drm: extract drm_gem_object_init

This function can be used by drivers who allocate the drm gem object
on their own. No functional change in here, just preparation.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_gem.c

@@ -123,6 +123,31 @@ drm_gem_destroy(struct drm_device *dev)
 	dev->mm_private = NULL;
 }
 
+/**
+ * Initialize an already allocate GEM object of the specified size with
+ * shmfs backing store.
+ */
+int drm_gem_object_init(struct drm_device *dev,
+			struct drm_gem_object *obj, size_t size)
+{
+	BUG_ON((size & (PAGE_SIZE - 1)) != 0);
+
+	obj->dev = dev;
+	obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
+	if (IS_ERR(obj->filp))
+		return -ENOMEM;
+
+	kref_init(&obj->refcount);
+	kref_init(&obj->handlecount);
+	obj->size = size;
+
+	atomic_inc(&dev->object_count);
+	atomic_add(obj->size, &dev->object_memory);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_gem_object_init);
+
 /**
  * Allocate a GEM object of the specified size with shmfs backing store
  */
@@ -131,28 +156,22 @@ drm_gem_object_alloc(struct drm_device *dev, size_t size)
 {
 	struct drm_gem_object *obj;
 
-	BUG_ON((size & (PAGE_SIZE - 1)) != 0);
-
 	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
 	if (!obj)
 		goto free;
 
-	obj->dev = dev;
-	obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
-	if (IS_ERR(obj->filp))
+	if (drm_gem_object_init(dev, obj, size) != 0)
 		goto free;
 
-	kref_init(&obj->refcount);
-	kref_init(&obj->handlecount);
-	obj->size = size;
 	if (dev->driver->gem_init_object != NULL &&
 	    dev->driver->gem_init_object(obj) != 0) {
 		goto fput;
 	}
-	atomic_inc(&dev->object_count);
-	atomic_add(obj->size, &dev->object_memory);
 	return obj;
 fput:
+	/* Object_init mangles the global counters - readjust them. */
+	atomic_dec(&dev->object_count);
+	atomic_sub(obj->size, &dev->object_memory);
 	fput(obj->filp);
 free:
 	kfree(obj);

include/drm/drmP.h

@@ -1432,6 +1432,8 @@ void drm_gem_object_free(struct kref *kref);
 void drm_gem_object_free_unlocked(struct kref *kref);
 struct drm_gem_object *drm_gem_object_alloc(struct drm_device *dev,
 					    size_t size);
+int drm_gem_object_init(struct drm_device *dev,
+			struct drm_gem_object *obj, size_t size);
 void drm_gem_object_handle_free(struct kref *kref);
 void drm_gem_vm_open(struct vm_area_struct *vma);
 void drm_gem_vm_close(struct vm_area_struct *vma);