Re: [PATCH liburing] test/io_uring_passthrough: add test for vectored fixed-buffers

[Anuj gupta <anuj1072538@gmail.com>]

> LGTM, it's great to have the test, thanks Anuj. FWIW, that's the
> same way I tested the kernel patch.
>
> Somewhat unrelated questions, is there some particular reason why all
> vectored versions are limited to 1 entry iovec? And why do we even care
> calling io_uring_prep_read/write*() helpers when non of the rw related
> fields set are used by passthrough? i.e. iovec passed in the second half
> of the sqe.

Thanks, Pavel!

Regarding the vectored I/O being limited to 1 iovec — yeah, I kept it
simple initially because the plumbing was easier that way. It’s the same
in test/read-write.c, where vectored calls also use just one iovec. But
I agree, for better coverage, it makes sense to test with multiple
iovecs. I’ll prepare and post a follow-up patch that adds that.

About the use of io_uring_prep_read/write*() helpers — you're right,
they don’t really add much here since the passthrough command handles
the fields directly. I’ll work on a cleanup patch to remove those and
simplify the submission code.

>
> --
> Pavel Begunkov
>