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Subject[PATCH v3 3/8] vfio: ccw: new VFIO_CCW_EVENT_SCHIB_CHANGED event
Date
From: Pierre Morel <pmorel@linux.vnet.ibm.com>

The Sub channel event callback is threaded using workqueues.
The work uses the FSM introducing the VFIO_CCW_EVENT_SCHIB_CHANGED
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, 38 insertions(+), 21 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 095a2d9..e5a516a 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -75,6 +75,14 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
}

+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_SCHIB_CHANGED);
+}
+
/*
* Css driver callbacks
*/
@@ -122,6 +130,7 @@ 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;

@@ -168,28 +177,10 @@ 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);
+ if (work_pending(&private->event_work))
+ return -EAGAIN;
+ 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 1a0585f..94bf151 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -191,6 +191,24 @@ 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] = {
@@ -198,25 +216,30 @@ 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_SCHIB_CHANGED] = 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_SCHIB_CHANGED] = 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_SCHIB_CHANGED] = 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_SCHIB_CHANGED] = 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_SCHIB_CHANGED] = fsm_sch_event,
},
};
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index f526b18..a2be0c9 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_SCHIB_CHANGED,
/* last element! */
NR_VFIO_CCW_EVENTS
};
--
2.7.4
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