public inbox for [email protected]
 help / color / mirror / Atom feed
From: Stefan Metzmacher <[email protected]>
To: Jens Axboe <[email protected]>, io-uring <[email protected]>
Cc: 李通洲 <[email protected]>
Subject: Re: [PATCH] io_uring: add support for probing opcodes
Date: Thu, 16 Jan 2020 23:35:28 +0100	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>


[-- Attachment #1.1: Type: text/plain, Size: 1312 bytes --]

Am 16.01.20 um 18:23 schrieb Jens Axboe:
> The application currently has no way of knowing if a given opcode is
> supported or not without having to try and issue one and see if we get
> -EINVAL or not. And even this approach is fraught with peril, as maybe
> we're getting -EINVAL due to some fields being missing, or maybe it's
> just not that easy to issue that particular command without doing some
> other leg work in terms of setup first.
> 
> This adds IORING_REGISTER_PROBE, which fills in a structure with info
> on what it supported or not. This will work even with sparse opcode
> fields, which may happen in the future or even today if someone
> backports specific features to older kernels.

That's funny I was just thinking about exactly that topic before
I opened the io-uring mail folder:-)

That's will make it much easier to write a portable
vfs backend for samba that doesn't depend on the kernel
features at build time.

> +	p->last_op = IORING_OP_LAST - 1;
> +	/* stock kernel isn't sparse, so everything is supported */
> +	for (i = 0; i < nr_args; i++) {
> +		p->ops[i].op = i;

Shouldn't there be an if (i <= p->last_op) before we pretent to support
an opcode? Or we need to truncate nr_args

> +		p->ops[i].flags = IO_URING_OP_SUPPORTED;
> +	}

metze



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

  reply	other threads:[~2020-01-16 22:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 17:23 [PATCH] io_uring: add support for probing opcodes Jens Axboe
2020-01-16 22:35 ` Stefan Metzmacher [this message]
2020-01-16 22:36   ` Jens Axboe

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 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox