| Message ID | 87lhojcx0v.fsf@rustcorp.com.au (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 14, 2014 at 11:01:12AM +1030, Rusty Russell wrote: > "Michael S. Tsirkin" <mst@redhat.com> writes: > > 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. > > But AFAICT you never *read* dev->config_changed. > > You unconditionally trigger a config_changed event in > virtio_config_enable(). That's a bit weird, but probably OK. > > How about the following change (on top of your patch). I > think the renaming is clearer, and note the added if() test in > virtio_config_enable(). > > If you approve, I'll fold it in. > > Cheers, > Rusty. Hi Rusty, I'm okay with both changes. You can fold it in if you prefer, or just make it a patch on top. > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > index 2536701b098b..df598dd8c5c8 100644 > --- a/drivers/virtio/virtio.c > +++ b/drivers/virtio/virtio.c > @@ -122,7 +122,7 @@ 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; > + dev->config_change_pending = true; > else if (drv && drv->config_changed) > drv->config_changed(dev); > } > @@ -148,8 +148,9 @@ 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; > + if (dev->config_change_pending) > + __virtio_config_changed(dev); > + dev->config_change_pending = false; > spin_unlock_irq(&dev->config_lock); > } > > @@ -253,7 +254,7 @@ int register_virtio_device(struct virtio_device *dev) > > spin_lock_init(&dev->config_lock); > dev->config_enabled = false; > - dev->config_changed = false; > + dev->config_change_pending = false; > > /* We always start by resetting the device, in case a previous > * driver messed it up. This also tests that code path a little. */ > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 5636b119dc25..65261a7244fc 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -80,7 +80,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); > * @index: unique position on the virtio bus > * @failed: saved value for CONFIG_S_FAILED bit (for restore) > * @config_enabled: configuration change reporting enabled > - * @config_changed: configuration change reported while disabled > + * @config_change_pending: configuration change reported while disabled > * @config_lock: protects configuration change reporting > * @dev: underlying device. > * @id: the device type identification (used to match it with a driver). > @@ -94,7 +94,7 @@ struct virtio_device { > int index; > bool failed; > bool config_enabled; > - bool config_changed; > + bool config_change_pending; > spinlock_t config_lock; > struct device dev; > struct virtio_device_id id; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 2536701b098b..df598dd8c5c8 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -122,7 +122,7 @@ 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; + dev->config_change_pending = true; else if (drv && drv->config_changed) drv->config_changed(dev); } @@ -148,8 +148,9 @@ 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; + if (dev->config_change_pending) + __virtio_config_changed(dev); + dev->config_change_pending = false; spin_unlock_irq(&dev->config_lock); } @@ -253,7 +254,7 @@ int register_virtio_device(struct virtio_device *dev) spin_lock_init(&dev->config_lock); dev->config_enabled = false; - dev->config_changed = false; + dev->config_change_pending = false; /* We always start by resetting the device, in case a previous * driver messed it up. This also tests that code path a little. */ diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 5636b119dc25..65261a7244fc 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -80,7 +80,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); * @index: unique position on the virtio bus * @failed: saved value for CONFIG_S_FAILED bit (for restore) * @config_enabled: configuration change reporting enabled - * @config_changed: configuration change reported while disabled + * @config_change_pending: configuration change reported while disabled * @config_lock: protects configuration change reporting * @dev: underlying device. * @id: the device type identification (used to match it with a driver). @@ -94,7 +94,7 @@ struct virtio_device { int index; bool failed; bool config_enabled; - bool config_changed; + bool config_change_pending; spinlock_t config_lock; struct device dev; struct virtio_device_id id;