Revert the NET_LOCK() and bring back pf's contention lock for release.

For the moment the NET_LOCK() is always taken by threads running under
KERNEL_LOCK().  That means it doesn't buy us anything except a possible
deadlock that we did not spot.  So make sure this doesn't happen, we'll
have plenty of time in the next release cycle to stress test it.

ok visa@

1 files changed, 1 insertions, 13 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index c690c9281a9..c34b5b067f8 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.490 2017/03/08 09:19:45 mpi Exp $	*/
+/*	$OpenBSD: if.c,v 1.491 2017/03/17 17:19:16 mpi Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -230,12 +230,6 @@ struct taskq	*softnettq;
 struct task if_input_task_locked = TASK_INITIALIZER(if_netisr, NULL);
 
 /*
- * Serialize socket operations to ensure no new sleeping points
- * are introduced in IP output paths.
- */
-struct rwlock netlock = RWLOCK_INITIALIZER("netlock");
-
-/*
  * Network interface utility routines.
  */
 void
@@ -1152,10 +1146,7 @@ if_clone_create(const char *name, int rdomain)
 	if (ifunit(name) != NULL)
 		return (EEXIST);
 
-	/* XXXSMP breaks atomicity */
-	rw_exit_write(&netlock);
 	ret = (*ifc->ifc_create)(ifc, unit);
-	rw_enter_write(&netlock);
 
 	if (ret != 0 || (ifp = ifunit(name)) == NULL)
 		return (ret);
@@ -1197,10 +1188,7 @@ if_clone_destroy(const char *name)
 		splx(s);
 	}
 
-	/* XXXSMP breaks atomicity */
-	rw_exit_write(&netlock);
 	ret = (*ifc->ifc_destroy)(ifp);
-	rw_enter_write(&netlock);
 
 	return (ret);
 }