virtio_ccw: fix hang in set offline processing
During set offline processing virtio_grab_drvdata() incorrectly
calls dev_set_drvdata() to remove the virtio_ccw_device from the
parent ccw_device's driver data. This is wrong and ends up in a
hang during virtio_ccw_reset(), as the interrupt handler still
has need of the virtio_ccw_device.
A new field 'going_away' is introduced in struct virtio_ccw_device
to control the usage of the ccw_device's driver data pointer in
virtio_grab_drvdata().
Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 6a2b5fd..1e1fc67 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -61,6 +61,7 @@
unsigned long indicators2;
struct vq_config_block *config_block;
bool is_thinint;
+ bool going_away;
void *airq_info;
};
@@ -995,30 +996,39 @@
spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
vcdev = dev_get_drvdata(&cdev->dev);
- if (!vcdev) {
+ if (!vcdev || vcdev->going_away) {
spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
return NULL;
}
- dev_set_drvdata(&cdev->dev, NULL);
+ vcdev->going_away = true;
spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
return vcdev;
}
static void virtio_ccw_remove(struct ccw_device *cdev)
{
+ unsigned long flags;
struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);
if (vcdev && cdev->online)
unregister_virtio_device(&vcdev->vdev);
+ spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+ dev_set_drvdata(&cdev->dev, NULL);
+ spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
cdev->handler = NULL;
}
static int virtio_ccw_offline(struct ccw_device *cdev)
{
+ unsigned long flags;
struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);
- if (vcdev)
+ if (vcdev) {
unregister_virtio_device(&vcdev->vdev);
+ spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+ dev_set_drvdata(&cdev->dev, NULL);
+ spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+ }
return 0;
}