Since the driver does not act upon the max_sdu argument, 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@nxp.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 773e415cc2de..8e9c7d54fb4c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -922,13 +922,17 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	struct plat_stmmacenet_data *plat = priv->plat;
 	struct timespec64 time, current_time, qopt_time;
 	ktime_t current_time_ns;
+	int i, tc, ret = 0;
 	bool fpe = false;
-	int i, ret = 0;
 	u64 ctr;
 
 	if (!priv->dma_cap.estsel)
 		return -EOPNOTSUPP;
 
+	for (tc = 0; tc < TC_MAX_QUEUE; tc++)
+		if (qopt->max_sdu[tc])
+			return -EOPNOTSUPP;
+
 	switch (wid) {
 	case 0x1:
 		wid = 16;
-- 
2.34.1