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authorHeinz Graalfs <graalfs@linux.vnet.ibm.com>2014-02-27 14:34:35 +0100
committerChristian Borntraeger <borntraeger@de.ibm.com>2014-03-04 10:41:03 +0100
commit2e0210432d34bc7f01644905c2bb2d5d9be5b6ac (patch)
treeecc95786e82a53aeff50efb50913aeb4bb9b9f32 /drivers/s390/kvm/virtio_ccw.c
parentKVM: s390: get rid of local_int array (diff)
downloadlinux-dev-2e0210432d34bc7f01644905c2bb2d5d9be5b6ac.tar.xz
linux-dev-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/virtio_ccw.c')
-rw-r--r--drivers/s390/kvm/virtio_ccw.c35
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: