Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
To:     pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de
Cc:     subashab@codeaurora.org, netfilter-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Subject: [PATCH v2 1/3] Revert "netfilter: x_tables: Update remaining dereference to RCU"
Date:   Mon,  8 Mar 2021 14:24:11 +1300
Message-Id: <20210308012413.14383-2-mark.tomlinson@alliedtelesis.co.nz>
In-Reply-To: <20210308012413.14383-1-mark.tomlinson@alliedtelesis.co.nz>
References: <20210308012413.14383-1-mark.tomlinson@alliedtelesis.co.nz>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

This reverts commit 443d6e86f821a165fae3fc3fc13086d27ac140b1.

This (and the following) 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.

Revert these patches and fix the issue in a different way.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
---
 net/ipv4/netfilter/arp_tables.c | 2 +-
 net/ipv4/netfilter/ip_tables.c  | 2 +-
 net/ipv6/netfilter/ip6_tables.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tab=
les.c
index c576a63d09db..563b62b76a5f 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -1379,7 +1379,7 @@ static int compat_get_entries(struct net *net,
 	xt_compat_lock(NFPROTO_ARP);
 	t =3D xt_find_table_lock(net, NFPROTO_ARP, get.name);
 	if (!IS_ERR(t)) {
-		const struct xt_table_info *private =3D xt_table_get_private_protected=
(t);
+		const struct xt_table_info *private =3D t->private;
 		struct xt_table_info info;
=20
 		ret =3D compat_table_info(private, &info);
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_table=
s.c
index e8f6f9d86237..6e2851f8d3a3 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1589,7 +1589,7 @@ compat_get_entries(struct net *net, struct compat_i=
pt_get_entries __user *uptr,
 	xt_compat_lock(AF_INET);
 	t =3D xt_find_table_lock(net, AF_INET, get.name);
 	if (!IS_ERR(t)) {
-		const struct xt_table_info *private =3D xt_table_get_private_protected=
(t);
+		const struct xt_table_info *private =3D t->private;
 		struct xt_table_info info;
 		ret =3D compat_table_info(private, &info);
 		if (!ret && get.size =3D=3D info.size)
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tab=
les.c
index 0d453fa9e327..c4f532f4d311 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1598,7 +1598,7 @@ compat_get_entries(struct net *net, struct compat_i=
p6t_get_entries __user *uptr,
 	xt_compat_lock(AF_INET6);
 	t =3D xt_find_table_lock(net, AF_INET6, get.name);
 	if (!IS_ERR(t)) {
-		const struct xt_table_info *private =3D xt_table_get_private_protected=
(t);
+		const struct xt_table_info *private =3D t->private;
 		struct xt_table_info info;
 		ret =3D compat_table_info(private, &info);
 		if (!ret && get.size =3D=3D info.size)
--=20
2.30.1