Merge branch 'master' into for-linus

Conflicts:
	include/linux/percpu.h
	mm/percpu.c

1 files changed, 4 insertions, 28 deletions

diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c
index 1fa3468f0f3..9bb936ae245 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);