4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit e58edaa4863583b54409444f11b4f80dff0af1cd ]
Helmut reported a bug about division by zero while running traffic and doing physical cable pull test.
When the cable unplugged the ppms become zero, so when dividing the current ppms by the previous ppms in the next dim iteration there is division by zero.
This patch prevent this division for both ppms and epms.
Fixes: c3164d2fc48f ("net/mlx5e: Added BW check for DIM decision mechanism") Reported-by: Helmut Grauer helmut.grauer@de.ibm.com Signed-off-by: Talat Batheesh talatb@mellanox.com Signed-off-by: Saeed Mahameed saeedm@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c index 23ccec4cb7f5..a1f3556307c7 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c @@ -197,9 +197,15 @@ static int mlx5e_am_stats_compare(struct mlx5e_rx_am_stats *curr, return (curr->bpms > prev->bpms) ? MLX5E_AM_STATS_BETTER : MLX5E_AM_STATS_WORSE;
+ if (!prev->ppms) + return curr->ppms ? MLX5E_AM_STATS_BETTER : + MLX5E_AM_STATS_SAME; + if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms)) return (curr->ppms > prev->ppms) ? MLX5E_AM_STATS_BETTER : MLX5E_AM_STATS_WORSE; + if (!prev->epms) + return MLX5E_AM_STATS_SAME;
if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms)) return (curr->epms < prev->epms) ? MLX5E_AM_STATS_BETTER :