f2fs: avoid unneeded data copy in f2fs_ioc_move_range()

Fields in struct f2fs_move_range won't change in f2fs_ioc_move_range(),
let's avoid copying this structure's data to userspace.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -2898,12 +2898,6 @@ static int f2fs_ioc_move_range(struct file *filp, unsigned long arg)
 					range.pos_out, range.len);
 
 	mnt_drop_write_file(filp);
-	if (err)
-		goto err_out;
-
-	if (copy_to_user((struct f2fs_move_range __user *)arg,
-						&range, sizeof(range)))
-		err = -EFAULT;
 err_out:
 	fdput(dst);
 	return err;