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authorMichael S. Tsirkin <mst@redhat.com>2014-10-15 10:21:55 +1030
committerRusty Russell <rusty@rustcorp.com.au>2014-10-15 10:24:56 +1030
commit22b7050a024d7deb0c9ef1e14ed73e3b1e369f24 (patch)
treebe21b9a75aa1b5a95d8bb3ab7bf9470669e643bb /drivers/virtio
parentc6716bae52f97347e25166c6270aa98693d9212c (diff)
virtio: defer config changed notifications
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@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cosmetic changes)
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio.c58
1 files changed, 49 insertions, 9 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 8216b7311092..df598dd8c5c8 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -117,6 +117,43 @@ 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_change_pending = true;
+ else if (drv && drv->config_changed)
+ drv->config_changed(dev);
+}
+
+void virtio_config_changed(struct virtio_device *dev)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->config_lock, flags);
+ __virtio_config_changed(dev);
+ spin_unlock_irqrestore(&dev->config_lock, flags);
+}
+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;
+ if (dev->config_change_pending)
+ __virtio_config_changed(dev);
+ dev->config_change_pending = false;
+ spin_unlock_irq(&dev->config_lock);
+}
+
static int virtio_dev_probe(struct device *_d)
{
int err, i;
@@ -153,6 +190,8 @@ static int virtio_dev_probe(struct device *_d)
add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
if (drv->scan)
drv->scan(dev);
+
+ virtio_config_enable(dev);
}
return err;
@@ -163,6 +202,8 @@ static int virtio_dev_remove(struct device *_d)
struct virtio_device *dev = dev_to_virtio(_d);
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+ virtio_config_disable(dev);
+
drv->remove(dev);
/* Driver should have reset device. */
@@ -211,6 +252,10 @@ int register_virtio_device(struct virtio_device *dev)
dev->index = err;
dev_set_name(&dev->dev, "virtio%u", dev->index);
+ spin_lock_init(&dev->config_lock);
+ dev->config_enabled = 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. */
dev->config->reset(dev);
@@ -239,20 +284,13 @@ void unregister_virtio_device(struct virtio_device *dev)
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);
-void virtio_config_changed(struct virtio_device *dev)
-{
- struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
-
- if (drv && drv->config_changed)
- drv->config_changed(dev);
-}
-EXPORT_SYMBOL_GPL(virtio_config_changed);
-
#ifdef CONFIG_PM_SLEEP
int virtio_device_freeze(struct virtio_device *dev)
{
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+ virtio_config_disable(dev);
+
dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
if (drv && drv->freeze)
@@ -297,6 +335,8 @@ int virtio_device_restore(struct virtio_device *dev)
/* Finally, tell the device we're all set */
add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+ virtio_config_enable(dev);
+
return 0;
}
EXPORT_SYMBOL_GPL(virtio_device_restore);