[PATCH 1/1] vfio: ccw: fix error return in vfio_ccw_sch_event

[PATCH 1/1] vfio: ccw: fix error return in vfio_ccw_sch_event

[Dong Jia Shi]

If device has not been registered, or there is a pending work,
we should reschedule a sch_event call again.

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
---
 drivers/s390/cio/vfio_ccw_drv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index ea6a2d0b2894..770fa9cfc310 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -177,6 +177,7 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 	unsigned long flags;
+	int rc = -EAGAIN;
 
 	spin_lock_irqsave(sch->lock, flags);
 	if (!device_is_registered(&sch->dev))
@@ -187,6 +188,7 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 
 	if (cio_update_schib(sch)) {
 		vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
+		rc = 0;
 		goto out_unlock;
 	}
 
@@ -195,11 +197,12 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 		private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
 				 VFIO_CCW_STATE_STANDBY;
 	}
+	rc = 0;
 
 out_unlock:
 	spin_unlock_irqrestore(sch->lock, flags);
 
-	return 0;
+	return rc;
 }
 
 static struct css_device_id vfio_ccw_sch_ids[] = {
-- 
2.13.5

Re: [PATCH 1/1] vfio: ccw: fix error return in vfio_ccw_sch_event

[Cornelia Huck]

On Wed,  2 May 2018 09:25:59 +0200
Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:

> If device has not been registered, or there is a pending work,

s/a pending work/work pending/

> we should reschedule a sch_event call again.
> 
> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>

Slightly off-topic question: Is the mail address with or without the
'vnet' the one to go for?

> ---
>  drivers/s390/cio/vfio_ccw_drv.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index ea6a2d0b2894..770fa9cfc310 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -177,6 +177,7 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
>  {
>  	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
>  	unsigned long flags;
> +	int rc = -EAGAIN;
>  
>  	spin_lock_irqsave(sch->lock, flags);
>  	if (!device_is_registered(&sch->dev))
> @@ -187,6 +188,7 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
>  
>  	if (cio_update_schib(sch)) {
>  		vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
> +		rc = 0;
>  		goto out_unlock;
>  	}
>  
> @@ -195,11 +197,12 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process)
>  		private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
>  				 VFIO_CCW_STATE_STANDBY;
>  	}
> +	rc = 0;
>  
>  out_unlock:
>  	spin_unlock_irqrestore(sch->lock, flags);
>  
> -	return 0;
> +	return rc;
>  }
>  
>  static struct css_device_id vfio_ccw_sch_ids[] = {

Patch looks good to me.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

I guess I should pick this for 4.17?

Re: [PATCH 1/1] vfio: ccw: fix error return in vfio_ccw_sch_event

[Cornelia Huck]

On Thu, 3 May 2018 10:06:40 +0800
Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:

> * Cornelia Huck <cohuck@redhat.com> [2018-05-02 16:42:51 +0200]:
> 
> > On Wed,  2 May 2018 09:25:59 +0200
> > Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:
> >   
> > > If device has not been registered, or there is a pending work,  
> > 
> > s/a pending work/work pending/

Also, s/device/the device/

> >   
> > > we should reschedule a sch_event call again.
> > > 
> > > Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>  

(...)

> > 
> > I guess I should pick this for 4.17?
> >   
> I think there is no pressure for this one. So please feel free to decide
> as your convenience.
> 

OK, I've queued this for the next release. Will wait for more patches
(e.g. the ida check pushdown) before I send a pull request.