net/mlx5e: Update xon formula

Set xon = xoff - netdev's max_mtu.
netdev's max_mtu will give enough time for the pause frame to
arrive at the sender.

Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
index f00de0c987cd6a7ff0ebcc9b6dd349bd1209794e..4ab0d030b54486f67096a190471a747b1ac18c56 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
@@ -143,7 +143,7 @@ static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
 }
 
 static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
-                                u32 xoff, unsigned int mtu)
+                                u32 xoff, unsigned int max_mtu)
 {
        int i;
 
@@ -155,11 +155,12 @@ static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
                }
 
                if (port_buffer->buffer[i].size <
-                   (xoff + mtu + (1 << MLX5E_BUFFER_CELL_SHIFT)))
+                   (xoff + max_mtu + (1 << MLX5E_BUFFER_CELL_SHIFT)))
                        return -ENOMEM;
 
                port_buffer->buffer[i].xoff = port_buffer->buffer[i].size - xoff;
-               port_buffer->buffer[i].xon  = port_buffer->buffer[i].xoff - mtu;
+               port_buffer->buffer[i].xon  =
+                       port_buffer->buffer[i].xoff - max_mtu;
        }
 
        return 0;
@@ -167,7 +168,7 @@ static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
 
 /**
  * update_buffer_lossy()
- *   mtu: device's MTU
+ *   max_mtu: netdev's max_mtu
  *   pfc_en: <input> current pfc configuration
  *   buffer: <input> current prio to buffer mapping
  *   xoff:   <input> xoff value
@@ -184,7 +185,7 @@ static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
  *     Return 0 if no error.
  *     Set change to true if buffer configuration is modified.
  */
-static int update_buffer_lossy(unsigned int mtu,
+static int update_buffer_lossy(unsigned int max_mtu,
                               u8 pfc_en, u8 *buffer, u32 xoff,
                               struct mlx5e_port_buffer *port_buffer,
                               bool *change)
@@ -221,7 +222,7 @@ static int update_buffer_lossy(unsigned int mtu,
        }
 
        if (changed) {
-               err = update_xoff_threshold(port_buffer, xoff, mtu);
+               err = update_xoff_threshold(port_buffer, xoff, max_mtu);
                if (err)
                        return err;
 
@@ -231,6 +232,7 @@ static int update_buffer_lossy(unsigned int mtu,
        return 0;
 }
 
+#define MINIMUM_MAX_MTU 9216
 int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
                                    u32 change, unsigned int mtu,
                                    struct ieee_pfc *pfc,
@@ -242,12 +244,14 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
        bool update_prio2buffer = false;
        u8 buffer[MLX5E_MAX_PRIORITY];
        bool update_buffer = false;
+       unsigned int max_mtu;
        u32 total_used = 0;
        u8 curr_pfc_en;
        int err;
        int i;
 
        mlx5e_dbg(HW, priv, "%s: change=%x\n", __func__, change);
+       max_mtu = max_t(unsigned int, priv->netdev->max_mtu, MINIMUM_MAX_MTU);
 
        err = mlx5e_port_query_buffer(priv, &port_buffer);
        if (err)
@@ -255,7 +259,7 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
 
        if (change & MLX5E_PORT_BUFFER_CABLE_LEN) {
                update_buffer = true;
-               err = update_xoff_threshold(&port_buffer, xoff, mtu);
+               err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
                if (err)
                        return err;
        }
@@ -265,7 +269,7 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
                if (err)
                        return err;
 
-               err = update_buffer_lossy(mtu, pfc->pfc_en, buffer, xoff,
+               err = update_buffer_lossy(max_mtu, pfc->pfc_en, buffer, xoff,
                                          &port_buffer, &update_buffer);
                if (err)
                        return err;
@@ -277,8 +281,8 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
                if (err)
                        return err;
 
-               err = update_buffer_lossy(mtu, curr_pfc_en, prio2buffer, xoff,
-                                         &port_buffer, &update_buffer);
+               err = update_buffer_lossy(max_mtu, curr_pfc_en, prio2buffer,
+                                         xoff, &port_buffer, &update_buffer);
                if (err)
                        return err;
        }
@@ -302,7 +306,7 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
                        return -EINVAL;
 
                update_buffer = true;
-               err = update_xoff_threshold(&port_buffer, xoff, mtu);
+               err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
                if (err)
                        return err;
        }
@@ -310,7 +314,7 @@ int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
        /* Need to update buffer configuration if xoff value is changed */
        if (!update_buffer && xoff != priv->dcbx.xoff) {
                update_buffer = true;
-               err = update_xoff_threshold(&port_buffer, xoff, mtu);
+               err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
                if (err)
                        return err;
        }