[PATCH net 1/2] net: ethernet: mediatek: fix inconsistency between TXD and the used buffer

[sean.wang]

From: Sean Wang <sean.w...@mediatek.com>

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.w...@mediatek.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 17 ++++++++---------
 1 file 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 14e1bd1..48ba617 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)) |
-- 
1.9.1