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_tun.c b/sys/net/if_tun.c
index 6b352e8..03dd4ab 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -391,7 +391,7 @@ tuncreate(const char *name, struct cdev *dev)
 	IFQ_SET_MAXLEN(&ifp->if_snd, ifqmaxlen);
 	ifp->if_snd.ifq_drv_maxlen = 0;
 	IFQ_SET_READY(&ifp->if_snd);
-	knlist_init(&sc->tun_rsel.si_note, NULL, NULL, NULL, NULL);
+	knlist_init_mtx(&sc->tun_rsel.si_note, NULL);
 
 	if_attach(ifp);
 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));