On Mon, Oct 06, 2014 at 01:33:38PM +0200, Cornelia Huck wrote:
> On Sun, 5 Oct 2014 19:07:05 +0300
> "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
>
> > Defer config changed notifications that arrive during
> > probe/scan/freeze/restore.
> >
> > This will allow drivers to set DRIVER_OK earlier, without worrying about
> > racing with config change interrupts.
> >
> > This change will also benefit old hypervisors (before 2009)
> > that send interrupts without checking DRIVER_OK: previously,
> > the callback could race with driver-specific initialization.
> >
> > This will also help simplify drivers.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > ---
> > include/linux/virtio.h | 6 ++++++
> > drivers/virtio/virtio.c | 55 +++++++++++++++++++++++++++++++++++++++++--------
> > 2 files changed, 52 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> > index 657f817..578e02d 100644
> > --- a/drivers/virtio/virtio.c
> > +++ b/drivers/virtio/virtio.c
> > @@ -117,6 +117,40 @@ void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
> > }
> > EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
> >
> > +static void __virtio_config_changed(struct virtio_device *dev)
> > +{
> > + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> > +
> > + if (!dev->config_enabled)
> > + dev->config_changed = true;
> > + else if (drv && drv->config_changed)
> > + drv->config_changed(dev);
> > +}
> > +
> > +void virtio_config_changed(struct virtio_device *dev)
> > +{
> > + spin_lock_irq(&dev->config_lock);
> > + __virtio_config_changed(dev);
> > + spin_unlock_irq(&dev->config_lock);
>
> Hm, isn't this function called from the interrupt handler?
>
Good catch, will fix up, thanks!
> > +}
> > +EXPORT_SYMBOL_GPL(virtio_config_changed);
> > +
> > +static void virtio_config_disable(struct virtio_device *dev)
> > +{
> > + spin_lock_irq(&dev->config_lock);
> > + dev->config_enabled = false;
> > + spin_unlock_irq(&dev->config_lock);
> > +}
> > +
> > +static void virtio_config_enable(struct virtio_device *dev)
> > +{
> > + spin_lock_irq(&dev->config_lock);
> > + dev->config_enabled = true;
> > + __virtio_config_changed(dev);
> > + dev->config_changed = false;
> > + spin_unlock_irq(&dev->config_lock);
> > +}
> > +
>
> Maybe call these virtio_config_change_{dis,en}able()?
>
> > static int virtio_dev_probe(struct device *_d)
> > {
> > int err, i;
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