Fix the recent panics/LORs/hangs created by my kqueue commit by:

- Introducing the possibility of using locks different than mutexes
for the knlist locking. In order to do this, we add three arguments to
knlist_init() to specify the functions to use to lock, unlock and
check if the lock is owned. If these arguments are NULL, we assume
mtx_lock, mtx_unlock and mtx_owned, respectively.

- Using the vnode lock for the knlist locking, when doing kqueue operations
on a vnode. This way, we don't have to lock the vnode while holding a
mutex, in filt_vfsread.

Reviewed by:	jmg
Approved by:	re (scottl), scottl (mentor override)
Pointyhat to:	ssouhlal
Will be happy:	everyone

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 8a6585b..6263432 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -2865,8 +2865,8 @@ ttymalloc(struct tty *tp)
 	mtx_lock(&tty_list_mutex);
 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
 	mtx_unlock(&tty_list_mutex);
-	knlist_init(&tp->t_rsel.si_note, &tp->t_mtx);
-	knlist_init(&tp->t_wsel.si_note, &tp->t_mtx);
+	knlist_init(&tp->t_rsel.si_note, &tp->t_mtx, NULL, NULL, NULL);
+	knlist_init(&tp->t_wsel.si_note, &tp->t_mtx, NULL, NULL, NULL);
 	return (tp);
 }