[AF_UNIX]: Convert to use a spinlock instead of rwlock

From: Benjamin LaHaise <bcrl@kvack.org>

In af_unix, a rwlock is used to protect internal state.  At least on my 
P4 with HT it is faster to use a spinlock due to the simpler memory 
barrier used to unlock.  This patch raises bw_unix to ~690K/s.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 7d3fe6aebcdb..1ddd36d50091 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -564,7 +564,7 @@ static struct sock * unix_create1(struct socket *sock)
         u         = unix_sk(sk);
         u->dentry = NULL;
         u->mnt    = NULL;
-        rwlock_init(&u->lock);
+        spin_lock_init(&u->lock);
         atomic_set(&u->inflight, sock ? 0 : -1);
         init_MUTEX(&u->readsem); /* single task reading lock */
         init_waitqueue_head(&u->peer_wait);