On Fri, Jun 09, 2017 at 06:36:32PM +0300, Andy Shevchenko wrote:
> On Fri, Jun 9, 2017 at 1:54 PM, Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx> wrote:
> > In hotplug logic, it always indicates non-specific failure to
> > platform through _OST when handing acpi hot-remove event failed. Then
> > platform terminates the hot-remove process but it can not identify
> > the reason.
> >
> > Base on current hot-remove code, there have two situations that it
> > returns busy:
> > - OSPM try to offline an individual device, but the device offline
> > function returns busy.
> > - When the ejection event is applied to an "not offlined yet" container.
> > OSPM send kobject change event to userspace and returns busy.
> >
> > Both of them will returns -EBUSY to acpi device hotplug function then
> > hotplug function indicates non-specific failure to platform just like
> > any other error, e.g. -ENODEV or -EIO.
> >
> > The benefit to platform for identifying the OS busy state is that
> > platform can be applied different approach to handle the busy but
> > not just terminate the hot-remove process by unknown reason. For
> > example, platform can wait for a while then triggers hot-remove
> > again.
> >
> > This RFC patch adds one more parameter to the handler function of
> > acpi generic hotplug event to give the function a chance to propose
> > the return code of _OST. In this case, it sets ost return code to
> > ACPI_OST_SC_DEVICE_BUSY when the acpi hot remove function returns
> > -EBUSY.
>
> Below looks better for my taste.
> See also comments.
>
Still thanks for your review.
> > +static int acpi_ost_status_code(u32 src, int error)
> > +{
> > + switch (src) {
> > + case ACPI_NOTIFY_EJECT_REQUEST:
> > + case ACPI_OST_EC_OSPM_EJECT:
>
> > + if (error == -EPERM)
> > + return ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> > + else if (error == -EBUSY)
>
> Redundant else...
>
You are right, I will remove it.
> > + return ACPI_OST_SC_DEVICE_BUSY;
>
> Perhaps switch case here as well?
> switch (error) {
> case -EPERM;
> return X;
> case -EBUSY:
> return Y;
> }
>
I want to use the event source as the target of switch because
different event source has different ost_src definition. If I
add the support of insertion event then the code will be like
this:
static int acpi_ost_status_code(u32 src, int error)
{
switch (src) {
case ACPI_NOTIFY_EJECT_REQUEST:
case ACPI_OST_EC_OSPM_EJECT:
if (error == -EPERM)
return ACPI_OST_SC_EJECT_NOT_SUPPORTED;
if (error == -EBUSY)
return ACPI_OST_SC_DEVICE_BUSY;
break;
case ACPI_OST_EC_OSPM_INSERTION:
if (error == -EPERM)
return ACPI_OST_SC_INSERT_NOT_SUPPORTED;
if (error == -EBUSY)
return ACPI_OST_SC_INSERT_IN_PROGRESS;
break;
}
return error ? ACPI_OST_SC_NON_SPECIFIC_FAILURE : ACPI_OST_SC_SUCCESS;
}
The ACPI_OST_EC_OSPM_INSERTION represents "Insertion Processing
(Source Event: 0x200)" that it has different ost code definition.
Just we didn't support it in kernel (maybe just didn't see any
machine used it).
> > + break;
> > + }
> > + return error ? ACPI_OST_SC_NON_SPECIFIC_FAILURE : ACPI_OST_SC_SUCCESS;
> > +}
>
>
> > + ost_code = acpi_ost_status_code(src, error);
> > err_out:
>
> I guess you need to swap those lines.
>
Do you mean move the "err_out:" to the position before
acpi_ost_status_code()? The err_out tag used by the
validation checking of acpi handler that it wants to
jump to evaluate _OST:
void acpi_device_hotplug(struct acpi_device *adev, u32 src)
{
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
int error = -ENODEV;
lock_device_hotplug();
mutex_lock(&acpi_scan_lock);
/*
* The device object's ACPI handle cannot become invalid as long as we
* are holding acpi_scan_lock, but it might have become invalid before
* that lock was acquired.
*/
if (adev->handle == INVALID_ACPI_HANDLE)
goto err_out;
[...snip]
> > err_out:
> > acpi_evaluate_ost(adev->handle, src, ost_code, NULL);
>
Thanks a lot!
Joey Lee
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