[PATCH 5.0 040/117] net/mlx5e: Update xoff formula

Greg Kroah-Hartman
2019-04-15T19:10:57Z

[ Upstream commit 5ec983e924c7978aaec3cf8679ece9436508bb20 ]

Set minimum speed in xoff threshold formula to 40Gbps

Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/mellanox/mlx5/core/en/port_buffer.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

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 eac245a93f91..f00de0c987cd 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
@@ -122,7 +122,9 @@ static int port_set_buffer(struct mlx5e_priv *priv,
return err;
}

-/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B]) */
+/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B])
+ * minimum speed value is 40Gbps
+ */
static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
{
u32 speed;
@@ -130,10 +132,9 @@ static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
int err;

err = mlx5e_port_linkspeed(priv->mdev, &speed);
- if (err) {
- mlx5_core_warn(priv->mdev, "cannot get port speed\n");
- return 0;
- }
+ if (err)
+ speed = SPEED_40000;
+ speed = max_t(u32, speed, SPEED_40000);

xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;

--
2.19.1