net: ag71xx: remove unnecessary MTU reservation

commit 04b385f325080157ab1b5f8ce1b1de07ce0d9e27 upstream.

2 bytes of the MTU are reserved for Atheros DSA tag, but DSA core
has already handled that since commit dc0fe7d47f9f.
Remove the unnecessary reservation.

Fixes: d51b6ce441d3 ("net: ethernet: add ag71xx driver")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20210218034514.3421-1-dqfext@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/atheros/ag71xx.c b/drivers/net/ethernet/atheros/ag71xx.c
index dd5c8a9..a60ce90 100644 (file)
--- a/drivers/net/ethernet/atheros/ag71xx.c
+++ b/drivers/net/ethernet/atheros/ag71xx.c
@@ -223,8 +223,6 @@
 #define AG71XX_REG_RX_SM       0x01b0
 #define AG71XX_REG_TX_SM       0x01b4
 
-#define ETH_SWITCH_HEADER_LEN  2
-
 #define AG71XX_DEFAULT_MSG_ENABLE      \
        (NETIF_MSG_DRV                  \
        | NETIF_MSG_PROBE               \
@@ -933,7 +931,7 @@ static void ag71xx_hw_setup(struct ag71xx *ag)
 
 static unsigned int ag71xx_max_frame_len(unsigned int mtu)
 {
-       return ETH_SWITCH_HEADER_LEN + ETH_HLEN + VLAN_HLEN + mtu + ETH_FCS_LEN;
+       return ETH_HLEN + VLAN_HLEN + mtu + ETH_FCS_LEN;
 }
 
 static void ag71xx_hw_set_macaddr(struct ag71xx *ag, unsigned char *mac)