From: Przemek Kitszel przemyslaw.kitszel@intel.com
[ Upstream commit 257310e998700e60382fbd3f4fd275fdbd9b2aaf ]
Simplify stats accumulation logic to fix the case where we don't take previous stat value into account, we should always respect it.
Main netdev stats of our PF (Tx/Rx packets/bytes) were reported orders of magnitude too big during OpenStack reconfiguration events, possibly other reconfiguration cases too.
The regression was reported to be between 6.1 and 6.2, so I was almost certain that on of the two "preserve stats over reset" commits were the culprit. While reading the code, it was found that in some cases we will increase the stats by arbitrarily large number (thanks to ignoring "-prev" part of condition, after zeroing it).
Note that this fixes also the case where we were around limits of u64, but that was not the regression reported.
Full disclosure: I remember suggesting this particular piece of code to Ben a few years ago, so blame on me.
Fixes: 2fd5e433cd26 ("ice: Accumulate HW and Netdev statistics over reset") Reported-by: Nebojsa Stevanovic nebojsa.stevanovic@gcore.com Link: https://lore.kernel.org/intel-wired-lan/VI1PR02MB439744DEDAA7B59B9A2833FE912... Reported-by: Christian Rohmann christian.rohmann@inovex.de Link: https://lore.kernel.org/intel-wired-lan/f38a6ca4-af05-48b1-a3e6-17ef2054e525... Reviewed-by: Jacob Keller jacob.e.keller@intel.com Signed-off-by: Przemek Kitszel przemyslaw.kitszel@intel.com Reviewed-by: Simon Horman horms@kernel.org Tested-by: Pucha Himasekhar Reddy himasekharx.reddy.pucha@intel.com (A Contingent worker at Intel) Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/ice/ice_main.c | 24 +++++++++++------------ 1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index d23f2ebddeb45..8ebb6517f6b96 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -6557,6 +6557,7 @@ static void ice_update_vsi_ring_stats(struct ice_vsi *vsi) { struct rtnl_link_stats64 *net_stats, *stats_prev; struct rtnl_link_stats64 *vsi_stats; + struct ice_pf *pf = vsi->back; u64 pkts, bytes; int i;
@@ -6602,21 +6603,18 @@ static void ice_update_vsi_ring_stats(struct ice_vsi *vsi) net_stats = &vsi->net_stats; stats_prev = &vsi->net_stats_prev;
- /* clear prev counters after reset */ - if (vsi_stats->tx_packets < stats_prev->tx_packets || - vsi_stats->rx_packets < stats_prev->rx_packets) { - stats_prev->tx_packets = 0; - stats_prev->tx_bytes = 0; - stats_prev->rx_packets = 0; - stats_prev->rx_bytes = 0; + /* Update netdev counters, but keep in mind that values could start at + * random value after PF reset. And as we increase the reported stat by + * diff of Prev-Cur, we need to be sure that Prev is valid. If it's not, + * let's skip this round. + */ + if (likely(pf->stat_prev_loaded)) { + net_stats->tx_packets += vsi_stats->tx_packets - stats_prev->tx_packets; + net_stats->tx_bytes += vsi_stats->tx_bytes - stats_prev->tx_bytes; + net_stats->rx_packets += vsi_stats->rx_packets - stats_prev->rx_packets; + net_stats->rx_bytes += vsi_stats->rx_bytes - stats_prev->rx_bytes; }
- /* update netdev counters */ - net_stats->tx_packets += vsi_stats->tx_packets - stats_prev->tx_packets; - net_stats->tx_bytes += vsi_stats->tx_bytes - stats_prev->tx_bytes; - net_stats->rx_packets += vsi_stats->rx_packets - stats_prev->rx_packets; - net_stats->rx_bytes += vsi_stats->rx_bytes - stats_prev->rx_bytes; - stats_prev->tx_packets = vsi_stats->tx_packets; stats_prev->tx_bytes = vsi_stats->tx_bytes; stats_prev->rx_packets = vsi_stats->rx_packets;