({ if (skb_tailroom(skb) < (int)NFA_SPACE(attrlen)) goto nfattr_failure; \
    __nfa_fill(skb, attrtype, attrlen, data); })
 
-extern struct semaphore nfnl_sem;
-
-#define nfnl_shlock()          down(&nfnl_sem)
-#define nfnl_shlock_nowait()   down_trylock(&nfnl_sem)
-
-#define nfnl_shunlock()                do { up(&nfnl_sem); \
-                                    if(nfnl && nfnl->sk_receive_queue.qlen) \
-                                           nfnl->sk_data_ready(nfnl, 0); \
-                               } while(0)
-
-extern void nfnl_lock(void);
-extern void nfnl_unlock(void);
-
 extern int nfnetlink_subsys_register(struct nfnetlink_subsystem *n);
 extern int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n);
 
 
 /* Protocol registration. */
 extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
-
-extern struct nf_conntrack_l3proto *
-nf_ct_l3proto_find_get(u_int16_t l3proto);
-
+extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
 extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
 
 /* Existing built-in protocols */
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <net/sock.h>
+#include <net/netlink.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
 
 
 static struct sock *nfnl = NULL;
 static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
-DECLARE_MUTEX(nfnl_sem);
+static DEFINE_MUTEX(nfnl_mutex);
 
-void nfnl_lock(void)
+static void nfnl_lock(void)
 {
-       nfnl_shlock();
+       mutex_lock(&nfnl_mutex);
 }
 
-void nfnl_unlock(void)
+static int nfnl_trylock(void)
 {
-       nfnl_shunlock();
+       return !mutex_trylock(&nfnl_mutex);
+}
+
+static void __nfnl_unlock(void)
+{
+       mutex_unlock(&nfnl_mutex);
+}
+
+static void nfnl_unlock(void)
+{
+       mutex_unlock(&nfnl_mutex);
+       if (nfnl->sk_receive_queue.qlen)
+               nfnl->sk_data_ready(nfnl, 0);
 }
 
 int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
        ss = nfnetlink_get_subsys(type);
        if (!ss) {
 #ifdef CONFIG_KMOD
-               /* don't call nfnl_shunlock, since it would reenter
+               /* don't call nfnl_unlock, since it would reenter
                 * with further packet processing */
-               up(&nfnl_sem);
+               __nfnl_unlock();
                request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
-               nfnl_shlock();
+               nfnl_lock();
                ss = nfnetlink_get_subsys(type);
                if (!ss)
 #endif
        do {
                struct sk_buff *skb;
 
-               if (nfnl_shlock_nowait())
+               if (nfnl_trylock())
                        return;
 
                while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
                        kfree_skb(skb);
                }
 
-               /* don't call nfnl_shunlock, since it would reenter
+               /* don't call nfnl_unlock, since it would reenter
                 * with further packet processing */
-               up(&nfnl_sem);
+               __nfnl_unlock();
        } while(nfnl && nfnl->sk_receive_queue.qlen);
 }