Add a test for read -> link timeout -> nop where the read completes
with a short pipe read, the link timeout is naturally disarmed with
-ECANCELED, and the linked nop still completes successfully.

Requires the kernel fix for short pipe read completion.

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
---
 test/link-timeout.c | 102 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/test/link-timeout.c b/test/link-timeout.c
index 0e91604f..07856ff3 100644
--- a/test/link-timeout.c
+++ b/test/link-timeout.c
@@ -671,6 +671,103 @@ err:
 	return 1;
 }
 
+/*
+ * Test short pipe read that naturally disarms a link timeout
+ */
+static int test_link_timeout_natural_disarm_chain(struct io_uring *ring)
+{
+	struct __kernel_timespec ts;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int fds[2], ret, i;
+	struct iovec iov;
+	char buffer[128];
+	char byte = 'x';
+
+	if (pipe(fds)) {
+		perror("pipe");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto err;
+	}
+
+	iov.iov_base = buffer;
+	iov.iov_len = sizeof(buffer);
+	io_uring_prep_readv(sqe, fds[0], &iov, 1, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto err;
+	}
+
+	ts.tv_sec = 3600;
+	ts.tv_nsec = 0;
+	io_uring_prep_link_timeout(sqe, &ts, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 2;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto err;
+	}
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 3;
+
+	ret = io_uring_submit(ring);
+	if (ret != 3) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	if (write(fds[1], &byte, 1) != 1) {
+		perror("write");
+		goto err;
+	}
+
+	for (i = 0; i < 3; i++) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret < 0) {
+			printf("wait completion %d\n", ret);
+			goto err;
+		}
+		switch (cqe->user_data) {
+		case 1:
+			if (cqe->res != 1) {
+				fprintf(stderr, "Read got %d, wanted 1\n", cqe->res);
+				goto err;
+			}
+			break;
+		case 2:
+			if (cqe->res != -ECANCELED) {
+				fprintf(stderr, "Link timeout got %d, wanted -ECANCELED\n",
+					cqe->res);
+				goto err;
+			}
+			break;
+		case 3:
+			if (cqe->res) {
+				fprintf(stderr, "Req %" PRIu64 " got %d\n",
+					(uint64_t) cqe->user_data, cqe->res);
+				goto err;
+			}
+			break;
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	return 0;
+err:
+	return 1;
+}
+
 static int test_timeout_link_chain1(struct io_uring *ring)
 {
 	struct __kernel_timespec ts;
@@ -1262,6 +1359,11 @@ int main(int argc, char *argv[])
 		return ret;
 	}
 
+	ret = test_link_timeout_natural_disarm_chain(&ring);
+	if (ret) {
+		printf("test_link_timeout_natural_disarm_chain failed\n");
+		return ret;
+	}
 
 	return T_EXIT_PASS;
 }
-- 
2.25.1