From owner-freebsd-stable@FreeBSD.ORG  Wed May 20 14:18:30 2009
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 0537B1065698;
	Wed, 20 May 2009 14:18:30 +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 D13618FC2B;
	Wed, 20 May 2009 14:18:28 +0000 (UTC) (envelope-from avg@freebsd.org)
Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua
	[212.40.38.101])
	by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id RAA18094;
	Wed, 20 May 2009 17:18:27 +0300 (EEST)
	(envelope-from avg@freebsd.org)
Message-ID: <4A141132.5010308@freebsd.org>
Date: Wed, 20 May 2009 17:18:26 +0300
From: Andriy Gapon <avg@freebsd.org>
User-Agent: Thunderbird 2.0.0.21 (X11/20090406)
MIME-Version: 1.0
To: John Baldwin <jhb@freebsd.org>
References: <4A1165A0.6000800@icyb.net.ua> <4A1167A2.6040407@freebsd.org>
	<4A13F30A.2090401@freebsd.org> <200905200832.00771.jhb@freebsd.org>
In-Reply-To: <200905200832.00771.jhb@freebsd.org>
X-Enigmail-Version: 0.95.7
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Cc: freebsd-stable@freebsd.org, Chagin Dmitry <dchagin@freebsd.org>
Subject: Re: stack abuse by linux_ioctl_cdrom
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 20 May 2009 14:18:30 -0000

on 20/05/2009 15:32 John Baldwin said the following:
> On Wednesday 20 May 2009 8:09:46 am Andriy Gapon wrote:
>> This is a patch that I currently use to fix the problem for myself - both 2KB
>> structs are allocated on the heap.
>> I am not sure what is the proper style for chained calls using chained if-else,
>> but I think that the chaining is the best way to organize that piece of code, so
>> that there is only one exit point from case-block to make sure that FREE is always
>> called.
> 
> I usually use goto for that.  Error handling does seem to be one of the few
> appropriate uses of goto.  In this case you would basically be replacing all
> the 'break's with 'goto out' or some such.  Also, please do not use the MALLOC()
> or FREE() macros in new code as they are deprecated (I think they are completely
> removed in 8).

I used MALLOC/FREE only because I saw that this is what was used in that file
before. I will fix this.

I was reluctant to use goto and label within a case block. In my personal taste
that looks uglier and less safe (e.g. accidental goto from another case or from
outside of switch). I would preferred goto if label was outside of switch/case.
But maybe it's my personal prejudice.
I will follow the style that you will recommend.

-- 
Andriy Gapon