[ALSA] Unregister device files at disconnection

Orignally proposed by Sam Revitch <sam.revitch@gmail.com>.
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 <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 9 insertions, 18 deletions

diff --git a/sound/core/control.c b/sound/core/control.c
index e9c8854d2f7b..f0c7272a2d48 100644
--- a/sound/core/control.c
+++ b/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;
 }
 
@@ -1404,23 +1413,6 @@ static int snd_ctl_dev_free(struct snd_device *device)
 }
 
 /*
- * 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);