Re: [virtio] Re: [virtio-comment] Re: [PATCH v10 03/10] admin: introduce group administration commands

[Cornelia Huck <cohuck@redhat.com>]

On Mon, Feb 13 2023, "Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, Feb 13, 2023 at 02:13:43PM +0100, Cornelia Huck wrote:
>> On Mon, Feb 13 2023, Max Gurtovoy <mgurtovoy@nvidia.com> wrote:
>> 
>> > On 13/02/2023 14:42, Cornelia Huck wrote:
>> >> On Mon, Feb 13 2023, Max Gurtovoy <mgurtovoy@nvidia.com> wrote:
>> >> 
>> >>> On 13/02/2023 10:16, Michael S. Tsirkin wrote:
>> >>>> On Mon, Feb 13, 2023 at 02:54:47AM +0200, Max Gurtovoy wrote:
>> >>>>>> For some system calls and library functions (e.g.,
>> >>>>>>           getpriority(2)), -1 is a valid return on success.  In such cases,
>> >>>>>>           a successful return can be distinguished from an error return by
>> >>>>>>           setting errno to zero before the call, and then, if the call
>> >>>>>>           returns a status that indicates that an error may have occurred,
>> >>>>>>           checking to see if errno has a nonzero value.
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>> Description is already good enough to describe what they are.
>> >>>>>>> Can we please drop Linux wording?
>> >>>>>>
>> >>>>>> But why should we? It's where 22 comes from so this way people are not
>> >>>>>> wondering about the value, and it's somewhat helpful for Linux
>> >>>>>> developers.
>> >>>>>>
>> >>>>>
>> >>>>> I also think we should not mention Linux. I don't think it's mentioned
>> >>>>> currently in the spec and no good reason to do so now.
>> >>>>
>> >>>> But we do: fuse, input at least both do.
>> >>>>
>> >>>>> Also value of 22 is not mandatory for this EINVAL status code. It can be
>> >>>>> just 1 (the first number after the OK status).
>> >>>>
>> >>>> 22 makes it a tiny bit easier for kvm. So why not.
>> >>>
>> >>> Because people comment on that in the review :) and because a
>> >>> specification should be OS independent.
>> >>> 22 might be EINVAL in Linux but a success in MyOS is my lucky number is 22.
>> >>>
>> >>> not a big issue for me, but I prefer to have a cleaner spec than maybe
>> >>> simplify something in a very specific OS.
>> >> 
>> >> Well, my take is:
>> >> - we have to pick *something*
>> >> - using EINVAL == 22 is very convenient for one of the most common (the
>> >>    most common?) implementors
>> >> - noting that we're trying to follow what Linux uses makes it clear what
>> >>    to pick for any new return codes
>> >> 
>> >
>> > Can we agree on 22 without mentioning Linux ?
>> 
>> See my third point above: we want people to be aware why we chose 22, so
>> any new values will match up as well.
>
> In fact I think it is a good idea to
> 1. actually link to where one can see EINVAL=22 so people know where to find
>    more values
> 2. ask driver to handle any other error same as EINVAL for now - we don't want
>    new feature bits if all we do down the road is add more error codes.
>
> I'll add this in the next version.

Wfm.