linux-kernel - Re: [PATCH 3/4] dmaengine: Add Freescale i.MX SDMA support

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Message-ID: <AANLkTi=YY_bZ0mFy6dA18-mifM52H7wNJVHqgvfxR6zc@mail.gmail.com>
Date:	Thu, 7 Oct 2010 17:14:59 -0700
From:	Dan Williams <dan.j.williams@...el.com>
To:	Sascha Hauer <s.hauer@...gutronix.de>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/4] dmaengine: Add Freescale i.MX SDMA support

On Thu, Sep 30, 2010 at 6:56 AM, Sascha Hauer <s.hauer@...gutronix.de> wrote:
> This patch adds support for the Freescale i.MX SDMA engine.
>

Applied, this set, however...

> +static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
> +               struct dma_chan *chan, struct scatterlist *sgl,
> +               unsigned int sg_len, enum dma_data_direction direction,
> +               unsigned long flags)
> +{
> +       struct sdma_channel *sdmac = to_sdma_chan(chan);
> +       struct sdma_engine *sdma = sdmac->sdma;
> +       int ret, i, count;
> +       int channel = chan->chan_id;
> +       struct scatterlist *sg;
> +
> +       if (sdmac->status == DMA_IN_PROGRESS)
> +               return NULL;
> +       sdmac->status = DMA_IN_PROGRESS;

...shouldn't this be an atomic test and set operation to ensure a
single user at a time?

--
Dan
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