control: remove snd_konctrol_volatile::owner_pid field

We do not need to save the ID of the process that locked a control
because that information is already available in the owner's file data.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/control.h

@@ -56,7 +56,6 @@ struct snd_kcontrol_new {
 
 struct snd_kcontrol_volatile {
 	struct snd_ctl_file *owner;	/* locked */
-	pid_t owner_pid;
 	unsigned int access;	/* access rights */
 };
 

sound/core/control.c

@@ -672,7 +672,7 @@ static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 			info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 			if (vd->owner == ctl)
 				info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
-			info->owner = vd->owner_pid;
+			info->owner = vd->owner->pid;
 		} else {
 			info->owner = -1;
 		}
@@ -827,7 +827,6 @@ static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 			result = -EBUSY;
 		else {
 			vd->owner = file;
-			vd->owner_pid = current->pid;
 			result = 0;
 		}
 	}
@@ -858,7 +857,6 @@ static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 			result = -EPERM;
 		else {
 			vd->owner = NULL;
-			vd->owner_pid = 0;
 			result = 0;
 		}
 	}