[PATCH net] net: nixge: fix potential memory leak in nixge_start_xmit()

[Zhang Changzhong <zhangchangzhong@huawei.com>]

The nixge_start_xmit() returns NETDEV_TX_OK but does not free skb on two
error handling cases, which can lead to memory leak.

To fix this, return NETDEV_TX_BUSY in case of nixge_check_tx_bd_space()
fails and add dev_kfree_skb_any() in case of dma_map_single() fails.

Fixes: 492caffa8a1a ("net: ethernet: nixge: Add support for National Instruments XGE netdev")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
---
 drivers/net/ethernet/ni/nixge.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
index 19d043b593cc..b9091f9bbc77 100644
--- a/drivers/net/ethernet/ni/nixge.c
+++ b/drivers/net/ethernet/ni/nixge.c
@@ -521,13 +521,15 @@ static netdev_tx_t nixge_start_xmit(struct sk_buff *skb,
 	if (nixge_check_tx_bd_space(priv, num_frag)) {
 		if (!netif_queue_stopped(ndev))
 			netif_stop_queue(ndev);
-		return NETDEV_TX_OK;
+		return NETDEV_TX_BUSY;
 	}
 
 	cur_phys = dma_map_single(ndev->dev.parent, skb->data,
 				  skb_headlen(skb), DMA_TO_DEVICE);
-	if (dma_mapping_error(ndev->dev.parent, cur_phys))
+	if (dma_mapping_error(ndev->dev.parent, cur_phys)) {
+		dev_kfree_skb_any(skb);
 		goto drop;
+	}
 	nixge_hw_dma_bd_set_phys(cur_p, cur_phys);
 
 	cur_p->cntrl = skb_headlen(skb) | XAXIDMA_BD_CTRL_TXSOF_MASK;
-- 
2.31.1