net: enetc: fix the off-by-one issue in enetc_map_tx_tso_buffs()

There is an off-by-one issue for the err_chained_bd path, it will free
one more tx_swbd than expected. But there is no such issue for the
err_map_data path. To fix this off-by-one issue and make the two error
handling consistent, the increment of 'i' and 'count' remain in sync
and enetc_unwind_tx_frame() is called for error handling.

Fixes: fb8629e2cbfc ("net: enetc: add support for software TSO")
Cc: stable@vger.kernel.org
Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Link: https://patch.msgid.link/20250224111251.1061098-9-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 9801c51b6a590e45bec3fca42f95beb0aabedf4a..2106861463e40fb5a7df34534010c9ef77df845e 100644 (file)
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -859,8 +859,13 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb
                        err = enetc_map_tx_tso_data(tx_ring, skb, tx_swbd, txbd,
                                                    tso.data, size,
                                                    size == data_len);
-                       if (err)
+                       if (err) {
+                               if (i == 0)
+                                       i = tx_ring->bd_count;
+                               i--;
+
                                goto err_map_data;
+                       }
 
                        data_len -= size;
                        count++;
@@ -889,13 +894,7 @@ err_map_data:
        dev_err(tx_ring->dev, "DMA map error");
 
 err_chained_bd:
-       do {
-               tx_swbd = &tx_ring->tx_swbd[i];
-               enetc_free_tx_frame(tx_ring, tx_swbd);
-               if (i == 0)
-                       i = tx_ring->bd_count;
-               i--;
-       } while (count--);
+       enetc_unwind_tx_frame(tx_ring, count, i);
 
        return 0;
 }