dmaengine: at_xdmac: Fix concurrency over chan's completed_cookie

Caller of dma_cookie_complete is expected to hold a lock to prevent
concurrency over the channel's completed cookie marker. Call
dma_cookie_complete() with the lock held.

Fixes: e1f7c9e ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-5-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: ambarus

drivers/dma/at_xdmac.c

@@ -1703,11 +1703,10 @@ static void at_xdmac_tasklet(struct tasklet_struct *t)
 		}
 
 		txd = &desc->tx_dma_desc;
-
+		dma_cookie_complete(txd);
 		at_xdmac_remove_xfer(atchan, desc);
 		spin_unlock_irq(&atchan->lock);
 
-		dma_cookie_complete(txd);
 		if (txd->flags & DMA_PREP_INTERRUPT)
 			dmaengine_desc_get_callback_invoke(txd, NULL);