Messages in this thread | | | Subject | Re: [PATCH v2 06/10] vfio: ccw: Make FSM functions atomic | From | Pierre Morel <> | Date | Tue, 5 Jun 2018 15:10:11 +0200 |
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On 05/06/2018 13:38, Cornelia Huck wrote: > On Fri, 25 May 2018 12:21:14 +0200 > Pierre Morel <pmorel@linux.vnet.ibm.com> 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
> >> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com> >> --- >> 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.
> >> } >> >> static void vfio_ccw_sch_event_todo(struct work_struct *work)
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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