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Date: Mon, 22 Mar 2010 21:16:37 +0100
From: Andreas Bombe <aeb@debian.org>
To: Leon Woestenberg <leon.woestenberg@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Memory-mapped I/O barriers, state of affairs?
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On Mon, Mar 22, 2010 at 08:18:49PM +0100, Leon Woestenberg wrote:
> What is the current solution for that particular problem, i.e. how
> should I make sure host memory writes are committed before I have an
> external DMA device act on it?

The dma_sync_* functions, if you reuse DMA buffers without unmapping,
take care of that.  Otherwise the process of mapping them handles it.

Documentation/DMA-API.txt and Documentation/PCI/PCI-DMA-mapping.txt
document those functions.