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

[Stefan Hajnoczi <stefanha@redhat.com>]

On Thu, Mar 02, 2023 at 07:01:56PM -0500, Michael S. Tsirkin wrote:
> On Thu, Mar 02, 2023 at 03:19:12PM -0500, Stefan Hajnoczi wrote:
> > On Thu, Mar 02, 2023 at 06:40:29PM +0000, Parav Pandit wrote:
> > > 
> > > > From: Michael S. Tsirkin <mst@redhat.com>
> > > > Sent: Thursday, March 2, 2023 8:05 AM
> > > 
> > > > +When \field{status} is VIRTIO_ADMIN_STATUS_OK, \field{status_qialifier}
> > > > +is reserved and set to zero by the device.
> > > > +
> > > s/status_qialifier/status_qualifier
> > > Missed from v10 of Feb.
> > > 
> > > > +When \field{status} is VIRTIO_ADMIN_STATUS_EINVAL, the following table
> > > > +describes possible \field{status_qialifier} values:
> > > s/status_qialifier/status_qualifier
> > > 
> > > Can you please add other useful error codes in addition to the EINVAL?
> > > Few that we are needed EAGAIN, ENOMEM, EBUSY, ENODEV.
> > 
> > Please define a unique constant for each error condition that can occur
> > instead of sharing catch-all errno constants between multiple error
> > conditions. If a driver wants to squash them together into an errno,
> > that's fine, but I think doing this at the hardware interface level is
> > just propagating the mistakes of errnos.
> > 
> > Only status_qualifier is needed and the vague status field can be
> > dropped. It's not clear to me why adding EAGAIN, ENOMEM, EBUSY, and
> > ENODEV is useful. They have no meaning to the driver, only the
> > status_qualifier really indicates what is going on.
> 
> At a high level at the moment we have only two cases:
> - ok
> - invalid input supplied by driver
> 
> maybe we will have more reasons for a failure - remains to
> be seen.
> 
> 
> 
> 
> 
> > 
> > I'm sure you guys have discussed this previously, but please provide
> > rationale in the spec because it looks weird to someone with fresh eyes.
> > 
> > Stefan
> 
> Really most drivers just want to propagate errno to userspace.
> All the detailed reporting is for sure well intentional but
> in the end it is at best printed into log - end to end
> people just end up with a switch statement
> converting these to errno codes.
> So we are passing them from device and this way there will be
> some uniformity.

Please clarify the rationale in the spec. I don't agree with it, as
explained in my earlier email, but as long as its documented, people can
try to follow it.

Stefan

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