* Kenji Kaneshige :
> Alex Chiang wrote:
>> Ugh, I'm not sure which is worse, an unbalanced API vs passing a
>> hotplug_slot to pci_destroy_slot.
>> pci_destroy_slot should never touch the pci_slot->hotplug
>> argument, I think, because it is possible for non-hotplug callers
>> to call pci_create_slot.
>> I think the rule should just be:
>> - all hotplug drivers must use pci_hp_register/deregister
>> - hotplug drivers must pass a valid hotplug_slot argument
>> - all detection drivers must use pci_create/destroy_slot
>> - detection drivers must pass NULL for hotplug_slot

> I'm still concerned about one thing. Now that we added hotplug
> arg to pci_create_slot(), pci_bus_sem could be used for changing
> pci_slot->hotplug. But if there is no generic API to clean up
> pci_slot->hotplug, we can't use pci_bus_sem because pci hotplug
> core cannot hold pci_bus_sem. As a result, we need to add the
> following rule in addition to the above rules.
> - hotplug core driver must hold some mutex/semaphore when
> calling pci_create_slot()
> - hotplug core driver must hold the same mutex/semaphore
> when cleaning up pci_slot->hotplug.
> That is, even though pci_create_slot provides the interface to
> setup pci_slot->hotplug, caller needs to pay attention to race
> condition about pci_slot->hotplug. I think it's a little strange.

I think we can use your earlier patch that replaced the hotplug
list spinlock with a pci_hp_mutex, and that should implement the
two new rules you mention, right?

Let me try and insert your patch into the rest of my series and
see how it looks.


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