[src/trunk]: src/sys/dev/usb In the HUP-wait path in ucomopen():

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

details:   https://anonhg.NetBSD.org/src/rev/c733a5456f90
branches:  trunk
changeset: 373825:c733a5456f90
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sun Mar 05 13:49:12 2023 +0000

description:
In the HUP-wait path in ucomopen():
- Use cv_timedwait() rather than cv_timedwait_sig(); the wait here is
  bounded (and fairly short besides) and seems appropriate to treat like
  other uninterruptible waits.  The behavior is now consistent with com(4)
  in this regard.
- Map EWOULDBLOCK return from cv_timedwait() to 0, as the successful passage
  of time is not an error in this case.
- If the HUP-wait time has passed, clear the HUP-wait timestamp.

kern/57259 (although insufficient -- another change to vfs_syscalls.c
is required)

diffstat:

 sys/dev/usb/ucom.c |  11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diffs (36 lines):

diff -r f5ac0ce95f49 -r c733a5456f90 sys/dev/usb/ucom.c
--- a/sys/dev/usb/ucom.c        Sat Mar 04 21:15:30 2023 +0000
+++ b/sys/dev/usb/ucom.c        Sun Mar 05 13:49:12 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ucom.c,v 1.136 2023/02/17 23:44:18 riastradh Exp $     */
+/*     $NetBSD: ucom.c,v 1.137 2023/03/05 13:49:12 thorpej Exp $       */
 
 /*
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.136 2023/02/17 23:44:18 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.137 2023/03/05 13:49:12 thorpej Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -552,11 +552,16 @@
                        ms = MIN(INT_MAX - 1000, delta.tv_sec*1000);
                        ms += howmany(delta.tv_usec, 1000);
                        ticks = MAX(1, MIN(INT_MAX, mstohz(ms)));
-                       error = cv_timedwait_sig(&sc->sc_statecv, &sc->sc_lock,
+                       error = cv_timedwait(&sc->sc_statecv, &sc->sc_lock,
                            ticks);
                        mutex_exit(&sc->sc_lock);
+                       /* The successful passage of time is not an error. */
+                       if (error == EWOULDBLOCK) {
+                               error = 0;
+                       }
                        return error ? error : ERESTART;
                }
+               timerclear(&sc->sc_hup_time);
        }
 
        /*