#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 __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
/*
* Add a protocol handler to the hash tables
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((const struct net_protocol **)&inet_protos[hash],
+ NULL, prot) ? 0 : -1;
}
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((const struct net_protocol **)&inet_protos[hash],
+ prot, NULL) == prot) ? 0 : -1;
synchronize_net();