[src/trunk]: src/sys/dev/audio audio(4): When closing /dev/audioN, drain befo...

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

details:   https://anonhg.NetBSD.org/src/rev/c630f31648b8
branches:  trunk
changeset: 1021544:c630f31648b8
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jun 04 08:57:05 2021 +0000

description:
audio(4): When closing /dev/audioN, drain before removing from list.

Previously, in revision 1.100, I factored the SLIST_REMOVE out of
audio_unlink and audio_close up into audioclose since it is now used
by /dev/audio, /dev/audioctl, and /dev/mixer alike.  But I didn't
realize that the order

1. audio_track_drain
2. SLIST_REMOVE from sc_files

was significant; it matters because audio_track_drain waits for
wakeups that are delivered by hardware interrupts only to files
listed in sc_files.

This also fixes a bug introduced with the audiobell -- it was missing
the SLIST_REMOVE altogether.

For now, duplicate the SLIST_REMOVE calls in a few more places --
this is suboptimal but I want to make sure the logic works before
factoring it all out to tidy up.

diffstat:

 sys/dev/audio/audio.c |  25 ++++++++++++++++++-------
 1 files changed, 18 insertions(+), 7 deletions(-)

diffs (62 lines):

diff -r caa9c6769553 -r c630f31648b8 sys/dev/audio/audio.c
--- a/sys/dev/audio/audio.c     Fri Jun 04 08:17:53 2021 +0000
+++ b/sys/dev/audio/audio.c     Fri Jun 04 08:57:05 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.102 2021/06/01 21:27:36 riastradh Exp $    */
+/*     $NetBSD: audio.c,v 1.103 2021/06/04 08:57:05 riastradh Exp $    */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -138,7 +138,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.102 2021/06/01 21:27:36 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.103 2021/06/04 08:57:05 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "audio.h"
@@ -1747,20 +1747,25 @@
        bound = curlwp_bind();
        sc = audio_sc_acquire_fromfile(file, &sc_ref);
        if (sc) {
-               mutex_enter(sc->sc_lock);
-               mutex_enter(sc->sc_intr_lock);
-               SLIST_REMOVE(&sc->sc_files, file, audio_file, entry);
-               mutex_exit(sc->sc_intr_lock);
-               mutex_exit(sc->sc_lock);
                switch (AUDIODEV(dev)) {
                case SOUND_DEVICE:
                case AUDIO_DEVICE:
                        error = audio_close(sc, file);
                        break;
                case AUDIOCTL_DEVICE:
+                       mutex_enter(sc->sc_lock);
+                       mutex_enter(sc->sc_intr_lock);
+                       SLIST_REMOVE(&sc->sc_files, file, audio_file, entry);
+                       mutex_exit(sc->sc_intr_lock);
+                       mutex_exit(sc->sc_lock);
                        error = 0;
                        break;
                case MIXER_DEVICE:
+                       mutex_enter(sc->sc_lock);
+                       mutex_enter(sc->sc_intr_lock);
+                       SLIST_REMOVE(&sc->sc_files, file, audio_file, entry);
+                       mutex_exit(sc->sc_intr_lock);
+                       mutex_exit(sc->sc_lock);
                        error = mixer_close(sc, file);
                        break;
                default:
@@ -2569,6 +2574,12 @@
                mutex_exit(sc->sc_lock);
        }
 
+       mutex_enter(sc->sc_lock);
+       mutex_enter(sc->sc_intr_lock);
+       SLIST_REMOVE(&sc->sc_files, file, audio_file, entry);
+       mutex_exit(sc->sc_intr_lock);
+       mutex_exit(sc->sc_lock);
+
        error = audio_exlock_enter(sc);
        if (error) {
                /*