net: mvpp2: only free the TSO header buffers when it was allocated

This patch adds a check to only free the TSO header buffer when its
allocation previously succeeded.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2.c

@@ -5802,6 +5802,7 @@ static int mvpp2_txq_init(struct mvpp2_port *port,
 		txq_pcpu->reserved_num = 0;
 		txq_pcpu->txq_put_index = 0;
 		txq_pcpu->txq_get_index = 0;
+		txq_pcpu->tso_headers = NULL;
 
 		txq_pcpu->stop_threshold = txq->size - MVPP2_MAX_SKB_DESCS;
 		txq_pcpu->wake_threshold = txq_pcpu->stop_threshold / 2;
@@ -5829,10 +5830,13 @@ static void mvpp2_txq_deinit(struct mvpp2_port *port,
 		txq_pcpu = per_cpu_ptr(txq->pcpu, cpu);
 		kfree(txq_pcpu->buffs);
 
-		dma_free_coherent(port->dev->dev.parent,
-				  txq_pcpu->size * TSO_HEADER_SIZE,
-				  txq_pcpu->tso_headers,
-				  txq_pcpu->tso_headers_dma);
+		if (txq_pcpu->tso_headers)
+			dma_free_coherent(port->dev->dev.parent,
+					  txq_pcpu->size * TSO_HEADER_SIZE,
+					  txq_pcpu->tso_headers,
+					  txq_pcpu->tso_headers_dma);
+
+		txq_pcpu->tso_headers = NULL;
 	}
 
 	if (txq->descs)