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Subject[PATCH v3 2/8] vfio: ccw: Transform FSM functions to return state
Date
We change the FSM functions to return the next state,
and adapt the fsm_func_t function type.

Doing this change will allow to move the state changes out
of the action functions to a common point.
This is important to guaranty the coherency of the FSM
and add to readibility.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 2 --
drivers/s390/cio/vfio_ccw_fsm.c | 26 ++++++++++++++++----------
drivers/s390/cio/vfio_ccw_private.h | 5 +++--
3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 57ae1ab..095a2d9 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;
}

/*
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 24e1e04..1a0585f 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -65,7 +65,7 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
return ret;
}

-static void fsm_notoper(struct vfio_ccw_private *private,
+static int fsm_notoper(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = private->sch;
@@ -75,31 +75,34 @@ static void fsm_notoper(struct vfio_ccw_private *private,
* Probably we should send the machine check to the guest.
*/
css_sched_sch_todo(sch, SCH_TODO_UNREG);
- private->state = VFIO_CCW_STATE_NOT_OPER;
+ return VFIO_CCW_STATE_NOT_OPER;
}

/*
* No operation action.
*/
-static void fsm_nop(struct vfio_ccw_private *private,
+static int fsm_nop(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
+ return private->state;
}

-static void fsm_io_error(struct vfio_ccw_private *private,
+static int fsm_io_error(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state);
private->io_region.ret_code = -EIO;
+ return private->state;
}

-static void fsm_io_busy(struct vfio_ccw_private *private,
+static int fsm_io_busy(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
private->io_region.ret_code = -EBUSY;
+ return private->state;
}

-static void fsm_disabled_irq(struct vfio_ccw_private *private,
+static int fsm_disabled_irq(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct subchannel *sch = private->sch;
@@ -109,12 +112,13 @@ static void fsm_disabled_irq(struct vfio_ccw_private *private,
* successful - should not happen, but we try to disable again.
*/
cio_disable_subchannel(sch);
+ return private->state;
}

/*
* Deal with the ccw command request from the userspace.
*/
-static void fsm_io_request(struct vfio_ccw_private *private,
+static int fsm_io_request(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
union orb *orb;
@@ -151,7 +155,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
cp_free(&private->cp);
goto err_out;
}
- return;
+ return private->state;
} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
/* XXX: Handle halt. */
io_region->ret_code = -EOPNOTSUPP;
@@ -163,13 +167,13 @@ static void fsm_io_request(struct vfio_ccw_private *private,
}

err_out:
- private->state = VFIO_CCW_STATE_IDLE;
+ return VFIO_CCW_STATE_IDLE;
}

/*
* Got an interrupt for a normal io (state busy).
*/
-static void fsm_irq(struct vfio_ccw_private *private,
+static int fsm_irq(struct vfio_ccw_private *private,
enum vfio_ccw_event event)
{
struct irb *irb = &private->irb;
@@ -182,6 +186,8 @@ static void fsm_irq(struct vfio_ccw_private *private,

if (private->io_trigger)
eventfd_signal(private->io_trigger, 1);
+
+ return VFIO_CCW_STATE_IDLE;
}

/*
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 78a66d9..f526b18 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -83,13 +83,14 @@ enum vfio_ccw_event {
/*
* Action called through jumptable.
*/
-typedef void (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event);
+typedef int (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event);
extern fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS];

static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private,
int event)
{
- vfio_ccw_jumptable[private->state][event](private, event);
+ private->state = vfio_ccw_jumptable[private->state][event](private,
+ event);
}

extern struct workqueue_struct *vfio_ccw_work_q;
--
2.7.4
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