From owner-freebsd-usb@FreeBSD.ORG  Tue Dec 20 14:59:06 2011
Return-Path: <owner-freebsd-usb@FreeBSD.ORG>
Delivered-To: freebsd-usb@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 0EDA8106564A;
	Tue, 20 Dec 2011 14:59:06 +0000 (UTC) (envelope-from avg@FreeBSD.org)
Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140])
	by mx1.freebsd.org (Postfix) with ESMTP id 267928FC13;
	Tue, 20 Dec 2011 14:59:04 +0000 (UTC)
Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua
	[212.40.38.100])
	by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id QAA02678;
	Tue, 20 Dec 2011 16:59:03 +0200 (EET) (envelope-from avg@FreeBSD.org)
Received: from localhost ([127.0.0.1])
	by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD))
	id 1Rd19j-000JQH-Ed; Tue, 20 Dec 2011 16:59:03 +0200
Message-ID: <4EF0A2B6.8050206@FreeBSD.org>
Date: Tue, 20 Dec 2011 16:59:02 +0200
From: Andriy Gapon <avg@FreeBSD.org>
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64;
	rv:8.0) Gecko/20111206 Thunderbird/8.0
MIME-Version: 1.0
To: Attilio Rao <attilio@FreeBSD.org>
References: <4EF088C8.8090906@FreeBSD.org>
	<CAJ-FndC+U2XkxEA=k-_FjOk1mKqhafUUrxA8fo8KAfeN8QfNYg@mail.gmail.com>
In-Reply-To: <CAJ-FndC+U2XkxEA=k-_FjOk1mKqhafUUrxA8fo8KAfeN8QfNYg@mail.gmail.com>
X-Enigmail-Version: undefined
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Cc: freebsd-usb@FreeBSD.org
Subject: Re: ukbd locking update
X-BeenThere: freebsd-usb@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: FreeBSD support for USB <freebsd-usb.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-usb>,
	<mailto:freebsd-usb-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-usb>
List-Post: <mailto:freebsd-usb@freebsd.org>
List-Help: <mailto:freebsd-usb-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-usb>,
	<mailto:freebsd-usb-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 20 Dec 2011 14:59:06 -0000

on 20/12/2011 16:00 Attilio Rao said the following:
> 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 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).

I put mtx_assert there.  I think that that should be sufficiently
self-documenting and self-protecting too.

-- 
Andriy Gapon