ALSA: timer: Introduce disconnect op to snd_timer_instance

Instead of the previous ugly hack, introduce a new op, disconnect, to
snd_timer_instance object for handling the wake up of pending tasks
more cleanly.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109431
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/timer.h

@@ -104,6 +104,7 @@ struct snd_timer_instance {
 			   int event,
 			   struct timespec * tstamp,
 			   unsigned long resolution);
+	void (*disconnect)(struct snd_timer_instance *timeri);
 	void *callback_data;
 	unsigned long ticks;		/* auto-load ticks when expired */
 	unsigned long cticks;		/* current ticks */

sound/core/timer.c

@@ -899,11 +899,6 @@ static int snd_timer_dev_register(struct snd_device *dev)
 	return 0;
 }
 
-/* just for reference in snd_timer_dev_disconnect() below */
-static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
-				     int event, struct timespec *tstamp,
-				     unsigned long resolution);
-
 static int snd_timer_dev_disconnect(struct snd_device *device)
 {
 	struct snd_timer *timer = device->device_data;
@@ -913,13 +908,8 @@ static int snd_timer_dev_disconnect(struct snd_device *device)
 	list_del_init(&timer->device_list);
 	/* wake up pending sleepers */
 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
-		/* FIXME: better to have a ti.disconnect() op */
-		if (ti->ccallback == snd_timer_user_ccallback) {
-			struct snd_timer_user *tu = ti->callback_data;
-
-			tu->disconnected = true;
-			wake_up(&tu->qchange_sleep);
-		}
+		if (ti->disconnect)
+			ti->disconnect(ti);
 	}
 	mutex_unlock(&register_mutex);
 	return 0;
@@ -1227,6 +1217,14 @@ static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
 	wake_up(&tu->qchange_sleep);
 }
 
+static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
+{
+	struct snd_timer_user *tu = timeri->callback_data;
+
+	tu->disconnected = true;
+	wake_up(&tu->qchange_sleep);
+}
+
 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
 				      unsigned long resolution,
 				      unsigned long ticks)
@@ -1600,6 +1598,7 @@ static int snd_timer_user_tselect(struct file *file,
 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
 		tu->timeri->ccallback = snd_timer_user_ccallback;
 		tu->timeri->callback_data = (void *)tu;
+		tu->timeri->disconnect = snd_timer_user_disconnect;
 	}
 
       __err: