[src/trunk]: src/sys/dev/usb usbnet: Assert IFNET_LOCKED in usbnet_media_upd.

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

details:   https://anonhg.NetBSD.org/src/rev/32263407adc7
branches:  trunk
changeset: 362496:32263407adc7
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Mar 03 05:48:30 2022 +0000

description:
usbnet: Assert IFNET_LOCKED in usbnet_media_upd.

This ensures, if the device is being initialized or stopped,
usbnet_media_upd will not run until it's done, so the reset sequence
has exclusive access to the device registers used by mii.

diffstat:

 sys/dev/usb/usbnet.c |  7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diffs (28 lines):

diff -r 78dddfe76e0f -r 32263407adc7 sys/dev/usb/usbnet.c
--- a/sys/dev/usb/usbnet.c      Thu Mar 03 05:48:22 2022 +0000
+++ b/sys/dev/usb/usbnet.c      Thu Mar 03 05:48:30 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: usbnet.c,v 1.56 2022/03/03 05:48:22 riastradh Exp $    */
+/*     $NetBSD: usbnet.c,v 1.57 2022/03/03 05:48:30 riastradh Exp $    */
 
 /*
  * Copyright (c) 2019 Matthew R. Green
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.56 2022/03/03 05:48:22 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.57 2022/03/03 05:48:30 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -983,6 +983,9 @@
        /* ifmedia layer ensures core_lock is held. */
        usbnet_isowned_core(un);
 
+       /* ifmedia changes only with IFNET_LOCK held.  */
+       KASSERTMSG(IFNET_LOCKED(ifp), "%s", ifp->if_xname);
+
        if (unp->unp_dying)
                return EIO;