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From: Vinod Koul <vinod.koul@intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Olof Johansson <olof@lixom.net>,
	"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] dmaengine: pl08x: fix conversioin for generic unmap data
Date: Thu, 28 Nov 2013 11:30:03 +0530	[thread overview]
Message-ID: <20131128060003.GN8834@intel.com> (raw)
In-Reply-To: <CAPcyv4hCO62DFA0DO0pH2JO+nEPFT2ZmjG=E5=AJTYrtUACr_g@mail.gmail.com>

On Wed, Nov 27, 2013 at 11:55:01AM -0800, Dan Williams wrote:
> On Tue, Nov 26, 2013 at 8:53 PM, Olof Johansson <olof@lixom.net> wrote:
> > commit d38a8c622a1b ('dmaengine: prepare for generic 'unmap' data')
> > added a generic unmap call but used the wrong argument for it. Fix it.
> >
> > Fixes: d38a8c622a1b ('dmaengine: prepare for generic 'unmap' data')
> > Signed-off-by: Olof Johansson <olof@lixom.net>
> > ---
> >
> > I can't actually tell what the intent of d38a8cc622a1b and how mappings
> > are expected to be managed, but it's obviously passing the wrong thing
> > in here so it seems like the appropriate fix.
> >
> 
> For most dma-slave usage cases the client is explicitly handling the
> lifetime of the dma mappings.  It's primarily the mem-to-mem usage
> cases that rely on the dma driver to do the unmapping when the
> transaction is complete.  dma_descriptor_unmap() is a common
> implementation rather than requiring each driver to implement it
> uniquely.  Longer term we can require all clients to handle their
> mapping lifetimes and remove the responsibility from the individual
> drivers completely.
I think that would make sense and also remove any abuiguity on who does the
mapping in different usages..

~Vinod

  reply	other threads:[~2013-11-28  6:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-27  4:53 [PATCH] dmaengine: pl08x: fix conversioin for generic unmap data Olof Johansson
2013-11-27 19:38 ` Dan Williams
2013-11-27 19:44   ` Olof Johansson
2013-11-27 19:49     ` Dan Williams
2013-11-27 19:55 ` Dan Williams
2013-11-28  6:00   ` Vinod Koul [this message]
2013-11-28  6:00 ` Vinod Koul

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