From: Jens Axboe <axboe@kernel.dk>
To: "Stefan Bühler" <source@stbuehler.de>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: io_uring: not good enough for release
Date: Tue, 23 Apr 2019 16:07:53 -0600 [thread overview]
Message-ID: <bc077192-56cc-7497-ee43-6a0bcc369d16@kernel.dk> (raw)
In-Reply-To: <37071226-375a-07a6-d3d3-21323145de71@kernel.dk>
On 4/23/19 2:31 PM, Jens Axboe wrote:
>> 1. An error for a submission should be returned as completion for that
>> submission. Please don't break my main event loop with strange error
>> codes just because a single operation is broken/not supported/...
>
> So that's the case I was referring to above. We can just make that change,
> there's absolutely no reason to have errors passed back through a different
> channel.
Thinking about this a bit more, and I think the current approach is the
best one. The issue is that only submission side events tied to an sqe
can return an cqe, the rest have to be returned through the system call
value. So I think it's cleaner to keep it as-is, honestly.
>> (Also RWF_NOWAIT doesn't work in io_uring right now: IOCB_NOWAIT is
>> always removed in the workqueue context, and I don't see an early EAGAIN
>> completion).
>
> That's a case I didn't consider, that you'd want to see EAGAIN after
> it's been punted. Once punted, we're not going to return EAGAIN since
> we can now block. Not sure how you'd want to handle that any better...
I think I grok this one too now - what you're saying is that if the
caller has RWF_NOWAIT set, then the EAGAIN should be returned instead of
being punted to the workqueue? I totally agree with that, that's a bug.
--
Jens Axboe
next prev parent reply other threads:[~2019-04-23 22:07 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-23 19:06 io_uring: not good enough for release Stefan Bühler
2019-04-23 20:31 ` Jens Axboe
2019-04-23 22:07 ` Jens Axboe [this message]
2019-04-24 16:09 ` Jens Axboe
2019-04-27 16:05 ` io_uring: RWF_NOWAIT support Stefan Bühler
2019-04-27 18:34 ` [PATCH v1 1/1] [io_uring] fix handling SQEs requesting NOWAIT Stefan Bühler
2019-04-30 15:40 ` Jens Axboe
2019-04-27 15:50 ` io_uring: submission error handling Stefan Bühler
2019-04-30 16:02 ` Jens Axboe
2019-04-30 16:15 ` Jens Axboe
2019-04-30 18:15 ` Stefan Bühler
2019-04-30 18:42 ` Jens Axboe
2019-05-01 11:49 ` [PATCH v1 1/1] [io_uring] don't stall on submission errors Stefan Bühler
2019-05-01 12:43 ` Jens Axboe
2019-04-27 21:07 ` io_uring: closing / release Stefan Bühler
2019-05-11 16:26 ` Stefan Bühler
2019-04-28 15:54 ` io_uring: O_NONBLOCK/IOCB_NOWAIT/RWF_NOWAIT mess Stefan Bühler
2019-05-11 16:34 ` Stefan Bühler
2019-05-11 16:57 ` [PATCH 1/5] fs: RWF flags override default IOCB flags from file flags Stefan Bühler
2019-05-11 16:57 ` [PATCH 2/5] tcp: handle SPLICE_F_NONBLOCK in tcp_splice_read Stefan Bühler
2019-05-11 16:57 ` [PATCH 3/5] pipe: use IOCB_NOWAIT instead of O_NONBLOCK Stefan Bühler
2019-05-11 16:57 ` [PATCH 4/5] socket: " Stefan Bühler
2019-05-11 16:57 ` [PATCH 5/5] io_uring: use FMODE_NOWAIT to detect files supporting IOCB_NOWAIT Stefan Bühler
2019-05-03 9:47 ` [PATCH 1/2] io_uring: restructure io_{read,write} control flow Stefan Bühler
2019-05-03 9:47 ` [PATCH 2/2] io_uring: punt to workers if file doesn't support async Stefan Bühler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bc077192-56cc-7497-ee43-6a0bcc369d16@kernel.dk \
--to=axboe@kernel.dk \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=source@stbuehler.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.