[src/jmcneill-audiomp3]: src/sys/dev avoid passing size 0 to kmem_alloc when ...

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

details:   https://anonhg.NetBSD.org/src/rev/3df5545bea7b
branches:  jmcneill-audiomp3
changeset: 771379:3df5545bea7b
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sun Nov 20 20:00:15 2011 +0000

description:
avoid passing size 0 to kmem_alloc when the sequencer device is opened and
no midi devices are attached

diffstat:

 sys/dev/sequencer.c |  33 +++++++++++++++++++++------------
 1 files changed, 21 insertions(+), 12 deletions(-)

diffs (63 lines):

diff -r f19b794696cb -r 3df5545bea7b sys/dev/sequencer.c
--- a/sys/dev/sequencer.c       Sun Nov 20 19:44:50 2011 +0000
+++ b/sys/dev/sequencer.c       Sun Nov 20 20:00:15 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sequencer.c,v 1.52.14.1 2011/11/19 21:49:35 jmcneill Exp $     */
+/*     $NetBSD: sequencer.c,v 1.52.14.2 2011/11/20 20:00:15 jmcneill Exp $     */
 
 /*
  * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
@@ -55,7 +55,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sequencer.c,v 1.52.14.1 2011/11/19 21:49:35 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sequencer.c,v 1.52.14.2 2011/11/20 20:00:15 jmcneill Exp $");
 
 #include "sequencer.h"
 
@@ -268,17 +268,22 @@
        SEQ_QINIT(&sc->outq);
        sc->lowat = SEQ_MAXQ / 2;
 
-       mutex_exit(&sc->lock);
-       sc->devs = kmem_alloc(sc->ndevs * sizeof(struct midi_dev *), KM_SLEEP);
-       for (unit = 0; unit < sc->ndevs; unit++) {
-               md = midiseq_open(unit, flags);
-               if (md) {
-                       sc->devs[sc->nmidi++] = md;
-                       md->seq = sc;
-                       md->doingsysex = 0;
+       if (sc->ndevs > 0) {
+               mutex_exit(&sc->lock);
+               sc->devs = kmem_alloc(sc->ndevs * sizeof(struct midi_dev *),
+                   KM_SLEEP);
+               for (unit = 0; unit < sc->ndevs; unit++) {
+                       md = midiseq_open(unit, flags);
+                       if (md) {
+                               sc->devs[sc->nmidi++] = md;
+                               md->seq = sc;
+                               md->doingsysex = 0;
+                       }
                }
+               mutex_enter(&sc->lock);
+       } else {
+               sc->devs = NULL;
        }
-       mutex_enter(&sc->lock);
 
        /* Only now redirect input from MIDI devices. */
        for (unit = 0; unit < sc->nmidi; unit++) {
@@ -385,7 +390,11 @@
 
        for (unit = 0; unit < sc->nmidi; unit++)
                midiseq_close(sc->devs[unit]);
-       kmem_free(sc->devs, sc->ndevs * sizeof(struct midi_dev *));
+       if (sc->devs != NULL) {
+               KASSERT(sc->ndevs > 0);
+               kmem_free(sc->devs, sc->ndevs * sizeof(struct midi_dev *));
+               sc->devs = NULL;
+       }
 
        mutex_enter(&sc->lock);
        sc->isopen = 0;