[PATCH v2 net-next 07/12] net: dsa: sja1105: deny tc-taprio changes to per-tc max SDU

[Vladimir Oltean]

Since the driver does not act upon the max_sdu argument (which it
should, in full offload mode), deny any other values except the default
all-zeroes, which means that all traffic classes should use the same MTU
as the port itself.

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
v1->v2: none

 drivers/net/dsa/sja1105/sja1105_tas.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_tas.c b/drivers/net/dsa/sja1105/sja1105_tas.c
index e6153848a950..607f4714fb01 100644
--- a/drivers/net/dsa/sja1105/sja1105_tas.c
+++ b/drivers/net/dsa/sja1105/sja1105_tas.c
@@ -511,7 +511,7 @@ int sja1105_setup_tc_taprio(struct dsa_switch *ds, int port,
 {
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_tas_data *tas_data = &priv->tas_data;
-	int other_port, rc, i;
+	int other_port, rc, i, tc;
 
 	/* Can't change an already configured port (must delete qdisc first).
 	 * Can't delete the qdisc from an unconfigured port.
@@ -519,6 +519,10 @@ int sja1105_setup_tc_taprio(struct dsa_switch *ds, int port,
 	if (!!tas_data->offload[port] == admin->enable)
 		return -EINVAL;
 
+	for (tc = 0; tc < TC_MAX_QUEUE; tc++)
+		if (admin->max_sdu[tc])
+			return -EOPNOTSUPP;
+
 	if (!admin->enable) {
 		taprio_offload_free(tas_data->offload[port]);
 		tas_data->offload[port] = NULL;
-- 
2.34.1