[PATCH] net: macb: add check for dma mapping error in start_xmit()

[Alexey Khoroshilov]

at91ether_start_xmit() does not check for dma mapping errors.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshi...@ispras.ru>
---
 drivers/net/ethernet/cadence/macb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb.c 
b/drivers/net/ethernet/cadence/macb.c
index b32444a3ed79..533653bd7aec 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -2673,6 +2673,12 @@ static int at91ether_start_xmit(struct sk_buff *skb, 
struct net_device *dev)
                lp->skb_length = skb->len;
                lp->skb_physaddr = dma_map_single(NULL, skb->data, skb->len,
                                                        DMA_TO_DEVICE);
+               if (dma_mapping_error(NULL, lp->skb_physaddr)) {
+                       dev_kfree_skb_any(skb);
+                       dev->stats.tx_dropped++;
+                       netdev_err(dev, "%s: DMA mapping error\n", __func__);
+                       return NETDEV_TX_OK;
+               }
 
                /* Set address of the data in the Transmit Address register */
                macb_writel(lp, TAR, lp->skb_physaddr);
-- 
2.7.4