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* [PATCH] doc:dmaengine: clarify DMA desc. pointer after submission
@ 2019-02-08 15:30 Federico Vaga
  2019-02-11 11:54 ` Vinod Koul
  2019-02-11 15:40 ` Jonathan Corbet
  0 siblings, 2 replies; 4+ messages in thread
From: Federico Vaga @ 2019-02-08 15:30 UTC (permalink / raw)
  To: Vinod Koul, Jonathan Corbet
  Cc: dmaengine, linux-doc, linux-kernel, Federico Vaga

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
-- 
2.15.0


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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

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