Merge branch 'topic/timer-fixes' into for-next

Pull yet another ALSA core timer fixes and cleanups.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/timer.h

@@ -43,7 +43,6 @@
 #define SNDRV_TIMER_IFLG_START	  0x00000004
 #define SNDRV_TIMER_IFLG_AUTO	  0x00000008	/* auto restart */
 #define SNDRV_TIMER_IFLG_FAST	  0x00000010	/* fast callback (do not use tasklet) */
-#define SNDRV_TIMER_IFLG_CALLBACK 0x00000020	/* timer callback is active */
 #define SNDRV_TIMER_IFLG_EXCLUSIVE 0x00000040	/* exclusive owner - no more instances */
 #define SNDRV_TIMER_IFLG_EARLY_EVENT 0x00000080	/* write early event to the poll queue */
 

sound/core/timer.c

@@ -38,6 +38,7 @@
 
 /* internal flags */
 #define SNDRV_TIMER_IFLG_PAUSED		0x00010000
+#define SNDRV_TIMER_IFLG_DEAD		0x00020000
 
 #if IS_ENABLED(CONFIG_SND_HRTIMER)
 #define DEFAULT_TIMER_LIMIT 4
@@ -353,20 +354,25 @@ EXPORT_SYMBOL(snd_timer_open);
  */
 static int snd_timer_close_locked(struct snd_timer_instance *timeri)
 {
-	struct snd_timer *timer = NULL;
+	struct snd_timer *timer = timeri->timer;
 	struct snd_timer_instance *slave, *tmp;
 
+	if (timer) {
+		spin_lock_irq(&timer->lock);
+		timeri->flags |= SNDRV_TIMER_IFLG_DEAD;
+		spin_unlock_irq(&timer->lock);
+	}
+
 	list_del(&timeri->open_list);
 
 	/* force to stop the timer */
 	snd_timer_stop(timeri);
 
-	timer = timeri->timer;
 	if (timer) {
 		timer->num_instances--;
 		/* wait, until the active callback is finished */
 		spin_lock_irq(&timer->lock);
-		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
+		while (!list_empty(&timeri->ack_list)) {
 			spin_unlock_irq(&timer->lock);
 			udelay(10);
 			spin_lock_irq(&timer->lock);
@@ -497,6 +503,10 @@ static int snd_timer_start1(struct snd_timer_instance *timeri,
 		return -EINVAL;
 
 	spin_lock_irqsave(&timer->lock, flags);
+	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
+		result = -EINVAL;
+		goto unlock;
+	}
 	if (timer->card && timer->card->shutdown) {
 		result = -ENODEV;
 		goto unlock;
@@ -541,11 +551,16 @@ static int snd_timer_start_slave(struct snd_timer_instance *timeri,
 				 bool start)
 {
 	unsigned long flags;
+	int err;
 
 	spin_lock_irqsave(&slave_active_lock, flags);
+	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
+		err = -EINVAL;
+		goto unlock;
+	}
 	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
-		spin_unlock_irqrestore(&slave_active_lock, flags);
-		return -EBUSY;
+		err = -EBUSY;
+		goto unlock;
 	}
 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
 	if (timeri->master && timeri->timer) {
@@ -556,8 +571,10 @@ static int snd_timer_start_slave(struct snd_timer_instance *timeri,
 				  SNDRV_TIMER_EVENT_CONTINUE);
 		spin_unlock(&timeri->timer->lock);
 	}
+	err = 1; /* delayed start */
+ unlock:
 	spin_unlock_irqrestore(&slave_active_lock, flags);
-	return 1; /* delayed start */
+	return err;
 }
 
 /* stop/pause a master timer */
@@ -720,41 +737,61 @@ static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_l
 	timer->sticks = ticks;
 }
 
-/*
- * timer tasklet
- *
- */
-static void snd_timer_tasklet(unsigned long arg)
+/* call callbacks in timer ack list */
+static void snd_timer_process_callbacks(struct snd_timer *timer,
+					struct list_head *head)
 {
-	struct snd_timer *timer = (struct snd_timer *) arg;
 	struct snd_timer_instance *ti;
-	struct list_head *p;
 	unsigned long resolution, ticks;
-	unsigned long flags;
 
-	if (timer->card && timer->card->shutdown)
-		return;
-
-	spin_lock_irqsave(&timer->lock, flags);
-	/* now process all callbacks */
-	while (!list_empty(&timer->sack_list_head)) {
-		p = timer->sack_list_head.next;		/* get first item */
-		ti = list_entry(p, struct snd_timer_instance, ack_list);
-
-		/* remove from ack_list and make empty */
-		list_del_init(p);
+	while (!list_empty(head)) {
+		ti = list_first_entry(head, struct snd_timer_instance,
+				      ack_list);
 
+		if (!(ti->flags & SNDRV_TIMER_IFLG_DEAD)) {
 			ticks = ti->pticks;
 			ti->pticks = 0;
 			resolution = ti->resolution;
 
-		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
 			spin_unlock(&timer->lock);
 			if (ti->callback)
 				ti->callback(ti, resolution, ticks);
 			spin_lock(&timer->lock);
-		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
 		}
+
+		/* remove from ack_list and make empty */
+		list_del_init(&ti->ack_list);
+	}
+}
+
+/* clear pending instances from ack list */
+static void snd_timer_clear_callbacks(struct snd_timer *timer,
+				      struct list_head *head)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&timer->lock, flags);
+	while (!list_empty(head))
+		list_del_init(head->next);
+	spin_unlock_irqrestore(&timer->lock, flags);
+}
+
+/*
+ * timer tasklet
+ *
+ */
+static void snd_timer_tasklet(unsigned long arg)
+{
+	struct snd_timer *timer = (struct snd_timer *) arg;
+	unsigned long flags;
+
+	if (timer->card && timer->card->shutdown) {
+		snd_timer_clear_callbacks(timer, &timer->sack_list_head);
+		return;
+	}
+
+	spin_lock_irqsave(&timer->lock, flags);
+	snd_timer_process_callbacks(timer, &timer->sack_list_head);
 	spin_unlock_irqrestore(&timer->lock, flags);
 }
 
@@ -767,16 +804,18 @@ static void snd_timer_tasklet(unsigned long arg)
 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
 {
 	struct snd_timer_instance *ti, *ts, *tmp;
-	unsigned long resolution, ticks;
-	struct list_head *p, *ack_list_head;
+	unsigned long resolution;
+	struct list_head *ack_list_head;
 	unsigned long flags;
 	int use_tasklet = 0;
 
 	if (timer == NULL)
 		return;
 
-	if (timer->card && timer->card->shutdown)
+	if (timer->card && timer->card->shutdown) {
+		snd_timer_clear_callbacks(timer, &timer->ack_list_head);
 		return;
+	}
 
 	spin_lock_irqsave(&timer->lock, flags);
 
@@ -790,6 +829,8 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
 	 */
 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
 				 active_list) {
+		if (ti->flags & SNDRV_TIMER_IFLG_DEAD)
+			continue;
 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
 			continue;
 		ti->pticks += ticks_left;
@@ -839,23 +880,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
 	}
 
 	/* now process all fast callbacks */
-	while (!list_empty(&timer->ack_list_head)) {
-		p = timer->ack_list_head.next;		/* get first item */
-		ti = list_entry(p, struct snd_timer_instance, ack_list);
-
-		/* remove from ack_list and make empty */
-		list_del_init(p);
-
-		ticks = ti->pticks;
-		ti->pticks = 0;
-
-		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
-		spin_unlock(&timer->lock);
-		if (ti->callback)
-			ti->callback(ti, resolution, ticks);
-		spin_lock(&timer->lock);
-		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
-	}
+	snd_timer_process_callbacks(timer, &timer->ack_list_head);
 
 	/* do we have any slow callbacks? */
 	use_tasklet = !list_empty(&timer->sack_list_head);