ALSA: Add a reference counter to card instance

[pandora-kernel.git] / sound / core / init.c

diff --git a/sound/core/init.c b/sound/core/init.c
index 3ac49b1..fa0f35b 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -212,6 +212,7 @@ int snd_card_create(int idx, const char *xid,
        spin_lock_init(&card->files_lock);
        INIT_LIST_HEAD(&card->files_list);
        init_waitqueue_head(&card->shutdown_sleep);
+       atomic_set(&card->refcount, 0);
 #ifdef CONFIG_PM
        mutex_init(&card->power_lock);
        init_waitqueue_head(&card->power_sleep);
@@ -445,21 +446,36 @@ static int snd_card_do_free(struct snd_card *card)
        return 0;
 }
 
+/**
+ * snd_card_unref - release the reference counter
+ * @card: the card instance
+ *
+ * Decrements the reference counter.  When it reaches to zero, wake up
+ * the sleeper and call the destructor if needed.
+ */
+void snd_card_unref(struct snd_card *card)
+{
+       if (atomic_dec_and_test(&card->refcount)) {
+               wake_up(&card->shutdown_sleep);
+               if (card->free_on_last_close)
+                       snd_card_do_free(card);
+       }
+}
+EXPORT_SYMBOL(snd_card_unref);
+
 int snd_card_free_when_closed(struct snd_card *card)
 {
-       int free_now = 0;
-       int ret = snd_card_disconnect(card);
-       if (ret)
-               return ret;
+       int ret;
 
-       spin_lock(&card->files_lock);
-       if (list_empty(&card->files_list))
-               free_now = 1;
-       else
-               card->free_on_last_close = 1;
-       spin_unlock(&card->files_lock);
+       atomic_inc(&card->refcount);
+       ret = snd_card_disconnect(card);
+       if (ret) {
+               atomic_dec(&card->refcount);
+               return ret;
+       }
 
-       if (free_now)
+       card->free_on_last_close = 1;
+       if (atomic_dec_and_test(&card->refcount))
                snd_card_do_free(card);
        return 0;
 }
@@ -473,7 +489,7 @@ int snd_card_free(struct snd_card *card)
                return ret;
 
        /* wait, until all devices are ready for the free operation */
-       wait_event(card->shutdown_sleep, list_empty(&card->files_list));
+       wait_event(card->shutdown_sleep, !atomic_read(&card->refcount));
        snd_card_do_free(card);
        return 0;
 }
@@ -854,6 +870,7 @@ int snd_card_file_add(struct snd_card *card, struct file *file)
                return -ENODEV;
        }
        list_add(&mfile->list, &card->files_list);
+       atomic_inc(&card->refcount);
        spin_unlock(&card->files_lock);
        return 0;
 }
@@ -876,7 +893,6 @@ EXPORT_SYMBOL(snd_card_file_add);
 int snd_card_file_remove(struct snd_card *card, struct file *file)
 {
        struct snd_monitor_file *mfile, *found = NULL;
-       int last_close = 0;
 
        spin_lock(&card->files_lock);
        list_for_each_entry(mfile, &card->files_list, list) {
@@ -891,19 +907,13 @@ int snd_card_file_remove(struct snd_card *card, struct file *file)
                        break;
                }
        }
-       if (list_empty(&card->files_list))
-               last_close = 1;
        spin_unlock(&card->files_lock);
-       if (last_close) {
-               wake_up(&card->shutdown_sleep);
-               if (card->free_on_last_close)
-                       snd_card_do_free(card);
-       }
        if (!found) {
                snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
                return -ENOENT;
        }
        kfree(found);
+       snd_card_unref(card);
        return 0;
 }