diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index a333748..ec70c9f 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -680,6 +680,9 @@
 
 	/* FIXME: Document how the locking works. */
 	if (ohci->generation != packet->generation) {
+		if (packet->payload_length > 0)
+			dma_unmap_single(ohci->card.device, payload_bus,
+					 packet->payload_length, DMA_TO_DEVICE);
 		packet->ack = RCODE_GENERATION;
 		return -1;
 	}