io_uring: test IORING_TIMEOUT_ETIME_SUCCESS

Make sure we don't fail links on ETIME when IORING_TIMEOUT_ETIME_SUCCESS
is set.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d1a5b6bdbcfa1ec6b5ca014248e12b3b1edb4e5d.1633259449.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index 7aa43fc..61683bd 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -162,6 +162,7 @@
 #define IORING_TIMEOUT_BOOTTIME		(1U << 2)
 #define IORING_TIMEOUT_REALTIME		(1U << 3)
 #define IORING_LINK_TIMEOUT_UPDATE	(1U << 4)
+#define IORING_TIMEOUT_ETIME_SUCCESS	(1U << 5)
 #define IORING_TIMEOUT_CLOCK_MASK	(IORING_TIMEOUT_BOOTTIME | IORING_TIMEOUT_REALTIME)
 #define IORING_TIMEOUT_UPDATE_MASK	(IORING_TIMEOUT_UPDATE | IORING_LINK_TIMEOUT_UPDATE)
 /*
diff --git a/test/timeout.c b/test/timeout.c
index 775063f..f8ba973 100644
--- a/test/timeout.c
+++ b/test/timeout.c
@@ -1267,6 +1267,67 @@
 	return 0;
 }
 
+
+static int test_not_failing_links(void)
+{
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct __kernel_timespec ts;
+	int ret;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+
+	msec_to_ts(&ts, 1);
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_timeout(sqe, &ts, 0, IORING_TIMEOUT_ETIME_SUCCESS);
+	sqe->user_data = 1;
+	sqe->flags |= IOSQE_IO_LINK;
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "%s: sqe submit failed: %d\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "%s: wait completion %d\n", __FUNCTION__, ret);
+		return 1;
+	} else if (cqe->user_data == 1 && cqe->res == -EINVAL) {
+		fprintf(stderr, "ETIME_SUCCESS is not supported, skip\n");
+		goto done;
+	} else if (cqe->res != -ETIME || cqe->user_data != 1) {
+		fprintf(stderr, "timeout failed %i %i\n", cqe->res,
+				(int)cqe->user_data);
+		return 1;
+	}
+	io_uring_cqe_seen(&ring, cqe);
+
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "%s: wait completion %d\n", __FUNCTION__, ret);
+		return 1;
+	} else if (cqe->res || cqe->user_data != 2) {
+		fprintf(stderr, "nop failed %i %i\n", cqe->res,
+				(int)cqe->user_data);
+		return 1;
+	}
+done:
+	io_uring_cqe_seen(&ring, cqe);
+	io_uring_queue_exit(&ring);
+	return 0;
+}
+
+
 int main(int argc, char *argv[])
 {
 	struct io_uring ring, sqpoll_ring;
@@ -1450,6 +1511,12 @@
 		return ret;
 	}
 
+	ret = test_not_failing_links();
+	if (ret) {
+		fprintf(stderr, "test_not_failing_links failed\n");
+		return ret;
+	}
+
 	if (sqpoll)
 		io_uring_queue_exit(&sqpoll_ring);
 	return 0;