1 files changed, 26 insertions, 12 deletions

diff --git a/sound/firewire/tascam/tascam-hwdep.c b/sound/firewire/tascam/tascam-hwdep.c
index 9afa827af05d..8f34cede2e9f 100644
--- a/sound/firewire/tascam/tascam-hwdep.c
+++ b/sound/firewire/tascam/tascam-hwdep.c
@@ -16,14 +16,30 @@
 
 #include "tascam.h"
 
+static long tscm_hwdep_read_locked(struct snd_tscm *tscm, char __user *buf,
+				   long count, loff_t *offset)
+{
+	struct snd_firewire_event_lock_status event = {
+		.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,
+	};
+
+	event.status = (tscm->dev_lock_count > 0);
+	tscm->dev_lock_changed = false;
+	count = min_t(long, count, sizeof(event));
+
+	spin_unlock_irq(&tscm->lock);
+
+	if (copy_to_user(buf, &event, count))
+		return -EFAULT;
+
+	return count;
+}
+
 static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
 		       loff_t *offset)
 {
 	struct snd_tscm *tscm = hwdep->private_data;
 	DEFINE_WAIT(wait);
-	union snd_firewire_event event = {
-		.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,
-	};
 
 	spin_lock_irq(&tscm->lock);
 
@@ -37,15 +53,13 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
 		spin_lock_irq(&tscm->lock);
 	}
 
-	event.lock_status.status = (tscm->dev_lock_count > 0);
-	tscm->dev_lock_changed = false;
-
-	spin_unlock_irq(&tscm->lock);
-
-	count = min_t(long, count, sizeof(event.lock_status));
-
-	if (copy_to_user(buf, &event, count))
-		return -EFAULT;
+	// NOTE: The acquired lock should be released in callee side.
+	if (tscm->dev_lock_changed) {
+		count = tscm_hwdep_read_locked(tscm, buf, count, offset);
+	} else {
+		spin_unlock_irq(&tscm->lock);
+		count = 0;
+	}
 
 	return count;
 }