Add test case for -EAGAIN issue

Signed-off-by: Jens Axboe <axboe@kernel.dk>

test/eeed8b54e0df-test.c

@@ -0,0 +1,87 @@
+/*
+ * Description: -EAGAIN handling
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "../src/liburing.h"
+
+static int get_file_fd(void)
+{
+	char *buf;
+	int fd;
+
+	fd = open("testfile", O_RDWR | O_CREAT, 0644);
+	if (fd < 0) {
+		perror("open file");
+		return -1;
+	}
+
+	buf = malloc(4096);
+	write(fd, buf, 4096);
+	fsync(fd);
+
+	if (posix_fadvise(fd, 0, 4096, POSIX_FADV_DONTNEED)) {
+		perror("fadvise");
+		close(fd);
+		free(buf);
+		return -1;
+	}
+
+	free(buf);
+	return fd;
+}
+
+static void put_file_fd(int fd)
+{
+	close(fd);
+	unlink("testfile");
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	struct iovec iov;
+	int ret, fd;
+
+	iov.iov_base = malloc(4096);
+	iov.iov_len = 4096;
+
+	ret = io_uring_queue_init(2, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		return 1;
+	}
+
+	fd = get_file_fd();
+	if (fd < 0)
+		return 1;
+
+	io_uring_prep_readv(sqe, fd, &iov, 1, 0);
+	sqe->rw_flags = RWF_NOWAIT;
+
+	ret = io_uring_submit(&ring);
+	if (ret != -EAGAIN) {
+		printf("Got submit %d, expected EAGAIN\n", ret);
+		goto err;
+	}
+
+	put_file_fd(fd);
+	return 0;
+err:
+	put_file_fd(fd);
+	return 1;
+}