kernel: vm: Fix vm_obj_destroy()

- Set vp->vmobj to NULL *only* if vp is set
- Refcount starts at 0, not 1
- Refcount check comes first

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/sys/vm/vm_obj.c b/sys/vm/vm_obj.c
index 6dbe777..b501c6b 100644
--- a/sys/vm/vm_obj.c
+++ b/sys/vm/vm_obj.c
@@ -74,13 +74,13 @@ vm_obj_destroy(struct vm_object *obj)
 {
     struct vnode *vp = obj->vnode;
 
-    if (vp->vmobj != NULL)
-        vp->vmobj = NULL;
-
     /* Check the ref count */
-    if (obj->ref > 1)
+    if (obj->ref > 0)
         return -EBUSY;
 
+    if (vp != NULL)
+        vp->vmobj = NULL;
+
     dynfree(obj);
     --obj_count;
     return 0;