From owner-freebsd-current@FreeBSD.ORG  Thu Dec  4 11:24:29 2008
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 61ECA106564A
	for <current@freebsd.org>; Thu,  4 Dec 2008 11:24:29 +0000 (UTC)
	(envelope-from yanefbsd@gmail.com)
Received: from rv-out-0506.google.com (rv-out-0506.google.com [209.85.198.234])
	by mx1.freebsd.org (Postfix) with ESMTP id 2A2658FC08
	for <current@freebsd.org>; Thu,  4 Dec 2008 11:24:29 +0000 (UTC)
	(envelope-from yanefbsd@gmail.com)
Received: by rv-out-0506.google.com with SMTP id b25so3854057rvf.43
	for <current@freebsd.org>; Thu, 04 Dec 2008 03:24:28 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma;
	h=domainkey-signature:received:received:message-id:date:from:to
	:subject:cc:in-reply-to:mime-version:content-type
	:content-transfer-encoding:content-disposition:references;
	bh=Sg5+b9u/6cnipKk7glL/8nLc7EBc/wdDGb/1y3QKLSY=;
	b=lfhZhPVPxJgAJmRcUaaISM/jT05COUol+7oW0bqSxne5Fd4DHrY+OhUCIN7/o5Mken
	XAaP2YKJcsHQ5qBY+3vCUEbLRR/TbCSTEF3pq6l0fn7n0g3K6aQtK1xouhaV39M090pX
	gS/nsMNRI9eo7rDjLo0qKenP6ZvHo8CQ6gLVk=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma;
	h=message-id:date:from:to:subject:cc:in-reply-to:mime-version
	:content-type:content-transfer-encoding:content-disposition
	:references;
	b=P1lPC/k4u5kzhg02CVEN2wt258m5hxIsPrMwMq0KB2IQI1LF+IMVMsshAaUFN0/GMU
	OF8cOkADfjo/7apbHGOxYi4H3aFHunwCqFnN1VfKm5734Cvvsm4Z/WzuWa79DdND2wdK
	lpUlnNaqPLxJZv/eoXw2ITm0FOYR0uoakwWGM=
Received: by 10.141.26.19 with SMTP id d19mr6872734rvj.184.1228389868758;
	Thu, 04 Dec 2008 03:24:28 -0800 (PST)
Received: by 10.140.158.13 with HTTP; Thu, 4 Dec 2008 03:24:28 -0800 (PST)
Message-ID: <7d6fde3d0812040324y3bf0901cy1f4a6d961362c314@mail.gmail.com>
Date: Thu, 4 Dec 2008 03:24:28 -0800
From: "Garrett Cooper" <yanefbsd@gmail.com>
To: "Maksim Yevmenkin" <maksim.yevmenkin@gmail.com>
In-Reply-To: <bb4a86c70812021701i621fdcfjb6a58a7f5cf781d5@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <bb4a86c70812021701i621fdcfjb6a58a7f5cf781d5@mail.gmail.com>
Cc: "current@freebsd.org" <current@freebsd.org>
Subject: Re: RFC: small syscons and kbd patch
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 04 Dec 2008 11:24:29 -0000

On Tue, Dec 2, 2008 at 5:01 PM, Maksim Yevmenkin
<maksim.yevmenkin@gmail.com> wrote:
> Dear Hackers,
>
> can someone please review the attached small patch for syscons and
> kbd? it should be a no-op mostly. the patch basically does
>
> 1) removes bogus layering in syscons, i.e. basically removes sccngetch();
> 2) implements advisory lock for kbd (based on atomic(9));
> 3) implements new POLLED flag for kbd;
>
> this is a part of a plan to fix keyboard access races in syscons.
>
> thanks,
> max

Max,
     Why are you double and triple negating on this line?

+	return (atomic_cmpset_acq_int(&kbd->kb_locked, !!!on, !!on));

-Garrett