This is a note to let you know that I've just added the patch titled
virtio: allow driver to disable the configure change notification
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
virtio-allow-driver-to-disable-the-configure-change-.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d9911970d14285164bba60ebddf7707fb1ef5b1d
Author: Jason Wang <jasowang@xxxxxxxxxx>
Date: Wed Aug 14 13:22:26 2024 +0800
virtio: allow driver to disable the configure change notification
[ Upstream commit 224de6f886f8184fd448700a6d78f216694de948 ]
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@xxxxxxxxxx>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Link: https://patch.msgid.link/20240814052228.4654-3-jasowang@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: c392d6019398 ("virtio-net: synchronize probe with ndo_set_features")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 6b692b0fa578b..b9095751e43bb 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -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);
}
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index de6d3cc176d96..306137a15d075 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -119,6 +119,8 @@ struct virtio_admin_cmd {
* @index: unique position on the virtio bus
* @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
* @config_core_enabled: configuration change reporting enabled by core
+ * @config_driver_disabled: configuration change reporting disabled by
+ * a driver
* @config_change_pending: configuration change reported while disabled
* @config_lock: protects configuration change reporting
* @vqs_list_lock: protects @vqs.
@@ -136,6 +138,7 @@ struct virtio_device {
int index;
bool failed;
bool config_core_enabled;
+ bool config_driver_disabled;
bool config_change_pending;
spinlock_t config_lock;
spinlock_t vqs_list_lock;
@@ -166,6 +169,10 @@ void __virtqueue_break(struct virtqueue *_vq);
void __virtqueue_unbreak(struct virtqueue *_vq);
void virtio_config_changed(struct virtio_device *dev);
+
+void virtio_config_driver_disable(struct virtio_device *dev);
+void virtio_config_driver_enable(struct virtio_device *dev);
+
#ifdef CONFIG_PM_SLEEP
int virtio_device_freeze(struct virtio_device *dev);
int virtio_device_restore(struct virtio_device *dev);
