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
Date: Mon, 11 Feb 2019 08:40:38 -0700 [thread overview]
Message-ID: <20190211084038.0647430b@lwn.net> (raw)
In-Reply-To: <20190208153038.23272-1-federico.vaga@cern.ch>
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
prev parent reply other threads:[~2019-02-11 15:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 15:30 [PATCH] doc:dmaengine: clarify DMA desc. pointer after submission Federico Vaga
2019-02-11 11:54 ` Vinod Koul
2019-02-11 12:10 ` Federico Vaga
2019-02-11 15:40 ` Jonathan Corbet [this message]
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