Revert "netfilter: x_tables: Update remaining dereference to RCU"

[ Upstream commit abe7034b9a8d57737e80cc16d60ed3666990bdbf ]

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>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 680a1320399d68a0606b96f9befa7f9bcd3472d5..f1f78a742b36a18962a7a66884607e2aaa0a28bb 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -1406,7 +1406,7 @@ static int compat_get_entries(struct net *net,
        xt_compat_lock(NFPROTO_ARP);
        t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
        if (!IS_ERR(t)) {
-               const struct xt_table_info *private = xt_table_get_private_protected(t);
+               const struct xt_table_info *private = t->private;
                struct xt_table_info info;
 
                ret = compat_table_info(private, &info);

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 8c320b7a423cadb7c5bfb16ead958d830a00773c..10b91ebdf2131168bd70641072557c8564193d1f 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1616,7 +1616,7 @@ compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,
        xt_compat_lock(AF_INET);
        t = xt_find_table_lock(net, AF_INET, get.name);
        if (!IS_ERR(t)) {
-               const struct xt_table_info *private = xt_table_get_private_protected(t);
+               const struct xt_table_info *private = t->private;
                struct xt_table_info info;
                ret = compat_table_info(private, &info);
                if (!ret && get.size == info.size)

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 85d8ed970cdca58769f2b01e21e2aeacac163d38..c973ace208c513a2db8c52c71f184193a89c34e9 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1625,7 +1625,7 @@ compat_get_entries(struct net *net, struct compat_ip6t_get_entries __user *uptr,
        xt_compat_lock(AF_INET6);
        t = xt_find_table_lock(net, AF_INET6, get.name);
        if (!IS_ERR(t)) {
-               const struct xt_table_info *private = xt_table_get_private_protected(t);
+               const struct xt_table_info *private = t->private;
                struct xt_table_info info;
                ret = compat_table_info(private, &info);
                if (!ret && get.size == info.size)