[PATCH v4 0/5] io_uring passthrough for nvme

[Jens Axboe]

On 5/6/22 12:42 AM, Kanchan Joshi wrote:
> On Thu, May 05, 2022 at 12:29:27PM -0600, Jens Axboe wrote:
>> On 5/5/22 12:20 PM, Jens Axboe wrote:
>>> On 5/5/22 12:06 AM, Kanchan Joshi wrote:
>>>> This iteration is against io_uring-big-sqe brach (linux-block).
>>>> On top of a739b2354 ("io_uring: enable CQE32").
>>>>
>>>> fio testing branch:
>>>> https://protect2.fireeye.com/v1/url?k=b0d23f72-d1592a52-b0d3b43d-74fe485fb347-02541f801e3b5f5f&q=1&e=ef4bb07a-7707-4854-819c-98abcabb5d2d&u=https%3A%2F%2Fgithub.com%2Fjoshkan%2Ffio%2Ftree%2Fbig-cqe-pt.v4
>>>
>>> I folded in the suggested changes, the branch is here:
>>>
>>> https://protect2.fireeye.com/v1/url?k=40e9c3d0-2162d6f0-40e8489f-74fe485fb347-f8e801be1f796980&q=1&e=ef4bb07a-7707-4854-819c-98abcabb5d2d&u=https%3A%2F%2Fgit.kernel.dk%2Fcgit%2Flinux-block%2Flog%2F%3Fh%3Dfor-5.19%2Fio_uring-passthrough
>>>
>>> I'll try and run the fio test branch, but please take a look and see what
>>> you think.
>>
>> Tested that fio branch and it works for me with what I had pushed out.
>> Also tested explicit deferral of requests.
> 
> Thanks for sorting everything out! I could test this out now only :-(
> Fio scripts ran fine (post refreshing SQE128/CQE32 flag values;repushed fio).
> 
> I think these two changes are needed in your branch:
> 
> 1. since uring-cmd can be without large-cqe, we need to add that
> condition in io_uring_cmd_done(). This change in patch 1 -
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 884f40f51536..c24469564ebc 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -4938,7 +4938,10 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2)
> 
>        if (ret < 0)
>                req_set_fail(req);
> -       __io_req_complete32(req, 0, ret, 0, res2, 0);
> +       if (req->ctx->flags & IORING_SETUP_CQE32)
> +               __io_req_complete32(req, 0, ret, 0, res2, 0);
> +       else
> +               io_req_complete(req, ret);
> }
> EXPORT_SYMBOL_GPL(io_uring_cmd_done);

Ah yes, good catch, I missed that it's cqe32 exclusive right now.

> 2. In the commit-message of patch 1, we should delete last line.
> i.e.
> "This operation can be issued only on the ring that is
> setup with both IORING_SETUP_SQE128 and IORING_SETUP_CQE32 flags."
> 
> And/or we can move this commit-message of patch 4.

I killed the line.

> You can either take these changes in, or I can respin the series. LMK.

I folded it in and will process Christoph's suggestions.

-- 
Jens Axboe