Re: [PATCH] doc:dmaengine: clarify DMA desc. pointer after submission

Jonathan Corbet
2019-02-11T15:40:45Z

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