[PATCH 4.12 27/52] net/mlx5e: Dont override user RSS upon set channels

[Greg Kroah-Hartman]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Inbar Karmy <inbark@xxxxxxxxxxxx>


[ Upstream commit 5a8e12678c767ccf8bb16d6237569e4a707d655b ]

Currently, increasing the number of combined channels is changing
the RSS spread to use the new created channels.
Prevent the RSS spread change in case the user explicitly declare it,
to avoid overriding user configuration.

Tested:
when RSS default:

# ethtool -L ens8 combined 4
RSS spread will change and point to 4 channels.

# ethtool -X ens8 equal 4
# ethtool -L ens8 combined 6
RSS will not change after increasing the number of the channels.

Fixes: 8bf368620486 ('ethtool: ensure channel counts are within bounds during SCHANNELS')
Signed-off-by: Inbar Karmy <inbark@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -580,8 +580,10 @@ static int mlx5e_set_channels(struct net
 
 	new_channels.params = priv->channels.params;
 	new_channels.params.num_channels = count;
-	mlx5e_build_default_indir_rqt(priv->mdev, new_channels.params.indirection_rqt,
-				      MLX5E_INDIR_RQT_SIZE, count);
+	if (!netif_is_rxfh_configured(priv->netdev))
+		mlx5e_build_default_indir_rqt(priv->mdev,
+					      new_channels.params.indirection_rqt,
+					      MLX5E_INDIR_RQT_SIZE, count);
 
 	if (!test_bit(MLX5E_STATE_OPENED, &priv->state)) {
 		priv->channels.params = new_channels.params;