sfc: Don't leak PCI DMA maps in the TSO code when the queue fills up

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

drivers/net/sfc/tx.c

@@ -1096,6 +1096,11 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
 		efx_stop_queue(tx_queue->efx);
 
  unwind:
+	/* Free the DMA mapping we were in the process of writing out */
+	if (state.ifc.unmap_len)
+		pci_unmap_page(tx_queue->efx->pci_dev, state.ifc.unmap_addr,
+			       state.ifc.unmap_len, PCI_DMA_TODEVICE);
+
 	efx_enqueue_unwind(tx_queue);
 	return rc2;
 }