[PATCH v1 02/18] vfio/ccw: Fix FSM state if mdev probe fails

Eric Farman
2022-06-02T17:20:17Z

The FSM is in STANDBY state when arriving in vfio_ccw_mdev_probe(),
and this routine converts it to IDLE as part of its processing.
The error exit sets it to IDLE (again) but clears the private->mdev
pointer.

The FSM should of course be managing the state itself, but the
correct thing for vfio_ccw_mdev_probe() to do would be to put
the state back the way it found it.

The corresponding check of private->mdev in vfio_ccw_sch_io_todo()
can be removed, since the distinction is unnecessary at this point.

Fixes: 3bf1311f351ef ("vfio/ccw: Convert to use vfio_register_emulated_iommu_dev()")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 2 +-
drivers/s390/cio/vfio_ccw_ops.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 35055eb94115..b18b4582bc8b 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -108,7 +108,7 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
* has finished. Do not overwrite a possible processing
* state if the final interrupt was for HSCH or CSCH.
*/
- if (private->mdev && cp_is_finished)
+ if (cp_is_finished)
private->state = VFIO_CCW_STATE_IDLE;

if (private->io_trigger)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index bebae21228aa..a403d059a4e6 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -146,7 +146,7 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
vfio_uninit_group_dev(&private->vdev);
atomic_inc(&private->avail);
private->mdev = NULL;
- private->state = VFIO_CCW_STATE_IDLE;
+ private->state = VFIO_CCW_STATE_STANDBY;
return ret;
}

--
2.32.0