From 28fd8700b4045baf4c80b24f8de768297ca6b7ea Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Thu, 28 Jul 2022 09:33:34 +0200
Subject: [PATCH] Revert "ALSA: jack: Access input_dev under mutex"

This reverts commit e2b8681769f6e205382f026b907d28aa5ec9d59a which is
commit 1b6a6fc5280e97559287b61eade2d4b363e836f2 upstream.

It breaks the Android kernel ABI and is not needed for Android devices,
so it is safe to revert for now.  If it is determined that it is needed
in the future, it can be brought back in an abi-preserving way.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I3b24427044ea6b385a2f686c71c6b239a3d00f18
---
 include/sound/jack.h |  1 -
 sound/core/jack.c    | 34 +++++++---------------------------
 2 files changed, 7 insertions(+), 28 deletions(-)

diff --git a/include/sound/jack.h b/include/sound/jack.h
index 781ac4bb1086..70400b20e952 100644
--- a/include/sound/jack.h
+++ b/include/sound/jack.h
@@ -63,7 +63,6 @@ struct snd_jack {
 	const char *id;
 #ifdef CONFIG_SND_JACK_INPUT_DEV
 	struct input_dev *input_dev;
-	struct mutex input_dev_lock;
 	int registered;
 	int type;
 	char name[100];
diff --git a/sound/core/jack.c b/sound/core/jack.c
index 45e28db6ea38..dc2e06ae2414 100644
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -34,11 +34,8 @@ static int snd_jack_dev_disconnect(struct snd_device *device)
 #ifdef CONFIG_SND_JACK_INPUT_DEV
 	struct snd_jack *jack = device->device_data;
 
-	mutex_lock(&jack->input_dev_lock);
-	if (!jack->input_dev) {
-		mutex_unlock(&jack->input_dev_lock);
+	if (!jack->input_dev)
 		return 0;
-	}
 
 	/* If the input device is registered with the input subsystem
 	 * then we need to use a different deallocator. */
@@ -47,7 +44,6 @@ static int snd_jack_dev_disconnect(struct snd_device *device)
 	else
 		input_free_device(jack->input_dev);
 	jack->input_dev = NULL;
-	mutex_unlock(&jack->input_dev_lock);
 #endif /* CONFIG_SND_JACK_INPUT_DEV */
 	return 0;
 }
@@ -86,11 +82,8 @@ static int snd_jack_dev_register(struct snd_device *device)
 	snprintf(jack->name, sizeof(jack->name), "%s %s",
 		 card->shortname, jack->id);
 
-	mutex_lock(&jack->input_dev_lock);
-	if (!jack->input_dev) {
-		mutex_unlock(&jack->input_dev_lock);
+	if (!jack->input_dev)
 		return 0;
-	}
 
 	jack->input_dev->name = jack->name;
 
@@ -115,7 +108,6 @@ static int snd_jack_dev_register(struct snd_device *device)
 	if (err == 0)
 		jack->registered = 1;
 
-	mutex_unlock(&jack->input_dev_lock);
 	return err;
 }
 #endif /* CONFIG_SND_JACK_INPUT_DEV */
@@ -236,11 +228,9 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
 		return -ENOMEM;
 	}
 
-#ifdef CONFIG_SND_JACK_INPUT_DEV
-	mutex_init(&jack->input_dev_lock);
-
-	/* don't create input device for phantom jack */
+	/* don't creat input device for phantom jack */
 	if (!phantom_jack) {
+#ifdef CONFIG_SND_JACK_INPUT_DEV
 		int i;
 
 		jack->input_dev = input_allocate_device();
@@ -258,8 +248,8 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
 				input_set_capability(jack->input_dev, EV_SW,
 						     jack_switch_types[i]);
 
-	}
 #endif /* CONFIG_SND_JACK_INPUT_DEV */
+	}
 
 	err = snd_device_new(card, SNDRV_DEV_JACK, jack, &ops);
 	if (err < 0)
@@ -299,14 +289,10 @@ EXPORT_SYMBOL(snd_jack_new);
 void snd_jack_set_parent(struct snd_jack *jack, struct device *parent)
 {
 	WARN_ON(jack->registered);
-	mutex_lock(&jack->input_dev_lock);
-	if (!jack->input_dev) {
-		mutex_unlock(&jack->input_dev_lock);
+	if (!jack->input_dev)
 		return;
-	}
 
 	jack->input_dev->dev.parent = parent;
-	mutex_unlock(&jack->input_dev_lock);
 }
 EXPORT_SYMBOL(snd_jack_set_parent);
 
@@ -354,8 +340,6 @@ EXPORT_SYMBOL(snd_jack_set_key);
 
 /**
  * snd_jack_report - Report the current status of a jack
- * Note: This function uses mutexes and should be called from a
- * context which can sleep (such as a workqueue).
  *
  * @jack:   The jack to report status for
  * @status: The current status of the jack
@@ -375,11 +359,8 @@ void snd_jack_report(struct snd_jack *jack, int status)
 					    status & jack_kctl->mask_bits);
 
 #ifdef CONFIG_SND_JACK_INPUT_DEV
-	mutex_lock(&jack->input_dev_lock);
-	if (!jack->input_dev) {
-		mutex_unlock(&jack->input_dev_lock);
+	if (!jack->input_dev)
 		return;
-	}
 
 	for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
 		int testbit = SND_JACK_BTN_0 >> i;
@@ -398,7 +379,6 @@ void snd_jack_report(struct snd_jack *jack, int status)
 	}
 
 	input_sync(jack->input_dev);
-	mutex_unlock(&jack->input_dev_lock);
 #endif /* CONFIG_SND_JACK_INPUT_DEV */
 }
 EXPORT_SYMBOL(snd_jack_report);