3 files changed, 12 insertions, 1 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b07d96b8c0d1..8cf5aece8c84 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1054,6 +1054,10 @@ static long vhost_net_set_owner(struct vhost_net *n)
         int r;
 
         mutex_lock(&n->dev.mutex);
+        if (vhost_dev_has_owner(&n->dev)) {
+                r = -EBUSY;
+                goto out;
+        }
         r = vhost_net_set_ubuf_info(n);
         if (r)
                 goto out;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index beee7f5787e6..60aa5ad09a2f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -344,13 +344,19 @@ static int vhost_attach_cgroups(struct vhost_dev *dev)
 }
 
 /* Caller should have device mutex */
+bool vhost_dev_has_owner(struct vhost_dev *dev)
+{
+        return dev->mm;
+}
+
+/* Caller should have device mutex */
 long vhost_dev_set_owner(struct vhost_dev *dev)
 {
         struct task_struct *worker;
         int err;
 
         /* Is there an owner already? */
-        if (dev->mm) {
+        if (vhost_dev_has_owner(dev)) {
                 err = -EBUSY;
                 goto err_mm;
         }
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index a7ad63592987..64adcf99ff33 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -133,6 +133,7 @@ struct vhost_dev {
 
 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 long vhost_dev_set_owner(struct vhost_dev *dev);
+bool vhost_dev_has_owner(struct vhost_dev *dev);
 long vhost_dev_check_owner(struct vhost_dev *);
 struct vhost_memory *vhost_dev_reset_owner_prepare(void);
 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);