net: stmmac: Fixed mtu channged by cache aligned

Since the original mtu is not used when the mtu is updated,
the mtu is aligned with cache, this will get an incorrect.
For example, if you want to configure the mtu to be 1500,
but mtu 1536 is configured in fact.

Fixed: eaf4fac478077 ("net: stmmac: Do not accept invalid MTU values")
Signed-off-by: David Wu <david.wu@rock-chips.com>
Link: https://lore.kernel.org/r/20210113034109.27865-1-david.wu@rock-chips.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2d90d6856ec580535f7d61c016fdafee062b1c47..26b971cd4da5abfb8407fe9b8bf3aa63c6f87c52 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4026,6 +4026,7 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
 {
        struct stmmac_priv *priv = netdev_priv(dev);
        int txfifosz = priv->plat->tx_fifo_size;
+       const int mtu = new_mtu;
 
        if (txfifosz == 0)
                txfifosz = priv->dma_cap.tx_fifo_size;
@@ -4043,7 +4044,7 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
        if ((txfifosz < new_mtu) || (new_mtu > BUF_SIZE_16KiB))
                return -EINVAL;
 
-       dev->mtu = new_mtu;
+       dev->mtu = mtu;
 
        netdev_update_features(dev);