[PATCH 5.9 040/133] net: dsa: qca8k: Fix port MTU setting

[Greg Kroah-Hartman]

From: Jonathan McDowell <noodles@xxxxxxxx>

[ Upstream commit 99cab7107d914a71c57f5a4e6d34292425fbbb61 ]

The qca8k only supports a switch-wide MTU setting, and the code to take
the max of all ports was only looking at the port currently being set.
Fix to examine all ports.

Reported-by: DENG Qingfang <dqfext@xxxxxxxxx>
Fixes: f58d2598cf70 ("net: dsa: qca8k: implement the port MTU callbacks")
Signed-off-by: Jonathan McDowell <noodles@xxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Link: https://lore.kernel.org/r/20201030183315.GA6736@xxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/dsa/qca8k.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1219,8 +1219,8 @@ qca8k_port_change_mtu(struct dsa_switch
 	priv->port_mtu[port] = new_mtu;
 
 	for (i = 0; i < QCA8K_NUM_PORTS; i++)
-		if (priv->port_mtu[port] > mtu)
-			mtu = priv->port_mtu[port];
+		if (priv->port_mtu[i] > mtu)
+			mtu = priv->port_mtu[i];
 
 	/* Include L2 header / FCS length */
 	qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, mtu + ETH_HLEN + ETH_FCS_LEN);