| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 09 Sep 2010 00:56:16 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>
Subject: [PATCH net-next-2.6] net: inet_add_protocol() can use cmpxchg()
Use cmpxchg() to get rid of spinlocks in inet_add_protocol() and
friends.
inet_protos[] & inet6_protos[] are moved to read_mostly section
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
net/ipv4/protocol.c | 31 +++++--------------------------
net/ipv6/protocol.c | 32 ++++----------------------------
2 files changed, 9 insertions(+), 54 deletions(-)
diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c
index f2d2973..65699c2 100644
--- a/net/ipv4/protocol.c
+++ b/net/ipv4/protocol.c
@@ -28,8 +28,7 @@
#include <linux/spinlock.h>
#include <net/protocol.h>
-const struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp;
-static DEFINE_SPINLOCK(inet_proto_lock);
+const struct net_protocol *inet_protos[MAX_INET_PROTOS] __read_mostly;
/*
* Add a protocol handler to the hash tables
@@ -37,20 +36,9 @@ static DEFINE_SPINLOCK(inet_proto_lock);
int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
{
- int hash, ret;
+ int hash = protocol & (MAX_INET_PROTOS - 1);
- hash = protocol & (MAX_INET_PROTOS - 1);
-
- spin_lock_bh(&inet_proto_lock);
- if (inet_protos[hash]) {
- ret = -1;
- } else {
- inet_protos[hash] = prot;
- ret = 0;
- }
- spin_unlock_bh(&inet_proto_lock);
-
- return ret;
+ return !cmpxchg(&inet_protos[hash], NULL, prot) ? 0 : -1;
}
EXPORT_SYMBOL(inet_add_protocol);
@@ -60,18 +48,9 @@ EXPORT_SYMBOL(inet_add_protocol);
int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
{
- int hash, ret;
-
- hash = protocol & (MAX_INET_PROTOS - 1);
+ int ret, hash = protocol & (MAX_INET_PROTOS - 1);
- spin_lock_bh(&inet_proto_lock);
- if (inet_protos[hash] == prot) {
- inet_protos[hash] = NULL;
- ret = 0;
- } else {
- ret = -1;
- }
- spin_unlock_bh(&inet_proto_lock);
+ ret = (cmpxchg(&inet_protos[hash], prot, NULL) == prot) ? 0 : -1;
synchronize_net();
diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c
index 1fa3468..9bb936a 100644
--- a/net/ipv6/protocol.c
+++ b/net/ipv6/protocol.c
@@ -25,28 +25,14 @@
#include <linux/spinlock.h>
#include <net/protocol.h>
-const struct inet6_protocol *inet6_protos[MAX_INET_PROTOS];
-static DEFINE_SPINLOCK(inet6_proto_lock);
-
+const struct inet6_protocol *inet6_protos[MAX_INET_PROTOS] __read_mostly;
int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol)
{
- int ret, hash = protocol & (MAX_INET_PROTOS - 1);
-
- spin_lock_bh(&inet6_proto_lock);
-
- if (inet6_protos[hash]) {
- ret = -1;
- } else {
- inet6_protos[hash] = prot;
- ret = 0;
- }
-
- spin_unlock_bh(&inet6_proto_lock);
+ int hash = protocol & (MAX_INET_PROTOS - 1);
- return ret;
+ return !cmpxchg(&inet6_protos[hash], NULL, prot) ? 0 : -1;
}
-
EXPORT_SYMBOL(inet6_add_protocol);
/*
@@ -57,20 +43,10 @@ int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol
{
int ret, hash = protocol & (MAX_INET_PROTOS - 1);
- spin_lock_bh(&inet6_proto_lock);
-
- if (inet6_protos[hash] != prot) {
- ret = -1;
- } else {
- inet6_protos[hash] = NULL;
- ret = 0;
- }
-
- spin_unlock_bh(&inet6_proto_lock);
+ ret = (cmpxchg(&inet6_protos[hash], prot, NULL) == prot) ? 0 : -1;
synchronize_net();
return ret;
}
-
EXPORT_SYMBOL(inet6_del_protocol);
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists