ALSA: control: Provide a helper to look for the preferred subdevice
Instead of open-coding the search over the control file loop, provide
a helper function for the preferred subdevice assigned to the current
process.
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/control.c b/sound/core/control.c
index bb96a46..cd246a0 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -50,7 +50,7 @@
unsigned long flags;
struct snd_card *card;
struct snd_ctl_file *ctl;
- int err;
+ int i, err;
err = nonseekable_open(inode, file);
if (err < 0)
@@ -79,8 +79,8 @@
init_waitqueue_head(&ctl->change_sleep);
spin_lock_init(&ctl->read_lock);
ctl->card = card;
- ctl->prefer_pcm_subdevice = -1;
- ctl->prefer_rawmidi_subdevice = -1;
+ for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
+ ctl->preferred_subdevice[i] = -1;
ctl->pid = get_pid(task_pid(current));
file->private_data = ctl;
write_lock_irqsave(&card->ctl_files_rwlock, flags);
@@ -1607,6 +1607,27 @@
return fasync_helper(fd, file, on, &ctl->fasync);
}
+/* return the preferred subdevice number if already assigned;
+ * otherwise return -1
+ */
+int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
+{
+ struct snd_ctl_file *kctl;
+ int subdevice = -1;
+
+ read_lock(&card->ctl_files_rwlock);
+ list_for_each_entry(kctl, &card->ctl_files, list) {
+ if (kctl->pid == task_pid(current)) {
+ subdevice = kctl->preferred_subdevice[type];
+ if (subdevice != -1)
+ break;
+ }
+ }
+ read_unlock(&card->ctl_files_rwlock);
+ return subdevice;
+}
+EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
+
/*
* ioctl32 compat
*/