From 777e55e30d1275e0ddd70efdbcd8cf6f4dae554e Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Wed, 4 Aug 2021 16:54:34 +0300
Subject: [PATCH] net: dsa: sja1105: increase MTU to account for VLAN header on
DSA ports
Since all packets are transmitted as VLAN-tagged over a DSA link (this
VLAN tag represents the tag_8021q header), we need to increase the MTU
of these interfaces to account for the possibility that we are already
transporting a user-visible VLAN header.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/dsa/sja1105/sja1105_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index d1d4d956cae8..fffcaef6b148 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -982,7 +982,7 @@ static int sja1105_init_l2_policing(struct sja1105_private *priv)
for (port = 0; port < ds->num_ports; port++) {
int mtu = VLAN_ETH_FRAME_LEN + ETH_FCS_LEN;
- if (dsa_is_cpu_port(priv->ds, port))
+ if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
mtu += VLAN_HLEN;
policing[port].smax = 65535; /* Burst size in bytes */
@@ -2664,7 +2664,7 @@ static int sja1105_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
new_mtu += VLAN_ETH_HLEN + ETH_FCS_LEN;
- if (dsa_is_cpu_port(ds, port))
+ if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
new_mtu += VLAN_HLEN;
policing = priv->static_config.tables[BLK_IDX_L2_POLICING].entries;
--
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