ALSA: Fix Oops with usb-audio reconnection

Backport fixes for usb-audio Oops at reconnection.

9eb70e6... [ALSA] usb-audio - Fix race in reconnection
f18638d... [ALSA] Clean up snd_card_free*()
73d38b1... [ALSA] Fix the race of card instance unregistration

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 21 deletions

diff --git a/sound/core/init.c b/sound/core/init.c
index e3338d6071ef..6200f428033b 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -311,6 +311,9 @@ int snd_card_disconnect(struct snd_card *card)
 	struct file *file;
 	int err;
 
+	if (!card)
+		return -EINVAL;
+
 	spin_lock(&card->files_lock);
 	if (card->shutdown) {
 		spin_unlock(&card->files_lock);
@@ -322,6 +325,7 @@ int snd_card_disconnect(struct snd_card *card)
 	/* phase 1: disable fops (user space) operations for ALSA API */
 	mutex_lock(&snd_card_mutex);
 	snd_cards[card->number] = NULL;
+	snd_cards_lock &= ~(1 << card->number);
 	mutex_unlock(&snd_card_mutex);
 	
 	/* phase 2: replace file->f_op with special dummy operations */
@@ -360,6 +364,15 @@ int snd_card_disconnect(struct snd_card *card)
 		snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 
 	snd_info_card_disconnect(card);
+#ifndef CONFIG_SYSFS_DEPRECATED
+	if (card->card_dev) {
+		device_unregister(card->card_dev);
+		card->card_dev = NULL;
+	}
+#endif
+#ifdef CONFIG_PM
+	wake_up(&card->power_sleep);
+#endif
 	return 0;	
 }
 
@@ -401,33 +414,14 @@ static int snd_card_do_free(struct snd_card *card)
 		snd_printk(KERN_WARNING "unable to free card info\n");
 		/* Not fatal error */
 	}
-#ifndef CONFIG_SYSFS_DEPRECATED
-	if (card->card_dev)
-		device_unregister(card->card_dev);
-#endif
 	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);
-#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);
+	int ret = snd_card_disconnect(card);
 	if (ret)
 		return ret;
 
@@ -447,7 +441,7 @@ EXPORT_SYMBOL(snd_card_free_when_closed);
 
 int snd_card_free(struct snd_card *card)
 {
-	int ret = snd_card_free_prepare(card);
+	int ret = snd_card_disconnect(card);
 	if (ret)
 		return ret;