Add eventfd test case

Tests both the completion side, but also the recursion bug that was
fixed in commit 50167d5bc585 in mainline.

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

2 files changed, 105 insertions, 2 deletions

diff --git a/test/Makefile b/test/Makefile
index a975999..a311699 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -19,7 +19,7 @@ all_targets += poll poll-cancel ring-leak fsync io_uring_setup io_uring_register
 		poll-many b5837bd5311d-test accept-test d77a67ed5f27-test \
 		connect 7ad0e4b2f83c-test submit-reuse fallocate open-close \
 		file-update statx accept-reuse poll-v-poll fadvise madvise \
-		short-read openat2 probe shared-wq personality
+		short-read openat2 probe shared-wq personality eventfd
 
 include ../Makefile.quiet
 
@@ -46,7 +46,7 @@ test_srcs := poll.c poll-cancel.c ring-leak.c fsync.c io_uring_setup.c \
 	7ad0e4b2f83c-test.c submit-reuse.c fallocate.c open-close.c \
 	file-update.c statx.c accept-reuse.c poll-v-poll.c fadvise.c \
 	madvise.c short-read.c openat2.c probe.c shared-wq.c \
-	personality.c
+	personality.c eventfd.c
 
 test_objs := $(patsubst %.c,%.ol,$(test_srcs))
 
diff --git a/test/eventfd.c b/test/eventfd.c
new file mode 100644
index 0000000..54f6871
--- /dev/null
+++ b/test/eventfd.c
@@ -0,0 +1,103 @@
+/*
+ * Description: run various nop tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/poll.h>
+#include <sys/eventfd.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	uint64_t ptr;
+	struct iovec vec = {
+		.iov_base = &ptr,
+		.iov_len = sizeof(ptr)
+	};
+	int ret, evfd, i;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring setup failed: %d\n", ret);
+		return 1;
+	}
+
+	evfd = eventfd(0, EFD_CLOEXEC);
+	if (evfd < 0) {
+		perror("eventfd");
+		return 1;
+	}
+
+	ret = io_uring_register_eventfd(&ring, evfd);
+	if (ret) {
+		fprintf(stderr, "failed to register evfd: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_poll_add(sqe, evfd, POLLIN);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_readv(sqe, evfd, &vec, 1, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 3;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 3; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait: %d\n", ret);
+			return 1;
+		}
+		switch (cqe->user_data) {
+		case 1:
+			/* POLLIN */
+			if (cqe->res != 1) {
+				fprintf(stderr, "poll: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		case 2:
+			if (cqe->res != sizeof(ptr)) {
+				fprintf(stderr, "read: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		case 3:
+			if (cqe->res) {
+				fprintf(stderr, "nop: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	return 0;
+}