From 5165674ff5022d8a76f3147d75cab1fecd529497 Mon Sep 17 00:00:00 2001 From: Talat Batheesh Date: Wed, 17 Jan 2018 23:13:16 +0200 Subject: net/dim: Fix fixpoint divide exception in net_dim_stats_compare Helmut reported a bug about devision 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 devision by zero. This patch prevent this division for both ppms and epms. Fixes: c3164d2fc48f ("net/mlx5e: Added BW check for DIM decision mechanism") Fixes: 4c4dbb4a7363 ("net/mlx5e: Move dynamic interrupt coalescing code to include/linux") Reported-by: Helmut Grauer Signed-off-by: Talat Batheesh Signed-off-by: Tal Gilboa Signed-off-by: David S. Miller --- include/linux/net_dim.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/linux/net_dim.h b/include/linux/net_dim.h index 1c7e45016120..bebeaad897cc 100644 --- a/include/linux/net_dim.h +++ b/include/linux/net_dim.h @@ -244,10 +244,17 @@ static inline int net_dim_stats_compare(struct net_dim_stats *curr, return (curr->bpms > prev->bpms) ? NET_DIM_STATS_BETTER : NET_DIM_STATS_WORSE; + if (!prev->ppms) + return curr->ppms ? NET_DIM_STATS_BETTER : + NET_DIM_STATS_SAME; + if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms)) return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER : NET_DIM_STATS_WORSE; + if (!prev->epms) + return NET_DIM_STATS_SAME; + if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms)) return (curr->epms < prev->epms) ? NET_DIM_STATS_BETTER : NET_DIM_STATS_WORSE; -- cgit v1.2.3-59-g8ed1b