[net 09/12] net/mlx5e: Correctly handle changing the number of queues when the interface is down

[Saeed Mahameed]

From: Maxim Mikityanskiy <maxi...@mellanox.com>

This commit addresses two issues related to changing the number of
queues when the channels are closed:

1. Missing call to mlx5e_num_channels_changed to update
real_num_tx_queues when the number of TCs is changed.

2. When mlx5e_num_channels_changed returns an error, the channel
parameters must be reverted.

Two Fixes: tags correspond to the first commits where these two issues
were introduced.

Fixes: 3909a12e7913 ("net/mlx5e: Fix configuration of XPS cpumasks and netdev 
queues in corner cases")
Fixes: fa3748775b92 ("net/mlx5e: Handle errors from 
netif_set_real_num_{tx,rx}_queues")
Signed-off-by: Maxim Mikityanskiy <maxi...@mellanox.com>
Reviewed-by: Tariq Toukan <tar...@nvidia.com>
Signed-off-by: Saeed Mahameed <sae...@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c | 8 +++++++-
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c    | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index 2d37742a888c..302001d6661e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -447,12 +447,18 @@ int mlx5e_ethtool_set_channels(struct mlx5e_priv *priv,
                goto out;
        }
 
-       new_channels.params = priv->channels.params;
+       new_channels.params = *cur_params;
        new_channels.params.num_channels = count;
 
        if (!test_bit(MLX5E_STATE_OPENED, &priv->state)) {
+               struct mlx5e_params old_params;
+
+               old_params = *cur_params;
                *cur_params = new_channels.params;
                err = mlx5e_num_channels_changed(priv);
+               if (err)
+                       *cur_params = old_params;
+
                goto out;
        }
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 300e0e9f96b6..ac76d32bad7d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -3614,7 +3614,14 @@ static int mlx5e_setup_tc_mqprio(struct mlx5e_priv *priv,
        new_channels.params.num_tc = tc ? tc : 1;
 
        if (!test_bit(MLX5E_STATE_OPENED, &priv->state)) {
+               struct mlx5e_params old_params;
+
+               old_params = priv->channels.params;
                priv->channels.params = new_channels.params;
+               err = mlx5e_num_channels_changed(priv);
+               if (err)
+                       priv->channels.params = old_params;
+
                goto out;
        }
 
-- 
2.29.2