releases/4.19.35/net-mlx5e-update-xoff-formula.patch

   1 From 97a1a6eb533cd769fb833a7991019055f4f40e3b Mon Sep 17 00:00:00 2001
   2 From: Huy Nguyen <huyn@mellanox.com>
   3 Date: Thu, 7 Mar 2019 14:49:50 -0600
   4 Subject: net/mlx5e: Update xoff formula
   5
   6 [ Upstream commit 5ec983e924c7978aaec3cf8679ece9436508bb20 ]
   7
   8 Set minimum speed in xoff threshold formula to 40Gbps
   9
  10 Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
  11 Signed-off-by: Huy Nguyen <huyn@mellanox.com>
  12 Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
  13 Signed-off-by: Sasha Levin <sashal@kernel.org>
  14 ---
  15  .../net/ethernet/mellanox/mlx5/core/en/port_buffer.c  | 11 ++++++-----
  16  1 file changed, 6 insertions(+), 5 deletions(-)
  17
  18 diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
  19 index eac245a93f91..f00de0c987cd 100644
  20 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
  21 +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
  22 @@ -122,7 +122,9 @@ static int port_set_buffer(struct mlx5e_priv *priv,
  23         return err;
  24  }
  25
  26 -/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B]) */
  27 +/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B])
  28 + * minimum speed value is 40Gbps
  29 + */
  30  static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
  31  {
  32         u32 speed;
  33 @@ -130,10 +132,9 @@ static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
  34         int err;
  35
  36         err = mlx5e_port_linkspeed(priv->mdev, &speed);
  37 -       if (err) {
  38 -               mlx5_core_warn(priv->mdev, "cannot get port speed\n");
  39 -               return 0;
  40 -       }
  41 +       if (err)
  42 +               speed = SPEED_40000;
  43 +       speed = max_t(u32, speed, SPEED_40000);
  44
  45         xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;
  46
  47 --
  48 2.19.1
  49