[PATCH] doc:dmaengine: clarify DMA desc. pointer after submission
- Date: Fri, 8 Feb 2019 16:30:38 +0100
- From: Federico Vaga <federico.vaga@xxxxxxx>
- Subject: [PATCH] doc:dmaengine: clarify DMA desc. pointer after submission
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@xxxxxxx>
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
@@ -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
5. Issue pending DMA requests and wait for callback notification
The transactions in the pending queue can be activated by calling the