drm/gem: add drm_gem_create_mmap_offset_size()

Variant of drm_gem_create_mmap_offset() which doesn't make the
assumption that virtual size and physical size (obj->size) are the same.
This is needed in omapdrm to deal with tiled buffers.  And lets us get
rid of a duplicated and slightly modified version of
drm_gem_create_mmap_offset() in omapdrm.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_gem.c

@@ -316,6 +316,31 @@ drm_gem_free_mmap_offset(struct drm_gem_object *obj)
 }
 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
 
+/**
+ * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
+ * @obj: obj in question
+ * @size: the virtual size
+ *
+ * GEM memory mapping works by handing back to userspace a fake mmap offset
+ * it can use in a subsequent mmap(2) call.  The DRM core code then looks
+ * up the object based on the offset and sets up the various memory mapping
+ * structures.
+ *
+ * This routine allocates and attaches a fake offset for @obj, in cases where
+ * the virtual size differs from the physical size (ie. obj->size).  Otherwise
+ * just use drm_gem_create_mmap_offset().
+ */
+int
+drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
+{
+	struct drm_device *dev = obj->dev;
+	struct drm_gem_mm *mm = dev->mm_private;
+
+	return drm_vma_offset_add(&mm->vma_manager, &obj->vma_node,
+				  size / PAGE_SIZE);
+}
+EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
+
 /**
  * drm_gem_create_mmap_offset - create a fake mmap offset for an object
  * @obj: obj in question
@@ -327,14 +352,9 @@ EXPORT_SYMBOL(drm_gem_free_mmap_offset);
  *
  * This routine allocates and attaches a fake offset for @obj.
  */
-int
+int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
-drm_gem_create_mmap_offset(struct drm_gem_object *obj)
 {
-	struct drm_device *dev = obj->dev;
+	return drm_gem_create_mmap_offset_size(obj, obj->size);
-	struct drm_gem_mm *mm = dev->mm_private;
-
-	return drm_vma_offset_add(&mm->vma_manager, &obj->vma_node,
-				  obj->size / PAGE_SIZE);
 }
 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
 

include/drm/drmP.h

@@ -1614,6 +1614,7 @@ drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
 
 void drm_gem_free_mmap_offset(struct drm_gem_object *obj);
 int drm_gem_create_mmap_offset(struct drm_gem_object *obj);
+int drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size);
 
 struct drm_gem_object *drm_gem_object_lookup(struct drm_device *dev,
 					     struct drm_file *filp,