From owner-freebsd-hackers@FreeBSD.ORG  Sat May 30 14:47:40 2015
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 75468DEF;
 Sat, 30 May 2015 14:47:40 +0000 (UTC)
 (envelope-from ps06756@gmail.com)
Received: from mail-lb0-x232.google.com (mail-lb0-x232.google.com
 [IPv6:2a00:1450:4010:c04::232])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (Client CN "smtp.gmail.com",
 Issuer "Google Internet Authority G2" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id F059F12D3;
 Sat, 30 May 2015 14:47:39 +0000 (UTC)
 (envelope-from ps06756@gmail.com)
Received: by lbbuc2 with SMTP id uc2so63603444lbb.2;
 Sat, 30 May 2015 07:47:37 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
 h=mime-version:in-reply-to:references:from:date:message-id:subject:to
 :cc:content-type;
 bh=ncbsbG8Psvo3tTJ+ylIcElUOzMF/83lDAnu7OWHJEw0=;
 b=Cxj6OSCsy5t5ILUsegTcnmSomQWon8k3qHRVvTp5En6UF55FsF8xIC5W/IAsPZLwaD
 yd/SbCwaEY+rTBs3BhMwOKzmbAFvl1ewL+KHUW4eX91/NPPJu9f8nawD4xzdUdgIy7q/
 uiK5bSSlKYXjk0lD4f2Qw4/6wt/KcXI12KtEty1g+TKAa9YIbiOAR3hTzr5hmW1WSwOk
 Pc+rnEt6ucEBlWLzQvfK8E3jE3Xm9s1ZrEjxn55LHWW0u+gWlUp3JmSJzQSGFc68JeAC
 MY2QEPo2xyXYwFUr2wbjxlgw5c0OzMZE+56eLaEpt1+j6x/AsgGf7Dxbshax2g3zqZRA
 K+UQ==
X-Received: by 10.152.197.2 with SMTP id iq2mr13044819lac.103.1432997257755;
 Sat, 30 May 2015 07:47:37 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.25.196.150 with HTTP; Sat, 30 May 2015 07:47:17 -0700 (PDT)
In-Reply-To: <1432993550.1200.104.camel@freebsd.org>
References: <CAGf2gkMuL0JDnX5PRvWKRSnmAHOFY4jzQEOjM6MQ8u9G4FuLbA@mail.gmail.com>
 <1432993550.1200.104.camel@freebsd.org>
From: Pratik Singhal <ps06756@gmail.com>
Date: Sat, 30 May 2015 20:17:17 +0530
Message-ID: <CAGf2gkM1QNTpw5ROhPS-DXrohDc8v-D9jSfjUGPxLfaoG6v2Kg@mail.gmail.com>
Subject: Re: Difference b/w xfer_len and len fields
To: Ian Lepore <ian@freebsd.org>
Cc: freebsd-hackers <freebsd-hackers@freebsd.org>
Content-Type: text/plain; charset=UTF-8
X-Content-Filtered-By: Mailman/MimeDel 2.1.20
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/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: Sat, 30 May 2015 14:47:40 -0000

What do you mean by "driver-internal" variables ?

On Sat, May 30, 2015 at 7:15 PM, Ian Lepore <ian@freebsd.org> wrote:

> On Sat, 2015-05-30 at 11:26 +0530, Pratik Singhal wrote:
> > What is the difference b/w the xfer_len and the len fields in the struct
> > mmc_data in file sys/dev/mmc/mmcreg.h  ?
> >
> > AFAIK , len is the length of the data present in mmc_data , what is
> > xfer_len ?
> >
>
> The xfer_len field has historically been unused, until recently.  When
> the dwc mmc driver was added, it uses xfer_len as a driver-internal
> variable to track how much of the overal work is done as the IO
> proceeds.
>
> -- Ian
>
>


-- 
Regards,
Pratik Singhal