[3/4] I/OAT: fix async_tx.callback checking

async_tx.callback should be checked for the first
not the last descriptor in the chain.

Cc: <stable@kernel.org>
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/dma/ioat_dma.c

@@ -525,7 +525,7 @@ static dma_cookie_t ioat1_tx_submit(struct dma_async_tx_descriptor *tx)
 	}
 
 	hw->ctl = IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
-	if (new->async_tx.callback) {
+	if (first->async_tx.callback) {
 		hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_INT_GN;
 		if (first != new) {
 			/* move callback into to last desc */
@@ -617,7 +617,7 @@ static dma_cookie_t ioat2_tx_submit(struct dma_async_tx_descriptor *tx)
 	}
 
 	hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
-	if (new->async_tx.callback) {
+	if (first->async_tx.callback) {
 		hw->ctl |= IOAT_DMA_DESCRIPTOR_CTL_INT_GN;
 		if (first != new) {
 			/* move callback into to last desc */