io_uring.c

#include <err.h>
#include <errno.h>
#include <liburing.h>
#include <stdlib.h>

#include "stopwatch.h"

struct io_uring ring;

void init(__attribute__((unused)) int fd) {
	int res = io_uring_queue_init(1, &ring, 0);
	if (res < 0) {
		errno = -res;
		err(EXIT_FAILURE, "io_uring_setup failed");
	}
}

unsigned do_read(int fd, void *buf, size_t count) {
	start_watch();

	struct io_uring_sqe *sqe = io_uring_get_sqe(&ring);
	io_uring_prep_read(sqe, fd, buf, count, 0);

	int res = io_uring_submit_and_wait(&ring, 1);

	stop_watch();

	if (res < 0) err(EXIT_FAILURE, "io_uring_submit_and_wait failed");

	struct io_uring_cqe *cqe;
	res = io_uring_peek_cqe(&ring, &cqe);
	if (res < 0) err(EXIT_FAILURE, "io_uring_peek_cqe failed");

	if (cqe->res < 0) err(EXIT_FAILURE, "read request failed");
	return 1;
}