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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>
This commit is contained in:
Heinz Graalfs 2014-03-05 15:23:54 +01:00 committed by Cornelia Huck
parent 96b14536d9
commit 79629b208f
1 changed files with 13 additions and 3 deletions
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16
drivers/s390/kvm/virtio_ccw.c
View File

@ -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;
}