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authorEric Dumazet <edumazet@google.com>2017-03-29 20:45:44 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-30 22:40:34 +0300
commit142c6594acbcc32391af9c15f8cd65c6c177698f (patch)
treec5f1c429b886d50480e7244d2275e18defa5de22 /drivers/net/bonding
parented8bfd5c1ca6e2911c797da611fdada958ab44c0 (diff)
downloadlinux-142c6594acbcc32391af9c15f8cd65c6c177698f.tar.xz
bonding: refine bond_fold_stats() wrap detection
Some device drivers reset their stats at down/up events, possibly fooling bonding stats, since they operate with relative deltas. It is nearly not possible to fix drivers, since some of them compute the tx/rx counters based on per rx/tx queue stats, and the queues can be reconfigured (ethtool -L) between the down/up sequence. Lets avoid accumulating 'negative' values that render bonding stats useless. It is better to lose small deltas, assuming the bonding stats are fetched at a reasonable frequency. Fixes: 5f0c5f73e5ef ("bonding: make global bonding stats more reliable") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/bonding')
-rw-r--r--drivers/net/bonding/bond_main.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6cea964ab70a..27359dab78a1 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3332,12 +3332,17 @@ static void bond_fold_stats(struct rtnl_link_stats64 *_res,
for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {
u64 nv = new[i];
u64 ov = old[i];
+ s64 delta = nv - ov;
/* detects if this particular field is 32bit only */
if (((nv | ov) >> 32) == 0)
- res[i] += (u32)nv - (u32)ov;
- else
- res[i] += nv - ov;
+ delta = (s64)(s32)((u32)nv - (u32)ov);
+
+ /* filter anomalies, some drivers reset their stats
+ * at down/up events.
+ */
+ if (delta > 0)
+ res[i] += delta;
}
}