Re: [Qemu-devel] [PATCH 1/9] s390x/css: fix cc handling for XSCH

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 31 Aug 2017 07:51:17 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 30.08.2017 18:36, Halil Pasic wrote:
> > The function ioinst_handle_xsch is presenting cc 2 when it's supposed to
> > present cc 1 and the other way around, because css_do_xsch has the error
> > codes mixed up. Fixing the error codes also fixes the priority.
> > 
> > Let us fix this.  
> 
> (Nit: In case you respin, I'd suggest to remove the last sentence. You
> already used "fix" two times in the previous one)

I can also remove it on applying, if Halil agrees (I have not yet
reviewed it, though).

> 
> > Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> > Reported-by: Pierre Morel<pmorel@linux.vnet.ibm.com>  
> 
> Space missing -------------^

And I can also add that space on applying :)

> 
> > ---
> >  hw/s390x/css.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> > index 1880b1a0ff..a50fb0727e 100644
> > --- a/hw/s390x/css.c
> > +++ b/hw/s390x/css.c
> > @@ -1281,12 +1281,12 @@ int css_do_xsch(SubchDev *sch)
> >          (!(s->ctrl &
> >             (SCSW_ACTL_RESUME_PEND | SCSW_ACTL_START_PEND | SCSW_ACTL_SUSP))) ||
> >          (s->ctrl & SCSW_ACTL_SUBCH_ACTIVE)) {
> > -        ret = -EINPROGRESS;
> > +        ret = -EBUSY;
> >          goto out;
> >      }
> >  
> >      if (s->ctrl & SCSW_CTRL_MASK_STCTL) {
> > -        ret = -EBUSY;
> > +        ret = -EINPROGRESS;
> >          goto out;
> >      }  
> 
> Using both, EBUSY and EINPROGRESS as error codes sounds very confusing
> to me here ... what's the difference between busy and in-progress? So
> while you're at it, maybe you could replace the code for CC 2 ("CANCEL
> SUBCHANNEL not applicable") with a different error code?

IIRC, I used these two as they matched my idea of what happens best
(there's a difference between "subchannel is busy" and "the I/O is
already in progress, too late to cancel"). "xsch not applicable" is
very hard to translate to an Unix error code :/

I'll double-check with the PoP.