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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, DENG Qingfang <dqfext@gmail.com>,
        Jonathan McDowell <noodles@earth.li>,
        Andrew Lunn <andrew@lunn.ch>, Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.9 040/133] net: dsa: qca8k: Fix port MTU setting
Date:   Mon,  9 Nov 2020 13:55:02 +0100
Message-Id: <20201109125032.639079509@linuxfoundation.org>
In-Reply-To: <20201109125030.706496283@linuxfoundation.org>
References: <20201109125030.706496283@linuxfoundation.org>
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From: Jonathan McDowell <noodles@earth.li>

[ 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@gmail.com>
Fixes: f58d2598cf70 ("net: dsa: qca8k: implement the port MTU callbacks")
Signed-off-by: Jonathan McDowell <noodles@earth.li>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201030183315.GA6736@earth.li
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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);