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path: root/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
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Diffstat (limited to 'drivers/net/ethernet/stmicro/stmmac/stmmac_main.c')
-rw-r--r--drivers/net/ethernet/stmicro/stmmac/stmmac_main.c22
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d3895d7eecfc..208dbc68aaf9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4304,11 +4304,6 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
if (dma_mapping_error(priv->device, des))
goto dma_map_err;
- tx_q->tx_skbuff_dma[first_entry].buf = des;
- tx_q->tx_skbuff_dma[first_entry].len = skb_headlen(skb);
- tx_q->tx_skbuff_dma[first_entry].map_as_page = false;
- tx_q->tx_skbuff_dma[first_entry].buf_type = STMMAC_TXBUF_T_SKB;
-
if (priv->dma_cap.addr64 <= 32) {
first->des0 = cpu_to_le32(des);
@@ -4327,6 +4322,23 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
stmmac_tso_allocator(priv, des, tmp_pay_len, (nfrags == 0), queue);
+ /* In case two or more DMA transmit descriptors are allocated for this
+ * non-paged SKB data, the DMA buffer address should be saved to
+ * tx_q->tx_skbuff_dma[].buf corresponding to the last descriptor,
+ * and leave the other tx_q->tx_skbuff_dma[].buf as NULL to guarantee
+ * that stmmac_tx_clean() does not unmap the entire DMA buffer too early
+ * since the tail areas of the DMA buffer can be accessed by DMA engine
+ * sooner or later.
+ * By saving the DMA buffer address to tx_q->tx_skbuff_dma[].buf
+ * corresponding to the last descriptor, stmmac_tx_clean() will unmap
+ * this DMA buffer right after the DMA engine completely finishes the
+ * full buffer transmission.
+ */
+ tx_q->tx_skbuff_dma[tx_q->cur_tx].buf = des;
+ tx_q->tx_skbuff_dma[tx_q->cur_tx].len = skb_headlen(skb);
+ tx_q->tx_skbuff_dma[tx_q->cur_tx].map_as_page = false;
+ tx_q->tx_skbuff_dma[tx_q->cur_tx].buf_type = STMMAC_TXBUF_T_SKB;
+
/* Prepare fragments */
for (i = 0; i < nfrags; i++) {
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];