1 files changed, 332 insertions, 195 deletions

diff --git a/sound/core/init.c b/sound/core/init.c
index 0478847ba2b8..4ed5037d8693 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -13,7 +13,9 @@
 #include <linux/time.h>
 #include <linux/ctype.h>
 #include <linux/pm.h>
+#include <linux/debugfs.h>
 #include <linux/completion.h>
+#include <linux/interrupt.h>
 
 #include <sound/core.h>
 #include <sound/control.h>
@@ -109,29 +111,40 @@ static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
 	return mask; /* unchanged */
 }
 
-/* the default release callback set in snd_device_initialize() below;
- * this is just NOP for now, as almost all jobs are already done in
- * dev_free callback of snd_device chain instead.
- */
-static void default_release(struct device *dev)
+/* the default release callback set in snd_device_alloc() */
+static void default_release_alloc(struct device *dev)
 {
+	kfree(dev);
 }
 
 /**
- * snd_device_initialize - Initialize struct device for sound devices
- * @dev: device to initialize
+ * snd_device_alloc - Allocate and initialize struct device for sound devices
+ * @dev_p: pointer to store the allocated device
  * @card: card to assign, optional
+ *
+ * For releasing the allocated device, call put_device().
  */
-void snd_device_initialize(struct device *dev, struct snd_card *card)
+int snd_device_alloc(struct device **dev_p, struct snd_card *card)
 {
+	struct device *dev;
+
+	*dev_p = NULL;
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
 	device_initialize(dev);
 	if (card)
 		dev->parent = &card->card_dev;
-	dev->class = sound_class;
-	dev->release = default_release;
+	dev->class = &sound_class;
+	dev->release = default_release_alloc;
+	*dev_p = dev;
+	return 0;
 }
-EXPORT_SYMBOL_GPL(snd_device_initialize);
+EXPORT_SYMBOL_GPL(snd_device_alloc);
 
+static int snd_card_init(struct snd_card *card, struct device *parent,
+			 int idx, const char *xid, struct module *module,
+			 size_t extra_size);
 static int snd_card_do_free(struct snd_card *card);
 static const struct attribute_group card_dev_attr_group;
 
@@ -149,8 +162,6 @@ static void release_card_device(struct device *dev)
  *  @extra_size: allocate this extra size after the main soundcard structure
  *  @card_ret: the pointer to store the created card instance
  *
- *  Creates and initializes a soundcard structure.
- *
  *  The function allocates snd_card instance via kzalloc with the given
  *  space for the driver to use freely.  The allocated struct is stored
  *  in the given card_ret pointer.
@@ -173,34 +184,131 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 	if (!card)
 		return -ENOMEM;
+
+	err = snd_card_init(card, parent, idx, xid, module, extra_size);
+	if (err < 0)
+		return err; /* card is freed by error handler */
+
+	*card_ret = card;
+	return 0;
+}
+EXPORT_SYMBOL(snd_card_new);
+
+static void __snd_card_release(struct device *dev, void *data)
+{
+	snd_card_free(data);
+}
+
+/**
+ * snd_devm_card_new - managed snd_card object creation
+ * @parent: the parent device object
+ * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
+ * @xid: card identification (ASCII string)
+ * @module: top level module for locking
+ * @extra_size: allocate this extra size after the main soundcard structure
+ * @card_ret: the pointer to store the created card instance
+ *
+ * This function works like snd_card_new() but manages the allocated resource
+ * via devres, i.e. you don't need to free explicitly.
+ *
+ * When a snd_card object is created with this function and registered via
+ * snd_card_register(), the very first devres action to call snd_card_free()
+ * is added automatically.  In that way, the resource disconnection is assured
+ * at first, then released in the expected order.
+ *
+ * If an error happens at the probe before snd_card_register() is called and
+ * there have been other devres resources, you'd need to free the card manually
+ * via snd_card_free() call in the error; otherwise it may lead to UAF due to
+ * devres call orders.  You can use snd_card_free_on_error() helper for
+ * handling it more easily.
+ *
+ * Return: zero if successful, or a negative error code
+ */
+int snd_devm_card_new(struct device *parent, int idx, const char *xid,
+		      struct module *module, size_t extra_size,
+		      struct snd_card **card_ret)
+{
+	struct snd_card *card;
+	int err;
+
+	*card_ret = NULL;
+	card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
+			    GFP_KERNEL);
+	if (!card)
+		return -ENOMEM;
+	card->managed = true;
+	err = snd_card_init(card, parent, idx, xid, module, extra_size);
+	if (err < 0) {
+		devres_free(card); /* in managed mode, we need to free manually */
+		return err;
+	}
+
+	devres_add(parent, card);
+	*card_ret = card;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_devm_card_new);
+
+/**
+ * snd_card_free_on_error - a small helper for handling devm probe errors
+ * @dev: the managed device object
+ * @ret: the return code from the probe callback
+ *
+ * This function handles the explicit snd_card_free() call at the error from
+ * the probe callback.  It's just a small helper for simplifying the error
+ * handling with the managed devices.
+ *
+ * Return: zero if successful, or a negative error code
+ */
+int snd_card_free_on_error(struct device *dev, int ret)
+{
+	struct snd_card *card;
+
+	if (!ret)
+		return 0;
+	card = devres_find(dev, __snd_card_release, NULL, NULL);
+	if (card)
+		snd_card_free(card);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_card_free_on_error);
+
+static int snd_card_init(struct snd_card *card, struct device *parent,
+			 int idx, const char *xid, struct module *module,
+			 size_t extra_size)
+{
+	int err;
+
 	if (extra_size > 0)
 		card->private_data = (char *)card + sizeof(struct snd_card);
 	if (xid)
-		strlcpy(card->id, xid, sizeof(card->id));
+		strscpy(card->id, xid, sizeof(card->id));
 	err = 0;
-	mutex_lock(&snd_card_mutex);
-	if (idx < 0) /* first check the matching module-name slot */
-		idx = get_slot_from_bitmask(idx, module_slot_match, module);
-	if (idx < 0) /* if not matched, assign an empty slot */
-		idx = get_slot_from_bitmask(idx, check_empty_slot, module);
-	if (idx < 0)
-		err = -ENODEV;
-	else if (idx < snd_ecards_limit) {
-		if (test_bit(idx, snd_cards_lock))
-			err = -EBUSY;	/* invalid */
-	} else if (idx >= SNDRV_CARDS)
-		err = -ENODEV;
+	scoped_guard(mutex, &snd_card_mutex) {
+		if (idx < 0) /* first check the matching module-name slot */
+			idx = get_slot_from_bitmask(idx, module_slot_match, module);
+		if (idx < 0) /* if not matched, assign an empty slot */
+			idx = get_slot_from_bitmask(idx, check_empty_slot, module);
+		if (idx < 0)
+			err = -ENODEV;
+		else if (idx < snd_ecards_limit) {
+			if (test_bit(idx, snd_cards_lock))
+				err = -EBUSY;	/* invalid */
+		} else if (idx >= SNDRV_CARDS)
+			err = -ENODEV;
+		if (!err) {
+			set_bit(idx, snd_cards_lock);		/* lock it */
+			if (idx >= snd_ecards_limit)
+				snd_ecards_limit = idx + 1; /* increase the limit */
+		}
+	}
 	if (err < 0) {
-		mutex_unlock(&snd_card_mutex);
 		dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
-			 idx, snd_ecards_limit - 1, err);
-		kfree(card);
+			idx, snd_ecards_limit - 1, err);
+		if (!card->managed)
+			kfree(card); /* manually free here, as no destructor called */
 		return err;
 	}
-	set_bit(idx, snd_cards_lock);		/* lock it */
-	if (idx >= snd_ecards_limit)
-		snd_ecards_limit = idx + 1; /* increase the limit */
-	mutex_unlock(&snd_card_mutex);
 	card->dev = parent;
 	card->number = idx;
 #ifdef MODULE
@@ -212,18 +320,24 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	rwlock_init(&card->ctl_files_rwlock);
 	INIT_LIST_HEAD(&card->controls);
 	INIT_LIST_HEAD(&card->ctl_files);
+#ifdef CONFIG_SND_CTL_FAST_LOOKUP
+	xa_init(&card->ctl_numids);
+	xa_init(&card->ctl_hash);
+#endif
 	spin_lock_init(&card->files_lock);
 	INIT_LIST_HEAD(&card->files_list);
 	mutex_init(&card->memory_mutex);
 #ifdef CONFIG_PM
 	init_waitqueue_head(&card->power_sleep);
+	init_waitqueue_head(&card->power_ref_sleep);
+	atomic_set(&card->power_ref, 0);
 #endif
 	init_waitqueue_head(&card->remove_sleep);
 	card->sync_irq = -1;
 
 	device_initialize(&card->card_dev);
 	card->card_dev.parent = parent;
-	card->card_dev.class = sound_class;
+	card->card_dev.class = &sound_class;
 	card->card_dev.release = release_card_device;
 	card->card_dev.groups = card->dev_groups;
 	card->dev_groups[0] = &card_dev_attr_group;
@@ -246,7 +360,11 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 		dev_err(parent, "unable to create card info\n");
 		goto __error_ctl;
 	}
-	*card_ret = card;
+
+#ifdef CONFIG_SND_DEBUG
+	card->debugfs_root = debugfs_create_dir(dev_name(&card->card_dev),
+						sound_debugfs_root);
+#endif
 	return 0;
 
       __error_ctl:
@@ -255,7 +373,6 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	put_device(&card->card_dev);
   	return err;
 }
-EXPORT_SYMBOL(snd_card_new);
 
 /**
  * snd_card_ref - Get the card object from the index
@@ -263,16 +380,17 @@ EXPORT_SYMBOL(snd_card_new);
  *
  * Returns a card object corresponding to the given index or NULL if not found.
  * Release the object via snd_card_unref().
+ *
+ * Return: a card object or NULL
  */
 struct snd_card *snd_card_ref(int idx)
 {
 	struct snd_card *card;
 
-	mutex_lock(&snd_card_mutex);
+	guard(mutex)(&snd_card_mutex);
 	card = snd_cards[idx];
 	if (card)
 		get_device(&card->card_dev);
-	mutex_unlock(&snd_card_mutex);
 	return card;
 }
 EXPORT_SYMBOL_GPL(snd_card_ref);
@@ -280,12 +398,8 @@ EXPORT_SYMBOL_GPL(snd_card_ref);
 /* return non-zero if a card is already locked */
 int snd_card_locked(int card)
 {
-	int locked;
-
-	mutex_lock(&snd_card_mutex);
-	locked = test_bit(card, snd_cards_lock);
-	mutex_unlock(&snd_card_mutex);
-	return locked;
+	guard(mutex)(&snd_card_mutex);
+	return test_bit(card, snd_cards_lock);
 }
 
 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
@@ -309,15 +423,15 @@ static int snd_disconnect_release(struct inode *inode, struct file *file)
 {
 	struct snd_monitor_file *df = NULL, *_df;
 
-	spin_lock(&shutdown_lock);
-	list_for_each_entry(_df, &shutdown_files, shutdown_list) {
-		if (_df->file == file) {
-			df = _df;
-			list_del_init(&df->shutdown_list);
-			break;
+	scoped_guard(spinlock, &shutdown_lock) {
+		list_for_each_entry(_df, &shutdown_files, shutdown_list) {
+			if (_df->file == file) {
+				df = _df;
+				list_del_init(&df->shutdown_list);
+				break;
+			}
 		}
 	}
-	spin_unlock(&shutdown_lock);
 
 	if (likely(df)) {
 		if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
@@ -376,36 +490,31 @@ static const struct file_operations snd_shutdown_f_ops =
  *  Note: The current implementation replaces all active file->f_op with special
  *        dummy file operations (they do nothing except release).
  */
-int snd_card_disconnect(struct snd_card *card)
+void snd_card_disconnect(struct snd_card *card)
 {
 	struct snd_monitor_file *mfile;
 
 	if (!card)
-		return -EINVAL;
+		return;
 
-	spin_lock(&card->files_lock);
-	if (card->shutdown) {
-		spin_unlock(&card->files_lock);
-		return 0;
-	}
-	card->shutdown = 1;
-	spin_unlock(&card->files_lock);
+	scoped_guard(spinlock, &card->files_lock) {
+		if (card->shutdown)
+			return;
+		card->shutdown = 1;
 
-	/* replace file->f_op with special dummy operations */
-	spin_lock(&card->files_lock);
-	list_for_each_entry(mfile, &card->files_list, list) {
-		/* it's critical part, use endless loop */
-		/* we have no room to fail */
-		mfile->disconnected_f_op = mfile->file->f_op;
+		/* replace file->f_op with special dummy operations */
+		list_for_each_entry(mfile, &card->files_list, list) {
+			/* it's critical part, use endless loop */
+			/* we have no room to fail */
+			mfile->disconnected_f_op = mfile->file->f_op;
 
-		spin_lock(&shutdown_lock);
-		list_add(&mfile->shutdown_list, &shutdown_files);
-		spin_unlock(&shutdown_lock);
+			scoped_guard(spinlock, &shutdown_lock)
+				list_add(&mfile->shutdown_list, &shutdown_files);
 
-		mfile->file->f_op = &snd_shutdown_f_ops;
-		fops_get(mfile->file->f_op);
+			mfile->file->f_op = &snd_shutdown_f_ops;
+			fops_get(mfile->file->f_op);
+		}
 	}
-	spin_unlock(&card->files_lock);	
 
 	/* notify all connected devices about disconnection */
 	/* at this point, they cannot respond to any calls except release() */
@@ -418,6 +527,9 @@ int snd_card_disconnect(struct snd_card *card)
 	/* notify all devices that we are disconnected */
 	snd_device_disconnect_all(card);
 
+	if (card->sync_irq > 0)
+		synchronize_irq(card->sync_irq);
+
 	snd_info_card_disconnect(card);
 	if (card->registered) {
 		device_del(&card->card_dev);
@@ -425,15 +537,15 @@ int snd_card_disconnect(struct snd_card *card)
 	}
 
 	/* disable fops (user space) operations for ALSA API */
-	mutex_lock(&snd_card_mutex);
-	snd_cards[card->number] = NULL;
-	clear_bit(card->number, snd_cards_lock);
-	mutex_unlock(&snd_card_mutex);
+	scoped_guard(mutex, &snd_card_mutex) {
+		snd_cards[card->number] = NULL;
+		clear_bit(card->number, snd_cards_lock);
+	}
 
 #ifdef CONFIG_PM
 	wake_up(&card->power_sleep);
+	snd_power_sync_ref(card);
 #endif
-	return 0;	
 }
 EXPORT_SYMBOL(snd_card_disconnect);
 
@@ -448,26 +560,18 @@ EXPORT_SYMBOL(snd_card_disconnect);
  */
 void snd_card_disconnect_sync(struct snd_card *card)
 {
-	int err;
-
-	err = snd_card_disconnect(card);
-	if (err < 0) {
-		dev_err(card->dev,
-			"snd_card_disconnect error (%d), skipping sync\n",
-			err);
-		return;
-	}
+	snd_card_disconnect(card);
 
-	spin_lock_irq(&card->files_lock);
+	guard(spinlock_irq)(&card->files_lock);
 	wait_event_lock_irq(card->remove_sleep,
 			    list_empty(&card->files_list),
 			    card->files_lock);
-	spin_unlock_irq(&card->files_lock);
 }
 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
 
 static int snd_card_do_free(struct snd_card *card)
 {
+	card->releasing = true;
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 	if (snd_mixer_oss_notify_callback)
 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
@@ -479,9 +583,14 @@ static int snd_card_do_free(struct snd_card *card)
 		dev_warn(card->dev, "unable to free card info\n");
 		/* Not fatal error */
 	}
+#ifdef CONFIG_SND_DEBUG
+	debugfs_remove(card->debugfs_root);
+	card->debugfs_root = NULL;
+#endif
 	if (card->release_completion)
 		complete(card->release_completion);
-	kfree(card);
+	if (!card->managed)
+		kfree(card);
 	return 0;
 }
 
@@ -493,14 +602,17 @@ static int snd_card_do_free(struct snd_card *card)
  * resource immediately, but tries to disconnect at first.  When the card
  * is still in use, the function returns before freeing the resources.
  * The card resources will be freed when the refcount gets to zero.
+ *
+ * Return: zero if successful, or a negative error code
  */
-int snd_card_free_when_closed(struct snd_card *card)
+void snd_card_free_when_closed(struct snd_card *card)
 {
-	int ret = snd_card_disconnect(card);
-	if (ret)
-		return ret;
+	if (!card)
+		return;
+
+	snd_card_disconnect(card);
 	put_device(&card->card_dev);
-	return 0;
+	return;
 }
 EXPORT_SYMBOL(snd_card_free_when_closed);
 
@@ -517,19 +629,24 @@ EXPORT_SYMBOL(snd_card_free_when_closed);
  * Return: Zero. Frees all associated devices and frees the control
  * interface associated to given soundcard.
  */
-int snd_card_free(struct snd_card *card)
+void snd_card_free(struct snd_card *card)
 {
-	struct completion released;
-	int ret;
+	DECLARE_COMPLETION_ONSTACK(released);
+
+	/* The call of snd_card_free() is allowed from various code paths;
+	 * a manual call from the driver and the call via devres_free, and
+	 * we need to avoid double-free. Moreover, the release via devres
+	 * may call snd_card_free() twice due to its nature, we need to have
+	 * the check here at the beginning.
+	 */
+	if (card->releasing)
+		return;
 
-	init_completion(&released);
 	card->release_completion = &released;
-	ret = snd_card_free_when_closed(card);
-	if (ret)
-		return ret;
+	snd_card_free_when_closed(card);
+
 	/* wait, until all devices are ready for the free operation */
 	wait_for_completion(&released);
-	return 0;
 }
 EXPORT_SYMBOL(snd_card_free);
 
@@ -626,7 +743,7 @@ static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
 	/* last resort... */
 	dev_err(card->dev, "unable to set card id (%s)\n", id);
 	if (card->proc_root->name)
-		strlcpy(card->id, card->proc_root->name, sizeof(card->id));
+		strscpy(card->id, card->proc_root->name, sizeof(card->id));
 }
 
 /**
@@ -642,23 +759,20 @@ void snd_card_set_id(struct snd_card *card, const char *nid)
 	/* check if user specified own card->id */
 	if (card->id[0] != '\0')
 		return;
-	mutex_lock(&snd_card_mutex);
+	guard(mutex)(&snd_card_mutex);
 	snd_card_set_id_no_lock(card, nid, nid);
-	mutex_unlock(&snd_card_mutex);
 }
 EXPORT_SYMBOL(snd_card_set_id);
 
-static ssize_t
-card_id_show_attr(struct device *dev,
-		  struct device_attribute *attr, char *buf)
+static ssize_t id_show(struct device *dev,
+		       struct device_attribute *attr, char *buf)
 {
 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
-	return scnprintf(buf, PAGE_SIZE, "%s\n", card->id);
+	return sysfs_emit(buf, "%s\n", card->id);
 }
 
-static ssize_t
-card_id_store_attr(struct device *dev, struct device_attribute *attr,
-		   const char *buf, size_t count)
+static ssize_t id_store(struct device *dev, struct device_attribute *attr,
+			const char *buf, size_t count)
 {
 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
 	char buf1[sizeof(card->id)];
@@ -674,29 +788,25 @@ card_id_store_attr(struct device *dev, struct device_attribute *attr,
 	}
 	memcpy(buf1, buf, copy);
 	buf1[copy] = '\0';
-	mutex_lock(&snd_card_mutex);
-	if (!card_id_ok(NULL, buf1)) {
-		mutex_unlock(&snd_card_mutex);
+	guard(mutex)(&snd_card_mutex);
+	if (!card_id_ok(NULL, buf1))
 		return -EEXIST;
-	}
 	strcpy(card->id, buf1);
 	snd_info_card_id_change(card);
-	mutex_unlock(&snd_card_mutex);
 
 	return count;
 }
 
-static DEVICE_ATTR(id, 0644, card_id_show_attr, card_id_store_attr);
+static DEVICE_ATTR_RW(id);
 
-static ssize_t
-card_number_show_attr(struct device *dev,
-		     struct device_attribute *attr, char *buf)
+static ssize_t number_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
 {
 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
-	return scnprintf(buf, PAGE_SIZE, "%i\n", card->number);
+	return sysfs_emit(buf, "%i\n", card->number);
 }
 
-static DEVICE_ATTR(number, 0444, card_number_show_attr, NULL);
+static DEVICE_ATTR_RO(number);
 
 static struct attribute *card_dev_attrs[] = {
 	&dev_attr_id.attr,
@@ -712,6 +822,8 @@ static const struct attribute_group card_dev_attr_group = {
  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
  * @card: card instance
  * @group: attribute group to append
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_card_add_dev_attr(struct snd_card *card,
 			  const struct attribute_group *group)
@@ -731,6 +843,11 @@ int snd_card_add_dev_attr(struct snd_card *card,
 }
 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
 
+static void trigger_card_free(void *data)
+{
+	snd_card_free(data);
+}
+
 /**
  *  snd_card_register - register the soundcard
  *  @card: soundcard structure
@@ -754,30 +871,41 @@ int snd_card_register(struct snd_card *card)
 		if (err < 0)
 			return err;
 		card->registered = true;
+	} else {
+		if (card->managed)
+			devm_remove_action(card->dev, trigger_card_free, card);
+	}
+
+	if (card->managed) {
+		err = devm_add_action(card->dev, trigger_card_free, card);
+		if (err < 0)
+			return err;
 	}
 
-	if ((err = snd_device_register_all(card)) < 0)
+	err = snd_device_register_all(card);
+	if (err < 0)
 		return err;
-	mutex_lock(&snd_card_mutex);
-	if (snd_cards[card->number]) {
-		/* already registered */
-		mutex_unlock(&snd_card_mutex);
-		return snd_info_card_register(card); /* register pending info */
-	}
-	if (*card->id) {
-		/* make a unique id name from the given string */
-		char tmpid[sizeof(card->id)];
-		memcpy(tmpid, card->id, sizeof(card->id));
-		snd_card_set_id_no_lock(card, tmpid, tmpid);
-	} else {
-		/* create an id from either shortname or longname */
-		const char *src;
-		src = *card->shortname ? card->shortname : card->longname;
-		snd_card_set_id_no_lock(card, src,
-					retrieve_id_from_card_name(src));
-	}
-	snd_cards[card->number] = card;
-	mutex_unlock(&snd_card_mutex);
+	scoped_guard(mutex, &snd_card_mutex) {
+		if (snd_cards[card->number]) {
+			/* already registered */
+			return snd_info_card_register(card); /* register pending info */
+		}
+		if (*card->id) {
+			/* make a unique id name from the given string */
+			char tmpid[sizeof(card->id)];
+
+			memcpy(tmpid, card->id, sizeof(card->id));
+			snd_card_set_id_no_lock(card, tmpid, tmpid);
+		} else {
+			/* create an id from either shortname or longname */
+			const char *src;
+
+			src = *card->shortname ? card->shortname : card->longname;
+			snd_card_set_id_no_lock(card, src,
+						retrieve_id_from_card_name(src));
+		}
+		snd_cards[card->number] = card;
+	}
 	err = snd_info_card_register(card);
 	if (err < 0)
 		return err;
@@ -798,8 +926,9 @@ static void snd_card_info_read(struct snd_info_entry *entry,
 	struct snd_card *card;
 
 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
-		mutex_lock(&snd_card_mutex);
-		if ((card = snd_cards[idx]) != NULL) {
+		guard(mutex)(&snd_card_mutex);
+		card = snd_cards[idx];
+		if (card) {
 			count++;
 			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 					idx,
@@ -809,7 +938,6 @@ static void snd_card_info_read(struct snd_info_entry *entry,
 			snd_iprintf(buffer, "                      %s\n",
 					card->longname);
 		}
-		mutex_unlock(&snd_card_mutex);
 	}
 	if (!count)
 		snd_iprintf(buffer, "--- no soundcards ---\n");
@@ -822,12 +950,12 @@ void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 	struct snd_card *card;
 
 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
-		mutex_lock(&snd_card_mutex);
-		if ((card = snd_cards[idx]) != NULL) {
+		guard(mutex)(&snd_card_mutex);
+		card = snd_cards[idx];
+		if (card) {
 			count++;
 			snd_iprintf(buffer, "%s\n", card->longname);
 		}
-		mutex_unlock(&snd_card_mutex);
 	}
 	if (!count) {
 		snd_iprintf(buffer, "--- no soundcards ---\n");
@@ -844,11 +972,11 @@ static void snd_card_module_info_read(struct snd_info_entry *entry,
 	struct snd_card *card;
 
 	for (idx = 0; idx < SNDRV_CARDS; idx++) {
-		mutex_lock(&snd_card_mutex);
-		if ((card = snd_cards[idx]) != NULL)
+		guard(mutex)(&snd_card_mutex);
+		card = snd_cards[idx];
+		if (card)
 			snd_iprintf(buffer, "%2i %s\n",
 				    idx, card->module->name);
-		mutex_unlock(&snd_card_mutex);
 	}
 }
 #endif
@@ -930,15 +1058,13 @@ int snd_card_file_add(struct snd_card *card, struct file *file)
 	mfile->file = file;
 	mfile->disconnected_f_op = NULL;
 	INIT_LIST_HEAD(&mfile->shutdown_list);
-	spin_lock(&card->files_lock);
+	guard(spinlock)(&card->files_lock);
 	if (card->shutdown) {
-		spin_unlock(&card->files_lock);
 		kfree(mfile);
 		return -ENODEV;
 	}
 	list_add(&mfile->list, &card->files_list);
 	get_device(&card->card_dev);
-	spin_unlock(&card->files_lock);
 	return 0;
 }
 EXPORT_SYMBOL(snd_card_file_add);
@@ -960,22 +1086,21 @@ int snd_card_file_remove(struct snd_card *card, struct file *file)
 {
 	struct snd_monitor_file *mfile, *found = NULL;
 
-	spin_lock(&card->files_lock);
-	list_for_each_entry(mfile, &card->files_list, list) {
-		if (mfile->file == file) {
-			list_del(&mfile->list);
-			spin_lock(&shutdown_lock);
-			list_del(&mfile->shutdown_list);
-			spin_unlock(&shutdown_lock);
-			if (mfile->disconnected_f_op)
-				fops_put(mfile->disconnected_f_op);
-			found = mfile;
-			break;
+	scoped_guard(spinlock, &card->files_lock) {
+		list_for_each_entry(mfile, &card->files_list, list) {
+			if (mfile->file == file) {
+				list_del(&mfile->list);
+				scoped_guard(spinlock, &shutdown_lock)
+					list_del(&mfile->shutdown_list);
+				if (mfile->disconnected_f_op)
+					fops_put(mfile->disconnected_f_op);
+				found = mfile;
+				break;
+			}
 		}
+		if (list_empty(&card->files_list))
+			wake_up_all(&card->remove_sleep);
 	}
-	if (list_empty(&card->files_list))
-		wake_up_all(&card->remove_sleep);
-	spin_unlock(&card->files_lock);
 	if (!found) {
 		dev_err(card->dev, "card file remove problem (%p)\n", file);
 		return -ENOENT;
@@ -988,36 +1113,48 @@ EXPORT_SYMBOL(snd_card_file_remove);
 
 #ifdef CONFIG_PM
 /**
- *  snd_power_wait - wait until the power-state is changed.
- *  @card: soundcard structure
- *  @power_state: expected power state
+ * snd_power_ref_and_wait - wait until the card gets powered up
+ * @card: soundcard structure
+ *
+ * Take the power_ref reference count of the given card, and
+ * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
+ * The refcount is down again while sleeping until power-up, hence this
+ * function can be used for syncing the floating control ops accesses,
+ * typically around calling control ops.
  *
- *  Waits until the power-state is changed.
+ * The caller needs to pull down the refcount via snd_power_unref() later
+ * no matter whether the error is returned from this function or not.
  *
- *  Return: Zero if successful, or a negative error code.
+ * Return: Zero if successful, or a negative error code.
  */
-int snd_power_wait(struct snd_card *card, unsigned int power_state)
+int snd_power_ref_and_wait(struct snd_card *card)
 {
-	wait_queue_entry_t wait;
-	int result = 0;
-
-	/* fastpath */
-	if (snd_power_get_state(card) == power_state)
+	snd_power_ref(card);
+	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
 		return 0;
-	init_waitqueue_entry(&wait, current);
-	add_wait_queue(&card->power_sleep, &wait);
-	while (1) {
-		if (card->shutdown) {
-			result = -ENODEV;
-			break;
-		}
-		if (snd_power_get_state(card) == power_state)
-			break;
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(30 * HZ);
-	}
-	remove_wait_queue(&card->power_sleep, &wait);
-	return result;
+	wait_event_cmd(card->power_sleep,
+		       card->shutdown ||
+		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
+		       snd_power_unref(card), snd_power_ref(card));
+	return card->shutdown ? -ENODEV : 0;
+}
+EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
+
+/**
+ * snd_power_wait - wait until the card gets powered up (old form)
+ * @card: soundcard structure
+ *
+ * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
+ *
+ * Return: Zero if successful, or a negative error code.
+ */
+int snd_power_wait(struct snd_card *card)
+{
+	int ret;
+
+	ret = snd_power_ref_and_wait(card);
+	snd_power_unref(card);
+	return ret;
 }
 EXPORT_SYMBOL(snd_power_wait);
 #endif /* CONFIG_PM */