lkml.org 
[lkml]   [2017]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH tip/core/rcu 14/21] netfilter: Remove now-redundant smp_read_barrier_depends()
Date
READ_ONCE() now implies smp_read_barrier_depends(), which means that
the instances in arpt_do_table(), ipt_do_table(), and ip6t_do_table()
are now redundant. This commit removes them and adjusts the comments.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netfilter-devel@vger.kernel.org>
Cc: <coreteam@netfilter.org>
Cc: <netdev@vger.kernel.org>
---
net/ipv4/netfilter/arp_tables.c | 7 +------
net/ipv4/netfilter/ip_tables.c | 7 +------
net/ipv6/netfilter/ip6_tables.c | 7 +------
3 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index f88221aebc9d..d242c2d29161 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -202,13 +202,8 @@ unsigned int arpt_do_table(struct sk_buff *skb,

local_bh_disable();
addend = xt_write_recseq_begin();
- private = table->private;
+ private = READ_ONCE(table->private); /* Address dependency. */
cpu = smp_processor_id();
- /*
- * Ensure we load private-> members after we've fetched the base
- * pointer.
- */
- smp_read_barrier_depends();
table_base = private->entries;
jumpstack = (struct arpt_entry **)private->jumpstack[cpu];

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 4cbe5e80f3bf..46866cc24a84 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -260,13 +260,8 @@ ipt_do_table(struct sk_buff *skb,
WARN_ON(!(table->valid_hooks & (1 << hook)));
local_bh_disable();
addend = xt_write_recseq_begin();
- private = table->private;
+ private = READ_ONCE(table->private); /* Address dependency. */
cpu = smp_processor_id();
- /*
- * Ensure we load private-> members after we've fetched the base
- * pointer.
- */
- smp_read_barrier_depends();
table_base = private->entries;
jumpstack = (struct ipt_entry **)private->jumpstack[cpu];

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index f06e25065a34..ac1db84722a7 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -282,12 +282,7 @@ ip6t_do_table(struct sk_buff *skb,

local_bh_disable();
addend = xt_write_recseq_begin();
- private = table->private;
- /*
- * Ensure we load private-> members after we've fetched the base
- * pointer.
- */
- smp_read_barrier_depends();
+ private = READ_ONCE(table->private); /* Address dependency. */
cpu = smp_processor_id();
table_base = private->entries;
jumpstack = (struct ip6t_entry **)private->jumpstack[cpu];
--
2.5.2
\
 
 \ /
  Last update: 2017-12-01 20:54    [W:1.331 / U:0.004 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site