On Thu, 24 Jan 2019 11:08:02 +0100 Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > On 23/01/2019 11:21, Cornelia Huck wrote: > > 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? > > > > Yes I postponed this work to not collide with your patch series. > > Do you think I should provide a new version of the FSM reworking series > based on the last comment I got? > > I would take into account that the asynchronous commands will come with > your patch series and only provide the framework changes. This was more an answer to Halil's concerns around state synchronization. I would prefer to first get this series (or a variation) into decent shape, and then address state machine handling on top of that (when we know more about the transitions involved), just to avoid confusion. Does that sound reasonable?