Re: [PATCH liburing] Test wait after under-consuming

From: Pavel Begunkov
Date: Fri Dec 13 2019 - 03:41:41 EST


On 12/13/2019 11:06 AM, Pavel Begunkov wrote:
> In case of an error submission won't consume all sqes. This tests that
> it will get back to the userspace even if (to_submit == to_wait)
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> test/link.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/test/link.c b/test/link.c
> index 8ec1649..93653f3 100644
> --- a/test/link.c
> +++ b/test/link.c
> @@ -384,6 +384,55 @@ err:
> return 1;
> }
>
> +static int test_early_fail_and_wait(struct io_uring *ring)
> +{
> + struct io_uring_cqe *cqe;
> + struct io_uring_sqe *sqe;
> + int ret, submitted, i;
> + const int invalid_fd = 42;
> + struct iovec iov = { .iov_base = NULL, .iov_len = 0 };
> +
> + sqe = io_uring_get_sqe(ring);
> + if (!sqe) {
> + printf("get sqe failed\n");
> + goto err;
> + }
> +
> + io_uring_prep_readv(sqe, invalid_fd, &iov, 1, 0);
> + sqe->user_data = 1;
> + sqe->flags |= IOSQE_IO_LINK;
> +
> + sqe = io_uring_get_sqe(ring);
> + if (!sqe) {
> + printf("get sqe failed\n");
> + goto err;
> + }
> +
> + io_uring_prep_nop(sqe);
> + sqe->user_data = 2;
> +
> + submitted = io_uring_submit_and_wait(ring, 2);
> + if (submitted == -EAGAIN)
> + return 0;

As io_uring isn't recreated for each test case, I need to complete all
cqes in any case. I'll resend

> + if (submitted <= 0) {
> + printf("sqe submit failed: %d\n", submitted);
> + goto err;
> + }
> +
> + for (i = 0; i < 2; i++) {
> + ret = io_uring_wait_cqe(ring, &cqe);
> + if (ret < 0) {
> + printf("wait completion %d\n", ret);
> + goto err;
> + }
> + io_uring_cqe_seen(ring, cqe);
> + }
> +
> + return 0;
> +err:
> + return 1;
> +}
> +
> int main(int argc, char *argv[])
> {
> struct io_uring ring, poll_ring;
> @@ -400,7 +449,6 @@ int main(int argc, char *argv[])
> if (ret) {
> printf("poll_ring setup failed\n");
> return 1;
> -
> }
>
> ret = test_single_link(&ring);
> @@ -439,5 +487,11 @@ int main(int argc, char *argv[])
> return ret;
> }
>
> + ret = test_early_fail_and_wait(&ring);
> + if (ret) {
> + fprintf(stderr, "test_early_fail_and_wait\n");
> + return ret;
> + }
> +
> return 0;
> }
>

--
Pavel Begunkov