file_fdatawait_range
ret = file_fdatawait_range(file, start, end);
ret = file_fdatawait_range(file, offset, endbyte);
ret = file_fdatawait_range(file, offset, endbyte);
extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
EXPORT_SYMBOL(file_fdatawait_range);