Remove misleading uvm reference counting that isn't actually used.

Make sure uvm_obj_init() is only called once.  Call uvm_obj_destroy()
when we release the GEM object that wraps an uvm object for which we
called uvm_obj_init().

ok mpi@, jsg@

2 files changed, 5 insertions, 3 deletions

diff --git a/sys/dev/pci/drm/drm_gem.c b/sys/dev/pci/drm/drm_gem.c
index 460bab4e807..79598398bf7 100644
--- a/sys/dev/pci/drm/drm_gem.c
+++ b/sys/dev/pci/drm/drm_gem.c
@@ -343,6 +343,7 @@ void drm_gem_private_object_init(struct drm_device *dev,
 	obj->filp = NULL;
 #else
 	obj->uao = NULL;
+	obj->uobj.pgops = NULL;
 #endif
 
 	kref_init(&obj->refcount);
@@ -1166,6 +1167,8 @@ drm_gem_object_release(struct drm_gem_object *obj)
 #else
 	if (obj->uao)
 		uao_detach(obj->uao);
+	if (obj->uobj.pgops)
+		uvm_obj_destroy(&obj->uobj);
 #endif
 
 	dma_resv_fini(&obj->_resv);
diff --git a/sys/dev/pci/drm/ttm/ttm_bo_vm.c b/sys/dev/pci/drm/ttm/ttm_bo_vm.c
index a2d27de6e3d..b78a807e27c 100644
--- a/sys/dev/pci/drm/ttm/ttm_bo_vm.c
+++ b/sys/dev/pci/drm/ttm/ttm_bo_vm.c
@@ -852,7 +852,6 @@ ttm_bo_vm_reference(struct uvm_object *uobj)
 	    (struct ttm_buffer_object *)uobj;
 
 	ttm_bo_get(bo);
-	uobj->uo_refs++;
 }
 
 void
@@ -860,7 +859,6 @@ ttm_bo_vm_detach(struct uvm_object *uobj)
 {
 	struct ttm_buffer_object *bo = (struct ttm_buffer_object *)uobj;
 
-	uobj->uo_refs--;
 	ttm_bo_put(bo);
 }
 
@@ -971,7 +969,8 @@ ttm_bo_mmap(struct file *filp, voff_t off, vsize_t size,
 	if (unlikely(ret != 0))
 		goto out_unref;
 
-	uvm_obj_init(&bo->base.uobj, &ttm_bo_vm_ops, 1);
+	if (bo->base.uobj.pgops == NULL)
+		uvm_obj_init(&bo->base.uobj, &ttm_bo_vm_ops, 1);
 	return &bo->base.uobj;
 out_unref:
 	ttm_bo_put(bo);