net: build_ehash_secret() and rt_bind_peer() cleanups
Eric Dumazet [Thu, 19 Aug 2010 06:10:45 +0000 (06:10 +0000)]
Now cmpxchg() is available on all arches, we can use it in
build_ehash_secret() and rt_bind_peer() instead of using spinlocks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/af_inet.c
net/ipv4/route.c

index 6a1100c..f581f77 100644 (file)
@@ -227,18 +227,16 @@ EXPORT_SYMBOL(inet_ehash_secret);
 
 /*
  * inet_ehash_secret must be set exactly once
- * Instead of using a dedicated spinlock, we (ab)use inetsw_lock
  */
 void build_ehash_secret(void)
 {
        u32 rnd;
+
        do {
                get_random_bytes(&rnd, sizeof(rnd));
        } while (rnd == 0);
-       spin_lock_bh(&inetsw_lock);
-       if (!inet_ehash_secret)
-               inet_ehash_secret = rnd;
-       spin_unlock_bh(&inetsw_lock);
+
+       cmpxchg(&inet_ehash_secret, 0, rnd);
 }
 EXPORT_SYMBOL(build_ehash_secret);
 
index 3f56b6e..85a67c9 100644 (file)
@@ -1268,18 +1268,11 @@ skip_hashing:
 
 void rt_bind_peer(struct rtable *rt, int create)
 {
-       static DEFINE_SPINLOCK(rt_peer_lock);
        struct inet_peer *peer;
 
        peer = inet_getpeer(rt->rt_dst, create);
 
-       spin_lock_bh(&rt_peer_lock);
-       if (rt->peer == NULL) {
-               rt->peer = peer;
-               peer = NULL;
-       }
-       spin_unlock_bh(&rt_peer_lock);
-       if (peer)
+       if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
                inet_putpeer(peer);
 }