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Diffstat (limited to 'drivers/vfio/vfio.c')
-rw-r--r--drivers/vfio/vfio.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 259ad282ae5d..c488da5db7c7 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -76,6 +76,7 @@ struct vfio_group {
struct notifier_block nb;
struct list_head vfio_next;
struct list_head container_next;
+ atomic_t opened;
};
struct vfio_device {
@@ -206,6 +207,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
INIT_LIST_HEAD(&group->device_list);
mutex_init(&group->device_lock);
atomic_set(&group->container_users, 0);
+ atomic_set(&group->opened, 0);
group->iommu_group = iommu_group;
group->nb.notifier_call = vfio_iommu_group_notifier;
@@ -1236,12 +1238,22 @@ static long vfio_group_fops_compat_ioctl(struct file *filep,
static int vfio_group_fops_open(struct inode *inode, struct file *filep)
{
struct vfio_group *group;
+ int opened;
group = vfio_group_get_from_minor(iminor(inode));
if (!group)
return -ENODEV;
+ /* Do we need multiple instances of the group open? Seems not. */
+ opened = atomic_cmpxchg(&group->opened, 0, 1);
+ if (opened) {
+ vfio_group_put(group);
+ return -EBUSY;
+ }
+
+ /* Is something still in use from a previous open? */
if (group->container) {
+ atomic_dec(&group->opened);
vfio_group_put(group);
return -EBUSY;
}
@@ -1259,6 +1271,8 @@ static int vfio_group_fops_release(struct inode *inode, struct file *filep)
vfio_group_try_dissolve_container(group);
+ atomic_dec(&group->opened);
+
vfio_group_put(group);
return 0;

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