On 24/04/2018 09:25, Dong Jia Shi wrote:
* Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx> [2018-04-19 16:48:05 +0200]:
We change the FSM functions to return the next state,
and adapt the fsm_func_t function type.
I think I'd need to read the rest patches to understand why we need this
one, but no hurt to write some ideas that I noticed at my first glance.
See below please.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_fsm.c | 24 ++++++++++++++++--------
drivers/s390/cio/vfio_ccw_private.h | 5 +++--
2 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index af88551..2f3108d 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -60,7 +60,7 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
}
}
-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;
@@ -71,30 +71,34 @@ static void fsm_notoper(struct vfio_ccw_private *private,
*/
css_sched_sch_todo(sch, SCH_TODO_UNREG);
private->state = VFIO_CCW_STATE_NOT_OPER;
Here..
+ return private->state;
}
/*
* 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;
@@ -104,12 +108,13 @@ 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;
@@ -141,7 +146,7 @@ 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;
@@ -154,12 +159,13 @@ static void fsm_io_request(struct vfio_ccw_private *private,
err_out:
private->state = VFIO_CCW_STATE_IDLE;
Here..
+ return private->state;
}
/*
* 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;
@@ -172,6 +178,8 @@ static void fsm_irq(struct vfio_ccw_private *private,
if (private->io_trigger)
eventfd_signal(private->io_trigger, 1);
+
+ return private->state;
}
/*
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);
Since here it assigns new value to private->state, there is no need to
do that inside each fsm_func?
Absolutely.
I just kept the previous code, just adding the return private->state in
the functions
in this patch.
merging the state and the return value is done in a later patch.
If you prefer I can do it in this patch.
}
extern struct workqueue_struct *vfio_ccw_work_q;
--
2.7.4
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
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