net: mvneta: Avoid unmapping the TSO header buffers

The buffers for the TSO headers belong to a DMA coherent region which is
allocated at ndo_open() time, and released at ndo_stop() time.

Therefore, and contrary to the TSO payload descriptor buffers, the TSO header
buffers don't need to be unmapped. This commit adds a check to detect a
TSO header buffer and explicitly prevent the unmap.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index f95e7cadb01b..45beca17fa50 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -264,6 +264,10 @@
               ETH_HLEN + ETH_FCS_LEN,                        \
               MVNETA_CPU_D_CACHE_LINE_SIZE)
 
+#define IS_TSO_HEADER(txq, addr) \
+        ((addr >= txq->tso_hdrs_phys) && \
+         (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
+
 #define MVNETA_RX_BUF_SIZE(pkt_size)   ((pkt_size) + NET_SKB_PAD)
 
 struct mvneta_pcpu_stats {
@@ -1291,8 +1295,10 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp,
 
                 mvneta_txq_inc_get(txq);
 
-                dma_unmap_single(pp->dev->dev.parent, tx_desc->buf_phys_addr,
-                                 tx_desc->data_size, DMA_TO_DEVICE);
+                if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
+                        dma_unmap_single(pp->dev->dev.parent,
+                                         tx_desc->buf_phys_addr,
+                                         tx_desc->data_size, DMA_TO_DEVICE);
                 if (!skb)
                         continue;
                 dev_kfree_skb_any(skb);
@@ -1642,7 +1648,7 @@ err_release:
          */
         for (i = desc_count - 1; i >= 0; i--) {
                 struct mvneta_tx_desc *tx_desc = txq->descs + i;
-                if (!(tx_desc->command & MVNETA_TXD_F_DESC))
+                if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
                         dma_unmap_single(pp->dev->dev.parent,
                                          tx_desc->buf_phys_addr,
                                          tx_desc->data_size,