From: Federico Vaga Date: Fri, 8 Feb 2019 15:30:38 +0000 (+0100) Subject: Documentation :dmaengine: clarify DMA desc. pointer after submission X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=85ed4f43db866fe1ea90bcca8cd1e5e628f04a6f;p=linux.git Documentation :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 Signed-off-by: Vinod Koul --- diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst index fbbb2831f29f8..45953f1715000 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. + Consequently, 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