Commit 4a68810d authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio: Tie IOMMU group reference to vfio group



Move the iommu_group reference from the device to the vfio_group.
This ensures that the iommu_group persists as long as the vfio_group
remains.  This can be important if all of the device from an
iommu_group are removed, but we still have an outstanding vfio_group
reference; we can still walk the empty list of devices.
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 60720a0f
...@@ -274,6 +274,7 @@ static void vfio_group_release(struct kref *kref) ...@@ -274,6 +274,7 @@ static void vfio_group_release(struct kref *kref)
{ {
struct vfio_group *group = container_of(kref, struct vfio_group, kref); struct vfio_group *group = container_of(kref, struct vfio_group, kref);
struct vfio_unbound_dev *unbound, *tmp; struct vfio_unbound_dev *unbound, *tmp;
struct iommu_group *iommu_group = group->iommu_group;
WARN_ON(!list_empty(&group->device_list)); WARN_ON(!list_empty(&group->device_list));
...@@ -287,6 +288,7 @@ static void vfio_group_release(struct kref *kref) ...@@ -287,6 +288,7 @@ static void vfio_group_release(struct kref *kref)
list_del(&group->vfio_next); list_del(&group->vfio_next);
vfio_free_group_minor(group->minor); vfio_free_group_minor(group->minor);
vfio_group_unlock_and_free(group); vfio_group_unlock_and_free(group);
iommu_group_put(iommu_group);
} }
static void vfio_group_put(struct vfio_group *group) static void vfio_group_put(struct vfio_group *group)
...@@ -625,6 +627,12 @@ int vfio_add_group_dev(struct device *dev, ...@@ -625,6 +627,12 @@ int vfio_add_group_dev(struct device *dev,
iommu_group_put(iommu_group); iommu_group_put(iommu_group);
return PTR_ERR(group); return PTR_ERR(group);
} }
} else {
/*
* A found vfio_group already holds a reference to the
* iommu_group. A created vfio_group keeps the reference.
*/
iommu_group_put(iommu_group);
} }
device = vfio_group_get_device(group, dev); device = vfio_group_get_device(group, dev);
...@@ -633,21 +641,19 @@ int vfio_add_group_dev(struct device *dev, ...@@ -633,21 +641,19 @@ int vfio_add_group_dev(struct device *dev,
dev_name(dev), iommu_group_id(iommu_group)); dev_name(dev), iommu_group_id(iommu_group));
vfio_device_put(device); vfio_device_put(device);
vfio_group_put(group); vfio_group_put(group);
iommu_group_put(iommu_group);
return -EBUSY; return -EBUSY;
} }
device = vfio_group_create_device(group, dev, ops, device_data); device = vfio_group_create_device(group, dev, ops, device_data);
if (IS_ERR(device)) { if (IS_ERR(device)) {
vfio_group_put(group); vfio_group_put(group);
iommu_group_put(iommu_group);
return PTR_ERR(device); return PTR_ERR(device);
} }
/* /*
* Added device holds reference to iommu_group and vfio_device * Drop all but the vfio_device reference. The vfio_device holds
* (which in turn holds reference to vfio_group). Drop extra * a reference to the vfio_group, which holds a reference to the
* group reference used while acquiring device. * iommu_group.
*/ */
vfio_group_put(group); vfio_group_put(group);
...@@ -702,7 +708,6 @@ void *vfio_del_group_dev(struct device *dev) ...@@ -702,7 +708,6 @@ void *vfio_del_group_dev(struct device *dev)
{ {
struct vfio_device *device = dev_get_drvdata(dev); struct vfio_device *device = dev_get_drvdata(dev);
struct vfio_group *group = device->group; struct vfio_group *group = device->group;
struct iommu_group *iommu_group = group->iommu_group;
void *device_data = device->device_data; void *device_data = device->device_data;
struct vfio_unbound_dev *unbound; struct vfio_unbound_dev *unbound;
...@@ -737,8 +742,6 @@ void *vfio_del_group_dev(struct device *dev) ...@@ -737,8 +742,6 @@ void *vfio_del_group_dev(struct device *dev)
vfio_group_put(group); vfio_group_put(group);
iommu_group_put(iommu_group);
return device_data; return device_data;
} }
EXPORT_SYMBOL_GPL(vfio_del_group_dev); EXPORT_SYMBOL_GPL(vfio_del_group_dev);
......
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