Toshi Kani <toshi.kani@xxxxxx>
Thanks,
-Toshi
> ---
> drivers/acpi/scan.c | 44 ++++++++++++++++++++++++++++----------------
> 1 file changed, 28 insertions(+), 16 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -1425,22 +1425,6 @@ static void acpi_device_set_id(struct ac
> }
> }
>
> -static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used,
> - void *not_used, void **ret_not_used)
> -{
> - 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 AE_OK;
> -}
> -
> void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
> int type, unsigned long long sta)
> {
> @@ -1647,8 +1631,36 @@ int acpi_bus_add(acpi_handle handle)
> }
> EXPORT_SYMBOL(acpi_bus_add);
>
> +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)) {
> + device->removal_type = ACPI_BUS_REMOVAL_EJECT;
> + device_release_driver(&device->dev);
> + }
> + return AE_OK;
> +}
> +
> +static acpi_status acpi_bus_remove(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))
> + acpi_device_unregister(device);
> +
> + return AE_OK;
> +}
> +
> int acpi_bus_trim(struct acpi_device *start)
> {
> + /* Detach all ACPI drivers from the device nodes being removed. */
> + 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);
> + /* Remove the device nodes. */
> 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);
>
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