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| author | Heinz Graalfs <graalfs@linux.vnet.ibm.com> | 2014-02-27 14:34:35 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-03-04 10:41:03 +0100 |
| commit | 2e0210432d34bc7f01644905c2bb2d5d9be5b6ac (patch) | |
| tree | ecc95786e82a53aeff50efb50913aeb4bb9b9f32 /drivers/s390/kvm | |
| parent | KVM: s390: get rid of local_int array (diff) | |
| download | linux-2e0210432d34bc7f01644905c2bb2d5d9be5b6ac.tar.xz linux-2e0210432d34bc7f01644905c2bb2d5d9be5b6ac.zip | |
virtio_ccw: fix vcdev pointer handling issues
The interrupt handler virtio_ccw_int_handler() using the vcdev pointer
is protected by the ccw_device lock. Resetting the pointer within the
ccw_device structure should be done when holding this lock.
Also resetting the vcdev pointer (under the ccw_device lock) prior to
freeing the vcdev pointer memory removes a critical path.
Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'drivers/s390/kvm')
| -rw-r--r-- | drivers/s390/kvm/virtio_ccw.c | 35 |
1 files changed, 28 insertions, 7 deletions
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index 0fc584832001..413c6304d511 100644 --- a/drivers/s390/kvm/virtio_ccw.c +++ b/drivers/s390/kvm/virtio_ccw.c @@ -636,6 +636,8 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, struct virtqueue *vq; struct virtio_driver *drv; + if (!vcdev) + return; /* Check if it's a notification from the host. */ if ((intparm == 0) && (scsw_stctl(&irb->scsw) == @@ -734,23 +736,37 @@ static int virtio_ccw_probe(struct ccw_device *cdev) return 0; } +static struct virtio_ccw_device *virtio_grab_drvdata(struct ccw_device *cdev) +{ + unsigned long flags; + struct virtio_ccw_device *vcdev; + + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); + vcdev = dev_get_drvdata(&cdev->dev); + if (!vcdev) { + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + return NULL; + } + dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + return vcdev; +} + static void virtio_ccw_remove(struct ccw_device *cdev) { - struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev); + struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - if (cdev->online) { + if (vcdev && cdev->online) unregister_virtio_device(&vcdev->vdev); - dev_set_drvdata(&cdev->dev, NULL); - } cdev->handler = NULL; } static int virtio_ccw_offline(struct ccw_device *cdev) { - struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev); + struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - unregister_virtio_device(&vcdev->vdev); - dev_set_drvdata(&cdev->dev, NULL); + if (vcdev) + unregister_virtio_device(&vcdev->vdev); return 0; } @@ -759,6 +775,7 @@ static int virtio_ccw_online(struct ccw_device *cdev) { int ret; struct virtio_ccw_device *vcdev; + unsigned long flags; vcdev = kzalloc(sizeof(*vcdev), GFP_KERNEL); if (!vcdev) { @@ -786,7 +803,9 @@ static int virtio_ccw_online(struct ccw_device *cdev) INIT_LIST_HEAD(&vcdev->virtqueues); spin_lock_init(&vcdev->lock); + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); dev_set_drvdata(&cdev->dev, vcdev); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); vcdev->vdev.id.vendor = cdev->id.cu_type; vcdev->vdev.id.device = cdev->id.cu_model; ret = register_virtio_device(&vcdev->vdev); @@ -797,7 +816,9 @@ static int virtio_ccw_online(struct ccw_device *cdev) } return 0; out_put: + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); put_device(&vcdev->vdev.dev); return ret; out_free: |