btrfs: drop lock parameter from update_ioctl_balance_args and rename

The parameter controls locking of the stats part but we can lock it
unconditionally, as this only happens once when balance starts. This is
not performance critical.

Add the prefix for an exported function.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ffb224b..397f026 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4305,7 +4305,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
-void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
+void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 			       struct btrfs_ioctl_balance_args *bargs)
 {
 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
@@ -4323,13 +4323,9 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
 
-	if (lock) {
-		spin_lock(&fs_info->balance_lock);
-		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
-		spin_unlock(&fs_info->balance_lock);
-	} else {
-		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
-	}
+	spin_lock(&fs_info->balance_lock);
+	memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
+	spin_unlock(&fs_info->balance_lock);
 }
 
 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
@@ -4515,7 +4511,7 @@ static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
 		goto out;
 	}
 
-	update_ioctl_balance_args(fs_info, 1, bargs);
+	btrfs_update_ioctl_balance_args(fs_info, bargs);
 
 	if (copy_to_user(arg, bargs, sizeof(*bargs)))
 		ret = -EFAULT;