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?
> +}
> +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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