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Date:      Tue, 20 Dec 2011 15:00:04 +0100
From:      Attilio Rao <attilio@freebsd.org>
To:        Andriy Gapon <avg@freebsd.org>
Cc:        freebsd-usb@freebsd.org
Subject:   Re: ukbd locking update
Message-ID:  <CAJ-FndC%2BU2XkxEA=k-_FjOk1mKqhafUUrxA8fo8KAfeN8QfNYg@mail.gmail.com>
In-Reply-To: <4EF088C8.8090906@FreeBSD.org>
References:  <4EF088C8.8090906@FreeBSD.org>

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2011/12/20 Andriy Gapon <avg@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 wi=
th
> Giant held. =C2=A0That's done either by the general newbus code or via
> usbd_enum_lock() when the operations are executed in the USB explore thre=
ad.

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


--=20
Peace can only be achieved by understanding - A. Einstein



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