[src/trunk]: src/sys/dev/usb Use callout_halt and usb_rem_task_wait in upgt(4).

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

details:   https://anonhg.NetBSD.org/src/rev/4d607485e1ac
branches:  trunk
changeset: 834128:4d607485e1ac
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Jul 29 02:01:54 2018 +0000

description:
Use callout_halt and usb_rem_task_wait in upgt(4).

Also comment in sketchiness in upgt_newstate that is beyond my scope
right now.

diffstat:

 sys/dev/usb/if_upgt.c |  15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diffs (43 lines):

diff -r 66ba0fae3767 -r 4d607485e1ac sys/dev/usb/if_upgt.c
--- a/sys/dev/usb/if_upgt.c     Sun Jul 29 02:01:43 2018 +0000
+++ b/sys/dev/usb/if_upgt.c     Sun Jul 29 02:01:54 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_upgt.c,v 1.20 2018/06/26 06:48:02 msaitoh Exp $     */
+/*     $NetBSD: if_upgt.c,v 1.21 2018/07/29 02:01:54 riastradh Exp $   */
 /*     $OpenBSD: if_upgt.c,v 1.49 2010/04/20 22:05:43 tedu Exp $ */
 
 /*
@@ -18,7 +18,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_upgt.c,v 1.20 2018/06/26 06:48:02 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_upgt.c,v 1.21 2018/07/29 02:01:54 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -504,8 +504,10 @@
                upgt_stop(sc);
 
        /* remove tasks and timeouts */
-       usb_rem_task(sc->sc_udev, &sc->sc_task_newstate);
-       usb_rem_task(sc->sc_udev, &sc->sc_task_tx);
+       callout_halt(&sc->scan_to, NULL);
+       callout_halt(&sc->led_to, NULL);
+       usb_rem_task_wait(sc->sc_udev, &sc->sc_task_newstate, USB_TASKQ_DRIVER);
+       usb_rem_task_wait(sc->sc_udev, &sc->sc_task_tx, USB_TASKQ_DRIVER);
        callout_destroy(&sc->scan_to);
        callout_destroy(&sc->led_to);
 
@@ -1346,6 +1348,11 @@
 {
        struct upgt_softc *sc = ic->ic_ifp->if_softc;
 
+       /*
+        * XXXSMP: This does not wait for the task, if it is in flight,
+        * to complete.  If this code works at all, it must rely on the
+        * kernel lock to serialize with the USB task thread.
+        */
        usb_rem_task(sc->sc_udev, &sc->sc_task_newstate);
        callout_stop(&sc->scan_to);