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Commit 30d8340b authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: control: obsolete user_ctl_lock 



At a previous commit, concurrent requests for TLV data are maintained
exclusively between read requests and write/command requests. TLV
callback handlers in each driver has no risk from concurrent access for
reference/change.

In current implementation, 'struct snd_card' has a mutex to control
concurrent accesses to user-defined element sets. This commit obsoletes it.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 4c8099e9

include/sound/core.h

+0 −2
Original line number Diff line number Diff line
@@ -118,8 +118,6 @@ struct snd_card { 
	int user_ctl_count;		/* count of all user controls */

	struct list_head controls;	/* all controls for this card */

	struct list_head ctl_files;	/* active control files */

	struct mutex user_ctl_lock;	/* protects user controls against

					   concurrent access */



	struct snd_info_entry *proc_root;	/* root for soundcard specific files */

	struct snd_info_entry *proc_id;	/* the card id */

sound/core/control.c

+13 −24
Original line number Diff line number Diff line
@@ -1095,9 +1095,7 @@ static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol, 
	char *src = ue->elem_data +

			snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;



	mutex_lock(&ue->card->user_ctl_lock);

	memcpy(&ucontrol->value, src, size);

	mutex_unlock(&ue->card->user_ctl_lock);

	return 0;

}
@@ -1110,11 +1108,9 @@ static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol, 
	char *dst = ue->elem_data +

			snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;



	mutex_lock(&ue->card->user_ctl_lock);

	change = memcmp(&ucontrol->value, dst, size) != 0;

	if (change)

		memcpy(dst, &ucontrol->value, size);

	mutex_unlock(&ue->card->user_ctl_lock);

	return change;

}
@@ -1124,44 +1120,37 @@ static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol, 
				 unsigned int __user *tlv)

{

	struct user_element *ue = kcontrol->private_data;

	int change = 0;

	void *new_data;



	if (op_flag == SNDRV_CTL_TLV_OP_WRITE) {

		int change;

		void *new_data;



		if (size > 1024 * 128)	/* sane value */

			return -EINVAL;



		new_data = memdup_user(tlv, size);

		if (IS_ERR(new_data))

			return PTR_ERR(new_data);

		mutex_lock(&ue->card->user_ctl_lock);

		change = ue->tlv_data_size != size;

		if (!change)

			change = memcmp(ue->tlv_data, new_data, size);

		kfree(ue->tlv_data);

		ue->tlv_data = new_data;

		ue->tlv_data_size = size;

		mutex_unlock(&ue->card->user_ctl_lock);



		return change;

	} else {

		int ret = 0;

		if (!ue->tlv_data_size || !ue->tlv_data)

			return -ENXIO;



		if (size < ue->tlv_data_size)

			return -ENOSPC;



		mutex_lock(&ue->card->user_ctl_lock);

		if (!ue->tlv_data_size || !ue->tlv_data) {

			ret = -ENXIO;

			goto err_unlock;

		}

		if (size < ue->tlv_data_size) {

			ret = -ENOSPC;

			goto err_unlock;

		}

		if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))

			ret = -EFAULT;

err_unlock:

		mutex_unlock(&ue->card->user_ctl_lock);

		if (ret)

			return ret;

			return -EFAULT;



		return 0;

	}

	return change;

}



static int snd_ctl_elem_init_enum_names(struct user_element *ue)

sound/core/init.c

+0 −1
Original line number Diff line number Diff line
@@ -248,7 +248,6 @@ int snd_card_new(struct device *parent, int idx, const char *xid, 
	INIT_LIST_HEAD(&card->devices);

	init_rwsem(&card->controls_rwsem);

	rwlock_init(&card->ctl_files_rwlock);

	mutex_init(&card->user_ctl_lock);

	INIT_LIST_HEAD(&card->controls);

	INIT_LIST_HEAD(&card->ctl_files);

	spin_lock_init(&card->files_lock);