Patchwork doc:dmaengine: clarify DMA desc. pointer after submission

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Submitter Federico Vaga
Date Feb. 8, 2019, 3:30 p.m.
Message ID <20190208153038.23272-1-federico.vaga@cern.ch>
Download mbox | patch
Permalink /patch/721681/
State New
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Federico Vaga - Feb. 8, 2019, 3:30 p.m.
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(+)
Vinod Koul - Feb. 11, 2019, 11:54 a.m.
On 08-02-19, 16:30, Federico Vaga 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

Consequently

> +      descriptor.
> +

Applied after fixing the typo and added tag as Documentation: dmaengine...

>  5. Issue pending DMA requests and wait for callback notification
>  
>     The transactions in the pending queue can be activated by calling the
> -- 
> 2.15.0
Federico Vaga - Feb. 11, 2019, 12:10 p.m.
On Monday, February 11, 2019 12:54:11 PM CET Vinod Koul wrote:
> On 08-02-19, 16:30, Federico Vaga 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
> Consequently

I'm not a native speaker but consequentially and consequently should be 
synonymous. As fa as I understood. but I do not mind to change it if you think 
is better.

> > +      descriptor.
> > +
> 
> Applied after fixing the typo and added tag as Documentation: dmaengine...

I used doc to make the string shorter

> 
> >  5. Issue pending DMA requests and wait for callback notification
> >  
> >     The transactions in the pending queue can be activated by calling the
Jonathan Corbet - Feb. 11, 2019, 3:40 p.m.
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

Patch

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