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From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vivien Didelot <vivien.didelot@gmail.com>
Subject: [RFC PATCH net-next 08/10] net: dsa: sja1105: increase MTU to account for VLAN header on DSA ports
Date: Sat, 31 Jul 2021 03:14:06 +0300	[thread overview]
Message-ID: <20210731001408.1882772-9-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20210731001408.1882772-1-vladimir.oltean@nxp.com>

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>
---
 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 31dd4b5a2c80..2bca922d7b8c 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1020,7 +1020,7 @@ 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 */
@@ -2714,7 +2714,7 @@ 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;
-- 
2.25.1


  parent reply	other threads:[~2021-07-31  0:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-31  0:13 [RFC PATCH net-next 00/10] NXP SJA1105 driver support for "H" switch topologies Vladimir Oltean
2021-07-31  0:13 ` [RFC PATCH net-next 01/10] net: dsa: rename teardown_default_cpu to teardown_cpu_ports Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 02/10] net: dsa: give preference to local CPU ports Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 03/10] net: dsa: sja1105: configure the cascade ports based on topology Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 04/10] net: dsa: sja1105: manage the forwarding domain towards DSA ports Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 05/10] net: dsa: sja1105: manage VLANs on cascade ports Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 06/10] net: dsa: sja1105: suppress TX packets from looping back in "H" topologies Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 07/10] net: dsa: sja1105: prevent tag_8021q VLANs from being received on user ports Vladimir Oltean
2021-07-31  0:14 ` Vladimir Oltean [this message]
2021-07-31  0:14 ` [RFC PATCH net-next 09/10] net: dsa: sja1105: enable address learning on cascade ports Vladimir Oltean
2021-07-31  0:14 ` [RFC PATCH net-next 10/10] net: dsa: sja1105: drop untagged packets on the CPU and DSA ports Vladimir Oltean

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