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virtio: allow driver to disable the configure change notification

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Sometime, it would be useful to disable the configure change
notification from the driver. So this patch allows this by introducing
a variable config_change_driver_disabled and only allow the configure
change notification callback to be triggered when it is allowed by
both the virtio core and the driver. It is set to false by default to
hold the current semantic so we don't need to change any drivers.

The first user for this would be virtio-net.

Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20240814052228.4654-3-jasowang@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jason Wang
2024-08-14 13:22:26 +08:00
committed by Jakub Kicinski
parent 0cb70ee4a6
commit 224de6f886
2 changed files with 43 additions and 3 deletions
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39
drivers/virtio/virtio.c
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@@ -127,10 +127,12 @@ static void __virtio_config_changed(struct virtio_device *dev)
{
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
if (!dev->config_core_enabled)
if (!dev->config_core_enabled || dev->config_driver_disabled)
dev->config_change_pending = true;
else if (drv && drv->config_changed)
else if (drv && drv->config_changed) {
drv->config_changed(dev);
dev->config_change_pending = false;
}
}
void virtio_config_changed(struct virtio_device *dev)
@@ -143,6 +145,38 @@ void virtio_config_changed(struct virtio_device *dev)
}
EXPORT_SYMBOL_GPL(virtio_config_changed);
/**
* virtio_config_driver_disable - disable config change reporting by drivers
* @dev: the device to reset
*
* This is only allowed to be called by a driver and disabling can't
* be nested.
*/
void virtio_config_driver_disable(struct virtio_device *dev)
{
spin_lock_irq(&dev->config_lock);
dev->config_driver_disabled = true;
spin_unlock_irq(&dev->config_lock);
}
EXPORT_SYMBOL_GPL(virtio_config_driver_disable);
/**
* virtio_config_driver_enable - enable config change reporting by drivers
* @dev: the device to reset
*
* This is only allowed to be called by a driver and enabling can't
* be nested.
*/
void virtio_config_driver_enable(struct virtio_device *dev)
{
spin_lock_irq(&dev->config_lock);
dev->config_driver_disabled = false;
if (dev->config_change_pending)
__virtio_config_changed(dev);
spin_unlock_irq(&dev->config_lock);
}
EXPORT_SYMBOL_GPL(virtio_config_driver_enable);
static void virtio_config_core_disable(struct virtio_device *dev)
{
spin_lock_irq(&dev->config_lock);
@@ -156,7 +190,6 @@ static void virtio_config_core_enable(struct virtio_device *dev)
dev->config_core_enabled = true;
if (dev->config_change_pending)
__virtio_config_changed(dev);
dev->config_change_pending = false;
spin_unlock_irq(&dev->config_lock);
}