On Tue, 5 Jun 2018 15:10:11 +0200 Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > On 05/06/2018 13:38, Cornelia Huck wrote: > > On Fri, 25 May 2018 12:21:14 +0200 > > Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx> wrote: > > > >> We use mutex around the FSM function call to make the FSM > >> event handling and state change atomic. > > I'm still not really clear as to what this mutex is supposed to > > serialize: > > > > - Modification of the state? > > - Any calls in the state machine? > > - A combination? (That would imply that we only deal with the state in > > the state machine.) > > yes to all But wouldn't that imply that you need to either take the mutex if you do something dependent on the state, or fire an event in that case? > > > > >> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx> > >> --- > >> drivers/s390/cio/vfio_ccw_drv.c | 3 +-- > >> drivers/s390/cio/vfio_ccw_private.h | 3 +++ > >> 2 files changed, 4 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c > >> index 6b7112e..98951d5 100644 > >> --- a/drivers/s390/cio/vfio_ccw_drv.c > >> +++ b/drivers/s390/cio/vfio_ccw_drv.c > >> @@ -73,8 +73,6 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work) > >> > >> private = container_of(work, struct vfio_ccw_private, io_work); > >> vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT); > >> - if (private->mdev) > >> - private->state = VFIO_CCW_STATE_IDLE; > > Looks like an unrelated change? If you want to do all state changes > > under the mutex, that should rather be moved than deleted, shouldn't it? > > It is moved to fsm_irq() which is called under mutex. > fsm_irq() returns VFIO_CCW_STATE_IDLE. So, should that go into another patch? > > > > >> } > >> > >> static void vfio_ccw_sch_event_todo(struct work_struct *work) > >
