[PATCH 4.19 23/91] net/mlx5: Disable QoS when min_rates on all VFs are zero

[Greg Kroah-Hartman]

From: Vladyslav Tarasiuk <vladysl...@nvidia.com>

[ Upstream commit 470b74758260e4abc2508cf1614573c00a00465c ]

Currently when QoS is enabled for VF and any min_rate is configured,
the driver sets bw_share value to at least 1 and doesn’t allow to set
it to 0 to make minimal rate unlimited. It means there is always a
minimal rate configured for every VF, even if user tries to remove it.

In order to make QoS disable possible, check whether all vports have
configured min_rate = 0. If this is true, set their bw_share to 0 to
disable min_rate limitations.

Fixes: c9497c98901c ("net/mlx5: Add support for setting VF min rate")
Signed-off-by: Vladyslav Tarasiuk <vladysl...@nvidia.com>
Reviewed-by: Moshe Shemesh <mo...@nvidia.com>
Signed-off-by: Saeed Mahameed <sae...@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/eswitch.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
@@ -1999,12 +1999,15 @@ static u32 calculate_vports_min_rate_div
                max_guarantee = evport->info.min_rate;
        }
 
-       return max_t(u32, max_guarantee / fw_max_bw_share, 1);
+       if (max_guarantee)
+               return max_t(u32, max_guarantee / fw_max_bw_share, 1);
+       return 0;
 }
 
-static int normalize_vports_min_rate(struct mlx5_eswitch *esw, u32 divider)
+static int normalize_vports_min_rate(struct mlx5_eswitch *esw)
 {
        u32 fw_max_bw_share = MLX5_CAP_QOS(esw->dev, max_tsar_bw_share);
+       u32 divider = calculate_vports_min_rate_divider(esw);
        struct mlx5_vport *evport;
        u32 vport_max_rate;
        u32 vport_min_rate;
@@ -2018,9 +2021,9 @@ static int normalize_vports_min_rate(str
                        continue;
                vport_min_rate = evport->info.min_rate;
                vport_max_rate = evport->info.max_rate;
-               bw_share = MLX5_MIN_BW_SHARE;
+               bw_share = 0;
 
-               if (vport_min_rate)
+               if (divider)
                        bw_share = MLX5_RATE_TO_BW_SHARE(vport_min_rate,
                                                         divider,
                                                         fw_max_bw_share);
@@ -2045,7 +2048,6 @@ int mlx5_eswitch_set_vport_rate(struct m
        struct mlx5_vport *evport;
        u32 fw_max_bw_share;
        u32 previous_min_rate;
-       u32 divider;
        bool min_rate_supported;
        bool max_rate_supported;
        int err = 0;
@@ -2071,8 +2073,7 @@ int mlx5_eswitch_set_vport_rate(struct m
 
        previous_min_rate = evport->info.min_rate;
        evport->info.min_rate = min_rate;
-       divider = calculate_vports_min_rate_divider(esw);
-       err = normalize_vports_min_rate(esw, divider);
+       err = normalize_vports_min_rate(esw);
        if (err) {
                evport->info.min_rate = previous_min_rate;
                goto unlock;