On Tue, 22 Jan 2019 19:33:46 +0100
Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> On Mon, 21 Jan 2019 12:03:51 +0100
> Cornelia Huck <cohuck@xxxxxxxxxx> wrote:
>
> > --- a/drivers/s390/cio/vfio_ccw_private.h
> > +++ b/drivers/s390/cio/vfio_ccw_private.h
> > @@ -28,6 +28,7 @@
> > * @mdev: pointer to the mediated device
> > * @nb: notifier for vfio events
> > * @io_region: MMIO region to input/output I/O arguments/results
> > + * @io_mutex: protect against concurrent update of I/O structures
>
> We could be a bit more specific about what does this mutex guard.
> Is it only io_region, or cp, irb and the new regions a well? ->state does
> not seem to be covered, but should need some sort of synchronisation
> too, or?
I'm not sure. IIRC Pierre had some ideas about locking in the fsm?
>
> > * @cp: channel program for the current I/O operation
> > * @irb: irb info received from interrupt
> > * @scsw: scsw info
> > @@ -42,6 +43,7 @@ struct vfio_ccw_private {
> > struct mdev_device *mdev;
> > struct notifier_block nb;
> > struct ccw_io_region *io_region;
> > + struct mutex io_mutex;
> >
> > struct channel_program cp;
> > struct irb irb;
> > --
>
