[PATCH v2 0/3] Don't use RCU for x_tables synchronization

From: Mark Tomlinson
Date: Sun Mar 07 2021 - 20:29:24 EST


The patches to change to using RCU synchronization in x_tables cause
updating tables to be slowed down by an order of magnitude. This has
been tried before, see https://lore.kernel.org/patchwork/patch/151796/
and ultimately was rejected. As mentioned in the patch description, a
different method can be used to ensure ordering of reads/writes. This
can simply be done by changing from smp_wmb() to smp_mb().

changes in v2:
- Update commit messages only

Mark Tomlinson (3):
Revert "netfilter: x_tables: Update remaining dereference to RCU"
Revert "netfilter: x_tables: Switch synchronization to RCU"
netfilter: x_tables: Use correct memory barriers.

include/linux/netfilter/x_tables.h | 7 ++---
net/ipv4/netfilter/arp_tables.c | 16 +++++-----
net/ipv4/netfilter/ip_tables.c | 16 +++++-----
net/ipv6/netfilter/ip6_tables.c | 16 +++++-----
net/netfilter/x_tables.c | 49 +++++++++++++++++++++---------
5 files changed, 60 insertions(+), 44 deletions(-)

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2.30.1