[PATCH v2] dmaengine: edma: Implement device_synchronize callback

[Lars-Peter Clausen]

On 02/11/2016 10:08 AM, Peter Ujfalusi wrote:
> We need the callback to support the dmaengine_terminate_sync().
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>

Looks good, but I noticed a slight race condition in
edma_completion_handler(). You need to fetch echan->desc while holding the
vchan.lock. Otherwise this can race against terminate_all() and the callback
might get scheduled even though terminate_all() completed and then there is
a race where the synchronize() operation could be called before the callback
gets scheduled, which means it doesn't do its intended job. Highly unlikely
to happen, but theoretically possible.