backing_file_write_iter
EXPORT_SYMBOL_GPL(backing_file_write_iter);
ret = backing_file_write_iter(backing_file, iter, iocb, iocb->ki_flags,
ret = backing_file_write_iter(realfile, iter, iocb, ifl, &ctx);
ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,