From 32c3973d808301e7a980f80fee8818fdf7c82b09 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Sat, 17 Jul 2021 10:10:29 +0200 Subject: [PATCH] netfilter: flowtable: avoid possible false sharing The flowtable follows the same timeout approach as conntrack, use the same idiom as in cc16921351d8 ("netfilter: conntrack: avoid same-timeout update") but also include the fix provided by e37542ba111f ("netfilter: conntrack: avoid possible false sharing"). Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 1e50908b1b7e1..551976e4284ca 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -331,7 +331,11 @@ EXPORT_SYMBOL_GPL(flow_offload_add); void flow_offload_refresh(struct nf_flowtable *flow_table, struct flow_offload *flow) { - flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow); + u32 timeout; + + timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow); + if (READ_ONCE(flow->timeout) != timeout) + WRITE_ONCE(flow->timeout, timeout); if (likely(!nf_flowtable_hw_offload(flow_table))) return; -- 2.30.2