From: Stefano Garzarella <sgarzare@redhat.com>
To: David Laight <David.Laight@aculab.com>, Jakub Kicinski <kuba@kernel.org>
Cc: Colin King <colin.king@canonical.com>,
"David S . Miller" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"kernel-janitors@vger.kernel.org"
<kernel-janitors@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] vsock: ratelimit unknown ioctl error message
Date: Mon, 26 Oct 2020 11:01:12 +0100 [thread overview]
Message-ID: <20201026100112.qaorff6c6vucakyg@steredhat> (raw)
In-Reply-To: <3e34e4121f794355891fd7577c9dfbc0@AcuMS.aculab.com>
On Mon, Oct 26, 2020 at 09:46:17AM +0000, David Laight wrote:
>From: Stefano Garzarella
>> Sent: 26 October 2020 09:39
>>
>> On Mon, Oct 26, 2020 at 09:13:23AM +0000, David Laight wrote:
>> >From: Stefano Garzarella
>> >> Sent: 26 October 2020 08:43
>> >...
>> >> >Isn't the canonical error for unknown ioctl codes -ENOTTY?
>> >> >
>> >>
>> >> Oh, thanks for pointing that out!
>> >>
>> >> I had not paid attention to the error returned, but looking at it I
>> >> noticed that perhaps the most appropriate would be -ENOIOCTLCMD.
>> >> In the ioctl syscall we return -ENOTTY, if the callback returns
>> >> -ENOIOCTLCMD.
>> >>
>> >> What do you think?
>> >
>> >It is 729 v 443 in favour of ENOTTY (based on grep).
>>
>> Under net/ it is 6 vs 83 in favour of ENOIOCTLCMD.
>>
>> >
>> >No idea where ENOIOCTLCMD comes from, but ENOTTY probably
>> >goes back to the early 1970s.
>>
>> Me too.
>>
>> >
>> >The fact that the ioctl wrapper converts the value is a good
>> >hint that userspace expects ENOTTY.
>>
>> Agree on that, but since we are not interfacing directly with userspace,
>> I think it is better to return the more specific error (ENOIOCTLCMD).
>
>I bet Linux thought it could use a different error code then
>found that 'unknown ioctl' was spelt ENOTTY.
It could be :-)
Anyway, as you pointed out, I think we should change the -EINVAL with
-ENOTTY or -ENOIOCTLCMD.
@Jakub what do you suggest?
Thanks,
Stefano
next prev parent reply other threads:[~2020-10-26 10:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 12:21 [PATCH] vsock: ratelimit unknown ioctl error message Colin King
2020-10-23 14:09 ` Stefano Garzarella
2020-10-23 20:25 ` Jakub Kicinski
2020-10-23 21:30 ` David Laight
2020-10-26 8:43 ` Stefano Garzarella
2020-10-26 9:13 ` David Laight
2020-10-26 9:39 ` Stefano Garzarella
2020-10-26 9:46 ` David Laight
2020-10-26 10:01 ` Stefano Garzarella [this message]
2020-10-26 17:55 ` Jakub Kicinski
2020-10-26 18:24 ` Stefano Garzarella
2020-10-26 18:37 ` Jakub Kicinski
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