net: ethernet: mediatek: fix inconsistency between TXD and the used buffer

Fix inconsistency between the TXD descriptor and the used buffer that
would cause unexpected logic at mtk_tx_unmap() during skb housekeeping.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 9 deletions

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 9e757684816d..50a6fe87e990 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -613,7 +613,7 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
         struct mtk_mac *mac = netdev_priv(dev);
         struct mtk_eth *eth = mac->hw;
         struct mtk_tx_dma *itxd, *txd;
-        struct mtk_tx_buf *tx_buf;
+        struct mtk_tx_buf *itx_buf, *tx_buf;
         dma_addr_t mapped_addr;
         unsigned int nr_frags;
         int i, n_desc = 1;
@@ -627,8 +627,8 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
         fport = (mac->id + 1) << TX_DMA_FPORT_SHIFT;
         txd4 |= fport;
 
-        tx_buf = mtk_desc_to_tx_buf(ring, itxd);
-        memset(tx_buf, 0, sizeof(*tx_buf));
+        itx_buf = mtk_desc_to_tx_buf(ring, itxd);
+        memset(itx_buf, 0, sizeof(*itx_buf));
 
         if (gso)
                 txd4 |= TX_DMA_TSO;
@@ -647,9 +647,9 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
                 return -ENOMEM;
 
         WRITE_ONCE(itxd->txd1, mapped_addr);
-        tx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
-        dma_unmap_addr_set(tx_buf, dma_addr0, mapped_addr);
-        dma_unmap_len_set(tx_buf, dma_len0, skb_headlen(skb));
+        itx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
+        dma_unmap_addr_set(itx_buf, dma_addr0, mapped_addr);
+        dma_unmap_len_set(itx_buf, dma_len0, skb_headlen(skb));
 
         /* TX SG offload */
         txd = itxd;
@@ -685,10 +685,9 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
                                                last_frag * TX_DMA_LS0));
                         WRITE_ONCE(txd->txd4, fport);
 
-                        tx_buf->skb = (struct sk_buff *)MTK_DMA_DUMMY_DESC;
                         tx_buf = mtk_desc_to_tx_buf(ring, txd);
                         memset(tx_buf, 0, sizeof(*tx_buf));
-
+                        tx_buf->skb = (struct sk_buff *)MTK_DMA_DUMMY_DESC;
                         tx_buf->flags |= MTK_TX_FLAGS_PAGE0;
                         dma_unmap_addr_set(tx_buf, dma_addr0, mapped_addr);
                         dma_unmap_len_set(tx_buf, dma_len0, frag_map_size);
@@ -698,7 +697,7 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
         }
 
         /* store skb to cleanup */
-        tx_buf->skb = skb;
+        itx_buf->skb = skb;
 
         WRITE_ONCE(itxd->txd4, txd4);
         WRITE_ONCE(itxd->txd3, (TX_DMA_SWC | TX_DMA_PLEN0(skb_headlen(skb)) |