The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 84c8a87402cf073ba7948dd62d4815a3f4a224c8 Mon Sep 17 00:00:00 2001

From: Maxim Mikityanskiy maximmi@nvidia.com Date: Mon, 11 Oct 2021 18:39:35 +0300 Subject: [PATCH] net/mlx5e: Fix division by 0 in mlx5e_select_queue for representors

Commit 846d6da1fcdb ("net/mlx5e: Fix division by 0 in mlx5e_select_queue") makes mlx5e_build_nic_params assign a non-zero initial value to priv->num_tc_x_num_ch, so that mlx5e_select_queue doesn't fail with division by 0 if called before the first activation of channels. However, the initialization flow of representors doesn't call mlx5e_build_nic_params, so this bug can still happen with representors.

This commit fixes the bug by adding the missing assignment to mlx5e_build_rep_params.

Fixes: 846d6da1fcdb ("net/mlx5e: Fix division by 0 in mlx5e_select_queue") Signed-off-by: Maxim Mikityanskiy maximmi@nvidia.com Reviewed-by: Tariq Toukan tariqt@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c index 0439203fc7d9..0684ac6699b2 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c @@ -618,6 +618,11 @@ static void mlx5e_build_rep_params(struct net_device *netdev) params->mqprio.num_tc = 1; params->tunneled_offload_en = false;

+ /* Set an initial non-zero value, so that mlx5e_select_queue won't + * divide by zero if called before first activating channels. + */ + priv->num_tc_x_num_ch = params->num_channels * params->mqprio.num_tc; + mlx5_query_min_inline(mdev, &params->tx_min_inline_mode); }