On Wed, May 18, 2022 at 5:32 PM Cornelia Huck <cohuck@xxxxxxxxxx> wrote:
>
> On Wed, May 18 2022, Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> > This patch tries to implement the synchronize_cbs() for ccw. For the
> > vring_interrupt() that is called via virtio_airq_handler(), the
> > synchronization is simply done via the airq_info's lock. For the
> > vring_interrupt() that is called via virtio_ccw_int_handler(), a per
> > device rwlock is introduced ans used in the synchronization method.
>
> s/ans/and/
>
Will fix.
> >
> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> > Cc: Marc Zyngier <maz@xxxxxxxxxx>
> > Cc: Halil Pasic <pasic@xxxxxxxxxxxxx>
> > Cc: Cornelia Huck <cohuck@xxxxxxxxxx>
> > Cc: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx>
> > Cc: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
> > Cc: linux-s390@xxxxxxxxxxxxxxx
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> > drivers/s390/virtio/virtio_ccw.c | 27 +++++++++++++++++++++++++++
> > 1 file changed, 27 insertions(+)
> >
> > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > index d35e7a3f7067..22d36594bcdd 100644
> > --- a/drivers/s390/virtio/virtio_ccw.c
> > +++ b/drivers/s390/virtio/virtio_ccw.c
> > @@ -62,6 +62,7 @@ struct virtio_ccw_device {
> > unsigned int revision; /* Transport revision */
> > wait_queue_head_t wait_q;
> > spinlock_t lock;
> > + rwlock_t irq_lock;
> > struct mutex io_lock; /* Serializes I/O requests */
> > struct list_head virtqueues;
> > bool is_thinint;
> > @@ -984,6 +985,27 @@ static const char *virtio_ccw_bus_name(struct virtio_device *vdev)
> > return dev_name(&vcdev->cdev->dev);
> > }
> >
> > +static void virtio_ccw_synchronize_cbs(struct virtio_device *vdev)
> > +{
> > + struct virtio_ccw_device *vcdev = to_vc_device(vdev);
> > + struct airq_info *info = vcdev->airq_info;
> > +
> > + if (info) {
> > + /*
> > + * Synchronize with the vring_interrupt() with airq indicator
>
> Maybe
>
> /*
> * This device uses adapter interrupts: synchronize with
> * vring_interrupt() called by virtio_airq_handler() via the indicator
> * area lock.
> */
>
Fine.
> > + */
> > + write_lock_irq(&info->lock);
> > + write_unlock_irq(&info->lock);
> > + } else {
> > + /*
> > + * Synchronize with the vring_interrupt() called by
> > + * virtio_ccw_int_handler().
>
> /*
> * This device uses classic interrupts: synchronize with
> * vring_interrupt() called by virtio_ccw_int_handler() via the
> * per-device irq_lock.
> */
>
Looks fine.
> > + */
> > + write_lock_irq(&vcdev->irq_lock);
> > + write_unlock_irq(&vcdev->irq_lock);
> > + }
> > +}
> > +
> > static const struct virtio_config_ops virtio_ccw_config_ops = {
> > .get_features = virtio_ccw_get_features,
> > .finalize_features = virtio_ccw_finalize_features,
> > @@ -995,6 +1017,7 @@ static const struct virtio_config_ops virtio_ccw_config_ops = {
> > .find_vqs = virtio_ccw_find_vqs,
> > .del_vqs = virtio_ccw_del_vqs,
> > .bus_name = virtio_ccw_bus_name,
> > + .synchronize_cbs = virtio_ccw_synchronize_cbs,
> > };
> >
> >
> > @@ -1106,6 +1129,8 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
> > vcdev->err = -EIO;
> > }
> > virtio_ccw_check_activity(vcdev, activity);
> > + /* Local interrupt should be disabled at this time */
>
> /* Interrupts are disabled here. */
>
> ?
>
> Interrupts enabled here would surely be a bug.
Right.
Thanks
>
> > + read_lock(&vcdev->irq_lock);
> > for_each_set_bit(i, indicators(vcdev),
> > sizeof(*indicators(vcdev)) * BITS_PER_BYTE) {
> > /* The bit clear must happen before the vring kick. */
>
