[PATCH 03/10] vfio: ccw: new SCH_EVENT event

Pierre Morel
2018-04-19T14:48:06Z

The Sub channel event callback is threaded using workqueues.
The work uses the FSM introducing the VFIO_CCW_EVENT_SCH_EVENT
event.
The update of the SCHIB is now done inside the FSM function.

Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 33 +++++++++++++--------------------
drivers/s390/cio/vfio_ccw_fsm.c | 23 +++++++++++++++++++++++
drivers/s390/cio/vfio_ccw_private.h | 3 +++
3 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index f1b158c..8a91eee 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -77,6 +77,15 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
private->state = VFIO_CCW_STATE_IDLE;
}

+static void vfio_ccw_sch_event_todo(struct work_struct *work)
+{
+ struct vfio_ccw_private *private;
+
+ private = container_of(work, struct vfio_ccw_private, event_work);
+ vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_SCH_EVENT);
+}
+
+
/*
* Css driver callbacks
*/
@@ -125,6 +134,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
goto out_disable;

INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
+ INIT_WORK(&private->event_work, vfio_ccw_sch_event_todo);
atomic_set(&private->avail, 1);
private->state = VFIO_CCW_STATE_STANDBY;

@@ -171,28 +181,11 @@ static void vfio_ccw_sch_shutdown(struct subchannel *sch)
static int vfio_ccw_sch_event(struct subchannel *sch, int process)
{
struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
- unsigned long flags;

- spin_lock_irqsave(sch->lock, flags);
if (!device_is_registered(&sch->dev))
- goto out_unlock;
-
- if (work_pending(&sch->todo_work))
- goto out_unlock;
-
- if (cio_update_schib(sch)) {
- vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
- goto out_unlock;
- }
-
- private = dev_get_drvdata(&sch->dev);
- if (private->state == VFIO_CCW_STATE_NOT_OPER) {
- private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
- VFIO_CCW_STATE_STANDBY;
- }
-
-out_unlock:
- spin_unlock_irqrestore(sch->lock, flags);
+ return -1;
+ WARN_ON(work_pending(&private->event_work));
+ queue_work(vfio_ccw_work_q, &private->event_work);

return 0;
}
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 2f3108d..13751b4 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -183,6 +183,24 @@ static int fsm_irq(struct vfio_ccw_private *private,
}

/*
+ * Got a sub-channel event .
+ */
+static int fsm_sch_event(struct vfio_ccw_private *private,
+ enum vfio_ccw_event event)
+{
+ unsigned long flags;
+ int ret = private->state;
+ struct subchannel *sch = private->sch;
+
+ spin_lock_irqsave(sch->lock, flags);
+ if (cio_update_schib(sch))
+ ret = VFIO_CCW_STATE_NOT_OPER;
+ spin_unlock_irqrestore(sch->lock, flags);
+
+ return ret;
+}
+
+/*
* Device statemachine
*/
fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
@@ -190,25 +208,30 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_nop,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_disabled_irq,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_nop,
},
[VFIO_CCW_STATE_STANDBY] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_error,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
},
[VFIO_CCW_STATE_IDLE] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_request,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
},
[VFIO_CCW_STATE_BOXED] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
},
[VFIO_CCW_STATE_BUSY] = {
[VFIO_CCW_EVENT_NOT_OPER] = fsm_notoper,
[VFIO_CCW_EVENT_IO_REQ] = fsm_io_busy,
[VFIO_CCW_EVENT_INTERRUPT] = fsm_irq,
+ [VFIO_CCW_EVENT_SCH_EVENT] = fsm_sch_event,
},
};
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index f526b18..3284e64 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -33,6 +33,7 @@
* @scsw: scsw info
* @io_trigger: eventfd ctx for signaling userspace I/O results
* @io_work: work for deferral process of I/O handling
+ * @event_work: work for deferral process of sub-channel event
*/
struct vfio_ccw_private {
struct subchannel *sch;
@@ -49,6 +50,7 @@ struct vfio_ccw_private {

struct eventfd_ctx *io_trigger;
struct work_struct io_work;
+ struct work_struct event_work;
} __aligned(8);

extern int vfio_ccw_mdev_reg(struct subchannel *sch);
@@ -76,6 +78,7 @@ enum vfio_ccw_event {
VFIO_CCW_EVENT_NOT_OPER,
VFIO_CCW_EVENT_IO_REQ,
VFIO_CCW_EVENT_INTERRUPT,
+ VFIO_CCW_EVENT_SCH_EVENT,
/* last element! */
NR_VFIO_CCW_EVENTS
};
--
2.7.4