[PATCH] net: ethernet: ravb: fix dma mapping failure handling

[Nikita Yushchenko]

dma_mapping_error() depends on getting full 64-bit dma_addr_t and does
not work correctly if 32-bit value is passed instead.

Fix handling of dma_map_single() failures on Rx ring entries:
- do not store return value of dma_map_signle() in 32-bit variable,
- do not use dma_mapping_error() against 32-bit descriptor field when
  checking if unmap is needed, check for zero size instead.

Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/renesas/ravb_main.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 8649b3e90edb..4d4b5d44c4e7 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -256,8 +256,7 @@ static void ravb_rx_ring_free_gbeth(struct net_device *ndev, int q)
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
 		struct ravb_rx_desc *desc = &priv->gbeth_rx_ring[i];
 
-		if (!dma_mapping_error(ndev->dev.parent,
-				       le32_to_cpu(desc->dptr)))
+		if (le16_to_cpu(desc->ds_cc) != 0)
 			dma_unmap_single(ndev->dev.parent,
 					 le32_to_cpu(desc->dptr),
 					 GBETH_RX_BUFF_MAX,
@@ -281,8 +280,7 @@ static void ravb_rx_ring_free_rcar(struct net_device *ndev, int q)
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
 		struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
 
-		if (!dma_mapping_error(ndev->dev.parent,
-				       le32_to_cpu(desc->dptr)))
+		if (le16_to_cpu(desc->ds_cc) != 0)
 			dma_unmap_single(ndev->dev.parent,
 					 le32_to_cpu(desc->dptr),
 					 RX_BUF_SZ,
@@ -1949,7 +1947,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	struct ravb_tstamp_skb *ts_skb;
 	struct ravb_tx_desc *desc;
 	unsigned long flags;
-	u32 dma_addr;
+	dma_addr_t dma_addr;
 	void *buffer;
 	u32 entry;
 	u32 len;
-- 
2.39.2