[src/trunk]: src/sys/dev/mii Keep the change check invariant intact. The prev...

[kardel <kardel%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4b51e3e15f5c
branches:  trunk
changeset: 937720:4b51e3e15f5c
user:      kardel <kardel%NetBSD.org@localhost>
date:      Mon Aug 24 12:46:04 2020 +0000

description:
Keep the change check invariant intact. The previous code could miss
status updates by picking up a new status different from the tested
status. This left addresses in the DETACHED state although the
link status is already UP again.

addresses PR/kern 55538

diffstat:

 sys/dev/mii/mii_physubr.c |  19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)

diffs (45 lines):

diff -r db0c4fc4125a -r 4b51e3e15f5c sys/dev/mii/mii_physubr.c
--- a/sys/dev/mii/mii_physubr.c Mon Aug 24 12:45:48 2020 +0000
+++ b/sys/dev/mii/mii_physubr.c Mon Aug 24 12:46:04 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mii_physubr.c,v 1.92 2020/08/24 04:23:41 msaitoh Exp $ */
+/*     $NetBSD: mii_physubr.c,v 1.93 2020/08/24 12:46:04 kardel Exp $  */
 
 /*-
  * Copyright (c) 1998, 1999, 2000, 2001 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: mii_physubr.c,v 1.92 2020/08/24 04:23:41 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: mii_physubr.c,v 1.93 2020/08/24 12:46:04 kardel Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -440,16 +440,21 @@
 mii_phy_update(struct mii_softc *sc, int cmd)
 {
        struct mii_data *mii = sc->mii_pdata;
+       u_int mii_media_active;
+       int   mii_media_status;
 
        KASSERT(mii_locked(mii));
 
-       if (sc->mii_media_active != mii->mii_media_active ||
-           sc->mii_media_status != mii->mii_media_status ||
+       mii_media_active = mii->mii_media_active;
+       mii_media_status = mii->mii_media_status;
+
+       if (sc->mii_media_active != mii_media_active ||
+           sc->mii_media_status != mii_media_status ||
            cmd == MII_MEDIACHG) {
+               (*mii->mii_statchg)(mii->mii_ifp);
+               sc->mii_media_active = mii_media_active;
+               sc->mii_media_status = mii_media_status;
                mii_phy_statusmsg(sc);
-               (*mii->mii_statchg)(mii->mii_ifp);
-               sc->mii_media_active = mii->mii_media_active;
-               sc->mii_media_status = mii->mii_media_status;
        }
 }