[ALSA] Unregister device files at disconnection

Orignally proposed by Sam Revitch <[email protected]>.
Unregister device files at disconnection to avoid the futher accesses.
Also, the dev_unregister callback is removed and replaced with the
combination of disconnect + free.
A new function snd_card_free_when_closed() is introduced, which is
used in USB disconnect callback.

Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Jaroslav Kysela <[email protected]>

include/sound/core.h

@@ -71,7 +71,6 @@ struct snd_device_ops {
 	int (*dev_free)(struct snd_device *dev);
 	int (*dev_register)(struct snd_device *dev);
 	int (*dev_disconnect)(struct snd_device *dev);
-	int (*dev_unregister)(struct snd_device *dev);
 };
 
 struct snd_device {
@@ -131,6 +130,7 @@ struct snd_card {
 								state */
 	spinlock_t files_lock;		/* lock the files for this card */
 	int shutdown;			/* this card is going down */
+	int free_on_last_close;		/* free in context of file_release */
 	wait_queue_head_t shutdown_sleep;
 	struct work_struct free_workq;	/* for free in workqueue */
 	struct device *dev;
@@ -244,6 +244,7 @@ struct snd_card *snd_card_new(int idx, const char *id,
 			 struct module *module, int extra_size);
 int snd_card_disconnect(struct snd_card *card);
 int snd_card_free(struct snd_card *card);
+int snd_card_free_when_closed(struct snd_card *card);
 int snd_card_free_in_thread(struct snd_card *card);
 int snd_card_register(struct snd_card *card);
 int snd_card_info_init(void);

include/sound/timer.h

@@ -129,7 +129,6 @@ void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstam
 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer);
 int snd_timer_global_free(struct snd_timer *timer);
 int snd_timer_global_register(struct snd_timer *timer);
-int snd_timer_global_unregister(struct snd_timer *timer);
 
 int snd_timer_open(struct snd_timer_instance **ti, char *owner, struct snd_timer_id *tid, unsigned int slave_id);
 int snd_timer_close(struct snd_timer_instance *timeri);

sound/core/control.c

@@ -1375,6 +1375,11 @@ static int snd_ctl_dev_disconnect(struct snd_device *device)
 	struct snd_card *card = device->device_data;
 	struct list_head *flist;
 	struct snd_ctl_file *ctl;
+	int err, cardnum;
+
+	snd_assert(card != NULL, return -ENXIO);
+	cardnum = card->number;
+	snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
 
 	down_read(&card->controls_rwsem);
 	list_for_each(flist, &card->ctl_files) {
@@ -1383,6 +1388,10 @@ static int snd_ctl_dev_disconnect(struct snd_device *device)
 		kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
 	}
 	up_read(&card->controls_rwsem);
+
+	if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
+					 card, -1)) < 0)
+		return err;
 	return 0;
 }
 
@@ -1403,23 +1412,6 @@ static int snd_ctl_dev_free(struct snd_device *device)
 	return 0;
 }
 
-/*
- * de-registration of the control device
- */
-static int snd_ctl_dev_unregister(struct snd_device *device)
-{
-	struct snd_card *card = device->device_data;
-	int err, cardnum;
-
-	snd_assert(card != NULL, return -ENXIO);
-	cardnum = card->number;
-	snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
-	if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
-					 card, -1)) < 0)
-		return err;
-	return snd_ctl_dev_free(device);
-}
-
 /*
  * create control core:
  * called from init.c
@@ -1430,7 +1422,6 @@ int snd_ctl_create(struct snd_card *card)
 		.dev_free = snd_ctl_dev_free,
 		.dev_register =	snd_ctl_dev_register,
 		.dev_disconnect = snd_ctl_dev_disconnect,
-		.dev_unregister = snd_ctl_dev_unregister
 	};
 
 	snd_assert(card != NULL, return -ENXIO);

sound/core/device.c

@@ -71,7 +71,7 @@ EXPORT_SYMBOL(snd_device_new);
  * @device_data: the data pointer to release
  *
  * Removes the device from the list on the card and invokes the
- * callback, dev_unregister or dev_free, corresponding to the state.
+ * callbacks, dev_disconnect and dev_free, corresponding to the state.
  * Then release the device.
  *
  * Returns zero if successful, or a negative error code on failure or if the
@@ -90,16 +90,14 @@ int snd_device_free(struct snd_card *card, void *device_data)
 			continue;
 		/* unlink */
 		list_del(&dev->list);
-		if ((dev->state == SNDRV_DEV_REGISTERED ||
-		     dev->state == SNDRV_DEV_DISCONNECTED) &&
-		    dev->ops->dev_unregister) {
-			if (dev->ops->dev_unregister(dev))
-				snd_printk(KERN_ERR "device unregister failure\n");
-		} else {
-			if (dev->ops->dev_free) {
-				if (dev->ops->dev_free(dev))
-					snd_printk(KERN_ERR "device free failure\n");
-			}
+		if (dev->state == SNDRV_DEV_REGISTERED &&
+		    dev->ops->dev_disconnect)
+			if (dev->ops->dev_disconnect(dev))
+				snd_printk(KERN_ERR
+					   "device disconnect failure\n");
+		if (dev->ops->dev_free) {
+			if (dev->ops->dev_free(dev))
+				snd_printk(KERN_ERR "device free failure\n");
 		}
 		kfree(dev);
 		return 0;

sound/core/hwdep.c

@@ -42,7 +42,7 @@ static DEFINE_MUTEX(register_mutex);
 static int snd_hwdep_free(struct snd_hwdep *hwdep);
 static int snd_hwdep_dev_free(struct snd_device *device);
 static int snd_hwdep_dev_register(struct snd_device *device);
-static int snd_hwdep_dev_unregister(struct snd_device *device);
+static int snd_hwdep_dev_disconnect(struct snd_device *device);
 
 
 static struct snd_hwdep *snd_hwdep_search(struct snd_card *card, int device)
@@ -353,7 +353,7 @@ int snd_hwdep_new(struct snd_card *card, char *id, int device,
 	static struct snd_device_ops ops = {
 		.dev_free = snd_hwdep_dev_free,
 		.dev_register = snd_hwdep_dev_register,
-		.dev_unregister = snd_hwdep_dev_unregister
+		.dev_disconnect = snd_hwdep_dev_disconnect,
 	};
 
 	snd_assert(rhwdep != NULL, return -EINVAL);
@@ -439,7 +439,7 @@ static int snd_hwdep_dev_register(struct snd_device *device)
 	return 0;
 }
 
-static int snd_hwdep_dev_unregister(struct snd_device *device)
+static int snd_hwdep_dev_disconnect(struct snd_device *device)
 {
 	struct snd_hwdep *hwdep = device->device_data;
 
@@ -454,9 +454,9 @@ static int snd_hwdep_dev_unregister(struct snd_device *device)
 		snd_unregister_oss_device(hwdep->oss_type, hwdep->card, hwdep->device);
 #endif
 	snd_unregister_device(SNDRV_DEVICE_TYPE_HWDEP, hwdep->card, hwdep->device);
-	list_del(&hwdep->list);
+	list_del_init(&hwdep->list);
 	mutex_unlock(&register_mutex);
-	return snd_hwdep_free(hwdep);
+	return 0;
 }
 
 #ifdef CONFIG_PROC_FS

sound/core/init.c

@@ -327,22 +327,10 @@ EXPORT_SYMBOL(snd_card_disconnect);
  *  Returns zero. Frees all associated devices and frees the control
  *  interface associated to given soundcard.
  */
-int snd_card_free(struct snd_card *card)
+static int snd_card_do_free(struct snd_card *card)
 {
 	struct snd_shutdown_f_ops *s_f_ops;
 
-	if (card == NULL)
-		return -EINVAL;
-	mutex_lock(&snd_card_mutex);
-	snd_cards[card->number] = NULL;
-	mutex_unlock(&snd_card_mutex);
-
-#ifdef CONFIG_PM
-	wake_up(&card->power_sleep);
-#endif
-	/* wait, until all devices are ready for the free operation */
-	wait_event(card->shutdown_sleep, card->files == NULL);
-
 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 	if (snd_mixer_oss_notify_callback)
 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
@@ -371,10 +359,55 @@ int snd_card_free(struct snd_card *card)
 		card->s_f_ops = s_f_ops->next;
 		kfree(s_f_ops);
 	}
+	kfree(card);
+	return 0;
+}
+
+static int snd_card_free_prepare(struct snd_card *card)
+{
+	if (card == NULL)
+		return -EINVAL;
+	(void) snd_card_disconnect(card);
 	mutex_lock(&snd_card_mutex);
+	snd_cards[card->number] = NULL;
 	snd_cards_lock &= ~(1 << card->number);
 	mutex_unlock(&snd_card_mutex);
-	kfree(card);
+#ifdef CONFIG_PM
+	wake_up(&card->power_sleep);
+#endif
+	return 0;
+}
+
+int snd_card_free_when_closed(struct snd_card *card)
+{
+	int free_now = 0;
+	int ret = snd_card_free_prepare(card);
+	if (ret)
+		return ret;
+
+	spin_lock(&card->files_lock);
+	if (card->files == NULL)
+		free_now = 1;
+	else
+		card->free_on_last_close = 1;
+	spin_unlock(&card->files_lock);
+
+	if (free_now)
+		snd_card_do_free(card);
+	return 0;
+}
+
+EXPORT_SYMBOL(snd_card_free_when_closed);
+
+int snd_card_free(struct snd_card *card)
+{
+	int ret = snd_card_free_prepare(card);
+	if (ret)
+		return ret;
+
+	/* wait, until all devices are ready for the free operation */
+	wait_event(card->shutdown_sleep, card->files == NULL);
+	snd_card_do_free(card);
 	return 0;
 }
 
@@ -718,6 +751,7 @@ EXPORT_SYMBOL(snd_card_file_add);
 int snd_card_file_remove(struct snd_card *card, struct file *file)
 {
 	struct snd_monitor_file *mfile, *pfile = NULL;
+	int last_close = 0;
 
 	spin_lock(&card->files_lock);
 	mfile = card->files;
@@ -732,9 +766,14 @@ int snd_card_file_remove(struct snd_card *card, struct file *file)
 		pfile = mfile;
 		mfile = mfile->next;
 	}
-	spin_unlock(&card->files_lock);
 	if (card->files == NULL)
+		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 (!mfile) {
 		snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 		return -ENOENT;

sound/core/oss/mixer_oss.c

@@ -1310,21 +1310,19 @@ static int snd_mixer_oss_notify_handler(struct snd_card *card, int cmd)
 		card->mixer_oss = mixer;
 		snd_mixer_oss_build(mixer);
 		snd_mixer_oss_proc_init(mixer);
-	} else if (cmd == SND_MIXER_OSS_NOTIFY_DISCONNECT) {
-		mixer = card->mixer_oss;
-		if (mixer == NULL || !mixer->oss_dev_alloc)
-			return 0;
-		snd_unregister_oss_device(SNDRV_OSS_DEVICE_TYPE_MIXER, mixer->card, 0);
-		mixer->oss_dev_alloc = 0;
-	} else {		/* free */
+	} else {
 		mixer = card->mixer_oss;
 		if (mixer == NULL)
 			return 0;
+		if (mixer->oss_dev_alloc) {
 #ifdef SNDRV_OSS_INFO_DEV_MIXERS
-		snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_MIXERS, mixer->card->number);
+			snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_MIXERS, mixer->card->number);
 #endif
-		if (mixer->oss_dev_alloc)
 			snd_unregister_oss_device(SNDRV_OSS_DEVICE_TYPE_MIXER, mixer->card, 0);
+			mixer->oss_dev_alloc = 0;
+		}
+		if (cmd == SND_MIXER_OSS_NOTIFY_DISCONNECT)
+			return 0;
 		snd_mixer_oss_proc_done(mixer);
 		return snd_mixer_oss_free1(mixer);
 	}

sound/core/oss/pcm_oss.c

@@ -2929,25 +2929,23 @@ static int snd_pcm_oss_disconnect_minor(struct snd_pcm *pcm)
 			snd_unregister_oss_device(SNDRV_OSS_DEVICE_TYPE_PCM,
 						  pcm->card, 1);
 		}
-	}
-	return 0;
-}
-
-static int snd_pcm_oss_unregister_minor(struct snd_pcm *pcm)
-{
-	snd_pcm_oss_disconnect_minor(pcm);
-	if (pcm->oss.reg) {
 		if (dsp_map[pcm->card->number] == (int)pcm->device) {
 #ifdef SNDRV_OSS_INFO_DEV_AUDIO
 			snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_AUDIO, pcm->card->number);
 #endif
 		}
 		pcm->oss.reg = 0;
-		snd_pcm_oss_proc_done(pcm);
 	}
 	return 0;
 }
 
+static int snd_pcm_oss_unregister_minor(struct snd_pcm *pcm)
+{
+	snd_pcm_oss_disconnect_minor(pcm);
+	snd_pcm_oss_proc_done(pcm);
+	return 0;
+}
+
 static struct snd_pcm_notify snd_pcm_oss_notify =
 {
 	.n_register =	snd_pcm_oss_register_minor,