drm: Simplify drm_mm_clean()

Since commit ea7b1dd4 ("drm: mm: track free areas implicitly"),
to test whether there are any nodes allocated within the range manager,
we merely have to ask whether the node_list is empty.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-25-chris@chris-wilson.co.uk

drivers/gpu/drm/drm_mm.c

@@ -872,22 +872,6 @@ bool drm_mm_scan_remove_block(struct drm_mm_node *node)
 }
 EXPORT_SYMBOL(drm_mm_scan_remove_block);
 
-/**
- * drm_mm_clean - checks whether an allocator is clean
- * @mm: drm_mm allocator to check
- *
- * Returns:
- * True if the allocator is completely free, false if there's still a node
- * allocated in it.
- */
-bool drm_mm_clean(const struct drm_mm *mm)
-{
-	const struct list_head *head = drm_mm_nodes(mm);
-
-	return (head->next->next == head);
-}
-EXPORT_SYMBOL(drm_mm_clean);
-
 /**
  * drm_mm_init - initialize a drm-mm allocator
  * @mm: the drm_mm structure to initialize
@@ -928,10 +912,9 @@ EXPORT_SYMBOL(drm_mm_init);
  */
 void drm_mm_takedown(struct drm_mm *mm)
 {
-	if (WARN(!list_empty(drm_mm_nodes(mm)),
+	if (WARN(!drm_mm_clean(mm),
 		 "Memory manager not clean during takedown.\n"))
 		show_leaks(mm);
-
 }
 EXPORT_SYMBOL(drm_mm_takedown);
 

include/drm/drm_mm.h

@@ -342,7 +342,19 @@ void drm_mm_remove_node(struct drm_mm_node *node);
 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new);
 void drm_mm_init(struct drm_mm *mm, u64 start, u64 size);
 void drm_mm_takedown(struct drm_mm *mm);
-bool drm_mm_clean(const struct drm_mm *mm);
+
+/**
+ * drm_mm_clean - checks whether an allocator is clean
+ * @mm: drm_mm allocator to check
+ *
+ * Returns:
+ * True if the allocator is completely free, false if there's still a node
+ * allocated in it.
+ */
+static inline bool drm_mm_clean(const struct drm_mm *mm)
+{
+	return list_empty(drm_mm_nodes(mm));
+}
 
 struct drm_mm_node *
 __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last);