Revert "netfilter: x_tables: Switch synchronization to RCU"
This reverts commit
cc00bcaa589914096edef7fb87ca5cee4a166b5c.
This (and the preceding) patch basically re-implemented the RCU
mechanisms of patch
784544739a25. That patch was replaced because of the
performance problems that it created when replacing tables. Now, we have
the same issue: the call to synchronize_rcu() makes replacing tables
slower by as much as an order of magnitude.
Prior to using RCU a script calling "iptables" approx. 200 times was
taking 1.16s. With RCU this increased to 11.59s.
Revert these patches and fix the issue in a different way.
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>