Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 79629b20 authored by Heinz Graalfs's avatar Heinz Graalfs Committed by Cornelia Huck
Browse files

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: default avatarHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 96b14536

drivers/s390/kvm/virtio_ccw.c

+13 −3
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct virtio_ccw_device { 
	unsigned long indicators2;

	struct vq_config_block *config_block;

	bool is_thinint;

	bool going_away;

	void *airq_info;

};
@@ -995,30 +996,39 @@ static struct virtio_ccw_device *virtio_grab_drvdata(struct ccw_device *cdev) 


	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;

}