[PATCH] ALSA: control: Fix power_ref lock order for compat code, too

[Takashi Iwai <tiwai@xxxxxxx>]

In the previous change for swapping the power_ref and controls_rwsem
lock order, the code path for the compat layer was forgotten.
This patch covers the remaining code.

Fixes: fcc62b19104a ("ALSA: control: Take power_ref lock primarily")
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
 sound/core/control_compat.c | 45 ++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index 934bb945e702..ff0031cc7dfb 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -79,6 +79,7 @@ struct snd_ctl_elem_info32 {
 static int snd_ctl_elem_info_compat(struct snd_ctl_file *ctl,
 				    struct snd_ctl_elem_info32 __user *data32)
 {
+	struct snd_card *card = ctl->card;
 	struct snd_ctl_elem_info *data __free(kfree) = NULL;
 	int err;
 
@@ -95,7 +96,11 @@ static int snd_ctl_elem_info_compat(struct snd_ctl_file *ctl,
 	if (get_user(data->value.enumerated.item, &data32->value.enumerated.item))
 		return -EFAULT;
 
+	err = snd_power_ref_and_wait(card);
+	if (err < 0)
+		return err;
 	err = snd_ctl_elem_info(ctl, data);
+	snd_power_unref(card);
 	if (err < 0)
 		return err;
 	/* restore info to 32bit */
@@ -175,10 +180,7 @@ static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
 	if (info == NULL)
 		return -ENOMEM;
 	info->id = *id;
-	err = snd_power_ref_and_wait(card);
-	if (!err)
-		err = kctl->info(kctl, info);
-	snd_power_unref(card);
+	err = kctl->info(kctl, info);
 	if (err >= 0) {
 		err = info->type;
 		*countp = info->count;
@@ -275,8 +277,8 @@ static int copy_ctl_value_to_user(void __user *userdata,
 	return 0;
 }
 
-static int ctl_elem_read_user(struct snd_card *card,
-			      void __user *userdata, void __user *valuep)
+static int __ctl_elem_read_user(struct snd_card *card,
+				void __user *userdata, void __user *valuep)
 {
 	struct snd_ctl_elem_value *data __free(kfree) = NULL;
 	int err, type, count;
@@ -296,8 +298,21 @@ static int ctl_elem_read_user(struct snd_card *card,
 	return copy_ctl_value_to_user(userdata, valuep, data, type, count);
 }
 
-static int ctl_elem_write_user(struct snd_ctl_file *file,
-			       void __user *userdata, void __user *valuep)
+static int ctl_elem_read_user(struct snd_card *card,
+			      void __user *userdata, void __user *valuep)
+{
+	int err;
+
+	err = snd_power_ref_and_wait(card);
+	if (err < 0)
+		return err;
+	err = __ctl_elem_read_user(card, userdata, valuep);
+	snd_power_unref(card);
+	return err;
+}
+
+static int __ctl_elem_write_user(struct snd_ctl_file *file,
+				 void __user *userdata, void __user *valuep)
 {
 	struct snd_ctl_elem_value *data __free(kfree) = NULL;
 	struct snd_card *card = file->card;
@@ -318,6 +333,20 @@ static int ctl_elem_write_user(struct snd_ctl_file *file,
 	return copy_ctl_value_to_user(userdata, valuep, data, type, count);
 }
 
+static int ctl_elem_write_user(struct snd_ctl_file *file,
+			       void __user *userdata, void __user *valuep)
+{
+	struct snd_card *card = file->card;
+	int err;
+
+	err = snd_power_ref_and_wait(card);
+	if (err < 0)
+		return err;
+	err = __ctl_elem_write_user(file, userdata, valuep);
+	snd_power_unref(card);
+	return err;
+}
+
 static int snd_ctl_elem_read_user_compat(struct snd_card *card,
 					 struct snd_ctl_elem_value32 __user *data32)
 {
-- 
2.43.0