Re: [PATCH 15/16] dmaengine: add transfered member to dma_async_tx_descriptor

[Lars-Peter Clausen]

On 07/25/2013 05:12 PM, Sebastian Andrzej Siewior wrote:
> On 07/25/2013 04:57 PM, Lars-Peter Clausen wrote:
>> I'm not sure that this will work. Once you've submitted the descriptor it is
>> owned by the dmaengine driver and you are not allowed to dereference it
>> anymore since the dmaengine driver might free the memory at any time. You
>> should only reference the descriptor by the cookie returned by submit().
> 
> I see. But it can't be reused before calling the callback if it is
> going to call the callback, right?
> So if this is a no-no, I'm left with an additional argument to the
> complete callback?

Hm, maybe using dmaengine_tx_status() and checking the residue field of the
state struct. transferred is basically len - residue.

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