Re: [RFT PATCH 1/1] xhci: free xhci virtual devices with leaf nodes first

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 23.11.2016 15:32, Guenter Roeck wrote:
> On 11/23/2016 04:24 AM, Mathias Nyman wrote:
>> the tt_info provided by a HS hub might be in use to by a child device
>> Make sure we free the devices in the correct order.
>>
>> This is needed in special cases such as when xhci controller is
>> reset when resuming from hibernate, and all virt_devices are freed.
>>
>> Also free the virt_devices starting from max slot_id as children
>> more commonly have higher slot_id than parent.
>>
>> CC: <stable@vger.kernel.org>
>> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>>
>> ---
>>
>> Guenter Roeck, does this work for you?
>>
>> A rework of how tt_info is stored and used might be needed,
>> but that will take some time and won't go to stable as easily.
>
> I'll give it a try. One concern, though: xhci_free_virt_device() is called
> from multiple places, and does not always remove all devices. Is it save
> to assume that all other callers remove children first ?
>

This should be the only place that xhci does a massive xhci_free_virt_device(),

In the other places it's initiated per device by usb core which should handle
child-parent relationships, or then just error paths when failing to allocate
a device in the first place (no children yet)

-Mathias