From: Dan Williams <dan.j.williams@intel.com>
To: "Ira W. Snyder" <iws@ovro.caltech.edu>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFCv1 1/2] dmaengine: add support for scatterlist to scatterlist transfers
Date: Fri, 24 Sep 2010 15:20:14 -0700 [thread overview]
Message-ID: <1285366814.21375.30.camel@dwillia2-linux> (raw)
In-Reply-To: <20100924220419.GC24654@ovro.caltech.edu>
On Fri, 2010-09-24 at 15:04 -0700, Ira W. Snyder wrote:
> On Fri, Sep 24, 2010 at 02:53:14PM -0700, Dan Williams wrote:
> > What about overrun or underrun do we not care if src_total != dst_total?
> >
> > Otherwise looks ok.
> >
>
> I don't know if we should care about that. The algorithm handles that
> case just fine. It copies the maximum amount it can, which is exactly
> min(src_total, dst_total). Whichever scatterlist runs out of entries
> first is the shortest.
>
> As a real world example, my driver verifies that both scatterlists have
> exactly the right number of bytes available before trying to program the
> hardware.
Ok, just handle the prep failure and I think we are good to go.
--
Dan
next prev parent reply other threads:[~2010-09-24 22:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-24 19:46 [PATCH RFCv1 0/2] dma: add support for sg-to-sg transfers Ira W. Snyder
2010-09-24 19:46 ` [PATCH RFCv1 1/2] dmaengine: add support for scatterlist to scatterlist transfers Ira W. Snyder
2010-09-24 20:40 ` Dan Williams
2010-09-24 21:24 ` Ira W. Snyder
2010-09-24 21:53 ` Dan Williams
2010-09-24 22:04 ` Ira W. Snyder
2010-09-24 22:20 ` Dan Williams [this message]
2010-09-24 22:53 ` Ira W. Snyder
2010-09-24 19:46 ` [PATCH RFCv1 2/2] fsldma: use generic " Ira W. Snyder
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