Re: [PATCH v6 2/3] vfio-ccw: Reset FSM state to IDLE inside FSM

Matthew Rosato
2021-05-11T20:38:54Z

On 5/11/21 3:56 PM, Eric Farman wrote:
> When an I/O request is made, the fsm_io_request() routine
> moves the FSM state from IDLE to CP_PROCESSING, and then
> fsm_io_helper() moves it to CP_PENDING if the START SUBCHANNEL
> received a cc0. Yet, the error case to go from CP_PROCESSING
> back to IDLE is done after the FSM call returns.
>
> Let's move this up into the FSM proper, to provide some
> better symmetry when unwinding in this case.
>
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Acked-by: Matthew Rosato <mjrosato@linux.ibm.com>

> ---
> drivers/s390/cio/vfio_ccw_fsm.c | 1 +
> drivers/s390/cio/vfio_ccw_ops.c | 2 --
> 2 files changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
> index 23e61aa638e4..e435a9cd92da 100644
> --- a/drivers/s390/cio/vfio_ccw_fsm.c
> +++ b/drivers/s390/cio/vfio_ccw_fsm.c
> @@ -318,6 +318,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
> }
>
> err_out:
> + private->state = VFIO_CCW_STATE_IDLE;
> trace_vfio_ccw_fsm_io_request(scsw->cmd.fctl, schid,
> io_region->ret_code, errstr);
> }
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index 767ac41686fe..5971641964c6 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -276,8 +276,6 @@ static ssize_t vfio_ccw_mdev_write_io_region(struct vfio_ccw_private *private,
> }
>
> vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_IO_REQ);
> - if (region->ret_code != 0)
> - private->state = VFIO_CCW_STATE_IDLE;
> ret = (region->ret_code != 0) ? region->ret_code : count;
>
> out_unlock:
>