From owner-freebsd-hackers@FreeBSD.ORG  Fri Apr 16 19:05:11 2010
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 1AD501065676
	for <freebsd-hackers@freebsd.org>; Fri, 16 Apr 2010 19:05:11 +0000 (UTC)
	(envelope-from samrobb@averesystems.com)
Received: from zimbra.averesystems.com
	(75-149-8-243-Pennsylvania.hfc.comcastbusiness.net [75.149.8.243])
	by mx1.freebsd.org (Postfix) with ESMTP id E10778FC19
	for <freebsd-hackers@freebsd.org>; Fri, 16 Apr 2010 19:05:09 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
	by zimbra.averesystems.com (Postfix) with ESMTP id 924D18BC913
	for <freebsd-hackers@freebsd.org>; Fri, 16 Apr 2010 15:04:12 -0400 (EDT)
X-Virus-Scanned: amavisd-new at averesystems.com
Received: from zimbra.averesystems.com ([127.0.0.1])
	by localhost (zimbra.averesystems.com [127.0.0.1]) (amavisd-new,
	port 10024)
	with ESMTP id pUQzVPYVL1Dc for <freebsd-hackers@freebsd.org>;
	Fri, 16 Apr 2010 15:04:11 -0400 (EDT)
Received: from [10.0.1.224] (fw.arriad.com [10.0.0.16])
	by zimbra.averesystems.com (Postfix) with ESMTPSA id D356D8BC044
	for <freebsd-hackers@freebsd.org>; Fri, 16 Apr 2010 15:04:11 -0400 (EDT)
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Apple Message framework v1078)
From: Sam Robb <samrobb@averesystems.com>
In-Reply-To: <201004141718.05534.jhb@freebsd.org>
Date: Fri, 16 Apr 2010 15:06:40 -0400
Content-Transfer-Encoding: quoted-printable
Message-Id: <24EE4B09-0317-441A-822A-43F36D7D61E7@averesystems.com>
References: <1DF133F5-6B00-4F06-8837-946702226A54@averesystems.com>
	<201004141718.05534.jhb@freebsd.org>
To: freebsd-hackers@freebsd.org
X-Mailer: Apple Mail (2.1078)
Subject: Re: Going from struct disk to a fh?
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 16 Apr 2010 19:05:11 -0000

On Apr 14, 2010, at 5:18 PM, John Baldwin wrote:

> On Wednesday 14 April 2010 9:08:50 am Sam Robb wrote:
>> In the kernel, given a struct disk, is there a way to turn that into=20=

> something that can be used to read/write from the disk? Or is my best =
bet in=20
> this situation to figure out the device path for the disk, and just =
use=20
> kern_open() to access it?
>=20
> You can use dp->d_geom as the target of a bio via GEOM I think.  =
However, I=20
> don't have experience with sending bio's to a specific GEOM directly.  =
File=20
> systems usually use geom_vfs to feed requests from bread(), etc. to a =
mounted=20
> disk device using a devfs vnode for the associated disk device.

Thanks, John.  I've found another way around my problem in user space; =
if I revisit the kernel solution, I'll take a look at using bio.

-Samrobb=