target/linux/generic/backport-5.15/769-v5.19-01-net-dsa-qca8k-drop-MTU-tracking-from-qca8k_priv.patch

   1 From 69fd055957a02309ffdc23d887a01988b6e5bab1 Mon Sep 17 00:00:00 2001
   2 From: Ansuel Smith <ansuelsmth@gmail.com>
   3 Date: Sat, 16 Apr 2022 01:30:12 +0200
   4 Subject: [PATCH 1/6] net: dsa: qca8k: drop MTU tracking from qca8k_priv
   5
   6 DSA set the CPU port based on the largest MTU of all the slave ports.
   7 Based on this we can drop the MTU array from qca8k_priv and set the
   8 port_change_mtu logic on DSA changing MTU of the CPU port as the switch
   9 have a global MTU settingfor each port.
  10
  11 Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
  12 Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
  13 Signed-off-by: David S. Miller <davem@davemloft.net>
  14 ---
  15  drivers/net/dsa/qca8k.c | 26 +++++++++-----------------
  16  drivers/net/dsa/qca8k.h |  1 -
  17  2 files changed, 9 insertions(+), 18 deletions(-)
  18
  19 --- a/drivers/net/dsa/qca8k.c
  20 +++ b/drivers/net/dsa/qca8k.c
  21 @@ -1803,16 +1803,6 @@ qca8k_setup(struct dsa_switch *ds)
  22                                   QCA8K_PORT_HOL_CTRL1_WRED_EN,
  23                                   mask);
  24                 }
  25 -
  26 -               /* Set initial MTU for every port.
  27 -                * We have only have a general MTU setting. So track
  28 -                * every port and set the max across all port.
  29 -                * Set per port MTU to 1500 as the MTU change function
  30 -                * will add the overhead and if its set to 1518 then it
  31 -                * will apply the overhead again and we will end up with
  32 -                * MTU of 1536 instead of 1518
  33 -                */
  34 -               priv->port_mtu[i] = ETH_DATA_LEN;
  35         }
  36
  37         /* Special GLOBAL_FC_THRESH value are needed for ar8327 switch */
  38 @@ -2525,13 +2515,16 @@ static int
  39  qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
  40  {
  41         struct qca8k_priv *priv = ds->priv;
  42 -       int ret, i, mtu = 0;
  43 -
  44 -       priv->port_mtu[port] = new_mtu;
  45 +       int ret;
  46
  47 -       for (i = 0; i < QCA8K_NUM_PORTS; i++)
  48 -               if (priv->port_mtu[i] > mtu)
  49 -                       mtu = priv->port_mtu[i];
  50 +       /* We have only have a general MTU setting.
  51 +        * DSA always set the CPU port's MTU to the largest MTU of the slave
  52 +        * ports.
  53 +        * Setting MTU just for the CPU port is sufficient to correctly set a
  54 +        * value for every port.
  55 +        */
  56 +       if (!dsa_is_cpu_port(ds, port))
  57 +               return 0;
  58
  59         /* To change the MAX_FRAME_SIZE the cpu ports must be off or
  60          * the switch panics.
  61 @@ -2545,7 +2538,7 @@ qca8k_port_change_mtu(struct dsa_switch
  62                 qca8k_port_set_status(priv, 6, 0);
  63
  64         /* Include L2 header / FCS length */
  65 -       ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, mtu + ETH_HLEN + ETH_FCS_LEN);
  66 +       ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
  67
  68         if (priv->port_sts[0].enabled)
  69                 qca8k_port_set_status(priv, 0, 1);
  70 --- a/drivers/net/dsa/qca8k.h
  71 +++ b/drivers/net/dsa/qca8k.h
  72 @@ -392,7 +392,6 @@ struct qca8k_priv {
  73         struct device *dev;
  74         struct dsa_switch_ops ops;
  75         struct gpio_desc *reset_gpio;
  76 -       unsigned int port_mtu[QCA8K_NUM_PORTS];
  77         struct net_device *mgmt_master; /* Track if mdio/mib Ethernet is available */
  78         struct qca8k_mgmt_eth_data mgmt_eth_data;
  79         struct qca8k_mib_eth_data mib_eth_data;