Simplify filterops routines where klist_invalidate() is used.

klist_invalidate() detaches knotes from the list and rewires them
synchronously so that the original filterops routines do not get
called after the invalidation.

OK anton@, mpi@

3 files changed, 16 insertions, 77 deletions

diff --git a/sys/net/if_pppx.c b/sys/net/if_pppx.c
index 112fac18788..7ffc4903a57 100644
--- a/sys/net/if_pppx.c
+++ b/sys/net/if_pppx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_pppx.c,v 1.73 2020/01/24 06:42:13 jsg Exp $ */
+/*	$OpenBSD: if_pppx.c,v 1.74 2020/01/28 16:26:09 visa Exp $ */
 
 /*
  * Copyright (c) 2010 Claudio Jeker <claudio@openbsd.org>
@@ -541,9 +541,6 @@ filt_pppx_rdetach(struct knote *kn)
 	struct pppx_dev *pxd = (struct pppx_dev *)kn->kn_hook;
 	struct klist *klist = &pxd->pxd_rsel.si_note;
 
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
 	mtx_enter(&pxd->pxd_rsel_mtx);
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
 	mtx_leave(&pxd->pxd_rsel_mtx);
@@ -554,11 +551,6 @@ filt_pppx_read(struct knote *kn, long hint)
 {
 	struct pppx_dev *pxd = (struct pppx_dev *)kn->kn_hook;
 
-	if (ISSET(kn->kn_status, KN_DETACHED)) {
-		kn->kn_data = 0;
-		return (1);
-	}
-
 	kn->kn_data = mq_hdatalen(&pxd->pxd_svcq);
 
 	return (kn->kn_data > 0);
@@ -570,9 +562,6 @@ filt_pppx_wdetach(struct knote *kn)
 	struct pppx_dev *pxd = (struct pppx_dev *)kn->kn_hook;
 	struct klist *klist = &pxd->pxd_wsel.si_note;
 
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
 	mtx_enter(&pxd->pxd_wsel_mtx);
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
 	mtx_leave(&pxd->pxd_wsel_mtx);
@@ -1462,14 +1451,8 @@ pppackqfilter(dev_t dev, struct knote *kn)
 static void
 filt_pppac_rdetach(struct knote *kn)
 {
-	struct pppac_softc *sc;
-	struct klist *klist;
-
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
-	sc = kn->kn_hook;
-	klist = &sc->sc_rsel.si_note;
+	struct pppac_softc *sc = kn->kn_hook;
+	struct klist *klist = &sc->sc_rsel.si_note;
 
 	mtx_enter(&sc->sc_rsel_mtx);
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
@@ -1479,14 +1462,7 @@ filt_pppac_rdetach(struct knote *kn)
 static int
 filt_pppac_read(struct knote *kn, long hint)
 {
-	struct pppac_softc *sc;
-
-	if (ISSET(kn->kn_status, KN_DETACHED)) {
-		kn->kn_data = 0;
-		return (1);
-	}
-
-	sc = kn->kn_hook;
+	struct pppac_softc *sc = kn->kn_hook;
 
 	kn->kn_data = mq_hdatalen(&sc->sc_mq);
 
@@ -1496,14 +1472,8 @@ filt_pppac_read(struct knote *kn, long hint)
 static void
 filt_pppac_wdetach(struct knote *kn)
 {
-	struct pppac_softc *sc;
-	struct klist *klist;
-
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
-	sc = kn->kn_hook;
-	klist = &sc->sc_wsel.si_note;
+	struct pppac_softc *sc = kn->kn_hook;
+	struct klist *klist = &sc->sc_wsel.si_note;
 
 	mtx_enter(&sc->sc_wsel_mtx);
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index f853e76a4cd..7497db8cfea 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_tun.c,v 1.214 2020/01/27 11:00:44 dlg Exp $	*/
+/*	$OpenBSD: if_tun.c,v 1.215 2020/01/28 16:26:09 visa Exp $	*/
 /*	$NetBSD: if_tun.c,v 1.24 1996/05/07 02:40:48 thorpej Exp $	*/
 
 /*
@@ -1015,28 +1015,18 @@ void
 filt_tunrdetach(struct knote *kn)
 {
 	int			 s;
-	struct tun_softc	*sc;
+	struct tun_softc	*sc = kn->kn_hook;
 
-	sc = (struct tun_softc *)kn->kn_hook;
 	s = splhigh();
-	if (!(kn->kn_status & KN_DETACHED))
-		SLIST_REMOVE(&sc->sc_rsel.si_note, kn, knote, kn_selnext);
+	SLIST_REMOVE(&sc->sc_rsel.si_note, kn, knote, kn_selnext);
 	splx(s);
 }
 
 int
 filt_tunread(struct knote *kn, long hint)
 {
-	struct tun_softc	*sc;
-	struct ifnet		*ifp;
-
-	if (kn->kn_status & KN_DETACHED) {
-		kn->kn_data = 0;
-		return (1);
-	}
-
-	sc = (struct tun_softc *)kn->kn_hook;
-	ifp = &sc->sc_if;
+	struct tun_softc	*sc = kn->kn_hook;
+	struct ifnet		*ifp = &sc->sc_if;
 
 	kn->kn_data = ifq_hdatalen(&ifp->if_snd);
 
@@ -1047,28 +1037,18 @@ void
 filt_tunwdetach(struct knote *kn)
 {
 	int			 s;
-	struct tun_softc	*sc;
+	struct tun_softc	*sc = kn->kn_hook;
 
-	sc = (struct tun_softc *)kn->kn_hook;
 	s = splhigh();
-	if (!(kn->kn_status & KN_DETACHED))
-		SLIST_REMOVE(&sc->sc_wsel.si_note, kn, knote, kn_selnext);
+	SLIST_REMOVE(&sc->sc_wsel.si_note, kn, knote, kn_selnext);
 	splx(s);
 }
 
 int
 filt_tunwrite(struct knote *kn, long hint)
 {
-	struct tun_softc	*sc;
-	struct ifnet		*ifp;
-
-	if (kn->kn_status & KN_DETACHED) {
-		kn->kn_data = 0;
-		return (1);
-	}
-
-	sc = (struct tun_softc *)kn->kn_hook;
-	ifp = &sc->sc_if;
+	struct tun_softc	*sc = kn->kn_hook;
+	struct ifnet		*ifp = &sc->sc_if;
 
 	kn->kn_data = ifp->if_hdrlen + ifp->if_hardmtu;
 
diff --git a/sys/net/switchctl.c b/sys/net/switchctl.c
index a3b51481bd5..88a212afc5a 100644
--- a/sys/net/switchctl.c
+++ b/sys/net/switchctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: switchctl.c,v 1.18 2019/12/31 13:48:32 visa Exp $	*/
+/*	$OpenBSD: switchctl.c,v 1.19 2020/01/28 16:26:09 visa Exp $	*/
 
 /*
  * Copyright (c) 2016 Kazuya GODA <goda@openbsd.org>
@@ -420,9 +420,6 @@ filt_switch_rdetach(struct knote *kn)
 	struct switch_softc	*sc = (struct switch_softc *)kn->kn_hook;
 	struct klist		*klist = &sc->sc_swdev->swdev_rsel.si_note;
 
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
 }
 
@@ -431,11 +428,6 @@ filt_switch_read(struct knote *kn, long hint)
 {
 	struct switch_softc	*sc = (struct switch_softc *)kn->kn_hook;
 
-	if (ISSET(kn->kn_status, KN_DETACHED)) {
-		kn->kn_data = 0;
-		return (1);
-	}
-
 	if (!mq_empty(&sc->sc_swdev->swdev_outq) ||
 	    sc->sc_swdev->swdev_lastm != NULL) {
 		kn->kn_data = mq_len(&sc->sc_swdev->swdev_outq) +
@@ -452,9 +444,6 @@ filt_switch_wdetach(struct knote *kn)
 	struct switch_softc	*sc = (struct switch_softc *)kn->kn_hook;
 	struct klist		*klist = &sc->sc_swdev->swdev_wsel.si_note;
 
-	if (ISSET(kn->kn_status, KN_DETACHED))
-		return;
-
 	SLIST_REMOVE(klist, kn, knote, kn_selnext);
 }