vhost: check owner before we overwrite ubuf_info

[~andy/linux] / drivers / vhost / vhost.c

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index beee7f5787e6c814b2420f745be2555ca6a71af5..60aa5ad09a2fdb74a457ecadf0130f056f114c8e 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -343,6 +343,12 @@ static int vhost_attach_cgroups(struct vhost_dev *dev)
        return attach.ret;
 }
 
+/* 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)
 {
@@ -350,7 +356,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
        int err;
 
        /* Is there an owner already? */
-       if (dev->mm) {
+       if (vhost_dev_has_owner(dev)) {
                err = -EBUSY;
                goto err_mm;
        }