ALSA: ctl: fix to handle several elements added by one operation for userspace element
An element instance can have several elements with the same feature.
Some userspace applications can add such an element instance by add
operation with the number of elements. Then, the element instance
gets a memory object to keep states of these elements.
But the element instance has just one memory object for the elements.
This causes the same result to each read/write operations to the
different elements.
This commit fixes this bug by allocating enough memory objects to the
element instance for each of elements.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/control.c b/sound/core/control.c
index be5b97c..196a6fe 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1029,7 +1029,7 @@
struct user_element {
struct snd_ctl_elem_info info;
struct snd_card *card;
- void *elem_data; /* element data */
+ char *elem_data; /* element data */
unsigned long elem_data_size; /* size of element data in bytes */
void *tlv_data; /* TLV data */
unsigned long tlv_data_size; /* TLV data size */
@@ -1078,9 +1078,12 @@
struct snd_ctl_elem_value *ucontrol)
{
struct user_element *ue = kcontrol->private_data;
+ unsigned int size = ue->elem_data_size;
+ char *src = ue->elem_data +
+ snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
mutex_lock(&ue->card->user_ctl_lock);
- memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
+ memcpy(&ucontrol->value, src, size);
mutex_unlock(&ue->card->user_ctl_lock);
return 0;
}
@@ -1090,11 +1093,14 @@
{
int change;
struct user_element *ue = kcontrol->private_data;
+ unsigned int size = ue->elem_data_size;
+ char *dst = ue->elem_data +
+ snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
mutex_lock(&ue->card->user_ctl_lock);
- change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
+ change = memcmp(&ucontrol->value, dst, size) != 0;
if (change)
- memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
+ memcpy(dst, &ucontrol->value, size);
mutex_unlock(&ue->card->user_ctl_lock);
return change;
}
@@ -1278,7 +1284,7 @@
if (err < 0)
return err;
memcpy(&kctl->id, &info->id, sizeof(kctl->id));
- kctl->private_data = kzalloc(sizeof(struct user_element) + private_size,
+ kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
GFP_KERNEL);
if (kctl->private_data == NULL) {
kfree(kctl);