[RFC PATCH v2 4/4] vfio-ccw: Clean up how to react to a failed START

Eric Farman
2020-05-13T14:29:42Z

This is a fixup to the previous commits, and should be merged
as such. It's just left out to show that vfio-ccw needs to tell
the difference between getting a CC2 from a SSCH instruction,
and creating a CC2 because there's another (probably asynchronous)
command still outstanding. Without it, the FSM state would be reset
to IDLE and things would be no better than before.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_fsm.c | 6 +++++-
drivers/s390/cio/vfio_ccw_ops.c | 5 +----
2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index d8075a56eb9b..7d1c7031079c 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -264,7 +264,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
schid.ssid, schid.sch_no,
scsw_actl(scsw));
errstr = "pending";
- goto err_out;
+ goto err_out_nochange;
}

private->state = VFIO_CCW_STATE_CP_PROCESSING;
@@ -340,6 +340,10 @@ static void fsm_io_request(struct vfio_ccw_private *private,
}

err_out:
+ private->scsw.cmd.actl &= ~SCSW_ACTL_START_PEND;
+ private->state = VFIO_CCW_STATE_IDLE;
+
+err_out_nochange:
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 d2f9babb751c..d01d7abe6b00 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -269,10 +269,7 @@ 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;
- private->scsw.cmd.actl &= ~SCSW_ACTL_START_PEND;
- }
+
ret = (region->ret_code != 0) ? region->ret_code : count;

out_unlock:
--
2.17.1