Re: [PATCHv6] io_uring: add support for IORING_SETUP_SQE_MIXED

[Keith Busch <kbusch@kernel.org>]

On Wed, Oct 22, 2025 at 07:34:22AM -0600, Jens Axboe wrote:
> On 10/22/25 6:00 AM, Nathan Chancellor wrote:
> > On Tue, Oct 21, 2025 at 04:02:28PM -0600, Jens Axboe wrote:
> >>
> >> On Thu, 16 Oct 2025 11:09:38 -0700, Keith Busch wrote:
> >>> Normal rings support 64b SQEs for posting submissions, while certain
> >>> features require the ring to be configured with IORING_SETUP_SQE128, as
> >>> they need to convey more information per submission. This, in turn,
> >>> makes ALL the SQEs be 128b in size. This is somewhat wasteful and
> >>> inefficient, particularly when only certain SQEs need to be of the
> >>> bigger variant.
> >>>
> >>> [...]
> >>
> >> Applied, thanks!
> >>
> >> [1/1] io_uring: add support for IORING_SETUP_SQE_MIXED
> >>       commit: 31dc41afdef21f264364288a30013b538c46152e
> > 
> > This needs a pretty obvious fix up as clang points out:
> > 
> >   io_uring/fdinfo.c:103:22: error: variable 'sqe' is uninitialized when used here [-Werror,-Wuninitialized]
> >     103 |                 opcode = READ_ONCE(sqe->opcode);
> >         |                                    ^~~
> > 
> > I would have sent a formal patch but since it is at the top, I figured
> > it would get squashed anyways.
> 
> Indeed - I'll fold this in. Keith, can you add an fdinfo test case for
> mixed as well?

Thanks, and will do. Any quick hints on how to ensure fdinfo finds some
entries to report? I assume I can just put some entries on the queue,
but don't call io_uring_enter.