ALSA: Add a reference counter to card instance

[~andy/linux] / sound / core / sound_oss.c

diff --git a/sound/core/sound_oss.c b/sound/core/sound_oss.c
index e9528333e36d01e6e0282255639da08b7174e505..e1d79ee3590650d12e9d2c99a260ae63aed221c2 100644 (file)
--- a/sound/core/sound_oss.c
+++ b/sound/core/sound_oss.c
@@ -40,6 +40,9 @@
 static struct snd_minor *snd_oss_minors[SNDRV_OSS_MINORS];
 static DEFINE_MUTEX(sound_oss_mutex);
 
+/* NOTE: This function increments the refcount of the associated card like
+ * snd_lookup_minor_data(); the caller must call snd_card_unref() appropriately
+ */
 void *snd_lookup_oss_minor_data(unsigned int minor, int type)
 {
        struct snd_minor *mreg;
@@ -49,9 +52,11 @@ void *snd_lookup_oss_minor_data(unsigned int minor, int type)
                return NULL;
        mutex_lock(&sound_oss_mutex);
        mreg = snd_oss_minors[minor];
-       if (mreg && mreg->type == type)
+       if (mreg && mreg->type == type) {
                private_data = mreg->private_data;
-       else
+               if (mreg->card_ptr)
+                       atomic_inc(&mreg->card_ptr->refcount);
+       } else
                private_data = NULL;
        mutex_unlock(&sound_oss_mutex);
        return private_data;
@@ -123,6 +128,7 @@ int snd_register_oss_device(int type, struct snd_card *card, int dev,
        preg->device = dev;
        preg->f_ops = f_ops;
        preg->private_data = private_data;
+       preg->card_ptr = card;
        mutex_lock(&sound_oss_mutex);
        snd_oss_minors[minor] = preg;
        minor_unit = SNDRV_MINOR_OSS_DEVICE(minor);