ukbd locking update

[Attilio Rao]

2011/12/20 Andriy Gapon <avg at freebsd.org>:
>
> I completing a patch that changes some locking in ukbd to account for
> SCHEDULER_STOPPED and for other realities of the code.
>
> As a preview I would like to share couple of observations that had their effect
> on the patch.
>
> 1. Acquiring Giant in device_attach, _detach in similar newbus method
> implementations should be redundant because those are already executed with
> Giant held.  That's done either by the general newbus code or via
> usbd_enum_lock() when the operations are executed in the USB explore thread.

That's right, however, if you plan to axe those because of the newbus
assumption I'd prefer you add a comment for every function you touch
saying that it needs to be Giant protected (in order to cope with them
once newbus is made MPSAFE).

Attilio


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