Function test_read_drain_refill

test/buf-ring-stress.c:45–202

* Test: submit reads consuming all buffers, refill, repeat. * Verifies data integrity through the whole process. */

 * Verifies data integrity through the whole process.
 */
static int test_read_drain_refill(void)
{
	struct io_uring ring;
	struct io_uring_buf_ring *br;
	struct io_uring_sqe *sqe;
	struct io_uring_cqe *cqe;
	void *buf_base;
	char *file_data;
	const char *fname = ".buf-ring-stress-tmp";
	int fd, ret, round;
	int total_read = 0;

	ret = io_uring_queue_init(32, &ring, 0);
	if (ret) {
		fprintf(stderr, "ring setup: %d\n", ret);
		return T_EXIT_FAIL;
	}

	/* Setup buffer ring */
	br = io_uring_setup_buf_ring(&ring, NR_BUFS, BGID, 0, &ret);
	if (!br) {
		if (ret == -EINVAL || ret == -ENOENT) {
			io_uring_queue_exit(&ring);
			return T_EXIT_SKIP;
		}
		fprintf(stderr, "buf ring setup: %d\n", ret);
		io_uring_queue_exit(&ring);
		return T_EXIT_FAIL;
	}

	buf_base = malloc(NR_BUFS * BUF_SIZE);
	if (!buf_base)
		goto err;

	/* Create test file with known pattern */
	file_data = malloc(FILE_SIZE);
	if (!file_data)
		goto err;

	for (int i = 0; i < FILE_SIZE; i++)
		file_data[i] = (char)(i & 0xff);

	fd = open(fname, O_CREAT | O_WRONLY | O_TRUNC, 0644);
	if (fd < 0) {
		perror("open write");
		free(file_data);
		goto err;
	}
	if (write(fd, file_data, FILE_SIZE) != FILE_SIZE) {
		perror("write");
		close(fd);
		free(file_data);
		goto err;
	}
	close(fd);

	fd = open(fname, O_RDONLY);
	if (fd < 0) {