Adapt vfs kqfilter to the shared vnode lock used by zfs write vop. Use

vnode interlock to protect the knote fields [1]. The locking assumes
that shared vnode lock is held, thus we get exclusive access to knote
either by exclusive vnode lock protection, or by shared vnode lock +
vnode interlock.

Do not use kl_locked() method to assert either lock ownership or the
fact that curthread does not own the lock. For shared locks, ownership
is not recorded, e.g. VOP_ISLOCKED can return LK_SHARED for the shared
lock not owned by curthread, causing false positives in kqueue subsystem
assertions about knlist lock.

Remove kl_locked method from knlist lock vector, and add two separate
assertion methods kl_assert_locked and kl_assert_unlocked, that are
supposed to use proper asserts. Change knlist_init accordingly.

Add convenience function knlist_init_mtx to reduce number of arguments
for typical knlist initialization.

Submitted by:	jhb [1]
Noted by:	jhb [2]
Reviewed by:	jhb
Tested by:	rnoland

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index 9256301..6668d94 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -462,7 +462,7 @@ tapcreate(struct cdev *dev)
 	tp->tap_flags |= TAP_INITED;
 	mtx_unlock(&tp->tap_mtx);
 
-	knlist_init(&tp->tap_rsel.si_note, NULL, NULL, NULL, NULL);
+	knlist_init_mtx(&tp->tap_rsel.si_note, NULL);
 
 	TAPDEBUG("interface %s is created. minor = %#x\n", 
 		ifp->if_xname, dev2unit(dev));