[RFC PATCH v1 4/6] USB: EHCI: don't release ehci->lock if URB giveback in tasklet context

[Ming Lei]

On Wed, Jun 19, 2013 at 11:47 PM, Alan Stern <stern at rowland.harvard.edu> wrote:
> On Wed, 19 Jun 2013, Ming Lei wrote:
>
>> On Wed, Jun 19, 2013 at 12:43 AM, Alan Stern <stern at rowland.harvard.edu> wrote:
>> > On Tue, 18 Jun 2013, Ming Lei wrote:
>> >
>> >> If HCD_BH is set for HC driver's flags, URB giveback will be
>> >> done in tasklet context instead of interrupt context, so the
>> >> ehci->lock needn't to be released any more before calling
>> >> usb_hcd_giveback_urb().
>> >
>> > It is premature to do this now.  This should be part of the 6/6 patch,
>>
>> It is fine since HCD_BH isn't enabled.
>
> It's not "fine".  It will work -- nothing will crash -- but that
> doesn't mean it is good style.
>
>> > when it won't be necessary to test hcd_giveback_urb_in_bh().
>>
>> Keeping it is easy to compare test results between running complete()
>> in tasklet and in hard irq handler.
>
> It's just as easy to do your tests by keeping two copies of ehci-hcd.ko
> lying around; one with your changes and one without.  You can insmod
> whichever one you want to test.
>
>> Also it might be helpful for out of tree drivers.
>>
>> But it isn't a big deal, I can merge it to 6/6 if you care.
>
> Yes, please.

OK.

Thanks,
--
Ming Lei