From owner-freebsd-mips@FreeBSD.ORG  Wed Aug 29 03:43:01 2012
Return-Path: <owner-freebsd-mips@FreeBSD.ORG>
Delivered-To: freebsd-mips@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 61690106566B;
	Wed, 29 Aug 2012 03:43:01 +0000 (UTC)
	(envelope-from adrian.chadd@gmail.com)
Received: from mail-pz0-f54.google.com (mail-pz0-f54.google.com
	[209.85.210.54])
	by mx1.freebsd.org (Postfix) with ESMTP id 2DB008FC1A;
	Wed, 29 Aug 2012 03:43:00 +0000 (UTC)
Received: by dadr6 with SMTP id r6so82898dad.13
	for <multiple recipients>; Tue, 28 Aug 2012 20:43:00 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
	h=mime-version:sender:in-reply-to:references:date
	:x-google-sender-auth:message-id:subject:from:to:cc:content-type;
	bh=jAkn6SZBu2JgVIZ652zmxYoQqbVJv4IozJRs5iFCGlk=;
	b=mSMYI5CpEp2gvdQn3kwy3v0Eb6Jn1Y5R9sMr+/e8VpqxpeT01znHkhcxZClTCTC3zJ
	EJTKhNdZlS8ovVDq1d6t3xxi6S/UTvS8rCm7yFm+UL92xIbkItonPHLk/RY8k+4yG4P0
	f1Wr4cuGwmhpieEOLM5Y5Mwdaprzrj7k5PtIPN6SU69P5ZYhRsjSN8LLwYGY5Py3ShV7
	xzYHo2uShGfzM6ijEfKxQAkL0VUyq25vtZofVAwgQGt2aZuL8TQzT9AqUAGE6fKhFF7J
	Hi7+NynwQqiD/D/v92LftQVYwusIUpIQ7CR9fab1gyGHUDD0Z9qRuaZXo4iJX9RkhR99
	CaOw==
MIME-Version: 1.0
Received: by 10.66.74.196 with SMTP id w4mr514587pav.32.1346211780629; Tue, 28
	Aug 2012 20:43:00 -0700 (PDT)
Sender: adrian.chadd@gmail.com
Received: by 10.68.36.106 with HTTP; Tue, 28 Aug 2012 20:43:00 -0700 (PDT)
In-Reply-To: <1F780BF4-84C3-48D5-9832-EA32381969A6@bsdimp.com>
References: <CAJ-VmomuwKKaQ6AszeDo-iQwL+8DPJpBB9av0K+Vbaj2feHO7g@mail.gmail.com>
	<1F780BF4-84C3-48D5-9832-EA32381969A6@bsdimp.com>
Date: Tue, 28 Aug 2012 20:43:00 -0700
X-Google-Sender-Auth: MsWdTOezouk9q2q6hJT6qOrFyw0
Message-ID: <CAJ-VmokHX7=Jd06tJWmAJfTGtuF4WfgpgGb0f0PwUzfP-QpJ0Q@mail.gmail.com>
From: Adrian Chadd <adrian@freebsd.org>
To: Warner Losh <imp@bsdimp.com>
Content-Type: text/plain; charset=ISO-8859-1
Cc: scottl@freebsd.org, freebsd-mips@freebsd.org
Subject: Re: MIPS busdma map questions
X-BeenThere: freebsd-mips@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Porting FreeBSD to MIPS <freebsd-mips.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-mips>,
	<mailto:freebsd-mips-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-mips>
List-Post: <mailto:freebsd-mips@freebsd.org>
List-Help: <mailto:freebsd-mips-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-mips>,
	<mailto:freebsd-mips-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 29 Aug 2012 03:43:01 -0000

On 28 August 2012 20:24, Warner Losh <imp@bsdimp.com> wrote:
>
> On Aug 28, 2012, at 8:22 PM, Adrian Chadd wrote:
>
>> Hi,
>>
>> I have a couple of busdma map questions.
>>
>> #1 - in mips/mips/busdma_machdep.c, bus_dmamap_destroy() calls
>> _busdma_free_dmamap() and -then- goes and walks the dma map list. Is
>> this a good idea or not? :)
>
> Accessing free memory after freeing it is a free ticket to a free dose of free pain.  It should be freed after the if that checks to see if it is in use.

Excellent! Who knows busdma better than I and can wade through what
that code path is doing? :)



Adrian