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Date:   Mon, 11 Feb 2019 08:40:38 -0700
From:   Jonathan Corbet <corbet@lwn.net>
To:     Federico Vaga <federico.vaga@cern.ch>
Cc:     Vinod Koul <vkoul@kernel.org>, <dmaengine@vger.kernel.org>,
        <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] doc:dmaengine: clarify DMA desc. pointer after
 submission
Message-ID: <20190211084038.0647430b@lwn.net>
In-Reply-To: <20190208153038.23272-1-federico.vaga@cern.ch>
References: <20190208153038.23272-1-federico.vaga@cern.ch>
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On Fri, 8 Feb 2019 16:30:38 +0100
Federico Vaga <federico.vaga@cern.ch> wrote:

> It clarifies that the DMA description pointer returned by
> `dmaengine_prep_*` function should not be used after submission.
> 
> Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
> ---
>  Documentation/driver-api/dmaengine/client.rst | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst
> index fbbb2831f29f..d728e50105eb 100644
> --- a/Documentation/driver-api/dmaengine/client.rst
> +++ b/Documentation/driver-api/dmaengine/client.rst
> @@ -168,6 +168,13 @@ The details of these operations are:
>     dmaengine_submit() will not start the DMA operation, it merely adds
>     it to the pending queue. For this, see step 5, dma_async_issue_pending.
>  
> +   .. note::
> +
> +      After calling ``dmaengine_submit()`` the submitted transfer descriptor
> +      (``struct dma_async_tx_descriptor``) belongs to the DMA engine.
> +      Consequentially, the client must consider invalid the pointer to that
> +      descriptor.
> +
>  5. Issue pending DMA requests and wait for callback notification
>  
>     The transactions in the pending queue can be activated by calling the

Applied to the docs tree, thanks.

jon