Re: seqcount usage in xt_replace_table()

[Florian Westphal]

Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> Would using synchronize_rcu() not also mean you can get rid of that
> xt_write_recseq*() stuff entirely?

No, because those are used to synchronize with cpus that read
the ruleset counters, see

net/ipv4/netfilter/ip_tables.c:get_counters().

> Anyway, synchronize_rcu() can also take a little while, but I don't
> think anywere near 30 seconds.

Ok, I think in that case it would be best to just replace the
recseq value sampling with smp_mb + synchronize_rcu plus a comment
that explains why its done.