On Wed, 2013-11-06 at 02:35 +0100, Rafael J. Wysocki wrote:
> On Tuesday, November 05, 2013 05:39:27 PM Toshi Kani wrote:
> > On Wed, 2013-11-06 at 00:27 +0100, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > >
> > > In theory, an ACPI device object may be the parent of another
> > > device object whose hotplug is disabled by user space through its
> > > scan handler. In that case, the eject operation targeting the
> > > parent should fail as though the parent's own hotplug was disabled,
> > > but currently this is not the case, because acpi_scan_hot_remove()
> > > doesn't check the disable/enable hotplug status of the children
> > > of the top-most object passed to it.
> > >
> > > To fix this, modify acpi_bus_offline_companions() to return an
> > > error code if hotplug is disabled for the given device object.
> > > [Also change the name of the function to acpi_bus_offline(),
> > > because it is not only about companions any more, and change
> > > the name of acpi_bus_online_companions() accordingly.] Make
> > > acpi_scan_hot_remove() propagate that error to its callers.
> > >
> > :
> > > +static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,
> > > + void **ret_p)
> > > {
> > > struct acpi_device *device = NULL;
> > > struct acpi_device_physical_node *pn;
> > > @@ -214,26 +220,32 @@ static int acpi_scan_hot_remove(struct a
> > > * If the first pass is successful, the second one isn't needed, though.
> > > */
> > > errdev = NULL;
> > > - acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
> > > - NULL, acpi_bus_offline_companions,
> > > - (void *)false, (void **)&errdev);
> > > - acpi_bus_offline_companions(handle, 0, (void *)false, (void **)&errdev);
> > > + status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
> > > + NULL, acpi_bus_offline, (void *)false,
> > > + (void **)&errdev);
> > > + if (status == AE_SUPPORT) {
> > > + dev_warn(errdev, "Offline disabled.\n");
> > > + acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
> > > + acpi_bus_online, NULL, NULL, NULL);
> > > + put_device(&device->dev);
> > > + return -EPERM;
> > > + }
> > > + acpi_bus_offline(handle, 0, (void *)false, (void **)&errdev);
> > > if (errdev) {
> >
> > If the target object failed with AE_SUPPORT, shouldn't we skip the 2nd
> > pass and return with -EPERM after rollback?
>
> We've checked the target object already in acpi_hotplug_notify_cb() or in
> acpi_eject_store().
Oh, I see. Thanks for the clarification.
>
> Which is telling me that the previous version of the patch was better after
> all, because the hotplug.enabled thing takes precedence over
> acpi_force_hot_remove in the other places. So this:
>
> https://patchwork.kernel.org/patch/3135841/
>
> is the right version. Sorry for the confusion.
Agreed.
Acked-by: Toshi Kani <toshi.kani@xxxxxx>
-Toshi
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