Insert NULL pointer checking around devclass_get_maxunit(pcm_devclass, ..) .

Things can get ugly without it due to uninitialized class. RELENG_6 need
a simmilar, but different treatment as well.

err.. perhaps we should teach devclass_get_maxunit() to return -1 ?

MFC after:	1 day

3 files changed, 12 insertions, 6 deletions

diff --git a/sys/dev/sound/pcm/dsp.c b/sys/dev/sound/pcm/dsp.c
index 2d633b2..90453c1 100644
--- a/sys/dev/sound/pcm/dsp.c
+++ b/sys/dev/sound/pcm/dsp.c
@@ -1916,7 +1916,8 @@ dsp_oss_audioinfo(struct cdev *i_dev, oss_audioinfo *ai)
 	 * Search for the requested audio device (channel).  Start by
 	 * iterating over pcm devices.
 	 */ 
-	for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+	for (i = 0; pcm_devclass != NULL &&
+	    i < devclass_get_maxunit(pcm_devclass); i++) {
 		d = devclass_get_softc(pcm_devclass, i);
 		if (d == NULL)
 			continue;
diff --git a/sys/dev/sound/pcm/mixer.c b/sys/dev/sound/pcm/mixer.c
index b0c2176..b7b5032 100644
--- a/sys/dev/sound/pcm/mixer.c
+++ b/sys/dev/sound/pcm/mixer.c
@@ -940,7 +940,8 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
 	 * There's a 1:1 relationship between mixers and PCM devices, so
 	 * begin by iterating over PCM devices and search for our mixer.
 	 */
-	for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+	for (i = 0; pcm_devclass != NULL &&
+	    i < devclass_get_maxunit(pcm_devclass); i++) {
 		d = devclass_get_softc(pcm_devclass, i);
 		if (d == NULL)
 			continue;
diff --git a/sys/dev/sound/pcm/sound.c b/sys/dev/sound/pcm/sound.c
index 3fe301d..dee3c99 100644
--- a/sys/dev/sound/pcm/sound.c
+++ b/sys/dev/sound/pcm/sound.c
@@ -469,7 +469,8 @@ sysctl_hw_snd_maxautovchans(SYSCTL_HANDLER_ARGS)
 		if (v > SND_MAXVCHANS)
 			v = SND_MAXVCHANS;
 		snd_maxautovchans = v;
-		for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+		for (i = 0; pcm_devclass != NULL &&
+		    i < devclass_get_maxunit(pcm_devclass); i++) {
 			d = devclass_get_softc(pcm_devclass, i);
 			if (d == NULL)
 				continue;
@@ -914,7 +915,8 @@ sysctl_hw_snd_clone_gc(SYSCTL_HANDLER_ARGS)
 	err = sysctl_handle_int(oidp, &val, sizeof(val), req);
 
 	if (err == 0 && req->newptr != NULL && val != 0) {
-		for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+		for (i = 0; pcm_devclass != NULL &&
+		    i < devclass_get_maxunit(pcm_devclass); i++) {
 			d = devclass_get_softc(pcm_devclass, i);
 			if (d == NULL || d->clones == NULL)
 				continue;
@@ -1130,7 +1132,8 @@ pcm_unregister(device_t dev)
 		/*
 		 * Reassign default unit to the next available dev.
 		 */
-		for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+		for (i = 0; pcm_devclass != NULL &&
+		    i < devclass_get_maxunit(pcm_devclass); i++) {
 			if (device_get_unit(dev) == i ||
 			    devclass_get_softc(pcm_devclass, i) == NULL)
 				continue;
@@ -1332,7 +1335,8 @@ sound_oss_sysinfo(oss_sysinfo *si)
 	if (pcm_devclass != NULL) {
 		j = 0;
 
-		for (i = 0; i < devclass_get_maxunit(pcm_devclass); i++) {
+		for (i = 0; pcm_devclass != NULL &&
+		    i < devclass_get_maxunit(pcm_devclass); i++) {
 			d = devclass_get_softc(pcm_devclass, i);
 			if (!d)
 				continue;