Re: [PATCH 09/10] vfio: ccw: Suppressing the BOXED state

[Pierre Morel]

On 30/04/2018 17:47, Cornelia Huck wrote:
> On Wed, 25 Apr 2018 15:55:51 +0200
> Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On 25/04/2018 10:44, Cornelia Huck wrote:
> > > On Thu, 19 Apr 2018 16:48:12 +0200
> > > Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx> wrote:
> > >   
> > > > VFIO_CCW_STATE_BOXED and VFIO_CCW_STATE_BUSY are the same
> > > > states.
> > > > Let's only keep one: VFIO_CCW_STATE_BUSY
> > > >
> > > > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/s390/cio/vfio_ccw_fsm.c     | 9 ---------
> > > >    drivers/s390/cio/vfio_ccw_private.h | 1 -
> > > >    2 files changed, 10 deletions(-)
> > > I think they were initially supposed to cover two different things:
> > > - BUSY: we're currently dealing with an I/O request
> > > - BOXED: the device currently won't talk to us or we won't talk to it
> > >
> > > It seems we never really did anything useful with BOXED; but should we?
> > >   
> > I do not know what.
> The BUSY state is something we know that we'll get out of soon-ish
> (when the I/O request has finished). We could conceivably use a timeout
> and drop to the BOXED state if we don't get an answer.

Absolutely, timeout on requests is something I wanted to do in a second 
series.

> I think this plays also into the reserve/release and path handling
> questions. One of the more common reasons for devices to become boxed
> I've seen is another system doing a reserve on a dasd.

--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany