ALSA: pcm: Don't add internal PCMs to PCM device list

An internal PCM object shouldn't be added to the PCM device list, as
it's never accessed directly from the user-space, and it has no proc
or any similar accesses.  Currently, it's excluded in snd_pcm_get()
and snd_pcm_next(), but it's easier not to add such an object to the
list.

Actually, the whole snd_pcm_dev_register() can be skipped for an
internal PCM.  So this patch changes the code there, but also
addresses the uninitialized list_head access.

Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index d63d262c571ec5e81999b5cd1258902bc5669102..d440629e08e2da242a4c8d1c52586adab8ba32c4 100644 (file)
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -49,8 +49,6 @@ static struct snd_pcm *snd_pcm_get(struct snd_card *card, int device)
        struct snd_pcm *pcm;
 
        list_for_each_entry(pcm, &snd_pcm_devices, list) {
-               if (pcm->internal)
-                       continue;
                if (pcm->card == card && pcm->device == device)
                        return pcm;
        }
@@ -62,8 +60,6 @@ static int snd_pcm_next(struct snd_card *card, int device)
        struct snd_pcm *pcm;
 
        list_for_each_entry(pcm, &snd_pcm_devices, list) {
-               if (pcm->internal)
-                       continue;
                if (pcm->card == card && pcm->device > device)
                        return pcm->device;
                else if (pcm->card->number > card->number)
@@ -76,6 +72,9 @@ static int snd_pcm_add(struct snd_pcm *newpcm)
 {
        struct snd_pcm *pcm;
 
+       if (newpcm->internal)
+               return 0;
+
        list_for_each_entry(pcm, &snd_pcm_devices, list) {
                if (pcm->card == newpcm->card && pcm->device == newpcm->device)
                        return -EBUSY;
@@ -782,6 +781,9 @@ static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
        pcm->card = card;
        pcm->device = device;
        pcm->internal = internal;
+       mutex_init(&pcm->open_mutex);
+       init_waitqueue_head(&pcm->open_wait);
+       INIT_LIST_HEAD(&pcm->list);
        if (id)
                strlcpy(pcm->id, id, sizeof(pcm->id));
        if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK, playback_count)) < 0) {
@@ -792,8 +794,6 @@ static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
                snd_pcm_free(pcm);
                return err;
        }
-       mutex_init(&pcm->open_mutex);
-       init_waitqueue_head(&pcm->open_wait);
        if ((err = snd_device_new(card, SNDRV_DEV_PCM, pcm, &ops)) < 0) {
                snd_pcm_free(pcm);
                return err;
@@ -1075,15 +1075,16 @@ static int snd_pcm_dev_register(struct snd_device *device)
        if (snd_BUG_ON(!device || !device->device_data))
                return -ENXIO;
        pcm = device->device_data;
+       if (pcm->internal)
+               return 0;
+
        mutex_lock(&register_mutex);
        err = snd_pcm_add(pcm);
-       if (err) {
-               mutex_unlock(&register_mutex);
-               return err;
-       }
+       if (err)
+               goto unlock;
        for (cidx = 0; cidx < 2; cidx++) {
                int devtype = -1;
-               if (pcm->streams[cidx].substream == NULL || pcm->internal)
+               if (pcm->streams[cidx].substream == NULL)
                        continue;
                switch (cidx) {
                case SNDRV_PCM_STREAM_PLAYBACK:
@@ -1098,9 +1099,8 @@ static int snd_pcm_dev_register(struct snd_device *device)
                                          &snd_pcm_f_ops[cidx], pcm,
                                          &pcm->streams[cidx].dev);
                if (err < 0) {
-                       list_del(&pcm->list);
-                       mutex_unlock(&register_mutex);
-                       return err;
+                       list_del_init(&pcm->list);
+                       goto unlock;
                }
 
                for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
@@ -1110,8 +1110,9 @@ static int snd_pcm_dev_register(struct snd_device *device)
        list_for_each_entry(notify, &snd_pcm_notify_list, list)
                notify->n_register(pcm);
 
+ unlock:
        mutex_unlock(&register_mutex);
-       return 0;
+       return err;
 }
 
 static int snd_pcm_dev_disconnect(struct snd_device *device)