vfio/ccw: Create a CLOSE FSM event

Refactor the vfio_ccw_sch_quiesce() routine to extract the bit that
disables the subchannel and affects the FSM state. Use this to form
the basis of a CLOSE event that will mirror the OPEN event, and move
the subchannel back to NOT_OPER state.

A key difference with that mirroring is that while OPEN handles the
transition from NOT_OPER => STANDBY, the later probing of the mdev
handles the transition from STANDBY => IDLE. On the other hand,
the CLOSE event will move from one of the operating states {IDLE,
CP_PROCESSING, CP_PENDING} => NOT_OPER. That is, there is no stop
in a STANDBY state on the deconfigure path.

Add a call to cp_free() in this event, such that it is captured for
the various permutations of this event.

In the unlikely event that cio_disable_subchannel() returns -EBUSY,
the remaining logic of vfio_ccw_sch_quiesce() can still be used.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220707135737.720765-10-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 7d91896..f98c991 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -41,13 +41,6 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
        DECLARE_COMPLETION_ONSTACK(completion);
        int iretry, ret = 0;
 
-       spin_lock_irq(sch->lock);
-       if (!sch->schib.pmcw.ena)
-               goto out_unlock;
-       ret = cio_disable_subchannel(sch);
-       if (ret != -EBUSY)
-               goto out_unlock;
-
        iretry = 255;
        do {
 
@@ -74,9 +67,7 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
                spin_lock_irq(sch->lock);
                ret = cio_disable_subchannel(sch);
        } while (ret == -EBUSY);
-out_unlock:
-       private->state = VFIO_CCW_STATE_NOT_OPER;
-       spin_unlock_irq(sch->lock);
+
        return ret;
 }
 
@@ -256,7 +247,7 @@ static void vfio_ccw_sch_remove(struct subchannel *sch)
 {
        struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 
-       vfio_ccw_sch_quiesce(sch);
+       vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
        mdev_unregister_device(&sch->dev);
 
        dev_set_drvdata(&sch->dev, NULL);
@@ -270,7 +261,9 @@ static void vfio_ccw_sch_remove(struct subchannel *sch)
 
 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 {
-       vfio_ccw_sch_quiesce(sch);
+       struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
+
+       vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
 }
 
 /**

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 2811b20..89eb3fe 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -384,6 +384,27 @@ static void fsm_open(struct vfio_ccw_private *private,
        spin_unlock_irq(sch->lock);
 }
 
+static void fsm_close(struct vfio_ccw_private *private,
+                     enum vfio_ccw_event event)
+{
+       struct subchannel *sch = private->sch;
+       int ret;
+
+       spin_lock_irq(sch->lock);
+
+       if (!sch->schib.pmcw.ena)
+               goto out_unlock;
+
+       ret = cio_disable_subchannel(sch);
+       if (ret == -EBUSY)
+               vfio_ccw_sch_quiesce(sch);
+
+out_unlock:
+       private->state = VFIO_CCW_STATE_NOT_OPER;
+       spin_unlock_irq(sch->lock);
+       cp_free(&private->cp);
+}
+
 /*
  * Device statemachine
  */
@@ -394,6 +415,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
                [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_error,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_disabled_irq,
                [VFIO_CCW_EVENT_OPEN]           = fsm_open,
+               [VFIO_CCW_EVENT_CLOSE]          = fsm_nop,
        },
        [VFIO_CCW_STATE_STANDBY] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
@@ -401,6 +423,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
                [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_error,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
                [VFIO_CCW_EVENT_OPEN]           = fsm_notoper,
+               [VFIO_CCW_EVENT_CLOSE]          = fsm_close,
        },
        [VFIO_CCW_STATE_IDLE] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
@@ -408,6 +431,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
                [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_request,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
                [VFIO_CCW_EVENT_OPEN]           = fsm_notoper,
+               [VFIO_CCW_EVENT_CLOSE]          = fsm_close,
        },
        [VFIO_CCW_STATE_CP_PROCESSING] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
@@ -415,6 +439,7 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
                [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_retry,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
                [VFIO_CCW_EVENT_OPEN]           = fsm_notoper,
+               [VFIO_CCW_EVENT_CLOSE]          = fsm_close,
        },
        [VFIO_CCW_STATE_CP_PENDING] = {
                [VFIO_CCW_EVENT_NOT_OPER]       = fsm_notoper,
@@ -422,5 +447,6 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
                [VFIO_CCW_EVENT_ASYNC_REQ]      = fsm_async_request,
                [VFIO_CCW_EVENT_INTERRUPT]      = fsm_irq,
                [VFIO_CCW_EVENT_OPEN]           = fsm_notoper,
+               [VFIO_CCW_EVENT_CLOSE]          = fsm_close,
        },
 };

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index a7ea935..fc5b831 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -33,9 +33,7 @@ static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
         * There are still a lot more instructions need to be handled. We
         * should come back here later.
         */
-       ret = vfio_ccw_sch_quiesce(sch);
-       if (ret)
-               return ret;
+       vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
 
        ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
        if (!ret)
@@ -64,7 +62,6 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
                if (vfio_ccw_mdev_reset(private))
                        return NOTIFY_BAD;
 
-               cp_free(&private->cp);
                return NOTIFY_OK;
        }
 
@@ -159,15 +156,9 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
 
        vfio_unregister_group_dev(&private->vdev);
 
-       if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
-           (private->state != VFIO_CCW_STATE_STANDBY)) {
-               if (!vfio_ccw_sch_quiesce(private->sch))
-                       private->state = VFIO_CCW_STATE_STANDBY;
-               /* The state will be NOT_OPER on error. */
-       }
+       vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
 
        vfio_uninit_group_dev(&private->vdev);
-       cp_free(&private->cp);
        atomic_inc(&private->avail);
 }
 
@@ -217,7 +208,6 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
                /* The state will be NOT_OPER on error. */
        }
 
-       cp_free(&private->cp);
        vfio_ccw_unregister_dev_regions(private);
        vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 }

diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 93e136b..abac532 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -143,6 +143,7 @@ enum vfio_ccw_event {
        VFIO_CCW_EVENT_INTERRUPT,
        VFIO_CCW_EVENT_ASYNC_REQ,
        VFIO_CCW_EVENT_OPEN,
+       VFIO_CCW_EVENT_CLOSE,
        /* last element! */
        NR_VFIO_CCW_EVENTS
 };