From: Federico Vaga Date: Fri, 8 Feb 2019 15:30:38 +0000 (+0100) Subject: doc:dmaengine: clarify DMA desc. pointer after submission X-Git-Tag: v5.1-rc1~93^2~21 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=db693aded3fb419c763963246281e417c1c0e126;p=thirdparty%2Fkernel%2Flinux.git 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 Signed-off-by: Jonathan Corbet --- diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst index fbbb2831f29f8..d728e50105eb3 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